Symposium SB05—Emergent Order and Mesoscale Structure Formation in Soft Condensed Matter

Active matter systems feature the ability to form collective patterns as observed in a plethora of living systems, from schools of fish to swimming bacteria down to cytoskeletal structures. While many of these systems move in a wide, three-dimensional environment, several biological systems are confined by a curved topology. The role played by a non-Euclidean geometry on the self-organization of active systems is not yet fully understood, and few experimental systems are available to study it. Gliding assays, in which cytoskeletal filaments are driven by molecular motors grafted to a substrate, are an ideal candidate to address the microscopic mechanisms that underlie pattern formation in active systems. Here, we introduce an experimental setup in which actin filaments glide on the inner surface of a spherical lipid vesicle, thus embedding them in a curved geometry. We show that filaments self-assemble into polar, elongated structures and that, when these match the size of the spherical geometry, both confinement and topological constraints become relevant for the emergent patterns, leading to the formation of polar vortices and jammed states. These results experimentally demonstrate that activity-induced complex patterns can be shaped by spherical confinement and topology.

Collective behaviors are widely present in nature and artificial systems. The sizes of the constituting units range from nanometers to meters. Controllably tuning interactions among the constituting members in a swarm can result in complex assembling, structuring, and synchronous motion. Here, inspired by thermodynamic principles that govern phase transition in an equilibrium material system, we propose and explore a hypothesis for rationally creating various assembling modes in a non-equilibrium swarm made of semiconductor nanorods. Experimentally, we find the dense Si nanorods readily switch among three modes, i.e., enhanced collective rotation, droplet-like clustering, and network formation by simply modulating visible light and applied electric field. Theoretical modeling considering light-controlled electrostatic interactions sheds light to the observation. This research presents a general approach for creating reconfigurable patterning and operation modes in a non-equilibrium swarm that points towards new opportunities for fundamental studies and applications.

Transportation, in its broadest sense, is an important task in many fields, including engineering, physics, biology, and economics, and a great deal is known about optimal and efficient strategies to move matter, energy, and information around. But can we craft similar optimal protocols to transport autonomously moving (active) matter, such as self-propelled drops or migrating cells? I will discuss how we solve this inverse problem by using optimal control theory in the context of transporting a drop of an active fluid with minimal viscous dissipation by dynamically varying spatial active stresses within the drop. I will highlight natural strategies and characteristic trade-offs that emerge from the optimal policies, suggesting general principles for optimal transportation in synthetic and biological active systems.

The identification and classification of transitions in topological and microstructural regimes in pattern-forming processes is critical for understanding and fabricating microstructurally precise novel materials in many application domains. Unfortunately, relevant microstructure transitions may depend on process parameters in subtle and complex ways that are not captured by the classic theory of phase transition. While supervised machine learning methods may be useful for identifying transition regimes, they need labels which require prior knowledge of order parameters or relevant structures. Motivated by the universality principle for dynamical systems, we instead use a self-supervised approach to solve the inverse problem of predicting process parameters from observed microstructures using neural networks. This approach does not require labeled data about the target task of predicting microstructure transitions. We show that the difficulty of performing this prediction task is related to the goal of discovering microstructure regimes, because qualitative changes in microstructural patterns correspond to changes in uncertainty for our self-supervised prediction problem. We demonstrate the value of our approach by automatically discovering transitions in microstructural regimes in two distinct pattern-forming processes: the spinodal decomposition of a two-phase mixture and the formation of concentration modulations of binary alloys during physical vapor deposition of thin films. This approach opens a promising path forward for discovering and understanding unseen or hard-to-detect transition regimes, and ultimately for controlling complex pattern-forming processes. SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525. SAND2022-3365 A

There is high interest in new polymer synthesis routes, topologies, mechanisms, and templating (molecular and colloidal) for various applications. Mesoscale and hierarchically inspired assemblies have their origin in the microstructure and composition in soft matter. The choices for synthesis go from linear, grafted, and hyperbranched systems to hybrid organic-inorganic systems. However, there are many other topologies that are of high interest because of their relevance to cyclic and supramolecular polymerization routes that have yet to be demonstrated. Molecular templating is utilized for building "cavities" that facilitate high-resolution sensing and selectivity. This talk will focus on three concepts of targeted assembly and templating: 1) Dendimer topologies and hybrid nanoparticle electropolymerization, 2) Molecular imprinted polymer (MIP) using hybrid complexes, and 3) supramolecular polymer synthesis and assemblies in Knotty topologically inspired polymers. We also employ a number of macromolecular and surface characterization studies to define
successful synthesis strategies and assemblies The end goal are to demonstrate the topologies and patterns to produce higher throughput synthetic methods: unlocking the utility for real applications.

The spontaneous self-organization of nanoscale materials into complex macroscopic architectures has intrigued scientists for decades, because it offers insight into how complex structures can emerge from primitive building blocks. Hierarchical self-assembled systems offer structural advantages that are absent in isolated constituent units. Nature is replete with fascinating examples of hierarchical assembly, such as proteins or DNA, and natural photonic structures as seen in butterfly wings or fish. Although synthetic materials that afford the same level of accuracy and complexity as biomolecules are currently beyond reach, research into the self-organization of artificial units has increased dramatically. Organic molecules and copolymers are among the most commonly used elementary units to form large-area patterning. More recently, advances in nanomaterial synthesis have provided access to a versatile library of nanoparticle building blocks with tunable composition, morphology and atomic structure that give rise to physiochemical properties unattainable in naturally occurring materials.
In this study, highly aligned structures are obtained from an organic–inorganic mesophase composed of 1.5 nm monodisperse Cd37S18 magic-size cluster building blocks. Impressively, structural alignment spans over seven orders of magnitude in length scale: nanoscale magic-size clusters arrange into a hexagonal geometry organized inside micrometer-sized filaments; self-assembly of these filaments leads to fibers that then organize into uniform arrays of centimeter-scale bands with well-defined surface periodicity. Enhanced patterning can be achieved by controlling processing conditions, resulting in bullseye and ‘zigzag’ stacking patterns with periodicity in two directions. The multiscale arrangement of MSC building blocks in filaments and striped films presents intriguing analogies to hierarchical assemblies in biological systems as well as the pervasive hierarchical structural organization throughout the natural world. Additionally, our thin films show strong circular dichroism response and reversible, chemically induced isomerization which triggers more intriguing scientific questions on the properties. Overall, our work demonstrates the ability of semiconductor nanomaterials to assemble into complex macroscopic structures, which provides a potential platform to realize advanced function.

Topological phase transitions into skyrmion and half-skyrmion phases are widely observed in condensed matter, such as chiral magnets and liquid crystals. They are utilized to design magnetoelectric, optical, and mechanoresponsive materials by controlling such topological phases. However, the role of the elastic field in nonuniform topological phases is elusive. To elucidate this problem, we construct a model describing chiral molecules and colloids in quasi-two-dimensional molecular crystals, which incorporates intermolecular chiral twisting and spheroidal steric interactions. We reveal that emergence of the elastic fields from the competition between steric anisotropy and intermolecular twisting is a key to control uniform, helical, and half-skyrmion structures. By utilizing the coupling between the spheroidal orientations and the elastic fields, these topological phases are switched by temperature, external electromagnetic fields, and anisotropic stresses, where a re-entrant phase transition between the helical and the half-skyrmion phases is discovered. Our results imply that controlling the emergent elastic fields is crucial for obtaining a fundamental physical principle for controlling topological phases using chiral molecular and colloidal crystals.

Reference:
K. Takae and T. Kawasaki, Proc. Natl. Acad. Sci. U.S.A. 119, e2118492119 (2022).

Solid-liquid interfaces have notoriously haphazard atomic environments. While essentially amorphous, the liquid has short-range order and heterogeneous dynamics. The crystal, albeit ordered, contains a variety of defects ranging from adatoms to dislocation-created spiral steps. All these elements are of paramount importance in the crystal growth process, which makes the crystallization kinetics challenging to describe concisely in a single framework. In this talk I will present data-driven approaches to systematically detect, encode, and classify atomic-scale mechanisms of crystallization. It will also be shown how this approach naturally leads to a predictive kinetic model of crystallization that takes into account the entire zoo of microstructural elements present at solid-liquid interfaces. The result is an approach that blends prevailing scientific methods with data-science tools to produce physically-consistent models and novel conceptual knowledge

Numerous colloidal crystals have been designed and devised following via functionalization of nanoparticles. Size-asymmetric nanoparticle crystals are often stabilized by ionic-type bonding, where the smaller in size and/or charge component sits at fixed points within the lattice of the large nanoparticles. Here, we study the transition from ionic to metallic bonding, by which the lattice of the smaller component melts, yet the crystal of the large particles is preserved, as in metallic bonding. We discuss the physical properties of the system, including charge transport under an external field. Under a high external field, we find a transient state where the small particles condense into clusters. The resulting patterns are stabilized modifying the physical interactions.

The capabilities of coarse-grained simulations are applied to the modelling of two-dimensional Metal–Organic Framework (MOF) synthesis. The isoreticular chemistry of crystalline MOFs allows for modular and scalable reagents in synthesis, and furthermore, the simple nature of the synthesis allows for translation to coarse-grained simulations. The HOOMD-blue toolkit is used to construct the MOFs building blocks (metal nodes and organic linkers) from isotropic beads, retaining the basic symmetries of the molecular components. Lennard–Jones and Weeks–Chandler–Andersen pair potentials are used to model attractive and repulsive particle interactions, respectively. We analyze the crystallinity of the self-assembled products and explore the role of modulators—molecules that compete with the organic linkers in binding to the metal nodes to moderate the crystallization reaction—to explore the self-assembly mechanisms in defect-engineered MOFs.

Understanding how order emerges via crystallization is necessary for controlling the growth of meso- and nanoscale materials or targeting desired material properties. While crystal growth is well understood for simple, close-packed structures, theoretical descriptions break down when applied to structures of higher complexity, where identical particles can occupy different local coordination environments. Developing generalizable rules of how crystal growth proceeds for complex structures requires a sophisticated description of particle environments to understand their evolution throughout the self-assembly process. We use a high-dimensional order parameter that represents local environments with spherical harmonics and utilizes unsupervised machine learning to classify particle environments not only into solid, liquid, and gas, but also into different Wyckoff positions in the same crystal structure, outperforming nearest neighbor analysis approaches. Applying this order parameter to molecular dynamics simulations of self-assembled complex structures allows us to track the emergence of crystalline order from the melt and to observe how identical particles choose their distinct “roles” in a structure as the crystal grows.

The controlled organization of nanoparticles (NPs) into assemblies has gained increasing scientific interest. By modifying e.g. the size and shape of the individual NPs, the inter-particle distances or the chemical composition of the building blocks, assemblies with various shapes and functionalities have been obtained. Since the properties of these nanostructures are inseparably connected to their three-dimensional (3D) structure and shape, a thorough structural and morphological characterization is of great importance.

Transmission Electron Microscopy (TEM) is an ideal technique to investigate materials at the nanometer level or even at the atomic scale. The technique has therefore been widely used in the study of nano-assemblies. However, TEM images only correspond to a two-dimensional (2D) projection of a 3D object. Therefore, electron tomography, a technique that derives a 3D reconstruction from a tilt series of 2D projection images, has become a standard technique to characterize nano-assemblies in 3D. When assemblies of metallic nanoparticles are investigated, acquisition of electron tomography series is usually performed in High Angle Annular Dark-Field Scanning TEM (HAADF-STEM) mode. In this manner, diffraction contrast present in Bright-Field TEM (BF-TEM) images is minimized, and the projection requirement for tomography is fulfilled. For relatively small (consisting of 100 particles or less) or loose assemblies, in which the distance between the composing building blocks is rather large, conventional electron tomography techniques enable one to determine the morphology and the inner structure of the assemblies. Moreover, a manual segmentation allows one to determine, e.g. the 3D stacking of the nanoparticles in a quantitative manner. On the other hand, when the size and density (atomic number Z) of the investigated assembly increases, several challenges appear that hamper a reliable interpretation of the structure.

In this contribution, we will discuss how acquisition, reconstruction and segmentation during an electron tomography experiment can be optimised to enable a quantitative analysis of the structure under investigation [1-4]. Another challenge is related to the investigation of assemblies of nanoparticles under realistic conditions. We will therefore discuss how to combine a 3D characterization of nanoparticle assemblies with in situ and cryo TEM studies [5,6].

[1] Altantzis T, Wang D, Kadu A, van Blaaderen A, Bals S, Journal of Physical Chemistry C 125, 26240 (2021).
[2] Zanaga D, Bleichrodt F, Altantzis T, Winckelmans N, Palenstijn WJ, Sijbers J, de Nijs B, van Huis MA, Sanchez-Iglesias A, Liz-Marzán LM, van Blaaderen A, Joost Batenburg K, Bals S, Van Tendeloo G, Nanoscale 8, 292 (2016).
[3] Wang D, van der Wee EB, Zanaga D, Altantzis T, Wu Y, Dasgupta T, Dijkstra M, Murray CB, Bals S, van Blaaderen A, Nature Communications 12, 3980 (2021).
[4] Wang D, Dasgupta T, van der Wee EB, Zanaga D, Altantzis T, Wu Y, Coli GM, Murray CB, Bals S, Dijkstra M, van Blaaderen A, Nature Physics, 17, 128 (2021).
[5] Kumar J, Eraña H, López-Martínez E, Claes N, Martín VF, Solís DM, Bals S, Cortajarena AL, Castilla J, Liz-Marzán LM, Proceedings of The National Academy of Sciences of The United States Of America 115, 3225 (2018).
[6] Baginski M, Pedrazo-Tardajos A, Altantzis T, Tupikowska M, Vetter A, Tomczyk E, Suryadharma RNS, Pawlak M, Andruszkiewicz A, Górecka E, Pociecha D, Rockstuhl C, Bals S, Lewandowski W, ACS Nano 15, 4916 (2021).

Block copolymers can self-assemble into a variety of ordered nanostructures, including the triply-periodic, bicontinuous double-gyroid (DG), double-diamond (DD), and double-primitive (DP) network phases. These phases consist of complex, intercatenated, labyrinthine domains, yet are supramolecular soft crystals with long-range order. Despite a history of experimental observations, as well as theoretical and computational studies, the formation and stability of these phases remains poorly understood and reliant on the vague notion of packing frustration. Here, we paint a picture of packing frustration -- an interplay between the thermodynamics governing interface geometry and chain stretching that is required by packing constraints of the polymer melt -- by turning to the strong segregation theory of block copolymers. The thermodynamic costs of satisfying this packing constraint is closely connected to the geometry of the terminal boundaries of each domain, i.e. the set of points defining the extent of chain stretching from the intermaterial dividing surfaces. We show that these terminal boundaries are well-approximated by a suitable set of medial surfaces, and that such medial geometry is essential to the stability of the network phases, resolving a long-standing puzzle of the stability of network phases in the strong segregation theory. Furthermore, we uncover new heuristics for polymer architectures that promote stability of the DG phase and explore how the medial geometry of the DG phase makes it more optimal than the competitor DD and DP phases. Finally, we introduce a map of packing frustration "hot spots" in each phase and illustrate how targeted infill of these hot spots can stabilize the DD and DP phases over the DG phase.

Understanding the controlling factors for structure formation in colloids is highly complex and currently the subject of intense scientific study. As we learn to synthesize a diverse array of individual particles, with varying shapes and sizes, we also aim to understand how to assemble those particles into useful structures. This study uses computational methods to examine the assembly of a class of tetrahedrally shaped particles, with assembly controlled via confinement inside of a spherical container. These particles exhibit a variety of assembled structures depending on their vertex truncation; however, their assembly behavior in confinement has not previously been explored. We show how small spherical containers force assembly into concentric shells, whose high curvature favors a vertex-to-vertex motif. In larger containers, the particles' behavior changes to conform to a locally flat wall. This effect favors a vertex-to-midpoint motif, causing shapes near the phase boundary to modify their assembled local structure in order to better pack against this lower-curvature wall. We show how the geometry of the confining wall interacts with particle shape anisotropy to change the resultant structure, and we propose using these walls as a medium for enhancing the crystallinity of colloidal crystals. Further, we show how wall geometry can cause texture, biasing the structure to orient along certain crystal axes relative to the wall, thus allowing for reproducible and controllable growth. Through understanding the interactions of confinement geometry and crystal structure, we demonstrate a method for understanding and controlling the assembly of anisotropic particles.

Mesostructured microcapsules with a core-shell structure are good candidates for housing, protecting, delivering, and capturing biocargo. Mesostructured soft-matter shells made from benign materials such as polymers confine the encapsulant within a compatible environment as well as control its mass transport and exchange with the external environment. Synchronous communication of the encapsulants with the changeable external environment requires smart response of the capsule shells for desired molecular exchange. Reversibly stimuli-triggered responsive capsules could regulate the molecular diffusion across the shell by altering its molecular affinity and permeability. However, large property changes upon stimuli and the reversibility of the trigger-response of such dynamic capsules remain a challenge due to limitation of promising soft materials and their fabrication as mesoscaled architectures. Here we introduce reconfigurable and mesostructured liquid-shelled capsules with reversible stimuli-triggered changes of the shell phase composition and structure. Liquids in contrast to polymers offer fast dynamics and in combination with colloidal assemblies and large solid-liquid interfaces can undergo reversible changes of key property metrics without material degradation or fatigue. To this end, we employ microfluidics to template colloidosome microcapsules by introducing surface-functionalized particles in the shell of water-oil-water double emulsions. Upon self-assembly and crosslinking of the colloidal particles, we achieve a porous nearly close-packed particle framework in the liquid double emulsion shell. For colloidosome capsules with reversible stimuli-triggered property change, double emulsions with shell liquids composed of a dual oil system with temperature-dependent miscibility are fabricated. Upon temperature change, the shell undergoes liquid-liquid phase separation, therefore causing the reconfiguration of the double emulsion shell to a two-phase shell, a path towards controlled wetting-dewetting transitions of the porous colloidal shell framework to enable, for example, active closing and opening of the capsules to molecular and particle diffusion.

Creating materials with structure that is independently controllable at a range of scales requires breaking naturally occurring hierarchies. Breaking these hierarchies can be achieved via the decoupling of building block attributes from structure during assembly. Here, we demonstrate, through computer simulations and experiments, that shape and interaction decoupling occur in colloidal cuboids suspended in evaporating emulsion droplets. The resulting colloidal clusters serve as "preassembled" mesoscale building blocks for larger-scale structures. We show that clusters of up to nine particles form mesoscale building blocks with geometries that are independent of the particles’ degree of faceting and dipolar magnetic interactions. To highlight the potential of these superball clusters for hierarchical assembly, we demonstrate, using computer simulations, that clusters of six to nine particles can assemble into higher-order structures that differ from bulk self-assembly of individual particles. Our results suggest that preassembled building blocks present a viable route to hierarchical materials design.

Moiré patterns from misaligned periodic structures can bring merit to not only artistic designs but to material properties, a salient example being magic angle graphene where superconducting phase can be observed. Here, with liquid-phase transmission electron microscope (TEM), we construct nanoparticle superlattices and obtain for the first time Moiré patterns at the nanoscale in real time and real space, where we investigate laws of order emergence and evolution from a dispersion of nanosized entities. To be specific, layers of hexagonal lattices are assembled from individual gold nanoparticles. Distinct from 2D materials where the interlayer and intralayer interactions are with limited control, we control the nanoparticle shape to manipulate the interlayer and intralayer interactions, which leads to different Moiré patterns. We apply neural network-based machine learning to investigate the structures and single particle dynamics with high spatiotemporal resolution, which further helps to reveal the interplay between the Moiré pattern and the grain boundary evolution. Furthermore, calculations based on pairwise interaction potential show distinct local position adjustment in different Moiré patterns both in plane and out of plan, resulting in normal, reduced order and disordered Moiré patterns. This work provides better understandings on nanoscale interactions, which can serve as a guideline for bottom-up material design and helps to study related optical properties.

Naturally-sourced cellulose nanocrystals (CNCs) are elongated nanoparticles that spontaneously form a left-handed cholesteric liquid crystal phase in aqueous suspension. This self-assembly process has been shown to be a promising way to create structurally colored films from sustainable materials (Adv. Mater. (2018) 30, 1704477), but the underlying mechanism by which chiral ordering emerges has remained unclear. Although the morphology of individual CNCs is believed to play an important role, most particles are not significantly twisted, and suspensions exhibit considerable polydispersity in both particle size and shape.

Here we will present an in-depth morphological analysis of sub-populations of individual CNCs, as imaged by transmission electron microscopy (TEM) and atomic force microscopy (AFM). We gradually tuned the size and shape of the CNCs using ultrasonication and correlated the morphology of individual particles with their ensemble behavior in suspension and in photonic films. This analysis revealed that CNC “bundles” (i.e. clusters of laterally-bound elementary crystallites) are essential for the formation of a cholesteric phase. These bundles act as chiral dopants, analogous to those used for molecular liquid crystals, and therefore explain how chirality is transferred across length-scales from the morphology of individual CNCs to the photonic nanostructure (Nat. Commun. (2022) 13, 2657).

Materials with three-dimensional network structures (Nets) on sub-micron length scales are of great interest for their optical properties. The vivid colors of insect wing scales and bird feathers arise from naturally occurring Nets with spatial periodicities ranging 400 – 700 nm, which interact with visible light as photonic crystals. On the other hand, Nets with sub-wavelength scale periodicities (< 400 nm) have potential applications as optical metamaterials with exciting properties such as negative refraction and strong circular dichroisms. While Nets may be fabricated by top-down methods such as two-photon lithography, such methods are limited by their achievable lengthscales and the challenges associated with fabrication throughput. Bottom-up self-assembly of block copolymers provides a possible alternative for addressing these limitations. For example, Vignolini et al. prepared a gold single gyroid nanomaterial using a template based on ABC triblock terpolymer self-assembly and demonstrated its strong, orientation-dependent dichroic responses. Although these results suggest the promise of bottom-up self-assembly as means of accessing Nets, a significant challenge facing these approaches is the lack of control over Net grain sizes and their orientations relative to a substrate that are important in their optical applications.
The self-assembly of block copolymers can be directed using chemical patterns or external fields, but few studies have applied these methods to block copolymers that form double gyroid (DG) Nets. Of these few examples, many rely on solvent annealing of block copolymer thin films sometimes in the presence of chemically or topographically patterned surfaces. In this study, we report a solvent-free, thermal processing method for producing pseudo-single grain DG thin films on silicon wafers bearing native oxide layers. Through top-down and cross-section scanning electron microscopy (SEM), we identify the well-defined orientation of the DG mesostructure with respect to the underlying substrate. These findings are corroborated using grazing-incidence small-angle X-ray scattering (GISAXS), and we use azimuthal angle-dependent GISAXS to investigate the degree of microstructural orientation. Thus, this thermal processing approach enables efficient unidirectional alignment of mesoscopic DG structures over large areas for future optical materials applications.

Mathematical descriptors of mirror asymmetry are continuous, but chirality in chemical disciplines is often viewed as a binary characteristic of molecules and there was no known chemical structure with widely variable chirality measures. Here we show that sub-microscale nanostructured particles can be self-assembled from anisotropic building blocks with widely variable geometry, chirality measures and optical asymmetry while retaining consistent bowtie shapes. The self-limited self-organization of anisotropic building blocks [¹] makes possible high synthetic reproducibility and computational predictability of their geometries for different concentrations of reagents, ionic components, enantiomeric compositions, media polarity and other parameters. The positive and negative chiroptical peaks observed from UV to IR parts of the spectrum originate from absorptive and scattering phenomena with contribution from both dipolar and quadrupolar modes characteristic of nanostructured particles with submicron scale chirality.[²] The dependence of geometrical chirality measures and chiroptical characteristics enable the predictive synthesis of bowties with desirable polarization rotation. Controllable pitch, length, width, and thickness leads to tunable chiroptical activity across from UV to IR, which can be used to print chiroptical metasurfaces for photonic markers for machine vision devices.

References
1. Xia, Y. et al. Self-assembly of self-limiting monodisperse supraparticles from polydisperse nanoparticles. Nature Nanotechnology 6, 580–587 (2011).
2. Feng, W. et al. Assembly of mesoscale helices with near-unity enantiomeric excess and light-matter interactions for chiral semiconductors. Science Advances 3, (2017).

Training an artificial neural network requires solving an inverse problem, so it is natural to apply concepts underlying machine learning to solve inverse design problems in soft matter systems. I will describe how global minimization of a loss function can be used to teach physical networks how to perform functions inspired by biology, such as the ability of proteins (e.g. hemoglobin) to change their conformations upon binding of an atom (oxygen) or molecule, or the ability of the brain’s vascular network to send enhanced blood flow and oxygen to specific areas of the brain associated with a given task. Statistical physics teaches us that the ability to design ensembles of networks with the same function is crucial in order to understand the microscopic origins of collective phenomena. I will show how we apply persistent homology to such networks to learn how and what they learned. Finally, I will describe local learning methods that allow us to develop physical systems that can learn on their own, without requiring a processor or memory.

Self-assembled soft-matter crystal structures have the potential to exhibit structural variety that vastly exceeds that of atomic-scale structures, mainly due to their highly tunable particle interactions. In simulation, particles interacting via simple, isotropic pair potentials have been shown to self-assemble into a wide range of crystal structures, yet how the shape of the interaction potential influences the resulting structure is still poorly understood. To search for new crystal structures, we have developed a new functional form for the interaction potential in which all energy wells and maxima can be tuned independently. Through targeted searches in a high-dimensional parameter space, we discover 20 new crystal structures, 14 of which are low-coordinated with average coordination environments ranging from 2 to 7 nearest neighbors. We will present specific characteristics of these structures, as well as general trends of the investigated systems. Our findings highlight the structural diversity of soft condensed matter that can potentially be used to design new soft materials with functional properties.

The field of polymer blending, which aims to combine the properties of polymers to create specialised materials, has the potential to play an important role in helping to tackle some of the major challenges that society faces in the 21st century. However, to realise this in a sustainable and time-effective manner, we must advance our knowledge of structure-property relationships and find ways to leverage these relationships in the design and development process of new materials. One obstacle to developing structure-property relationships is the challenge of characterising complex phase-separated microstructures using accessible experimental data. To overcome this, we recently proposed a method for succinctly describing such microstructures in terms of well-defined and quantifiable characteristics from scattering data using machine learning [1], namely Gaussian process regression. Our findings, which we obtained using numerical simulation data, suggest there is an opportunity for a more complete characterisation of experimental phase-separated microstructures using scattering data. Scattering is a powerful technique for monitoring phase separation in real-time. As such, the careful application of our method to future predictions of the scattering data could allow one to predict the future characteristics of the microstructure as it evolves. In the absence of a satisfactory nonlinear theory describing the time evolution of the scattering data during phase separation, we have demonstrated the ability of dynamic mode decomposition, a data-driven modelling method, to make accurate future predictions of numerical scattering data. We aim to combine these two works to develop a control system to manipulate phase separation to produce new materials with prescribed microstructures and, therefore, properties. We also aim to expand the scope of our work to systems other than polymer blends, for example, metallic alloys and ceramics.

[1] M. Jones and N. Clarke, Machine Learning Real Space Microstructure Characteristics from Scattering Data, Soft Matter, 14 (42) : 9689-9696, 2021

In the field of materials science and engineering, structural characterization is a critical step needed to link the materials’ structure to its macroscopic properties. Small angle scattering (SAS) is a useful technique to characterize structure at multiple length scales. The output of SAS experiments is the averaged scattering intensity at various wave vectors, I(q) vs. q, whose interpretation often relies on fitting with analytical models. The selection of analytical models can be a limitation for analyzing the scattering profile if and when appropriate analytical models exist for the material’s structure of interest. In this talk, we will present a computational method we have developed called Computational Reverse Engineering Analysis of Scattering Experiments (CREASE) and show its application for analysis of spherical nanoparticle mixtures’ assembled structure. We test the strengths and limitations of CREASE by using a variety of in silico I(q) obtained from simulations of binary nanoparticle assemblies and nanoparticle solutions with varying mixture composition/concentration, nanoparticle size distribution, and degree of mixing/aggregation. We will also highlight the machine learning (ML) model used in CREASE that links features of the nanoparticle solutions (e.g., concentration, nanoparticles’ tendency to aggregate) to computed scattering profile; this ML model is applicable to different nanoparticle sizes without the need for additional data to retrain the model to be specific to the size of interest. Finally, we show how the nanoparticle structure reconstructed from scattering using CREASE can serve as input to optical modeling and achieve a computed reflectance spectrum that matches ones from the experimental systems.

Quantitative small-angle and wide-angle X-ray scattering data of ionic liquid/water mixture systems were obtained and analyzed as training data sets for developing deep neural network (DNN) based computation architecture that can predict non-equilibrium, dynamical phenomena such as chemical reactions, self-assembly, and ionization. Quantum mechanics (QM) describes the physical laws that govern such processes, but the computational effort required to solve the equations given by QM makes predictive simulations of realistic systems practically impossible. Specialized DNN-based architectures have recently proved to be an accurate, general, and computationally efficient alternative to QM calculations for obtaining interatomic forces. While these DNN models have application potential in a wide range of chemical and materials discovery areas, they lack the ability to describe non-equilibrium processes such as the long-range transfer of electron charge and finite electron temperature effects. The research of probing mesoscale structures of ionic liquid/water mixtures provides quantitative information on mesoscale structures as well as cation-anion interactions to the DNN machine learning algorithm and serves as critical learning set to develop an efficient and accurate computational algorithm that can predict materials properties from molecular structure.
Ionic liquids are known to form various hierarchical, mesoscale ordered structures when mixed with water, similar to the phase behavior of lyotropic liquid crystals. The hierarchical self-assembly of soft materials including the ionic liquid systems is a complex phenomenon often not easily predictable by computation. Thus, the system of ionic liquid/water mixtures is an excellent platform to produce large data set to train the DNN algorithm. In addition, the ionic liquids are easy to synthesize yet they exhibit diverse possible ordered structures, which further justifies the use of the system in this study. Model systems of ionic liquids, consisting of a cation having linear hydrocarbon tail and simple anions such as thiocyanate or nitrate, were mixed with varying amounts of water to form microphase-separated, mesoscale ordered structures and subsequently measured by X-ray scattering. The obtained data were quantitatively analyzed by crystallographic methods and radial distribution function calculations.

Inspired by Nature’s ability to make complex structures, self-assembly has emerged as a powerful technique for synthesizing nanoscale materials. While living systems are brimming with examples of functional nanomaterials that have one or more self-limited dimensions, such as virus capsids, cytoskeletal filaments, or complex molecular machines, most examples of synthetic self-assembly tend to produce periodic lattice structures with macroscopically uncontrolled dimensions. In this talk, I will explore the trade-offs between addressable assembly and self-closing assembly as routes to self-limitation using a specific class of self-limiting structure: helical tubules. We make triangular subunits using DNA origami that have specific, valence-limited interactions and designed binding angles, and study their assembly into tubules that have a self-limited width that is much larger than the size of an individual subunit. In the simplest case, the tubules are assembled from a single component by programming the dihedral angles between neighboring subunits. We show that the tubules can reach many micrometers in length and that their average width can be prescribed through the dihedral angles. However, we find that the same set of triangular subunits produces an ensemble of tubules with different widths and chirality---a fundamental limitation of using geometrical specificity alone to program self-limitation. The observed distribution is captured by a simple theoretical model that considers only the elastic bending energy of a curved sheet and the irreversibility of tubule closure. Finally, we demonstrate that the distributions of tubules can be further sculpted by increasing the number of subunit species, thereby increasing the assembly complexity. Rather than using a single type of triangular subunit, we use two species of triangles with distinct sets of specific interactions and show that even this simple binary mixture can eliminate half of the total number of off-target structures. Taken together, our findings highlight the complementary roles that programmed curvature and assembly complexity can play in self-limited assembly, which can be further generalized to the assembly of other complex, self-limited 3D geometries, such as helicoids, toroids, and crystalline frameworks.

Biology has discovered how to make exceedingly complex nano-machines — protein structures that consume energy to perform numerous functions, ranging from cargo transport to DNA replication. These machines are far more sophisticated than anything we can produce synthetically at this scale, limiting our ability to create new biological-like materials. Crucially, we lack a sufficient understanding of how such function can arise using simple synthetic building blocks. The past few decades have seen tremendous progress in synthesizing a variety of simple building blocks (e.g. DNA-coated colloids, de novo proteins, etc.) with controllable and specific interactions, and we are beginning to understand how to self-assemble complex structures out of them. However, biological nano-machines are more than just structure — they have kinetic and functional properties that cannot be inferred from their shape. I will show how differentiable programming enables us to design self-assembled nano-machines out of DNA-coated colloids. These machines have precisely controlled kinetics and can consume energy, drive themselves out of equilibrium without external input, and perform tasks. Finally, the simplicity of DNA-coated colloids as a model system enables us to learn general principles about functional self-assembly in non-biological settings.

The self-assembly of colloidal particles into highly-ordered structures offers great promise for advanced optical materials. DNA has emerged as a most versatile tool to drive targeted structure formation due to its programmability, which enables specific attractive binding with controllable interaction strength and length scale. However, control of disorder, defects, melting, and crystal growth is hindered by the lack of a microscopic understanding of DNA-mediated colloidal interactions. Here we use total internal reflection microscopy to measure in situ the interaction potential between DNA-coated colloids with nanometer resolution and the macroscopic melting behavior. [1] The range and strength of the interaction are measured and linked to key material design parameters, including DNA sequence, polymer length, grafting density, and complementary fraction. We present a first-principles model that quantitatively reproduces our experimental data over a wide range of DNA ligand designs. Our theory identifies a subtle competition between DNA binding and steric repulsion and accurately predicts adhesion and melting at a molecular level. Combining experimental and theoretical results, our work provides a quantitative and predictive approach for guiding material design with DNA-nanotechnology and can be further extended to a diversity of colloidal and biological systems.

[1 ] Cui, F et. al., Nat. Commun. 2022, 13, 1.

My poster presentation discusses novel structures found in nanocrystal self-assemblies and nanocrystal-based structured materials, as well as new synchrotron-based techniques to enable comprehensive structural characterization. The term "structural materials" refers to solid materials whose internal structures have been optimized to perform certain functions such as high mechanical properties, green and efficient catalysis, and optical properties for metamaterials and batteries. In the past few years, there has been a great deal of research dedicated to exploring further structures at the atomic and mesoscales of materials, and thanks to the efforts of scientists to enable large scale synthesis of nanocrystals with a variety of shapes, methods of processing, and the introduction of novel characterization techniques, the use of nanocrystals has gained a great deal of interest because of the expectation that nanostructured materials can address these functionality.
My poster presentation shows structures both at the atomic level and at the mesoscale, including amorphous, quasicrystals, and crystals, along with the characterization methods. We present a series of our works related to novel nanocrystal synthesis, self-assembly of superlattices, and a new method of creating bulk materials (high-pressure nanocrystal coining), which produces a variety of materials that could not otherwise be obtained. States like amorphous and quasicrystals, for instance, aren't often the most thermodynamically stable states, so they're not commonly observed in conventional structured materials. We demonstrated that Pd metal nanocrystals with appropriate surface states can contain ~98% amorphous states within their atomic arrangements, which could not be achieved by conventional methods. By compacting these nanocrystals into a solid, we have created the first amorphous pure metal possessing a centimeter-scale size. Another example is silver nanocrystals that form superstructures very sensitively based on the nanocrystals' morphologies. The polymorph of nanocrystal superlattices we present here contains structures that differ from predicted structures by simulation, proving nanocrystal self-assemblies as a very powerful methodology for creating novel structured materials. Furthermore, we present our characterization strategy to assess the structures thoroughly with respect to both the position of nanocrystals and the orientation of crystal domains. Combining rotational XRD measurements with TEM measurements, we constructed 3D structures in the superstructures and in the orientation of the crystal domains.

Pressure-induced phase transformations have been widely observed in many crystalline materials. Molecular dynamics simulations, in particular, have been used to understand high-pressure phase transitions—a typical example being the graphite-to-diamond transition. Here, we investigate the influence of pressure on the behavior of 16 known crystal structure types that have been shown to self-assemble in molecular dynamics simulations using isotropic, pairwise interaction potentials. We reproduce several experimentally-observed solid–solid phase transitions, and we discover two new crystal structures by running simulations under increasing pressure. A variety of other transformation behaviors as a function of pressure are also observed and analyzed to investigate the connection between different high-pressure behaviors and structural parameters such as coordination number, symmetry, and complexity. The results reveal that many simulated structures tend to approach an average coordination number of 12 at high pressure. Our work expands current knowledge of the relationship between structure and pressure, and it helps pave the way for the exploration of new materials.

Polar nematic liquid crystals (PNLCs) are kind of new types of fluid materials co-possessing fluidity and ferroelectricity. Since its discovery in 2017, it has attracted a lot of attention to the potential for novel applications such as flexible optical/optoelectrical devices. One of the most fascinating physical properties of PNLCs is efficient generation of optical second harmonics, which is ~100 times larger than quartz. Additionally, due to its fluidity, we can dope FNLCs with other functional molecules, enabling modification of their physical properties.
By taking such advantages of PNLCs, we herein demonstrate a flexible up-conversion system of coherent light emission. By doping fluorescent molecule into PNLCs and placing that into an optical cavity consisting of two dielectric mirrors with a distance around ~5µm, PNLCs layer can equip two functions for laser oscillation and second harmonic generation (SHG), simultaneously. We investigate their spontaneous SHG conversion process of lasing emission inside the optical cavity. Upon excitation of the doped fluorescent molecules by a pulsed laser light, clear and sharp emission peak with nonlinearity is confirmed beyond a certain excitation threshold. Under the lasing regime, additional emission peaks at the half wavelengths of lasing peaks are also detected, meaning intra-cavity wavelength conversion through the SHG process. The SHG intensity correlates the lasing emission intensity upon the excitation power change. Perhaps with the aid of the increase of the intracavity electric field at the resonance mode, the SHG efficiency of the intracavity conversion process is slightly higher than that of outside cavity without the laser oscillation process. Such a brand-new type of flexible up-conversion device must be promising for future optical/optoelectric devices.

Elongated biological materials can be modeled as nematic liquid crystals which can actively move by energy consumption, known as “active nematics [1].” Recent studies have shown that such active nematic behaviors are observed in many biological systems, such as cytoskeleton-motor protein compounds and cell monolayers. In active nematic materials, the orientational order and the active behaviors are affected by topological defects, at which the orientation angle cannot be defined. Therefore, many studies have demonstrated spatial control of defect positions and movement by topographic guides or confinement to achieve the reproducible generation of targeted orientational patterns or defect movement. However, the geometrical effects of the guides or confinement have not been fully understood. For precise control of the orientational order, it is necessary to establish calculation methods to predict defect positions in various geometries.

To this end, this study aims to establish a calculation method for predicting and designing defect positions of confined active nematic materials. In our previous study [2], we derived an explicit formula of orientational angles and Frank elastic energy of nematic materials confined in a two-dimensional space. The formula was expressed by complex potentials defined on a unit disk and a conformal mapping from the unit disk to a simply-connected domain. Thus, the derived formula can be applied to any simply-connected domain, which is an advantage of the derived formula. However, our previous study cannot predict stochastic fluctuations of defect positions caused by random movement of the active nematic materials.

To quantify the stochasticity of the defect positions, we propose a numerical method to calculate equilibrium distributions of defects. By using the explicit formula of the Frank elastic energy described as a function of defect positions, the equilibrium distributions can be efficiently calculated based on Markov chain Monte Carlo methods. The computed distributions quantify spatial localization and stochastic fluctuations of defect positions in a confined space. Since the geometry of the confinement is expressed as a complex function in our approach, we can easily evaluate geometric effects on the spatial localization of the defects. Therefore, we can predict an optimal geometry for suppressing stochastic fluctuations of defects by tuning the parameters of the geometry.

The proposed method was experimentally verified by culturing mouse myoblast (C2C12) cells, which were used as a model of active nematic materials. The C2C12 cells were cultured on PDMS microgrooves whose geometries were parametrically expressed as f(z)=z+ az³. The cell alignment and the defects were observed by phase-contrast microscopy. The distributions of the defects were localized as the geometry became asymmetric, which were consistent with our proposed calculation method. The fluctuations of the defect positions were also evaluated from the experimental data by maximum likelihood methods. The evaluation suggested the spatial localization of the defects was mainly due to the geometric effects rather than the randomness of the cell migration and alignment. The proposed method will be applied to the high-reproducible and dependable fabrication of nematic orientational order in active nematic materials.

[1] A. Doostmohammadi et al., Nature Communications, Vol. 9, 3246, 2018.
[2] H. Miyazako et al., Royal Society Open Science, Vol.9, No.1, 211663, 2022.

A major focus in the area of recycling plastics has been towards chemically selecting and producing monomers for low ceiling temperature polymers. However, controlled depolymerization of abundantly used polyolefins remains a major challenge. Microwave irradiation can be used to cause such depolymerization by introducing microwave absorbing nano sheets in the bulk of the polymer. Under microwave irradiation, local temperature gradients are introduced in the bulk of the polymer in the vicinity of the nano sheets. In this work, we develop a framework for modeling the thermal degradation of polyolefins under the action of such local temperature gradients. We use the mesoscale energy conserving dissipative particle dynamics (eDPD) approach along with the modified segmental repulsive potential (mSRP) to model linear polymer melts under a thermal gradient. We model bond breaking via a stochastic approach that simulates first order degradation reaction kinetics with a local temperature dependent reaction rate constant. We first simulate the depolymerization under constant temperature conditions and track evolution of dispersity, average molecular weights, and molecular weight distribution in the system. The time evolution of these properties follows previously known analytical trends. Under the action of a temperature gradient, faster depolymerization near the high temperature region results in formation of shorter polymer fragments with higher diffusivity compared to the longer chains in the low temperature region. We analyze the time scale of diffusion of various fragments after the temperature gradient is removed. The framework we propose in this work can be used to model controlled depolymerization of polyolefins under the action of pulsed microwave irradiation.

Hierarchical structures found in biological systems play essential roles (e.g., strong adhesion of gecko lizard, nutrition absorption of tree roots, and effective mass transport between neurons). Many attempts to artificially replicate these hierarchical structures were made by inducing stochastic turbulent flow to form dendritic polymer particles, chemically treating the aramid or cellulose fibers. Although these top-down hierarchies were successfully demonstrated, bottom-up hierarchy of end-attached nanofibers arrays have not yet been presented. Nanofibers with bottom-up hierarchy and long-range order of alignment can inspire us to mimick the properties of hairy structures of villi, lotus leaf, and gecko feet. Unlike the inorganic materials, it is challenging to fabricate structured polymer materials due to the instrinsic amorphous properties of polymer chains. Recently, chemical vapor polymerization (CVP) templated by liquid crystalline (LC) film overcame these challenges and allowed for engineering the polymer nanofibers arrays with controlled diameter, length, and 3-dimensional morphologies. However, nanofibers obtained from LC-templated CVP lacked of hierarchy and their growth mechaisms were not fully understood. Here, we report the method to synthesize bottom-up hierarchical nanofiber arrays by lowering the polymerization temperature and unveil the growth mechanism of the nanofibers. First, we demonstrate that the order of hierarchy can be controlled by varying the synthesis temperature. Second, we control the CVP time to observe intermediate growth phases and elucidate the growth mechanisms. Finally, we qualitatively test the adhesiveness of nanofibers to the substrates by attaching PDMS tape to the fibers and observing where fracture is occurring when taking off the tape.

: Ice-binding proteins (IBPs) in natural, which are known as the important components for preventing organisms from freezing damage, have been of significant interest for freezing point depression. Their ice recrystallization inhibition (IRI) capability has been investigated mainly at local atomic interactions between binding planes of ice crystals and ice-binding moieties. However, IBPs have a specific structure at the macroscale and the flat region on the protein surface binds to ice. We emulated the structural binding of IBPs to ice through the peptide assembly nanostructure. Amphiphilic peptides can be a versatile building block for the fabrication of hierarchical nanostructures based on a couple of non-covalent interactions of amino acids. We designed amphiphilic peptides with aromatic ring, alkyl chain, and negative charge to adjust mutual interaction between peptides. These peptides formed a β-sheet structure to further assemble a two-dimensional (2D) nanosheet with one side hydrophilic and the other side hydrophobic. The ice-binding moieties, coupled to one end of the peptide sequence, were located on the surface of the 2D nanosheet binding with water molecules on the ice crystal surface. The hydrophobic alkyl chains on the other side shielded ice crystal from water molecules which have the potential of becoming ice, thereby inducing IRI. This Janus 2D nanostructure served like a patch which is applied to the surface of the ice crystals, forming a depletion layer of water molecule between the ice crystals. Furthermore, we demonstrated that IRI ability is better when peptides with ice-binding moieties are formed into 2D morphology than into one-dimensional (1D) morphology via subtle modulation of peptide sequence because 2D morphology has a large contact area which can form bonds with water molecules.

The potential application of ice-binding proteins (IBPs) produced by some plants, insects, and fishes to survive in subzero environments has been of great interest as material candidates for the cryopreservation of drugs, cells, tissues, and foods. IBP adsorption to the ice surface can depress the water-freezing point and avoid ice-crystal growth, which is closely related to the presence of binding moieties complementary to the ice crystal plane. Inspired by the distinctive properties of IBPs, cryoprotectants adsorb to the ice, and hinder the growth, thus prohibiting the freeze damage to cells or tissue. Meanwhile, metal-organic framework (MOF) nanoparticles (NPs) can be a promising nanoscaffold that adopts the natural characteristics of IBPs, including the regular configuration and location of functional moieties affecting ice nucleation and growth at the molecular scale. Herein, MOF NPs with good biocompatibility were used as a cryoprotectant that is well dispersed and colloidal-stable in an aqueous solution. The interaction between the MOF NPs and the ice crystal planes was facilitated, by matching the distribution of hydroxyl groups that could be hydrogen bond donors or acceptors on the MOF NP crystal plane, and the spacing of hydroxyl groups on different ice crystal planes. The limited ice growth between MOF-801 NPs pinning on the ice surface increased the local curvature of ice, reducing the radius of these convex growth regions and making them thermodynamically unstable. The MOF-801 NP was size-controlled, that small NPs were absorbed on the ice surface, and the concave growth zone of the ice narrowed, consequently increasing the curvature of the ice surface, and further enhancing the ice recrystallization inhibition (IRI) effect. The peptides acting as ice-binding moieties in natural IBPs, were incorporated into the surface of the MOF-801 NPs, further increasing the number of anchored clathrate water molecules and strengthening the IRI effects. The cryopreservation efficacy of these MOF NPs was measured on the nucleated cell line, and the MOF NPs having a high IRI effect due to the small size and introduction of peptides showed a good post-thaw cell recovery rate that can be a potential cryoprotectant. This research provided the favorable applicability of our developed MOF NPs in practical cellular cryopreservation and further, organ transplantation, cord blood storage, and vaccines/drugs.

Amorphous TiO₂ (a-TiO₂) has been widely studied in recent years since it was reported as an effective coating material for protecting photoanodes from corrosion in Photoelectrochemical (PEC) systems, which is an innovative approach for hydrogen production through solar water-splitting. The stability and longevity of a-TiO₂ is strongly affected by its synthesis method, thickness, structural heterogeneity, etc., which implies that understanding of the structure-property relationship of a-TiO₂ is crucial for improving the performance though targeted materials design.
This study characterized the structural and electronic properties of Atomic Layer Deposition (ALD) grown a-TiO₂ thin films (~17nm) on Si. Fluctuation spectra V(k) and angular correlation functions were determined with 4-dimensional scanning transmission electron microscopy (4D-STEM). The structural properties measured in this study and pair correlation function G(r) from previous literatures were combined with an interatomic potential and used together to determine a realistic atomic model of a-TiO₂. This atomic model was found with the StructOpt code using a genetic algorithm that simultaneously minimizes energy and maximizes match to experimental short- and medium-range order, represented by G(r) and V(k), respectively. Compared with melt-quenched models, the StructOpt a-TiO₂ model presents an improved agreements with the medium-range ordering as represented by V(k) and the k-space location of the dominant 2-fold angular correlations, although some minor higher order angular correlations are seen in the StructOpt structure that are not observed in the experiments. The electronic structure of the StructOpt a-TiO₂ model is studied by ab initio calculation and compared to experimental results on band gaps of crystalline and amorphous phases. This work provides a realistic a-TiO₂ structure model for further investigation of structure-property relationships and materials design and an updated StructOpt optimization package which optimizes against combined experimental and theoretical constraints to determine complex structures.

With increasing demand for printed electronics, roll-to-roll printing has been garnering attention from researchers due to its a cost-effectiveness and good scalability for mass production. In recent years, many researchers have focused on fabricating printed electronics that require high resolution using roll-to-roll printing. Few examples of such electronical devices include thin film transistors, sensors, and electronic circuits. For successful roll-to-roll printing, liquid transfer from pattern roll to target surface is of utmost importance, and the volume of liquid transferred divided by the total volume can be defined as transfer ratio. The desired liquid transfer can be achieved by precisely controlling the parameters that affect it such as physical properties of the liquid, volume, and surface wettability. Studies so far involving roll-to-roll printing have mainly focused on understanding the liquid transfer between two parallel plates by varying the parameters mentioned above. However, the actual roll-to-roll printing uses rolls instead of two parallel plates. In other words, the geometry is different for the two cases which results in change in the dynamics of the liquid transfer and hence the results of existing studies can no longer be applied. Therefore, in this study we replicate geometry closer to actual roll-to-roll printing system by using two nonparallel plates and we control their angle to study its effect on the transfer ratio of liquid between them. Additionally, we also vary the liquid viscosity, plate velocity and wettability to understand the synergistic effect on the transfer ratio.
For our study, the mechanism of liquid transfer and diverse factors affecting the transfer ratio are investigated via both experiment and numerical simulation. The experiments are performed by varying parameters that affect liquid transfer (viscosity, plate velocity, plate wettability and plate angle) using the in-house asymmetric plate extensional rheometer. The process of liquid transfer is recorded using a high-speed camera and transfer dynamics is analyzed using MATLAB. The numerical simulation, based on the phase-field model and dynamic contact angle, facilitates reproducing the complex contact line motion such as slip and pinning which can help us understand and compare with experimental results. Based on the results, regardless of plate inclination, we could divide the transfer ratio into three regimes: quasi-static regime, transition regime and dynamic regime which showed dependence on the plate velocity¹. Overall, the transfer ratio on the inclined plate increases in comparison to the parallel plate, and this phenomenon is further enhanced in the dynamic regime. Additionally, the liquid viscosity and surface wettability were also observed to significantly affect the transfer ratio. Hence, in this study we intend on developing an engineering framework that can be used for controlling the liquid transfer and further be applied to optimize the roll-to-roll printing conditions.

1. Chen, H., T. Tang, and A. Amirfazli. "Effects of surface wettability on fast liquid transfer." Physics of Fluids 27.11 (2015)

Acknowledgement
This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2021R1A6A1A03039696), the Ministry of Science, ICT & Future Planning (2020R1A2C3010568) and the Korea government (MIST) (2020R1A5A1019649).

Electrically conductive polymers are a class of polymers, which can conduct electricity. Conductive polymers have found niche applications such as anti-statics. The electrochemical energy storage devices, especially lithium-ion rechargeable batteries, has grown significantly in the past two decades. Recently multifunctional conductive polymers have been designed as dual ion and electron transport materials, and synthesized through a thermal process. These class of dual charge conducting polymers play a significant role as electrode binders for Silicon (Si) and Tin (Sn) alloy based anode electrode. Si is an attractive candidate for lithium-ion batteries because it delivers 10 times greater theoretical (∼4200 mAh/g) specific capacity than that of a traditional graphite anode (∼370 mAh/g). However, the widespread application of silicon materials has remained a significant challenge because of the large volume change during lithium insertion and extraction processes, disrupting both the Si electrode surface and electrode mechanical integrity. This large volume change causes electrode failure, leading to loss of the electrical contact and drastic capacity fading. Nanosizing the Si and Sn based anode materials provides better performance, but poses significant challenges to manufacturing of the electrode, including particle aggregation, and difficulties in maintaining constant electrical contacts to the nanoparticles, and excessive surface area. Conductive polymer binders can play multiple functions for Si electrode, including improved adhesion and connectivity, lithium ion compensation, better ion and electric conductivity as well as surface and interface modification. Organic and polymer chemistry has provided almost infinity possibilities to modify the polymeric binders to include the desired functionalities. This presentation will discuss the specific molecular design principles and synthetic steps to realize the structures and functionalities of the binders, how these binders interact with different alloy materials, and the electrochemical performances of the electrodes based on these binders.

To face formidable challenges of future electronics with complex functionality and architecture, not only new materials but also new fabrication method need to be developed. However, topographical micropatterns (such as microchannels) are conventionally fabricated by complicated lithographic method, which are usually expensive and time-consuming, and not suitable for high throughput manufacture. Therefore, a low-cost, large-scale method for topographical template preparation needs to be developed. Recently, cracks formed in drying colloidal film have been demonstrated as ideal materials for microscale manufacturing. In this work, we first studied the key parameters that affect the dimensions of colloidal microchannel, such as channel-to-channel distance, channel width, and theoretical model is proposed to provide insights on colloidal microchannel formation. Then, the criteria for 2D microchannel formation (i.e., microchannel formed in both x and y direction) are investigated. The dimensions of 2D microchannel will be tuned by varying non-equilibrium condition, such as convective flux, temperature and evaporation rate. This work will provide a general strategy for generating of 2D microchannels, thereby offering a low-cost, large-area and lithography-free method for fabrication of patterns for printed electronics.

Metal-organic frameworks (MOFs), nanoporous materials composed of metal nodes and organic ligands, are remarkably paid attention to as adsorption and storage medium for gases. A controllable pore-size nature of MOF enables species-specific adsorption for a particular purpose. However, the adsorption mechanism is not well understood yet. Among diverse gases, we focus on ammonia because it is popular for energy systems due to its nature of large vapor pressure and enthalpy of evaporation. The large vapor pressure can promote heat and mass transfer rate, and the large enthalpy of evaporation enables the reduction of the adsorption bed size.
Considering all the above, in this study, by employing extensive grand-canonical Monte Carlo (GCMC) simulations, we probe the adsorption mechanism of NH3 into MIL-101(Cr) MOF depending on the pore sizes. The pore size is modulated by increasing the number of benzene rings in the ligand. Three different ligands with one (original), two, and three benzene rings are considered while the metal node remains unchanged. As a result, the original MOF without modification has 6.8 Å, 26.1 Å, and 33.6 Å -sized pores, the MOF with two benzene rings has 9.7 Å, 39.4 Å, and 49.9 Å -sized pores, and the MOF with three benzene ring has 12.7 Å, 52.5 Å, and 66.1 Å -sized pores. For each structure, the isotherm is calculated by varying the pressure from 1 to 9 bar. Interestingly, the results show that the original MOF with the shortest ligand absorbs the ammonia most rather than the other MOFs with the longer ligands except for the high pressure of 9 bar. When the pressure is sufficiently high, the MOFs with two ligands adsorbs NH3 most. Also, we observe that at a certain pressure, the NH3 isotherm suddenly increases as the pore surface is closed (filled by gas completely) and the interior of the pore starts to be filled. At low pressure, the interaction between gas and MOF node governs the adsorption. However, at high pressure, the gas-gas interaction becomes dominant since all the nodes in a pore are occupied by the gas molecules already.
The potential energy analyses confirm the observations by GCMC simulations. Until the surface of the pore is fully occupied, the vicinity of the surface has the lowest energy sites. However, when the surface is closed by gas molecules and the pore interior starts to be filled, the NH3-attractive sites are found in the middle of the pores. When an NH3 molecule is adsorbed on the node, it creates additional favorable sites nearby for other NH3 molecules. Therefore, the small pores have a NH3 structure inside that is dominated by the shape of pore while the large pores permit regular NH3 structure inside because the NH3’s in the middle are adsorbed mostly on the site created by the other NH3 molecules.
This work was supported by Korea Institute of Energy Technology Evaluation and Planning (KETEP), which is funded by the Korean government (MOTIE) (No. 20212050100010, Chemisorption heat pump system using electrochemical compressor).

On average, one third of the energy consumed by passenger cars is used to overcome friction in the system. About 15% of this total energy loss is converted to heat by friction in the transmission. In order to understand the mechanism of low-friction tribofilm formation in transmission fluids, Multimodal Atomic Force Microscopy (MM-AFM) was used to generate tribofilms and monitor their development on steel surfaces. This technique allows in situ nanoscale imaging of the tribofilm, combining Friction Force Microscopy (FFM) to monitor friction changes, with Nanoscale infrared spectroscopy (nano-IR) to monitor chemical changes on the surface. Several friction modifiers combined with phosphorus-based antiwear chemistry were analyzed as a function of contact pressure. Using MM-AFM to track frictional and chemical behaviors during tribofilm formation provides unique insight into the evolution of low-friction films while helping advance toward the goal of developing more efficient drivetrains.

Epoxy resins are widely used in adhesives and fiber-reinforced plastics owing to their excellent adhesive and workable properties. The adhesive strength between the epoxy resin and inorganic surfaces directly affects the mechanical strength of composite materials. Therefore, understanding the origin of the adhesive properties has been anticipated. However, molecular-scale investigations on epoxy-resin/inorganic interfaces have little been performed due to the difficulty in measuring such “buried” interfaces. This study prepared the adhesive interfaces between an epoxy resin and two types of silicon substrates with different surface chemical states. Moreover, the compositional distributions in the vicinity of the epoxy-resin/silicon interfaces were analyzed with a 1-nm resolution using scanning transmission electron microscopy (STEM) and electron energy-loss spectroscopy (EELS).

Diglycidyl ether of bisphenol A (DGEBA) (Mitsubishi Chemical Co., Ltd., Japan) and para-diaminodicyclohexylmethane (PACM) (Tokyo Chemical Industry Co., Ltd., Japan) were used as the epoxy-resin prepolymer and curing agent. They were mixed so that the molar ratio of the epoxy groups to the active hydrogens of the amino groups becomes 1:1. (111) substrates of a silicon single crystal were prepared. The organic residue on the surface was removed with piranha solution. Subsequently, hydrogen (H)-terminated surfaces were prepared with 1.5 wt% hydrofluoric acid for 30 min. Some H-terminated surfaces were processed by water vapor plasma to be terminated with hydroxyl (OH) groups. The mixture of DGEBA and PACM was pasted on these silicon substrates and then cured at 100 °C for 90 min. Thin cross-sectional samples of the epoxy resin/silicon interfaces were fabricated using a Cryo Ion Slicer (JEOL Ltd., Japan). These samples were analyzed by annular dark-field STEM (ADF-STEM) and STEM-EELS using a transmission electron microscope JEM-ARM200F (JEOL Ltd., Japan).

ADF-STEM observation revealed that oxidized silicon layers with thicknesses of ~2 nm at both adhesive interfaces between the epoxy resin and H- or OH-terminated silicon substrates exist. In addition, C-K adsorption edge spectra, originating from the epoxy resin, were measured by EELS at 1 nm intervals in the vicinity of the adhesive interfaces. Because DGEBA contains aromatic rings in the molecular structure, a characteristic peak (π* peak) appears in the C-K edge. However, PACM does not show the π* peak in the C-K edge because it has no π bond in the molecular structure. The measured C-K edge spectra clarified that epoxy resin molecules infiltrated into the oxidized layers at the interfaces. Moreover, the π* peak became smaller only at the interface of the OH-terminated silicon, suggesting that the compositional ratio of PACM to DGEBA became more significant at the interface of the OH-terminated silicon rather than that of the H-terminated silicon. Our study revealed that the compositional ratio of epoxy resins, which results in adhesive properties, changes in the vicinity of the epoxy-resin/inorganic interfaces under the influence of the surface chemical conditions of inorganic materials.

Controlling the nanoscale morphology of the conjugated polymers (CPs) has been approaching an amount of interest due to its possibility of adjusting charge transfer property. In particular, one-dimensional nanostructures are ideal for charge transfer as they have effective carrier transport properties along the anisotropic stacking directions. Along this line, the pre-assembly of conjugated nanowires (NWs) in the solution state has drawn great interest as a potential replacement for the post-annealing process, securing roll-to-roll manufacturing with a large-area production and a significant cost decrease. The whisker method and the mixed solvent method are frequently utilized as typical solution processing techniques to provide additional driving forces for CPs assembly. Herein, in order to accomplish NW growth and doping without a physical driving force simultaneously, we have focused on charge transfer at the CPs and dopant contact, which can cause seeds-triggering growth of the CPs, rather than the doping procedure, which is often used to tune the electrical property of the CPs to induce the enhancement of the conductivity. Specifically, we will talk about the charge-transport driven CPs-crystal seeding and growth into NWs by adding dopant. Interestingly, it is clearly confirmed through in-situ liquid-cell TEM that controlling the concentration of the dopant or the molecular weight of the CP may have a strong effect on the formation of the NWs in the solution-state. This study might provide an innovative manufacturing strategy for mass production of high-efficiency doped organic semiconductor NWs for optoelectronic devices through solution-processing.

Alzheimer's pathology is correlated with structural conformation change of aggregated amyloid beta (Aβ) proteins. We identify the progressive aggregation stages of the Aβ protein growth in a buffer solution using by the near-field THz spectroscopy and the newly defined biophysical marker based on real-time THz optical conductance. Here, we clearly detected and analyzed the Aβ aggregation growth through solution-based label-free THz conductance measurement by precisely controlling the thickness of the protein sample in a buffer solution. Frequency-dependent conductance for Aβ aggregates was obtained by measuring the differential transmittance of the time-domain spectroscopy in the THz range with a molar concentration of monomer, oligomer, and fibrillar forms. The monotonic decrease in the conductance at low frequency was dominated by a simple Drude component in the monomer with concentration and nonlinear conductance behaviors in the oligomer and fibril. By extracting the structural localization parameter, a dimensionless constant, with the modified Drude–Smith model, we defined this to the biophysical value (0 < DQ < 1) as a structure-specific metric for a various Aβ aggregates at a low concentration of 0.1 μmol/L; DQ = 1.0 ± 0.002 (fibril by full localization, mainly by Smith component), DQ = 0.64 ± 0.013 (oligomer by intermixed localization), and DQ = 0.0 ± 0.000 (monomer by Drude component). Furthermore, we can label-free monitor Aβ growth dynamics to identify various morphological phase transitions and steps during macro scale fibrils from monomers under physiological conditions. This suggests the new biophysical characteristics with intrinsic property of Aβ proteins for Alzheimer’s disease.

Bulk self-assembly provides an efficient technique for large-scale production of materials which is often limited using the interfacial or deposition methods. One promising system in this context could be provided by functionalization of insulating nanosheets for the production of conductive/insulative heterostructures, for instance use in electronic devices. One such material is clay which completely delaminates in water to form insulating nanosheets, exhibiting one of the largest electron bandgaps known so far in 2D layers (1).

Here we present the self-assembly of graphene oxide (GO-) and synthetic fluorohectorite clay heterostructures in a bulk mixture of the two individual components in the presence of polyethyleneimine-ethyleneoxide (PEI-EO). The synthetic clay mineral used here is superior to other clays in terms of charge distribution, homogeneity, and crystalline perfection (2). This clay mineral delaminates in water to form nematic structures with cations present in the interlayer regions. Double layer clay nanosheets can be readily obtained via ordered stratification by partial interlayer cation exchange using ammonium cations (NH₄⁺), providing bilayers with a net negative charge, and which can be double side coated with the polymer (2, 3). The GO is incorporated onto the clay surface via the polymer adhesion layer to form the complex GO-clay heterostructures. These 2D nanosheets have been investigated using SPM and XRD to determine their composition, mechanical and adhesion properties.

The results indicate that the synthesized GO-clay nanosheets presents interesting properties for possible applications in electronics and semiconductive devices. We are currently extending this work and attempting the cleavage of the double layer GO-clay nanosheets into single GO-clay layers to produce micrometer sized GO-clay Janus platelets.

Reference:
(1) Pacakova B.; Vullum P.E.; Kirch A.; Breu J.; Miranda C.R.; Fossum J.O. Large Bandgap Insulating Superior Clay Nanosheets. MRS Bulletin. 2022, 47.
(2) Stoter M.; Godrich S.; Feicht P.; Rosenfeldt S.; Thurn H.; Neubauer J.W; Seuss M.; Linder P.; Kalo H.; Moller M.; Fery A.; Forster S.; Papastavrou G.; Breu J. Controlled Exfoliation of Layered Silicate Heterostructures into Bilayers and their Conversion into Giant Janus Platelets. Angew. Chem. Int. Ed. 2016, 55, 7398-7402.
(3) Michels-Brito P.H.; Malfatti-Gasperini A.; Mayr L.; Puentes-Martinez X.; Tenorio R.P.; Wagner D.R.; Knudsen K.D.; Araki K.; Oliveira R.G.; Breu J.; Cavalcanti L.P.; Fossum J.O. Unmodified Clay Nanosheets at the Air-Water Interface. Langmuir. 2021, 37, 1, 160-170.

Soft matter exhibits viscoelasticity, which is generally associated with the rheological structure of materials. To comprehensively understand the rheological structure and properties, it is, therefore, necessary to probe materials at the multiscale; materials should be measured with probes from bulk- to nano-scales, to fully reveal the internal structures of materials. However, conventional rheometers mostly limit the rheological measurements to the bulk scale. Here, we demonstrate multiscale measurement of structure and properties for polymer solutions, e.g., silicone oils, using a single platform: quartz tuning fork-based tribo-rheometer. This unique platform with different-sized probes allows to measure bulk rheological properties, molecularly ordered structures of polymers, and the tribo-rheological characteristics at solid interfaces. Our results offer a unified understanding of structures and properties relation for soft matter.

Structured soft materials have internal order that give rise to unusual mechanical properties and emergent organization of inclusions and defects. Here we present a composite structured liquid formed from biopolymers of distinct rigidities. Biopolymer filaments, such as actin and microtubules, behave as rigid rods when much shorter than their persistence length. These short, rigid filaments are known to crowd into a thin fluid layer that can form a nematic liquid crystal, where filaments have orientational order but not positional order. Here we investigate the phase space in a mixture of short, rigid, nematic forming filaments with more flexible biopolymers, which are much longer than their persistence length. Using fluorescence microscopy, we investigate the domain and defect formation as the phase separated polymer mixture evolves. Using a continuum model of lyotropic liquid crystal, we extract material properties of the liquid crystal. Our results suggest a novel structured soft composite, which potentially informs physical mechanisms of controlling material properties in structured fluids and templating functional polymeric materials.

Pressure processing emerges as a fast and clean mechanical method to fabricate and transform novel nanomaterials without involvement of chemical reactions and post-purification processes. Recent studies have revealed that the pressure-treatment of nanomaterials is able, not only to induce structure transformation at the atomic level, but also to regulate translational alignment at nano-, meso- and even macro-scales. Exciting nanomaterials with unique structures and properties have been generated through a stress-driven “permanent-sintering” process. In this talk, I will discuss several of our recent studies about pressure processing of different types of nanocrystals and their ordered and non-ordered assemblies, including halide perovskite nanocrystals, metal nanoparticles, and quantum dot-metal heterostructure nanocrystals. In particular, I will focus on our new discovery of a novel method to produce tailored grain-boundary conditions with nanoscale precision from colloidal metal nanocrystals by a pressure-sintering process. The resulting bulk grain-boundary materials (which we call ‘‘nanocrystal coins’’) possess a metal-like appearance, high conductivity and exceptional strength while inheriting the original domain features of the nanocrystal building blocks. Our studies may spur the development of new materials (through pressure-treatments) with functionalities crucially depends on the domain configuration at nanometer scale, such as superhard materials, thermoelectric generators, and functional electrodes.

The dynamics of glass formers exhibit dramatic slowdown below an onset temperature that delineates the high-temperature and supercooled regimes. For two-dimensional (2D) glass formers, we propose that the onset temperature can be described by a Kosterlitz-Thouless transition, driven by the elastic excitations underlying the relaxation mechanism for glassy dynamics. Analogous to dislocation-mediated melting in 2D crystals, the excitations exist as a bound dipole-dipole (or quadrupole) state in the supercooled regime and as free dipoles above the onset temperature. The Kosterlitz-Thouless scenario explains the emergent elastic behavior of 2D supercooled liquids at intermediate timescales, and thus the Mermin-Wagner fluctuations observed in experiments and simulations of 2D glass formers. The present work reveals the nature of 2D glass formers, where quasi-long-range order emerges in an analogous manner to 2D crystals at intermediate time scales, and is relevant to understanding colloidal films and other soft condensed matter systems under extreme confinement.

Colloids are exquisite mimics of atoms or molecules in condensed matter. Since the particles are thermalized by the solvent, they form the same phases of atomic or molecular systems such as crystals, glasses, alloys, and liquids. Each particle mimics the behavior of an individual atom and their collective behavior mimics that of a condensed phase. Due to experimentally accessible time and length scales, they serve as an excellent model system to investigate a variety of phase behaviors that have not been accessible to experiment on the atomic level. Intensive studies have been done using hard-sphere or soft-sphere colloids to elucidate mechanisms underlying crystallization, melting, solid-solid transitions, and glass deformation, which provided new fundamental insights into the phenomena; structure, dynamics, and their time-dependent evolution are directly measured to find out key parameters that govern the processes. Progress in the synthesis of model colloids with controllable surface chemistry allows an alteration in the simplest interaction potentials, which, however, is still far behind from mimicking real atoms and molecules. In general, pair potentials of atoms and molecules are described using the Lennard-Jones potential, which represents one particular type of Mie potential. Therefore, it remains of great importance to design realistic colloidal systems with Mie potential that can more closely depict the phase behavior of atoms and molecules.
We employ the depletion interaction in aqueous suspensions of spherical colloids to formulate total pair potential to be comparable with that of atoms and molecules. Depletion force has been applied to modulate interparticle interactions in colloidal systems. Depletants in the suspension are excluded from the surfaces of colloids, which causes outward osmotic flow from the depletant-depleted interstitial region among colloids, exerting attractive force. This attractive interaction has been used to assemble colloidal particles into condensed phases. We suspend polystyrene particles with negative surface charges in water containing sodium chloride and depletant of poly(acrylamide-co-acrylic acid) (p(Am-co-AAc)) with a hydrodynamic radius of r_h = 32.5 nm. In the presence of the depletant, depletion attraction contributes to total pair potential in the range of separation smaller than the diameter of the depletant. Superposition of the depletion attraction with electrostatic repulsion and van der Waals attraction renders the particles to strongly repel in very short-range, gently attract in middle, and not interact in long-range, similarly with Mie potential.
With the pair potential, fluids, crystals, and glasses are respectively represented depending on the depth and slope of the pair potential. For example, the phase boundary between the fluids and crystals is roughly defined by the depth of the potential well, whereas that between the crystals and glasses is represented by the rate of colloidal assembly. For the crystalline phases, the nucleation rate is dictated by the depth and the growth is limited by slow colloidal diffusion. During growth, Ostwald ripening causes large crystallites to get larger while small ones shrink and disappear, in particular for large Laplace pressure gradient. The final morphology of crystals is either dendritic or polygonal, which is selected by whether or not the concentration gradient is maintained during the growth. The shape of the dendrites is determined by the crystal orientation, to be either six-fold or elongated X-shaped. These crystal growth behaviors are highly relevant to atomic and molecular systems. As the growth is dictated by the nucleation rate, the depth of potential energy well is the most important determinant that governs the overall pathway of nucleation and crystal growth.

Bone mineralization refers to the crystallization of amorphous calcium phosphate in the extracellular matrix of all vertebrates. Human bones are composed of organic/inorganic mixture, and about 60% of inorganic components are hydroxyapatite (HAp), which is one of calcium phosphate. It is known that the crystallization of HAp does not follow classical nucleation theory. It has been found that the mineralization of HAp is achieved through a transient amorphous calcium phosphate (ACP) step both in vitro and in vivo. However, the proposed mechanisms of ACP transformation to HAP remained elusive for example, a dissolution-reprecipitation, the reconstruction of Posner’s clusters, and a surface-mediated transformation. Therefore, the study of ACP-mediated HAP nucleation pathways and mechanisms is required and has profound implications for biomineralization. Synthetic ACPs were discovered by Betts and Posner’s X-ray experiments in the 1970s to have a Ca:P molar ratio of ~1.5, a spherical feature, and a chemical structure of Ca₉(PO₄)₆. In human bone, it has been reported that Ca and P ions, which are constituents of HAp, are initiated from the mitochondria of osteoblast and are released in the form of ACP through the matrix vesicles (MV). After that, ACP crystallizes inside the collagen fibers to be crystalline hydroxyapatite platelets. So far, there are sufficient studies related to the properties of synthesized ACPs, but the analysis of crystallization of ACPs released from the cells into HAp is insufficient. In this study, the characteristics of ACPs secreted from cells and synthesized ACPs were analyzed, and collagen fibrils were mineralized using both ACPs. The Ca/P atomic ratio and chemical composition of ACPs were analyzed by Inductively Coupled Plasma and Transmission Electron Microscopy (TEM), and the phase of ACP was analyzed by powder X-ray diffraction. In the case of synthesized ACPs, spherical nucleation was observed in a solution containing Ca and P, and the Ca/P ratio in the process of becoming a ribbon was analyzed. The Ca/P ratio in the initial spherical state was about 0.9, but it increased with time. ACPs released by cells were obtained by ultrafiltration of matrix vesicles from osteoblasts and analyzed mainly by TEM. We dispersed cell exosomes on a TEM grid by using ultrafiltration and finding the dark contrast due to the electron scattering by inorganic substances, Ca and P, in bright-field imaging, we also analyzed the mineral contents. Based on the study on the characteristics of ACP, mineralization in the collagen matrix was carried out to conduct a study on the synthesis of bone formation from the actual release of ACPs from osteoblasts to the mineralization of collagen. Therefore, the results presented in this study may better understand the mechanism of HAp mineralization in collagen fibrils and the actual bone formation process and ultimately help in the successful material design of tissue engineering.

DNA linked quantum dot (QD) assemblies have been applied in biological drug delivery, programmable materials, and photonics. The mechanism of a DNA chain attaching to the QD surface is very important to developing new DNA-QD nanostructures. In this work, we combine all-atom molecular dynamics simulations and experiments to reveal the mechanism of a single-stranded DNA (ssDNA) attaching to the ZnS surface of CdSe-ZnS (core-shell) QDs. We verified the ssDNA model chain conformation through agreement with experimental and theoretical conformations in the literature. We report the ssDNA chain conformation on a flat ZnS surface and on differently sized ZnS QD surfaces. They depend on the combined effects of electrostatic repulsion and steric exclusion from 3-mercaptopropionic acid (MPA) and O-(2-mercaptoethyl)-O'-methyl-hexa (ethylene glycol) (mPEG) capping on ZnS QDs. Both simulations and Förster Resonance Energy Transfer (FRET) experiments indicate that ssDNA tail is closer to the QD surface when the QD size is larger. In addition, we find through both simulations and Transmission Electron Microscopy (TEM) experiments that the maximum valence numbers are 1, 2 and 3 on QDs of 6, 9 and 14 nm in diameter, respectively. We emphasize the critical role of the electrostatic repulsion on the conformation and the number of attached ssDNA on the QD surface.

The intrinsic thermodynamics of polymeric and molecular materials can drive assembly into advantageous structures on the nanometer length scale. Specifically, block copolymers with two or more chemically distinct and covalently linked blocks that are enthalpically immiscible have the propensity to phase separate. These phase-separated regions can conform to many interesting structures that have been useful in areas including lithography, optics, and membrane design. Likewise, molecular aggregates are structures that readily assemble to a similar macromolecular length scale and can have unique interactions with visible light. In these assemblies, the long-range order is limited by uncontrolled nucleation and growth. Well-defined long-range order in these materials can strengthen photonic coherence and can make them intriguing candidates for visible-light integrated circuits. With state-of-the art competencies at the Center for Integrated Nanotechnologies at Los Alamos National Laboratory, the structural assembly of soft materials can be assisted with polymer pen nanolithography. The polymer pen lithography technique is a novel approach to precise, high throughput application of soft materials onto a surface. In the case of polymeric assembly, strategic placement of defects can be used to predetermine nucleation sites and limit grain growth, effectively assisting the assembly process. In the case of molecular aggregates, printing of aggregate assemblies on the length scale of visible light can reduce the quantum incoherence of randomly assembled and multilayer grains. Here, a substrate can be pre-treated with a quasicrystalline-patterned poly(dimethylsiloxane) (PDMS) photoresist that is then photopolymerized to yield a durable and chemically selective defect architecture intended to influence the self-assembly of a poly(dimethylsiloxane)-block-poly(lactic acid) block copolymer. The structural and characteristics of the resulting assemblies are quantified using X-ray scattering and microscopy techniques.

The additive manufacturing of batteries offers great potential for the future of power integration in electronics, freeing up design space and enabling new device capabilities. This is especially true for thin film and flexible devices where current packaging (ex. coin cells, cylindrical cells, and pouches) prevents intimate incorporation of the battery into the device and must be designed around to maintain a device’s flexibility. The ability to fabricate a cell directly onto the device itself can remove this restriction, as the shape and structure of the cell can be tailored to the device, fitting into unique form factors or even being designed to enable deformation. To achieve this, additive manufacturing approaches must be developed to deposit high performance battery component materials and to combine these materials to create high functioning galvanic cells.

One of the great challenges in the additive manufacturing of batteries is developing process compatible materials with the suitable composition and microstructure to enable appropriate performance, particularly porosity and pore structure. Electrodes must be porous to allow for electrolyte penetration and ion conductivity, highly loaded with active material to maximize energy density, and electrically conductive to transport energy to and from the active material. Likewise, separator membranes must be porous for electrolyte penetration and ion conductivity, but these features must be small enough and mechanically robust enough to prevent shorting and dendrite growth. In addition, the processing requirements for these materials must be straight forward to make techniques like 3D printing and coating possible.

We have developed an evaporation induced phase separation technique that utilizes a mixed solvent system to fabricate polymer materials and polymer-particle composites with controlled porous microstructures. The polymer is dissolved in a solvent solution composed of a good and poor solvent for the polymer, chosen such that the good solvent evaporates preferentially to the poor solvent. This leads to an instability in the ink upon drying, thereby causing phase separation into polymer poor and polymer rich phases and creating porosity upon solidification. We have used this process to develop a PVDF and Al₂O₃ composite that functions as a separator membrane for lithium ion batteries and can be deposited by multiple printing and casting techniques. Additionally, we have demonstrated the ability to control the microstructures that form in these polymer-particle composites through the selection of particle size and loading, including creating both foam-like and granular morphologies. When combined with similar composite electrode materials, such as graphite or LiFePO₄ for lithium ion batteries, printed full cells can be achieved. Here, we explore approaches to how we can create fully printed batteries from these materials, as well as how to fabricate them on complex and non-planar substrates to enhance energy storage integration. Furthermore, we examine the challenges faced in controlling microstructure in multi-material and multi-layer additive manufacturing, particularly at the interfaces between different materials and how this can impact performance.

Template-directed self-assembly is a promising way of manipulating microstructure, enabling emergent functional properties including photonic, phononic, and mechanical. Moreover, the template can evolute microstructures that are distinct from initial starting structures, yielding ordered emerging patterns. However, instabilities at the interfaces between materials and templates hinder the formation of uniformly ordered emerging patterns in a long-range order, limiting practical applications. Here, we design low-thermal fluctuated templates which reduce instability of eutectic self-assembly materials at the interface, leading to a large area (~ 0.01 mm2), ordered checkerboard array of emerging patterns. The FDTD simulation suggests that the low thermal conductivity of the template can minimize temperature fluctuation, giving rise to uniformly ordered emerging patterns. In the serial sectioning of directionally self-assembled AgCl-KCl within the template, we note that microstructures are strongly influenced by the thermal conductivity of the template, and particularly large instability of microstructure at the interface between the template and material results in short-range order. The low thermal conductive template fabricated by porosification constrains thermal fluctuation caused by rapid thermal transport and produces a large-area emerging pattern. We also find that by using selective etching of self-assembled materials or templates, a variety of mesostructures are observed and can control optical properties, which reveal the promising potential for photonic and microscale-based applications.

As important raw materials utilized in fire-proof, sound insulation, thermal insulation, gas sorption, etc., the traditional solvent phase inversion methods to produce porous materials have resulted in air/water pollution and residual VOCs in the products, which have been restricted by many countries. Waterborne polymer products possess the superiority of being eco-friendly during manufacturing but are limited by foam stability. Pickering foam is an air-water mixture whose interface is stabilized by the particles without interfacial activity. Excess particle desorption energy from the air-water interface over surfactants ensures superior stability and potential templating porous material production. The classic view of Pickering foam requires specific particle wettability, explained through the maximum capillary pressure concept, which hinders its application in industry.

We have reported a new strategy to prepare ultra-stable aqueous foams from PVA-Silica binary component system1. A series of Pickering aqueous foams were therefore achieved as the hydrophilic polymer and hydrophobic colloidal particles stabilized the Janus bilayer air-water interface in one step without massive particle wettability modification. The resulting Pickering foam afforded convincing stability over one month and templated the porous materials monolith. The work opened a new door for binary component Pickering foam and waterborne composite porous materials preparation.

In our recent work, the stabilization mechanism and kinetics of binary colloidal particles stabilized Pickering foam are under investigation. We are seeking for the potential to get the typical Pickering foam applied as a low-cost and eco-friendly scheme for porous materials industrial production. The Pickering aqueous foam systems, including hydrophilic-hydrophobic and hydrophilic-hydrophilic colloidal particles systems, are derived from waterborne polyurethane (WPU), hydrophobic silica particles (SP), and cellulose nanofibrils (NF) with typical wettability, surface charge, size distribution have been achieved.

Key Words: Porous material, Pickering foam, WPU, Silica particles, Cellulose nanofibrils

Reference
1. Y. Sheng, K. Lin, B. P. Binks and T. Ngai, J Colloid Interface Sci, 2020, 579, 628-636.

Inspired by naturally occurring hierarchical materials, numerous beautiful and functional mesoscale architectures have been constructed in labs using solid-state nanoscale building blocks and bio- or biomimetic molecules via self-assembly. Their structures and assembly dynamics are tightly regulated by the system's convoluted energetics and entropic information, which may even respond to a minuscule change. For example, we recently reported a pH-regulated self-assembly of silica nanoparticles facilitated by an engineered bifunctional silica-binding protein sfGFP::Car9-Car9. The assembly and disassembly can be reversibly and cyclically modulated by alternating the solution pH between 7.5 and 8.5. In another study, we observed that an increment of the peptoid (i.e., the ligand) length by two monomers at a time would change the arrangement of a CdS quantum dot superlattice from close packing to square, further to monoclinic. However, the complexity of the nanoscale colloidal system often makes it difficult to probe the underlying physics via experimental means. Alternatively, we can construct suitable multi-scale theoretical toolkits by carefully selecting and combining theories and simulation algorithms from different levels (i.e., from ab initio to coarse-grained models) to connect the scales and gain physical insights into the assembly mechanisms. In this talk, I will elaborate on how we used multi-scale theoretical frameworks to reveal the key driving forces of self-assembly in these two cases. The knowledge we gained on the distinctive roles of organic ligands has further inspired new design principles in future studies.

Self-organization in colloidal systems has led to various fundamental studies on non-equilibrium systems and development of microrobot swarms. However, typical colloidal systems are limited in their behaviors and each system can only facilitate a few specialized studies. Therefore, developing a single model system that can controllably transition among diverse behaviors, would be very useful for various fundamental studies and for the development of microrobot swarms. We develop a collective system that utilizes the mutual interactions among its constituents, and its behaviors can be controlled via global stimuli. Our system consists magnetic micro-disks that interact via various physical interactions (magnetic dipole-dipole, hydrodynamic and capillary interactions) and the relative dominance of these interactions can be tuned by an external oscillating magnetic field. In this talk, we present various studies enabled by our system. First, we demonstrate that our system can form rotating collectives with varying degree of orientation order that can be controlled by a single control parameter: the rotation speed of the external magnetic field. These behaviors enable a fundamental study on development of a general-purpose order-parameter based on the information content of the self-assembled patterns. Next, we show that the mutual interactions among the micro-disks can be tuned to form various collective modes ranging from isotropic (rotating and static collectives) to anisotropic (chains) behaviors, and a gas-like behavior consisting self-propelling pairs. The mutual interactions are tuned by changing the profile of a 2D oscillating magnetic field, demonstrating that the external driving field and the mutual interactions can conjunctively generate transitions among behaviors and enable various controllable robotic functions. Last, we study the effect of heterogeneity in our system and demonstrate that our system can transition on-demand from a driven (following an external field) to an active (self-propelled) behavior or a mixture of both. Through these studies, we hope to convey that our system can act as a versatile model system facilitating fundamental studies that link driven and active behaviors, and also provide a step towards developing versatile and controllable microrobot collectives.

Extended nanostructured materials are abundant in natural systems such as butterfly wings and beetle shells with high interior periodic order that produces splendid optical appearances and multifunctional mechanical and interfacial properties. Inspired by the versatility, durability, and functionality of natural materials, material scientists are seeking synthetic analogues of functional materials in bulk phase with highly ordered three-dimensional nanostructure for various applications in optics, catalysis, water purification, and energy storage. Herein, we introduce a versatile and scalable concept towards the fabrication of bulk nanostructured functional materials. We take advantage of the self-assembly of synthetic triblock terpolymers with chemically distinct blocks that self-assemble into ordered continuous nanostructures as bulk materials. Each of the three blocks serves a distinct purpose: One block within the self-assembled bulk material can be selectively crosslinked with tunable crosslink density which enables the formation of organo-gels with controllable swelling degrees in various kinds of organic solvents with retention of the periodicity of the ordered nanostructures. Another functional block is chemically tunable towards attracting and depositing reagents and nano-sized functional building blocks, while a chemically inert third block acts as a freely swollen gel phase that enables mass transport throughout the bulk structure. The size and symmetry of the nano-scaled features are tunable through the block fraction, the molecular weight of the polymer, crosslink density, and solvent quality. The monolithic triblock terpolymer organo-gels can serve as a versatile soft-template for the creation of various functional materials attribute to the unique physical and chemical properties of the triblock terpolymer. Specifically, the varied affinity of the building blocks to solvents and reagents, as well as the tunability of the functional groups facilitate the mass transfer and selective chemical reactions in infusion-deposition templating, respectively.

Current understanding of two-dimensional crystal growth focuses on the interactions between flat substrates and flat growing crystals. By contrast, the understanding of the growth of curved crystals, especially those of non-zero Gaussian curvature of which limited examples exist, considers the stresses imposed by a curved template on a growing two-dimensional crystal, where molecular or colloidal units add to the growing crystal edges from above. In the current study, we demonstrate that when crystals grow within curved vesicle membranes, forces from the membrane and its bending, acting at the edges of the growing crystal, along with the impact of internal pressure, produce morphologies and scaling that run counter to expectations based on systems without the pulling of a growing crystal at its edges. In vesicle membranes, processing conditions, such as cooling rate and transport considerations cause variations in tension history, producing different interplays between bending energies and line tensions. The overall result, demonstrated in quantitative experiments and supported by modeling, is that flat compact solid domains grow reproducibly in small vesicles. However, despite more gradual curvature but higher membrane tension on larger vesicles, flower shaped domains are found and their shapes exhibit increasing complexity with increased vesicles size, tension and, ultimately, bending energy.

Poly-N, N’-disubstituted sulfamides [Kulow et al. Chem. Sci., 2020, 11, 7807-7812], a new class of polymers structurally analogous to polyureas, are gaining attention in organocatalysis and medicinal chemistry. It is essential to have a fundamental understanding of poly-N, N’-disubstituted sulfamides to facilitate their wider commercial applications as replacements of polyureas. In this talk, we present a collaborative computational and experimental study of polysulfamide chains and their assembly driven by hydrogen bonding interactions between the sulfamide groups. We first share our newly developed coarse-grained (CG) model of polysulfamide that captures the directionality of inter-chain hydrogen bonds between sulfamide groups and allows us to study self-assembly of polysulfamide chains in molecular dynamics (MD) simulations. These simulations link the contour length, bulkiness, and flexibility of the N, N’-substituents on either side of the sulfamide groups to the morphology (e.g., positional and orientational order) of the polysulfamide assembly. We validate our CG model and simulation approaches by showing that the MD simulation results agree with the trend in assembly crystallinity for various aliphatic and aromatic N, N’-substituent chemistries measured by X-ray diffraction (XRD) and infrared (IR) in experiments. We then use the validated computational approach to explore new substituent chemistries and study the effects of substituent length and bulkiness on morphology of polysulfamide self-assembly, with the predictions tested against additional experimental syntheses and characterizations.

Biomimetic bone regeneration remains a major challenge because of limited understanding of protein-controlled biomineralization to form oriented architecture at molecular level. During the study of an intrinsically disordered peptide (IDP) containing phosphoserine and pyrene, we unexpectedly found that calcium ions transform the IDP from nanoparticles to self-oriented filaments via hierarchical self-assembly. HAADF confirms the interaction between strontium and phosphate in the filaments. Cryo-EM structure reveals that the hydrophobic pyrene forms the structured core and the IDP constitutes the flexible periphery of the helical nanofibers. These results indicate that calcium ions interact with flexible periphery of the nanoparticles to form fibrils and enhance interfibrillar interactions to form oriented filaments. To further understand the roles of the IDP for forming filaments, we synthesized analogs with controlled phosphorylation site, hydrophobic interactions, sequences, chirality, and mode of pairing to evaluate the significance in forming oriented filaments. The results confirm that noncovalent pairing, phosphoserine, and a proline residue prior to phosphoserine in the IDP are critical for the formation of the oriented filaments. Combining cryo-EM structural elucidation and molecular engineering, this work illustrates a useful model system based on strong hydrophobic interactions and IDPs for understanding and mimicking the initiation of phosphoprotein-controlled biomineralization.

Porous metal structures can be applicable in wide range of fields including electrochemical or acid-base catalyst, heat dissipation, and bio filtration. Porous template mediated metal structures have higher surface area (1 m²g^-1) than pure metal structures. Though the template method has been advanced rapidly using starch gel, dextran, pumice, and alumina, sacrificial template method has been seldom investigated. Here, sponge-like porous Au structures were synthesized using agarose gel, HAuCl₄, and NaBH₄ as sacrificial soft template, Au precursor, and reductant with simple heating method. First, agarose gel has a 3D cross-linked pore structure, which is easy to control the porosity, shape, and scale. This implies that the use of agarose as a soft sacrificial template enables synthesis of pure Au sponges with purposed porosity and shape. To synthesize the porous Au structure, agarose gel was formed by mixing agarose with water at elevated temperature around 95 °C. The Au precursor was penetrated into the agarose gel by a capillary force at room temperature for 18 h in a sealed container. The metal ions were easily soaked into the 3D pores of agarose gel, as it has hydrophilic characteristics, which supply high loading amount of metal. The metal ions in agarose gel was reduced by NaBH₄. The agarose is composed of many aldehyde groups, which promotes the reduction of metal ions ad nucleation of metal clusters. Because of the reduction of Au ions in the pores of agarose, the agarose was getting darkened. The resulting Au-filled agarose gel was dried at room temperature and calcined for 5h at various temperatures to remove the agarose template and to form 3D Au structure. To understand the decomposition behavior during calcination step, thermal gravimetric analysis (TGA) was conducted. The weight loss observed from 200°C to 550°C by the decomposition of agarose template and the weight loss was around 80.5 wt %, which implies that the approximately 19.5 wt % of pure Au was formed in agarose gel. To investigate the structural change depending on the temperature, the Au-agarose bi-continuous structure was calcined at various temperatures of 200, 300, 500, 70, and 800 °C for 5 h. The porous Au showed continuous interconnected open-pore structure maintaining the intrinsic porous nature of the agarose matrix under 500 °C. In addition, the EDS showed that the synthesized Au had negligible impurities. However, the Au nanoparticles were aggregated showing dough-like structure without pore at the temperatures greater than 500 °C. The chemical states of the Au structure calcined at 200 °C are identical to that of pure Au crystal, demonstrating peak of Au (0) 4f_7/2 and Au (0) 4f_5/2 at 83.5 eV and 87.2 eV. The crystal structure of the Au sponge was also examined by XRD and Rietveld refinements. The measured lattice distance was 4.0705 Å, which is similar value to that of bulk Au (4.07 Å) calculated by DFT calculations. The chemical features at the interface between Au and carbon from agarose were investigated using TEM-EELS analysis. The EELS spectra of agarose template are identical to that of amorphous carbon with two peaks at 285 eV, and 290 eV, corresponding to the transition energy to the π* and σ* molecular orbitals of sp² bonds. Near the Au-carbon interface, slight peak shift of amorphous C signal was observed, indicating negligible interaction or bonding between Au and agarose template. In the Au region, the EELS spectra demonstrated strong localized electron energies. Based on the above results, the agarose template takes an excellent roll as a sacrificial template providing porous structure without interaction with Au nanoparticles and retaining the porous structures of Au sponges. In summary, the agarose is highly attractive material for the production of macroporous pure metal sponges with simple heating method. Furthermore, agarose gel is nature abundant, bio-degradable, and mechanically strong compared with other natural polymers.

The unusual structure and property of supercooled liquid metals have baffled scientists for decades. Unravelling the origin of the structural ordering in supercooled liquid gallium (Ga) has been a great scientific quest due to the recent emerging applications of liquid metals in soft electronics and sustainable energy. Hitherto, the liquid crystal (LC) properties of liquid gallium and eutectic gallium-indium have remained elusive. Here, reflective polarized optical microscopy on liquid Ga sandwiched between two glasses treated with rubbed polymers reveals the onset of an anisotropic reflection at 120 °C that increases on cooling and persists down to room temperature or below. The polymer rubbing usually aligns the director of thermotropic liquid crystals (LCs) parallel to the rubbing direction. On the other hand, when liquid Ga is sandwiched between substrates that align conventional LC molecules normal to the surface, the reflection is isotropic, but mechanical shear force induces anisotropic reflection that relaxes in seconds. The anisotropic response of the cell under the influence of mechanical force results in realignment of the aligned structure. Such alignment effects and shear-induced realignment are typical to conventional thermotropic LCs and indicate a LC structure behavior of liquid Ga.
Albeit, powder X-ray diffraction (PXRD) measurement conducted on the liquid gallium shows a downward shift of sharp peaks during heating above 70 °C in a glass capillary, the diffraction pattern cannot be indexed for any known gallium oxide or gallium hydroxide phase structure. Thus, the diffraction result could be attributed to a fluidic smectic behavior of the Ga clusters or plate-like structures in the supercooled liquid with layer arrangement. The characterization of the lamellar structure via atomic force microscopy was employed to measure the layer thickness of the nanometer-thick transparent films. We have exfoliated transparent lamellar films of tens of nanometer by the use of PDMS and clean glass surfaces at RT. The liquid-phase exfoliated transparent lamellar layers are obtained with thickness up to 120 nm, and parallel to the PDMS surface. Specifically, Ga textures obtained by atomic force and scanning electron microscopy reveal the existence of a lamellar structure corresponding to a smectic LC phase, where the nanometer-thin lamellar structure is transparent under transmission polarized optical microscopy. Counterintuitively, the molecular behavior of LC-Ga enabled electro–optics switching, where an anisotropically reflecting state was induced via the application of 1.8 V µm⁻¹ (DC) electric field at RT in between two ITO-coated glasses separated by 10 µm. Moreover, the homeotropic ITO cell was prepared by a polyimide (PI) polymer coating in which the electro–optical switching was realized by applying a square wave-alternating field (AC) of 1.9 V µm⁻¹ at 0.5 and 1 Hz across the cell.
Such spatial molecular arrangements may be attributed to dimer or plate-like molecular entities in the supercooled liquid Ga. The LC structure observation of electrically conductive liquid Ga can provide new opportunities in materials science, energy and LC applications.

Does a rotating bead always spin in place? Not if that bead is small and near a surface: in this case, rotating leads to translational motion, as well as fast flows around the bead, even quite far away. These flows cause strong hydrodynamic coupling to nearby microrollers (rotating beads), which leads to a rich variety of collective effects. This system is experimentally realized by using magnetically actuated colloidal particles, and we find that these collective effects manifest as a wide array of emergent structure from shocks, to fingering patterns, to stable, hydrodynamically-bound clusters. We study these emergent structures using a variety of computational and experimental techniques, including Stokesian dynamics simulations and a coupled magnetic-optical imaging system. We find that in all cases, the scale of the emergent structures is set by a single geometric parameter: the height of the microroller above the surface. Recently, we have begun to study the interaction of microrollers with a structured environment, for example a forest of fixed obstacles or a sea of passive particles. In the case of fixed obstacles, we find a strong hydrodynamic trapping effect occurs in our experimental system, and we have used our simulation methods to characterize this trapping in detail. When the obstacles are free to move, we observe that the microrollers restructure the landscape around them, at length scales many times the size the roller.

Colloids are outstanding model systems for the studies of phase transitions and related phenomena because Brownian motions of micrometer sized particles can be tracked by optical microscopy. Colloids with tunable attractions open the way to study solids’ free surfaces. Here we experimentally observed three surface wetting phenomena at the single-particle level for the first time: premelting of crystal and glass, and pre-solid-solid transition. The latter two phenomena are proposed by us.
1. Crystal surface typically premelts into a thin liquid layer slightly before reaching the melting point. We find that the thickness of the premelted surface liquid diverges as a power law (i.e. complete premelting) for monolayer colloidal crystals, whearas saturates to a constant (i.e. blocked premelting) for bilayer and trilayer crystals [1]. Such behaviors are verified by simulation [2].
2. We propose that a crystal’s surface can develop a thin layer of polymorphic crystal when the two crystals can form a coherent interface near their crystal-crystal transition point. We coin the word ‘pre-solid-solid transition’ because it is analogous to premelting or prefreezing with the same wetting mechanism: the total energy of the newly formed two interfaces is lower than the surface energy of the original solid. Although its mechanism is simple and should certainly hold, it is a blind spot in material science and can be viewed as the third type surface wetting precursor of phase transition. This phenomenon is confirmed by colloid experiments and simulations. The thickness of the surface crystal increases with the temperature as a power law, similar to premelting. It can also occur in nonequilibrium processes such as melting, crystallization and polycrystal annealing. We suggest several atomic and molecular crystals which may exhibit such phenomenon. Moreover, pre-solid-solid transition and premelting and can coexist under thermal equilibrium when two triple points are close [3].
3. Glass melting has been poorly explored experimentally at the single-particle level. We assemble monolayer and multilayer colloidal glasses by vapor deposition such that they are sufficiently stable to melt from the surface. Structural and dynamic parameters reach their bulk values at different depths, which define a surface liquid layer and an intermediate glassy layer. The thicknesses of both layers increase in power laws upon approaching the glass transition point by slow heating, similar to crystal premelting. This circumvents the ambiguity in distinguishing supercooled liquid and glass. Such power-law behavior has been reported in polymer glass melting, but was not called as premelting. Moreover, melting is studied by rapidly changing temperature across the glass melting temperature, and the melting front behaviors are similar to crystal melting [4].

[1] B. Li, et al. Modes of surface premelting in attractive colloidal crystals, Nature, 531, 485 (2016).
[2] X. Wang, et al. Surface roughening, premelting and melting ofmonolayer and bilayer crystals, Soft Matter, 17, 688 (2021)
[3] X. Wang, et al. Polymorphic crystalline wetting layers on crystal surfaces, submitted,
https://doi.org/10.21203/rs.3.rs-910546/v1
[4] Q. Zhang, et al. Surface premelting and melting of colloidal glasses, submitted,
https://doi.org/10.21203/rs.3.rs-1633832/v1

We experimentally investigated the rheology of confined granular suspensions during shear-thickening transitions. When the shear dimensions are reduced to tens of particle diameters, the dense suspensions show unexpected flow behaviors across multiple length scales in response to the physical confinements. On macroscopic scales, the stress-controlled shear rheology was highly dependent on the measuring time for each applied shear stress, and S-shaped flow curves were observed at steady states. At microscopic levels, by using boundary stress microscopy (BSM), we observed sustained local stress oscillations with a time interval of approximately twice the global rotation period of the shear plate. The temporal fluctuations were also associated with a dynamically evolved phase separation, which indicated the migrations of high-stress regions involving locally jammed suspensions. We further show that the non-monotonic flow curves and local stress oscillations will simultaneously reduce as the system size increases. The study shows how boundary confinements can induce sustained mechanical phase separation in dense suspensions, and therefore controls their global rheological properties.

Current electronics are inextricably linked to the carrier transport properties of
semiconducting materials. Novel requirements from wearable and ubiquitous computing applications, however, have highlighted the limitations of such materials in terms of scalable production, robustness, and achievable performance. We here demonstrate that complex electronic functionality can be achieved without the use of semiconductors. By controlling the connectivity 20 between metallic particles, emergent structures can be realized that exhibit directed carrier transport – a hallmark of semiconductor devices. Experimental realization of this prediction was
achieved in concentration gradients of percolative metal assemblies, where spatial changes in the number of neighbors produces distinct differences in conduction properties for carriers traveling with or against the direction of increasing concentration. This directed percolation process was 25 observed in both aqueous particle dispersions and solid-state particle/polymer composites and yielded electronic devices with performances comparable to conventional semiconductor diodes. Connectivity-controlled assemblies provide attractive alternatives to semiconductors due to their robustness, high carrier mobility and tunability of fundamental device properties. The underlying ratchet-like rectification process unexpectedly imparts metallic assemblies with sensitive light 30 detection abilities and opto-mechanical multifunctionality. Our advances not only open up a route
towards the ultra-large-scale production of future electronics but shed light at a century-old question about the foundation of electronic functionality.

The most brilliant colours in nature are obtained by structuring transparent materials on the scale of the wavelength of visible light. By designing the dimensions of such nanostructures, it is possible to achieve extremely intense colourations over the entire visible spectrum without using pigments or colorants. Colour obtained through structure, namely structural colour, is widespread in the animal and plant kingdom. Such natural photonic nanostructures are generally synthesised in ambient conditions using a limited range of biopolymers. Given these limitations, an amazing range of optical structures exists: from very ordered photonic structures, to partially disordered, to completely random ones.
In this seminar, I will introduce some striking examples of natural photonic structures and share some insight on their development. Then I will review our recent advances to fabricate bio-mimetic photonic structures using the same material as nature. Developing biomimetic structures with cellulose enables us to fabricate novel photonic materials using low-cost polymers in ambient conditions. Importantly, it also allows us to understand the biological processes at work during the growth of these structures in plants.

Ordered crystalline mesoporous metal oxides and carbon materials face risks of mesostructral collapse as a result of untamed atomic migration during crystallization at high temperatures and long hours. We introduce a facile approach combining block-copolymer-directed self-assembly with electric Joule heating (SNAP method) to realize ultrafast crystallization of various ordered nanocomposite systems, including Al₂O₃-carbon, Al₂O₃/MgO-carbon, TiO₂-carbon, Fe₂O₃-carbon and carbon structures. Removing the carbon matrix yields fully inorganic ordered Al₂O₃ and TiO₂ structures. SNAP-derived ordered oxide and oxide-carbon structures samples exhibit high CO₂ capture and efficient Li-ion battery performances than their furnace-treated counterparts. The SNAP method enables high energy efficiency and time savings and generalizability to other functional materials combinations that would appeal to a wide range of applications such as catalysis, sensing and clean energy generation.

Nanomedicine is an emerging and fast-growing field in which the application of nanotechnology to healthcare offers numerous improvements to medical diagnosis, therapy, etc. The design and development of novel fluorescent nanomaterials for biomedical applications have become one of the most important aspects of nanomedicine and have attracted increasing research interest. Previous studies have mainly focused on fluorescent inorganic nanoparticles, such as fluorescent carbon dots, metallic nanoclusters, etc. The major issues for their practical biomedical applications, especially in vivo applications, are still challenging, mainly due to their notorious toxicity to living organisms. As alternative nanomaterials for various biomedical applications, fluorescent organic nanoparticles have emerged and gained significant interest because of their various interesting optical properties, facile fabrication, and excellent biocompatibility. However, the fluorescence of most conventional organic dyes is quenched in the aggregate state or at high concentration, which is named aggregation-caused quenching (ACQ). This ACQ effect seriously hampers their potential applications in nanomedicine, such as bioimaging, diagnosis, and therapy. By contrast, aggregation-induced emission luminogens (AIEgens) are weakly emissive when molecules are uniformly dispersed in solution but “light up” when forming (nano)aggregates. With the significant advantages of high emission efficiency in the aggregate state, low background noise in dilute solution, excellent photostability, and large Stokes’ shift, AIEgens and AIE nanoparticles are especially suitable for bioimaging, diagnosis and therapy. AIEgens with various skeletons are designed as superior agents for biological process monitoring and disease theranostics. Moreover, AIEgens and AIE nanoparticles can be conveniently incorporated into the present theranostic platforms by combining them with various imaging and therapeutics modalities, such as multiphoton imaging, photoacoustic imaging, photothermal imaging, chemotherapy, photodynamic therapy, photothermal therapy, gene therapy, etc.
[1] Mei, J.; Leung, N. L. C.; Kwok, R. T. K.; Lam, J. W. Y.; Tang, B. Z. Chem. Rev. 2015, 115, 11718-11940.
[2] Gu, X.; Kwok, R. T. K.; Lam, J. W. Y.; Tang, B. Z. Biomaterials 2017, 146, 115.
[3] Qian, J.; Tang, B. Z. Chem 2017, 3, 56-91.
[4] Qi, J.; Chen, C.; Ding, D.; Tang, B. Z. Adv. Healthcare Mater. 2018, 1800477.
[5] Shen, H.; Xu, C.; Sun, F.;Zhao, M.; Wu, Q.; Zhang, J.; Li, S.; Zhang, J; Lam, J. W. Y.; Tang, B. Z., ChemMedChem 2022, 17, e202100578.
[6] Zuo, Y.; Shen, H.; Sun, F.; Li, P.; Sun, J.; Kwok, R. T. K.; Lam, J. W. Y.; Tang, B. Z., ACS Bio & Med Chem Au 2022, 2, 236-257.

The remarkable optomagnetic properties of the lanthanides (Ln) make Ln-based materials ideal for biomedical applications, including diagnostic (for instance, imaging or thermal sensing) and therapeutic (for instance, drug delivery and photodynamic therapy) approaches. This is due the unique electronic properties of the Ln (f-elements) allowing for upconversion and near-infrared emission under near-infrared excitation as well as high magnetic moments.
Sodium lanthanide fluorides (NaLnF₄) are our favorite materials, and we developed a fast and reliable microwave-assisted synthetic approach allowing crystalline phase and size control in the sub 15 nm realm. Such control is crucial for the understanding of fundamental structure-property relationships and to optimize their optical and magnetic properties, when aiming for the design of next-generation optical probes or contrast agents for magnetic resonance imaging (MRI). For instance, NaGdF₄ nanoparticles (NPs) are gaining interest as alternative MRI contrast agent, while co-doping with emitting Ln³⁺ ions endows the NPs with luminescent properties for applications as optical probes. The hexagonal crystalline phase of NaGdF₄ is known as the more efficient host material for upconversion emission (i.e., the emission of one higher energy photon following excitation with two or more lower energy photons). In contrast, we observed that the cubic phase of NaGdF₄ shows superior performance as MRI contrast agent.
Having a fast and reliable synthetic route towards NaLnF₄ NPs on hand, we now explore various nanoparticle architectures and compositions with the goal to optimize their optomagnetic properties, ultimately resulting in the design of biocompatible multimodal bioprobes. This includes MRI contrast agents based on Gd- and Dy-containing NPs, and novel near-infrared emitters based on Ho or Pr for deep tissue optical bioimaging under near-infrared illumination, matching the biological transparency windows. In this presentation, we will also have a look at luminescent NaLnF₄ NPs with various surface-modifications and the suitability of hyperspectral imaging to study their nano-bio interactions.

Trivalent lanthanide (Ln³⁺)-based nanoparticles (NPs) are outstanding candidates for a wide range of sensing, imaging, diagnostic and therapeutic applications. Characterized by an incomplete 4f shell shieled by the outer 5s² and 5p⁶ shells, the influence of the host lattice and surrounding environment on the optical properties of lanthanide ions is minimized. This results in long excited-state lifetimes and narrow absorption and emission bands that favour the use of excitation wavelengths in the near-infrared (NIR) region and leads to the emission of light in the ultraviolet (UV), visible, and NIR regions. By tailoring the choice of Ln³⁺ dopants, NIR-to-NIR wavelength conversion becomes possible, allowing for both the excitation and emission wavelengths to be compatible with the so-called biological transparency windows (NIR-I to NIR-III: 700 to 1870 nm). These optical properties make Ln³⁺-based NPs favorable fluorescent probes for biological and biomedical applications. The use of NIR light is of particular interest for overcoming some of the limitations of conventionally used organic molecular fluorescent probes, which require excitation with UV light, including photobleaching, tissue autofluorescence, phototoxicity and limited tissue penetration depths. NIR light matching the biological transparency windows suffers from less scattering and absorption by water and biological tissues, which in turn improves spatial resolution and sensitivity and allows for deeper light penetration depths. Current and past research efforts have primarily focused on the development of fluorescent materials that emit at wavelengths longer than 1000 nm in the NIR-II (1000 to 1350 nm) and NIR-III (1550 to 1870 nm) region, under excitation with NIR-I light (700 to 950 nm). Recently, a fourth biological window (NIR-IV) has been suggested, centered at 2200 nm, but there still presents a significant lack of optical probes, specifically at the nanoscale.
To close this gap, here, we propose novel Ln³⁺-doped NIR-IV emitting NPs to open the fourth biological window for exploration. Using the fast and reliable microwave-assisted thermal decomposition method, NIR-IV emitters praseodymium (Pr³⁺) or holmium (Ho³⁺) and sensitizing ytterbium (Yb³⁺) and/or neodymium (Nd³⁺) were doped into sodium rare earth fluoride (NaREF₄) host lattices to form sub-15 nm NPs. Co-doping with Yb³⁺ allows for 980 nm NIR excitation, while the absorption and scattering of the excitation light by biological tissues can be further reduced when using 808 nm excitation, which is achieved through co-doping with Nd³⁺. This presentation will shed light on the influence of NP composition, surface chemistry, and aqueous versus non-aqueous media for NP dispersion on the optical properties, i.e., sought after NIR-IV emission. Seeking potential biomedical (and beyond) applications, we further assessed the performance of these NIR-IV emitters as nanothermometers. Optical thermal sensing allows to extract information on the local temperature of a given system at the nanoscale, including thermal irregularities related to various diseases. Overall, the developed NPs are highly promising to open the fourth biological window for imaging and sensing, and thus, potential innovative biomedical applications.

Light is used in a wide range of biotechnologies, such as fluorescence imaging and optogenetics, yet a critical challenge of applying light in vivo arises from the poor penetration of photons in biological tissue due to scattering and absorption. Therefore, delivering photons deep into the body from an external light source requires invasive procedures, such as craniotomy, to surgically remove overlying tissues. Besides conventionally used external light sources, trap-engineered materials with persistent luminescence (PerL, as known as afterglow) and mechanoluminescence (ML) represent an arising opportunity for light delivery in deep tissue owing to their ability to store photon energy in their host structures. However, materials with strong short-wavelength PerL and ML are usually bulk particles (> 10 μm) synthesized via solid-state reactions at > 1000 ^oC to facilitate uniform doping and desirable polymorphs. Their large sizes prevent the formation of stable colloids in aqueous environment and prohibit their biological applications.
To address this challenge, here we report a bioinspired demineralization (BID) approach to synthesize stable colloidal solutions of solid-state PerL and ML nanoparticles with tunable wavelengths and remarkable luminescence intensity. Specifically, the BID approach is inspired by the strategy of biomineralization in nature: Biominerals, such as apatite in the dental enamel, can be gradually dissolved to nanostructures in a mildly acidic environment yet are resistant to further dissolution. This unconventional dissolution process, unlike the self-accelerating dissolution of soluble salts, is facilitated by the formation and growth of pits on the surface. The low solubility and thus high interfacial tension of biominerals results in a large critical size of 10 to 100 nm, below which the growth of dissolution pit is kinetically suppressed. In the BID approach, we demonstrated that sparingly soluble solid-state PerL and ML particles, similar to biominerals, also exhibited kinetically suppressed dissolution. Specifically, we used a citrate buffer to mimic the undersaturated environment and produce colloidal nanoparticles down to 20 nm from their solid-state precursors with emission wavelengths covering the entire visible spectrum, including Sr₂MgSi₂O₇:Eu,Dy (470 nm), Sr₄Al₁₄O₂₅:Eu,Dy (490 nm), ZnS:Cu,Al (534 nm), ZnS:Mn (578 nm), CaTiO₃:Pr (610 nm), and Ca_0.85Sr_0.15S:Eu,Tm (650 nm). Furthermore, these BID-produced nanoparticles can be stably suspended in aqueous solution, while preserving the optical properties of their solid-state precursors, including strong PerL or ML intensities.
Additionally, we demonstrated the utility of BID-produced colloids in biology via excitation-free imaging and ultrasound-mediated non-invasive optogenetics. On one hand, owing to their exceptionally bright luminescence, BID-produced PerL nanophosphors exhibited the highest signal-to-background ratio for in vivo imaging among reported materials, and yielded the first example of transcranial afterglow imaging of cerebral vessels in the mouse brain. Furthermore, the bright short-wavelength PerL nanophosphors acted as an intravital light source and provided internal excitation for genetically encoded fluorescent reporters in a mouse brain through the intact skull, thus enabling afterglow imaging of fluorescent proteins for the first time. On the other hand, the BID-produced ML fluids acted as an ultrasound-mediated light source in the body after systemic delivery. We were able to visualize the ultrasound-mediated light emission from the ML fluids in the vascular systems of multiple mouse organs (including brain, liver and kidney) for the first time, and used this light emission for non-invasive optogenetics stimulation in transgenic mice expressing light sensitive ion channel ChR2. The manuscripts based on these results were recently published in Sci. Adv. (DOI: 10.1126/sciadv.abo6743) and JACS (DOI: 10.1021/jacs.2c06724).

General context
Cancer is one of the major societal issues of the century . Even if several strategies of treatments exist, the conditions of life of the patient during and after the treatment are deteriorated by side effects of heavy therapies such as radiotherapy (use of X rays of High energy). The need to propose new strategies of therapies is therefore of great interest.
Introduction
We are aiming at a technology that will ensure efficient treatment of cancer with low side effects, allow to perform accurate diagnostic and give access to in situ monitoring of the treatment. Our goal is based on the association of two cutting-edge technologies: spectral photon counting scanner CT (SPCCT) which is a ground-breaking imaging modality and a new X-ray based treatment known as X-rays activated Photodynamic Therapy (X-PDT). The perfect match between these two technologies will be ensured with specifically designed nanoprobes probes acting both as contrast media and therapeutic agents(1).

The possibility to use new treatments such as XPDT is raising a great interest. PDT alone is a clinically approved cancer treatment but, the strong absorption of light by tissues limits its use to rather superficial tumors. X-PDT is a new technology involving the same mechanisms but spreading the potential of this treatment. The principle of XPDT is to irradiate with low energy X-Rays hybrid nanoprobes consisting in an inorganic core functionalized with organic moieties (Photosensitizers-PS). Upon excitation the inorganic particle will emits light (scintillation) which will be absorbed by the PS. The latter will reach an excited state, making it able to react with surrounding oxygen and leading to the production of reactive oxygen species able to kill tumor cells.(2)

Spectral Photon Counting Computed Tomography (SPCCT) is a new imaging modality, currently in development. The SPCCT scanner is an evolution of the conventional CT scanner, with a totally new type of detection chain designed to provide high count-rate capabilities while offering energy discrimination with high spatial resolution. Its main asset is the ability to map and quantify elements based on their K-edge. For that modality, the traditional iodine based contrast agents are not particularly suited due to iodine’s K-edge being outside the clinical X-ray spectrum, the use of new types of contrast agents is therefore necessary. (3)
Results
Based on our previous works on the design and surface modification of lanthanide fluoride nanocrystals (4) we describe the design of hybrid terbium (III)-doped gadolinium fluoride nanoparticles (NPs) which act as contrast media for spectral CT scanner and show scintillation properties (emission of light under low energy X-rays excitation). These nanoparticles can be considered as interesting nanoplatforms for further development related to X-Rays based imaging and treatment.
This presentation will first aim to highlight the results obtained concerning the luminescent properties of NPs under UV and X-ray excitation and their properties as contrast agent for spectral CT scanner (5). It will also describe the different strategies of surface modification for biocompatiblity and their effects on the optical properties of NPs. The proof of concept of the use of the nanoparticles as contrast agent in vivo as well as their ability to emit light when submitted to X-rays will be demonstrated. Finally, the functionalization of NPs by a PS will be discussed and results about in cellulo studies and singlet oxygen generation will be described.
Bibliography
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(4) F. Chaput, et al., Langmuir (2011), 27, 5555. / S. Karpati et al., Nanoscale 2020, 13, 3767. / A.L. Bulin et al., Adv. Sci., 2020, 7, 2001675. / V. Hubert et al., Adv. Sci, 2021, 17, 2101433 /
(5) N. Halttunen et al., Scientific Reports (2019), 9, 12090

Over the last 20 years, our laboratory has focused on the designed chemical synthesis, assembly and medical applications of uniform-sized nanocrystals. We demonstrated that ceria nanoparticles and ceria–zirconia nanoparticles can work as therapeutic antioxidants to treat various nasty diseases, including ischemic stroke, Alzheimer’s disease, sepsis, and Parkinson’s disease, rheumatoid arthritis, and radioprotectants.¹ We developed a click reaction-assisted immune cell targeting (CRAIT) strategy to deliver drug-loaded nanoparticles deep into tumor interiors, reducing tumor burden in an aggressive 4T1 breast cancer model without any systemic toxicity.² We synthesized MnFe₂O₄-anchored mesoporous silica nanoparticles to overcome hypoxia, and consequently enhancing the therapeutic efficiency of photodynamic therapy.³ We reported a heterogeneous chemodynamic therapy system based on copper-iron peroxide nanoparticles (CFp NPs) for tumor microenvironment-mediated synergistic cancer therapy.⁴ We report a highly sensitive and selective K⁺ nanosensor that can quantitatively monitor extracellular K⁺ concentration changes in the brains of freely moving mice experiencing epileptic seizures.⁵
We fabricated ultraflexible and/or stretchable soft-electronic and optoelectronic devices integrated with various functional nanomaterials and their applications to wearable and implantable medical and healthcare devices.⁶ We introduced electromechanical cardioplasty using an epicardial mesh made of electrically conductive and elastic Ag/Au nanowire-rubber composite material to resemble the innate cardiac tissue and confer cardiac conduction system function.⁷ We fabricated highly conductive and elastic nanomembrane for skin electronics.⁸ We synthesized a flexible, sticky, and biodegradable electronic patch for controlled drug delivery for GBM treatment.⁹ We developed a microneedle-based delivery method of theranostic NPs and high-energy photons to treat two types of brain tumors.¹⁰ Recently, we synthesized an injectable hydrogel nanocomposite for intracortical drug delivery to treat deep-seated brain tumors.¹¹

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11. “Penetrative and sustained drug delivery using injectable hydrogel nanocomposites for post-surgical brain tumor treatment”, Submitted.

Silicon nanostructures have been attractive materials in various field due to their unique properties such as large surface area, photoluminescence, semi-conductor. Despite enormous interest, synthesis of nanoscale (<100 nm) silicon nanostructures is challenging. Herein, we present the synthesis method of silicon nanostructures under 100nm through magnesiothermic reduction by handles of silica nanoparticles composition. During pretreatment of silica nanoparticles under vacuum condition, metal (Pd, Pt, Ni)-silicide and void space in silica nanoparticles play a key role to keep structures after conversion. We identified the optical properties of the silicon nanostructures and it is looking forward to giving high performance to Bio-application.

Deep partial- and full-thickness burn injuries are complicated traumas accompanying the severe failure of antioxidation, anti-inflammation, and inherent defense mechanisms against external bacteria. Accordingly, it is required to suppress oxidative stress and promote the recovery of intrinsic defense systems in burn wound lesions, but previous topical antipyrotics have been designed to date only to prevent bacterial infections. For this reason, it is an essential task to develop new efficient topical materials that can improve the intrinsic antioxidative and cellular defense mechanisms for the effective curing of deep burn wounds. Herein, we developed ultrathin WS₂ nanosheets exfoliated and functionalized with PCL-b-PEG (2H-WS₂) in aqueous solution, exhibiting superior scavenging ability and sustainability for a wide range of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in keratinocytes. The functionalized WS₂ nanosheets were found to scavenge intracellular ROS and RNS as well as extracellular reactive species, suppressing oxidative stress in the wound lesions of mice. At the same time, the representative antioxidases, including CAT and GPx, were largely up-regulated in the presence of 2H-WS₂ nanosheets in burn wounds, improving the inherent resistance to oxidative stress. The 2H-WS₂ nanosheets also attenudated inflammatory cytokine secretion along with the inhibition of the extrinsic pathway of apoptosis in wound lesions. Moreover, the 2H-WS₂ nanosheets stimulated the production of innate antimicrobial peptides in burn wounds, enhancing the intrinsic resistance of cellular systems to external bacteria. All these integrated effects triggered by 2H-WS₂ nanosheets resulted in the successful healing of deep burn wounds. 2H-WS₂ nanosheets can be extended for the therapy of other diseases induced by oxidative stress and inflammation.

Orthopedic implants are commonly used to improve the patient’s quality of life. Titanium-based alloys are widely employed in surgical implants due to their cytocompatibility and appropriate mechanical properties. However, the most common perspective problem that orthopedists face is implant-associated infection (IAI), which can lead to serious impacts such as the need for complex revision procedures, patient suffering, and even death. These complications that arise from the poor antibacterial property of titanium implants can be addressed by introducing antibacterial components such as silver. While researchers show the application of silver particles as an efficient anti-infection agent for Ti-based orthopedic implants, most of the developed products suffer from complicated and long fabrication/modification techniques, multi-step processing, high cost, unintended alteration in mechanical properties, unstable antibacterial effect, and leaching of the silver ions. Here we offer a simple and fast two-step technique for surface modification of the Ti-based implants using laser-assisted alloying (LAA). In this work, a nanosecond Nd:Yag laser was applied via optimized laser power for alloying of the coated Ag-ink film on the Ti surface. Besides, this prompt laser processing developed a micro/nano roughness on the Ti surface which was beneficial for osseointegration and cell mineralization. The Ti-Ag LAA samples prepared using a range of laser powers (8, 16, 24, 32, and 40 W) were characterized via various techniques. The scanning electron microscopy (SEM) images showed a developed hierarchical micro/nanostructure on the LAA surfaces. Energy-dispersive X-ray mapping and X-ray diffraction (XRD) results demonstrated enhanced oxygen level and Ag-Ti alloying. The Rockwell hardness tests of the Ti-Ag showed preserved bulk hardness of the samples with an average hardness of about 31 ± 1 HRC. This observation revealed a superficial alloying of the laser-assisted method which is essential for the Ti-based implant modification. The optimized Ti-Ag LAA sample (prepared with 32 W laser power) showed over 6-fold enhancement in antibacterial effect compared to the pristine Ti sample. This antibacterial property was shown to be effective on both gram-negative (E. coli) and gram-positive (S. aureus) bacteria during the test period of 12 days. On the other hand, the cell mineralization test showed over 2-fold increase in cell mineralization of the Ti-Ag LAA as compared to the pristine Ti sample which is due to the developed micro/nano features that provide active sites for cell attachment and growth. Moreover, the antibacterial effect of the developed surface helps the natural body cells to succeed in the competition on the implant surface toward the bacterial cell. The long-lasting antibacterial properties of the prepared Ti-Ag LAA samples along with cytotoxicity as low as 5- 10 % originated from the properly anchored Ag inside the Ti structure originated from the efficient laser surface alloying.

Biomimetic nanoparticles (NPs) are known to serve as nanoscale adjuvants, enzyme mimics, and amyloid fibrillation inhibitors. Their further development requires better understanding of their interactions with proteins. The abundant knowledge about protein-protein interactions can serve as a guide for designing protein-NP assemblies, but the chemical and biological inputs used in computational packages for protein-protein interactions are not applicable to inorganic NPs. Analyzing chemical (CH), geometrical (GE), and graph-theoretical (GT) descriptors for protein complexes, we found that GE and GT descriptors that are uniformly applicable to biological and inorganic nanostructures can predict interaction sites in protein pairs with accuracy >80% and classification probability ~90%. We extended the protein-trained machine learning algorithms to inorganic biomimetic NPs and found a nearly exact match between experimental and predicted interaction sites with proteins. These findings can be extended to other organic and inorganic NPs to predict their assemblies with chemically dissimilar structures.[1]
The design principles of and predictictive capabilities of NP-protein interactions have been utilized for formation of complexes of plasmonic NPs with proteins. They enabled polarization-based drug discovery platforms for Alzheimer syndrome,[2] materials for chiral catalysis,[3] and chiral antiviral vaccines.[4]
References
[1] Minjeong Cha, et al Unifying Structural Descriptors for Biological and Bioinspired Nanoscale Complexes, Nature Computational Science, 2022, 2, 243–252.
[2] Jun Lu, et al, Enhanced optical asymmetry in supramolecular chiroplasmonic assemblies with long-range order, Science, 2021, 371, 6536, 1368.
[3] Shuang Jiang, et al. Chiral Ceramic Nanoparticles of Tungsten Oxide and Peptide Catalysis, Journal of the American Chemical Society, 2017, 139 (39), 13701–13712.
[4] L. Xu, et al, Enantiomer-Dependent Immunological Response to Chiral Nanoparticles, Nature, 2022, 601, 366–373.

While the interaction between two-dimensional (2D) materials and cell membranes is of key importance to the development of nanomedicines and safe applications of nanotechnology, still very little is known about the biological interactions of many emerging 2D materials. Here we investigate how hexagonal boron nitride (hBN) interacts with the cell membrane by combining molecular dynamics (MD), liquid phase exfoliation and in vitro imaging methods. MD simulations reveal that a sharp hBN wedge could penetrate a lipid bilayer and simultaneously form a cross-membrane water channel along its exposed polar edges, while a round hBN sheet does not exhibit this behavior. We hypothesize that such water channels could facilitate cross-membrane transport, with important consequences including lysosomal membrane permeabilization (LMP), an emerging mechanism of cellular toxicity that involves the release of cathepsin B and generation of radical oxygen species leading to cell apoptosis. To test this hypothesis, we prepared two types of hBN nanosheets, the former with a rhomboidal, cornered morphology and the latter with a round morphology, and exposed human lung epithelial cells to both hBN nanosheets. The cornered hBN with exposed polar edges resulted in a dose dependent cytotoxic effect, whereas round hBN did not cause significant toxicity, thus confirming our hypothesis. The described water channel mechanism suggests various applications including the development of hBN-based drug delivery systems and safe design of future advanced hBN containing composites and devices.

Statement of Purpose: Arthritic disorders are a leading cause of disability worldwide¹. Current treatments result in unsatisfactory outcomes due to the lack of specificity, fast clearance, and inability to penetrate biological barriers. Advancements in nanotherapeutics have shown that electrostatic interactions and nano-sized particles are able to target and penetrate dense, negative tissues such as the joint cartilage². Previously, we have shown that nanoparticles (NPs) interact with proteins in the joint space, which dictate the NPs’ interactions with cells and cartilage tissue³. As it is known that NPs must interact with the cartilage extracellular matrix (ECM) proteins prior to reaching their cellular target, this study aimed to demonstrate that the NPs’ interactions with ECM can be used as a means to stabilize the tissue and reduce degradation.
Methods: A cationic NP panel that differed in size and charge was synthesized based on either poly(amidoamine) (PAMAM) dendrimers (DendritechR, Midland, MI, USA) or poly(lactic-co-glycolide) (PLGA; ResomerR, Essen, Germany) polymer particles (formulated by nanoprecipitation) decorated with either PEG or polyethylenimine (PEI)-PEG modifications. All particles were fluorescently labeled with FITC. NP size and charge were characterized by dynamic light scattering (DLS) as well as electron microscopy. To mimic the thickness of human cartilage, porcine articular cartilage explants were used in this study, and subjected to arthritis-relevant enzymes such as ADAMTS5 for 1 or 2 hours, followed by NP treatment of equivalent duration. Released ECM components including sulfated glycosaminoglycans (GAGs) were assessed by colorimetric assays and polyacrylamide gel electrophoresis (PAGE). NP tissue uptake was evaluated by confocal microscopy, while aggregate formation and tissue topography were determined by atomic force microscopy (AFM). The interactions between the NPs and ECM proteins were evaluated by isothermal titration calorimetry (ITC) and quantitative proteomics.
Results: Physicochemical characterization of PAMAM particles revealed sizes of 7.2 nm and 11.0 nm and zeta potentials of +17.0 mV and +4.0 mV for non-PEGylated and PEGylated NPs respectively. Control PLGA-based NP size varied between 270 nm and 264 nm with their respective zeta potentials exhibiting +22.2 mV and +3.78 mV. By treating porcine explants with the different particles after enzymatic stimulation, we measured a reduction of GAG concentration in the supernatants after 2- and 4-hour treatments compared to the control. To investigate the level of engagement between the particles and the tissue, we tracked the fluorescently labeled NPs using confocal fluorescent microscopy. To further analyze the specific interactions with the ECM proteins and individual NPs, proteomic analysis revealed several highly abundant integrity-associated proteins that could account for the NP-matrix stabilization interactions including proteoglycans such as biglycan and fibromodulin, as well as collagen-binding proteins such as matrilins that are essential for tissue integrity.
Significance: Soluble GAG concentration was inversely correlated to particle cationic charge, suggesting an effect based on electrostatic interactions with the anionic ECM components. NPs are usually studied as carriers for drug delivery applications, yet their physicochemical effects on the ECM are rarely reported. This study aims to be the first to demonstrate that interactions between cationic NPs and ECM components such as anionic GAGs can result in cartilage tissue stabilization in the catalytic proinflammatory arthritic environment.

References:
1. Allen K. D. N. C. Med. J. 2017, 78 (5), 306–309.
2. He T. J. Control. Release 2020, 318, 109–123.
3. von Mentzer U. Osteoarthr. Cartil. 2022, 30, 88-89.

The interaction between engineered nanostructures and biomolecules experiences to the improvement of advanced types of biosensors and biomolecular targets. Bio physiochemical reactions take place at the interface between inorganic nanostructures and biomolecules. So, it is very important to understand the surfaces and interfaces of the nano-bio conjugates. Highly Raman and PL active nanostructures of ZnO and highly Raman active DNA bases are chosen for the investigation of nano-bio interaction. ZnO nanostructures with varying annealing temperatures are synthesized using the hydrothermal method. The molecular level interaction at the interface has been investigated. The molecular level interaction at the interface has been investigated by using X-Ray Diffraction, Raman spectroscopy, Photoluminescence (PL), and Scanning Electron Microscopy (SEM). A visible green emission in the photoluminescence spectrum, mainly associated with the oxygen vacancies on the surface of the ZnOostructure area (4.6x107 cm2 to 7.6x105 cm2) is significantly reduced by the incorporation of cytosine and thymine biomolecules. Notable reduction of peak area and relative peak position of some of the cytosine (from 3062 cm-1 to 3109.9 cm-1) and thymine (from 420.7 cm-1 to 432.2 cm-1 at 400oC and 477.0 cm-1 at 500oc) and ZnO nanostructures in Raman spectra referred to the direct binding energy between this two nano and bio-components. Calculation of molecular bond force constants from Raman spectroscopy also reinforces our above-mentioned results. SEM images reveal that there are no noticeable changes in the morphology of ZnO nanostructures and cytosine and thymine biomolecules with varying temperatures. Scanning electron microscopy clearly shows the binding onto the ZnO nanostructures, which is also confirmed by electron dispersive X-ray spectroscopy (EDS) studies. We are convinced that Raman spectroscopy studies are informative in probing the bonding characteristics at the nano-bio interface and can be used elegantly for other nano-bio interactions. This study will also allow us to make more insightful decisions regarding the interaction kinetics in structurally related nano-bio junctions. Therefore, an interpretation of the nano-bio interface can be drafted and investigated.

In recent years nanomaterials have found a widespread application in material science, pharmaceutical, biomedical and medical fields. Various nanomaterials are applied, as well as in development, as high effective drugs or as drug delivery agents for targeted treatment, including cancer, viruses and etc. Here we show how the combination of computational chemistry, data mining and cheminformatics approaches can help in assessment of toxicity and virtual screening of fullerene nanostructures for combined drug-like and toxicity properties. We demonstrate how the combination of inverse molecular docking, quantum chemistry and machine learning methods can be applied to investigate these nanostructures. A high-throughput virtual screening was applied to both large set of fullerene nanostructures and known biological targets (human proteins), to assess binding scores and to investigate the potential interactions with biological targets. We show several case studies, including analysis of aquatic toxicity of fullerene derivatives, since it is crucial to understand their fate in the environment, particularly their effects on aquatic organisms. Regression models were built and artificial neural network algorithms were applied for property prediction and screening FDs for structural features responsible for binding activity and then highlighted the most active fulleren derivatives that may have the greatest impact on aquatic organisms.
The outcome of this study has the potential to reveal which structural features of fullerene nanostructures have the main impact on toxicity, to be able to decide what fullerene derivatives should be prioritized first. This will help to decrease the need for animal testing and make decisions on applications in advance of manufacturing.

In the modern era, the anti-bacterial efficacy of surgical implants in the body is attracting great attention. The method is to modify the surface of the implant to reduce the adhesion of bacteria to limit the formation of a biofilm or, on the other hand, to coat the implant with a functional material that kills the surrounding bacteria. However, most of these research results are difficult to mass-produce, or there are hurdles in practical application as materials that have not yet received FDA approval in the human body. In the case of the SLIPS surface, which has recently attracted attention, its excellent effect has been demonstrated by applying a physical barrier that bacteria cannot settle. However, in the case of an actual infection model, not only the problem of biofilm formation on the surface, but also the occurrence of infection around the implant, so simply a physical barrier on the surface cannot prevent the deterioration of the affected area. Additionally, fluoroalkyl silane used in the SLIPS method applied to implants is a material that has not yet been approved. Therefore, for practical application, the use of materials available to the human body, prevention of biofilm formation on the surface, and prevention of bacterial infection in the vicinity should be provided.
In this study, we used TiAl6V4 implant, which is currently the most used material in the medical industry, and manufactured an innovative coating that overcomes both infection models using only materials approved for the human body. In addition, SLIPS surfaces with proven superior function was fabricated, and comparison and efficacy were demonstrated through in vivo experiments.
TiAl6V4 plates were immersed in NaOH solution with 0.5 mol concentration at 180°C in the oven for formation of nanostructure. The formation of 20 nm scale structures of titanium dioxide (TiO₂) is a process of dissolution and precipitation reactions. Next, a mixture of Poloxamer 407, Octanoic acid, and EGCG was coated on the nano Ti surface. Poloxamer 407 and EGCG are mixed and placed in an oven at 100°C for about 30 minutes to liquefy. Since the mixed solution of Poloxamer407 and EGCG has a very high viscosity and is difficult to use for coating, Octinoic acid is used to dilute it.
The usefulness of titanium implant with nano-structure having a sustained-release coating of Poloxamer/Octanoic Acid both was verified in vitro and in vivo. In particular, we made a rabbit surgery model similar to fracture surgery performed in humans. We confirmed the usefulness of our coating by inducing Pseudomonas aeruginosa infection and biofilm formation. Our results confirmed that the poloxamer/octanoic acid coating material lowered the infection rate and had a low toxicity. We propose that a titanium implant with a nano surface structure having a poloxamer/octanoic acid coating could be a novel alternative for surgical metal processing.

The emergence of the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) brought a global pandemic as a result of the virus's ease of spreading and its potential to incubate in asymptomatic hosts. Coronavirus disease (COVID-19) can be developed when infected by the virus, resulting in potentially lethal respiratory distress. A human gets infected when exposed to infectious respiratory fluids. Therefore, the use s of personal protection equipment (PPE), such as masks, can protect from the direct route of infection. PPE are critical to the well-being of essential healthcare workers and the general public, reducing the spread of the virus. Given the magnitude of SARS-CoV-2 transmissibility, novel precautionary efforts are necessary to kill or halt the virus's spread even in the current pandemic or for future unknown emerging virus diseases. Recent involvements in nanotechnology have effectuated need-based virus-resistance face masks/shields developed through the addition of nanomaterial coatings or impregnating nanomaterials in the masks/shields to combat the virus and augment protection levels. We hypothesized that modifying existing PPE materials with engineered antiviral/antimicrobial nanoparticles could produce substantial improvement in the material’s efficacy in preventing transmission. The layer-by-layer (LbL) coating technique is a user-friendly and low-cost method chosen for PPE surface modification without using any acid or heat treatment. A wet chemistry method was used to synthesize the antiviral nanoparticles (<100 nm, silver, and gold). Synthesized nanoparticles added to cationic (chitosan, CHI) and anionic (poly(acrylic acid), PAA) polymer solution and co-solution were used to produce LbL coatings. Initially, PPE materials were applied to polyethyleneimine (PEI) or sulfuric acid treatment based on turning charge on the surface. The wet surface of face mask and face shield were immersed in the nanoparticles/CHI solution for 15 min followed by immersion in PAA for 15 min using the LbL coating technique. The fabricated thin films were characterized by XPS and SEM. Biological studies were performed using E. coli as a model bacterium to assess the fabricated coatings' antimicrobial activity. Coated PPEs exhibited considerable bacterial inhibition. Antiviral assays were performed with calicivirus as a model virus, and similar trends in antimicrobial results were obtained. According to these findings, silver and gold nanoparticle-based PPE coatings fabricated via LBL appear promising for COVID-19 prevention.

Gold nanoparticles (GNPs) with oxidase and peroxidase properties are great candidates for antibiotic-mimicking materials due to reactive oxygen species (ROS) production. However, the bioenzymic properties are not long-lasting due to the short lifespan of ROS and have only been observed from GNPs with a size of less than 20 nm, thus making the synthesis laborious and inefficient. Herein, GNPs with controllable size and effective ROS utilization are synthesized by an environmentally green process using natural phenols extracted from plants as the reducing and capping reagent. Functional metallic ions are chelated by taking advantage of the coordinating properties of phenols to form the versatile nanoframe (pGNP-Fe) that can self-assemble onto bacteria due to the inherent attraction rendered by phenols, and the physical pressure causes bacterial membrane damage. During internalization in bacteria, the cascade process resulting from the enzyme-like properties generates cytotoxic reactive ROS via oxidization, and the Fenton reaction enhances the antibacterial efficiency. This dual physical/chemical antibacterial process obviates the need for external antibiotics and antibacterial agents, which may otherwise pose toxicity in vivo. The fabrication strategy and materials properties described here provide insights into the design of antibioticmimicking materials based on enzymatic and physical effects.

One of the most challenges regarding wound healing is the microbial infection. It can increase healthcare cost and antibiotic resistance. At the present manuscript, the antibacterial effect of electrospun blends was reported. These ultrathin blends were designed merging polycaprolactone (PCL), polyethylene glycol (PEG) and gelatin methacryloyl (GelMA). PCL:PEG:GelMA was for the first time modified with glycidyl trimethyl ammonium chloride (GTMAC) in attempt to add a quaternary amine group. We characterized the morphology and chemical structure of the blends. Biofilms from Escherichia coli, Staphylococcus aureus and Staphylococcus epidermidis evaluated the antibacterial activity of the blends. Bacteria cells are negatively charged while the addition of the quaternary amine group in the blend caused an increasing in the reactive positive charge, killing more bacteria.

Over the past few years, silicon nitride (Si₃N₄) has gained much interest in the field of medical implant applications due to its attractive antibacterial, bioactive, and mechanical properties. Several research studies have reported that Si₃N₄ has the ability not only to inhibit the adhesion of a variety of both Gram-positive and Gram-negative bacteria without the requirement of antibiotics, but also enhance bone repair and lead to osteointegration. Due to these antibacterial and bioactive properties, combined with its excellent wear resistance, corrosion resistance, and fracture toughness, it has already been extensively used in orthopedic implant treatments including spinal surgeries and joint replacements. It is important to note that the synthetic routes leading to different surface chemistry and morphology play crucial roles on the required biological and mechanical properties of Si₃N₄. Several conventional methods such as chemical vapor deposition (CVD), physical vapor deposition (PVD), atomic layer deposition (ALD), and gas-pressure sintering have been used to synthesize Si₃N₄ for biomedical applications. However, these methods involve expensive vacuum systems and accessories, the use of toxic and extremely volatile precursor materials, multiple steps, and high temperature post-processing, which render them to be unfavorable for scalable manufacturing. To address this challenge, we have investigated the use of cold atmospheric plasma (CAP) technology to deposit Si₃N₄ coatings with a range thicknesses (100nm to 1µm) on various polymer and metal surfaces in a scalable fashion. A systematic study has been performed to optimize the CAP settings including plasma power, precursor flow, and carrier gas flow to obtain the coatings with excellent antibacterial properties and mechanical properties. Various characterization techniques such as SEM, EDX, FTIR, and Raman have been used to understand the effect of surface chemistry and morphology on the coating properties.

COVID-19 is a disease caused by the novel coronavirus SARS-CoV-2. According to the U.S. Centers for Disease Control and Prevention (CDC), SARS-CoV-2 is transmitted by exposure to infectious respiratory fluids caused by infected individuals talking, coughing, or sneezing, thus, spreading the virions in airborne droplets (∼370 virions in 1 μm and ∼360,000 virions in 10 μm) and in aerosol forms, which are called 'bioaerosols'. Bioaerosols are one of the particulate matters (PMs) carrying living organisms from biological sources which include fungi, bacteria, and viruses. To reduce the exposure of biological PMs in indoor air condition, an air filter could be applied in air conditioning system in order to collect the bioaerosols on the surface of the filter membrane. However, previous studies report that viruses remain infectious on various surfaces such as polymeric fibrous filters for a few days. That triggered a tremendous effort to develop antimicrobial fiber-based filters for prevention of infectious virus transmission by fomites. Herein, we present antimicrobial thin film of zinc oxide (ZnO) nano-spines on commecial fiber-based filters and its potential for infection prevention. By developing a novel technique of dry aerosol coating process, (Zn) nano-seed was well-covered on the commercial filter fiber. After hydrothermal treatment, high aspect-ratio ZnO nano-spines were densely exhibited on the filter surface, which have significant antimicrobial effect to airborne pathogens due to. their spiky morphology. This novel thin film hold potential for airborne microbial disinfection, and the design of microbicidal materials with wide applicability to commercial air filter.

Biological cells have evolved alongside of natural mineral clay (layered aluminosilicates) leading to intriguing interactions from beneficial to bio-adverse. Specifically, bacteria were shown to adhere to clay particles and even incorporate them into their biofilm¹. We endeavor to direct these interactions to neutralize a specific pathogenic bacterial srain in a heterogenous culture, maintaining the non-pathogenic populations unharmed and mitigating the global surge in antibiotic resistance. To that end, we utilize Halloysite nanotubes (HNTs), which are 600-900 nm long and 50 nm wide, and exhibit a hollow lumen with an inner diameter of 15 nm. This intrinsic mesoporous morphology of HNTs combined with their adsorptive silica surface renders the clay ideal for carrying various antimicrobial cargoes. The desired specific antibacterial effect is based on the selective binding of the clay to the target bacteria which is realized by antibodies we immobilize onto the HNTs’ surface². Next, we investigate the loading of the antibody-functionalized HNTs with two separate antimicrobial payloads: (1) the potent antibiotic ciprofloxacin (CIP) to be gradually released near the target bacteria³, or (2) plasmonic gold nanorods (AuNR) to be activated by near-infrared irradiation for a local photothermal effect.

The selective binding of the Ab-functionalized HNTs to their target bacteria is confirmed by fluorescence and electron microscopy along with high-throughput imaging flow cytometry⁴. Consequently, CIP-loaded Ab-HNTs exert a two-fold higher potency against the target bacteria, whereas in the same heterogeneous culture, the inhibition of non-target bacteria is decreased by 50-90%. Regarding the AuNR-Ab-HNTs hybrids, upon irradiation with a near-infrared laser, a superior antibacterial activity is observed in comparison to free AuNR, despite the 5-fold higher increase in bulk temperature induced by the latter⁴. In addition, the biocompatibility of the multifunctional clay is studied towards a physiologically relevant co-culture of human colon epithelial cells (Caco-2 / HT29) and the localization of the particles after administration is investigated.

In this presentation, I will discuss our findings as well as the preceding considerations involved from the bioconjugation step to the loading of the clay for obtaining the desired bio-nano interactions. We believe this work signifies the potential in comprehending the interface between biological cells and natural nanomaterials, which are abundant and easily obtainable, to utilize the latter for novel biomedical applications.

References:
1) Prinz Setter, O., Segal, E., 2020. Halloysite nanotubes - the nano-bio interface. Nanoscale 12, 23444–23460. https://doi.org/10.1039/d0nr06820a

2) Prinz Setter, O., Movsowitz, A., Goldberg, S., Segal, E., 2021. Antibody-Functionalized Halloysite Nanotubes for Targeting Bacterial Cells. ACS Appl. Bio Mater. 4, 4094–4104. https://doi.org/10.1021/acsabm.0c01332

3) Prinz Setter, O., Dahan, L., Abu Hamad, H., Segal, E., 2022. Acid-etched Halloysite Nanotubes as Superior Carriers for Ciprofloxacin. Appl. Clay Sci. 228, 106629. https://doi.org/10.1016/j.clay.2022.106629

4) Prinz Setter, O., Snoyman, I., Shalash, G., Segal, E., 2022. Gold Nanorod-Incorporated Halloysite Nanotubes Functionalized with Antibody for Superior Antibacterial Photothermal Treatment. Pharm. 2022, Vol. 14, Page 2094 14, 2094. https://doi.org/10.3390/PHARMACEUTICS14102094

Introduction: High rates of mortality and morbidity due to hospital acquired infectious (HAI) disease remains a serious problem in the healthcare sector. The application of nanotechnology as a novel antimicrobial agent has proven effective and is of high interest. Among them, cerium- and cerium oxide-based (ceria) nanoparticles (CNPs) have received much attention owing to their unique surface kinetics via auto-catalytic cycling between two oxidative states (Ce⁴⁺→Ce³⁺→Ce⁴⁺). CNPs have been shown to be less toxic to mammalian cell lines but effective in eradicating bacteria through the formation of reactive oxygen species (ROS). Nano-based silver is also known for its efficient antimicrobial action. The aim of this study was to investigate the antibacterial activity of silver-doped ceria nanoparticles (AgCNPs) on three bacterial genera both in a liquid and dry form and its potential role as a novel, self-disinfecting and residual coating for high-touch abiotic surfaces. We hypothesize that through heightened generation of ROS, AgCNPs interact with the bacterial membrane leading to oxidative stress and bacterial death.
Materials and Method: AgCNP was synthesized using a base-mediated forced hydrolysis method and material characterization performed. The minimum inhibitory concentration (MIC) of AgCNPs and CNPs was determined for Pseudomonas aeruginosa (PA), Staphylococcus aureus (SA), and methicillin resistant Staphylococcus aureus (MRSA). Experiments were conducted with AgCNP and CNP at concentrations of 100 µg/mL (PA), 300 µg/mL (SA and MRSA), AgNO₃ (20 µg/mL) and gentamicin (20 µg/mL). Cell viability, a time-scale assay using TEM, intracellular ROS, DNA, and membrane damage were analysed. The ability of each agent to generate superoxide (O₂^●-) and hydroxyl (OH^●) radicals, RNS, and H₂O₂ was determined. To test each agent’s residual antibacterial activity, solid surface (individual and multiple species) re-challenge tests were carried out with four cumulative doses (~10⁸ cells/mL) of bacteria. Biofilm from each bacterial species was allowed to form followed by treatment with each agent for three days at intervals of 24 h. Biofilm thickness and bacterial viability was assessed. All experiments were carried out in triplicate and a Mann-Whitney U test was used for statistical analysis where p values < 0.05 were considered significant.
Results: AgCNP consisted of particles composed of 53.7% Ce³⁺:Ce⁴⁺(%Ce³⁺) and 14.6% [Ag]/[Ag+Ce]. Treatment with AgCNP resulted in significant PA cell death (100%) after 60 mins (p < 0.0001) and SA and MRSA death after 180 mins (both p < 0.0001). AgCNP significantly induced ROS generation when given to all three bacteria (PA (~20-fold), SA (~7.4fold) and MRSA (~21fold)) when compared to control (all p < 0.0001). TEM analysis showed AgCNPs localized onto the bacterial membrane resulting in a significant and fatal increase in cell size (PA (p<0.01), SA and MRSA (p<0.05)). Results also revealed a significant increase in DNA damage following AgCNP treatment in all groups when compared to control (all p < 0.0001). Further, AgCNP induced a significantly increased amount of O₂^●-, OH^●, H₂O₂ and RNS compared to all other agents. An AgCNP-coated glass slide surface re-challenge test showed 100% inhibition of PA, SA and MRSA both individually and as a multispecies inoculation. Finally, AgCNPs were able to disrupt pre-formed biofilm in all three species and significantly eradicated shielded bacteria within (all p < 0.0001). AgCNPs outperformed CNPs, AgNO₃ and gentamicin.
Discussion and Significance: This study showed that AgCNPs, whether in a liquid or dry form, were able to eradicate S. aureus, MRSA, and P. aeruginosa. AgCNPs displayed synergistic and augmented antibacterial activity when compared to Ag or CNPs alone. We have demonstrated that AgCNP coatings may offer a new type of continuous disinfectant that leaves behind a continually disinfecting film with excellent antibacterial efficacy.

Bacteria acquire resistance by grouping together in spatially organized communities, embedded in a viscous extracellular matrix, called biofilms, which are the cause of dramatic chronic infections in plants, animals and humans. [1] Moreover, evolution and mutation within the biofilm enhances their drug resistance, with the consequent failure of conventional treatments of infectious diseases.

We are working on a safe-by-design multifunctional, multistimulable nanomaterials [2] for the eradication of bacterial biofilms by photothermia (PT) [3], magnetic hyperthermia [4] and drug targeting [5], with the aim of eliminating both planktonic and sessile bacteria.
A first approach involves the construction of assemblies of different building blocks, namely gold nanoparticles (NPs) of several shapes (rods, stars and spheres) with active molecules, notably enzymes, bactericides and inhibitors. In another approach, assemblies of magnetic iron oxide nanoparticles (MNPs), carbon dots (CDs) and active molecules, are constructed.

Nanotherapy is mediated by magnetic hyperthermia and/or PT: (i) upon magnetic actuation MNPs act as mechanical disruptors, damaging the biofilm irreversibly; (ii) PT of NPs and CDs weakens the bacterial membranes and releases the active molecules grafted onto NPs or MNPs via a thermolabile arm. The efficacy of these nanomaterials for the photothermal, magnetic actuation and drug release applications proposed was tested.

Promising results were obtained in the treatment of planktonic bacteria and biofilms by incubation with different nanohybrids. This approach exploits technologies in material biosciences, from the engineering of bacterial inhibitors to the design of colloidal nanoplatforms, to discover ways of penetrating biofilm structure. The employment of stimulable nanomaterials carrying relevant antibacterial agents will open up new perspectives in the field.

¹ C. Sahli, S. Moya, J.S. Lomas, C. Gravier-Pelletier, R. Briandet, M. Hémadi. Theranostics, 2022, 12, 2383.
² H. Belkahla, E. Mazarío, A. Plan Sangnier, J.S. Lomas, T. Gharbi, S. Ammar, O. Micheau, C. Wilhelm, M. Hémadi. Theranostics, 2019, 9: 5924-5936.
³ H. Belkahla, R. Boudjemaa, V. Caorsi, D. Pineau, A. Curcio, J.S. Lomas, P. Decorse, A. Chevillot-Biraud, T. Azaïs, C. Wilhelm, H. Randriamahazaka, M. Hémadi. Nanoscale Advances, 2019, 1, 2571.
⁴ J. Hai, H. Piraux, E. Mazario, J. Volatron, N.T. Ha-Duong, P. Decorse, J.S. Lomas, P. Verbeke, S. Ammar, C. Wilhelm, J.M. El Hage Chahine, M. Hémadi. J Mater Chem B, 2017, 5: 3154-3162.
⁵ J. Hai, N. Serradji, L. Mouton, V. Redeker, D. Cornu, J.M. El Hage Chahine, P. Verbeke, M. Hémadi. PLoS One, 2016, 11: e0150031.

Introduction
Acid-producing bacteria can be ubiquitous and detrimental, causing worldwide problems such as dental caries¹ and biocorrosion². Here, we report the design, preparation and characterization of a pH-responsive nanoscale drug carrier using a traditional drug for selective targeting and killing of acid-producing bacteria.

Methodology
The nano-size drug carrier was prepared through surface functionalization of mesoporous silica nanoparticles using a novel pH-responsive compound. Chlorhexidine, an antimicrobial agent used in oral rinse, was used to demonstrate the selective killing effects on a microbiome model that simulated human oral microbial community.

Results and Discussion
The success of surface functionalization was characterized by Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy. The drug loading was determined using Brunauer-Emmett-Teller method and thermogravimetric analysis. The drug loaded nano-carriers released chlorhexidine in response to the addition of acid, a metabolic product of acid-producing bacteria. The chlorhexidine-release was shut off at neutral pH without premature release. The kinetics of the chlorhexidine-release at various biological relevant pHs from 4.0 to 8.0 were determined. The chlorhexidine-release was switched on/off 5 times repetitively. Furthermore, successful selective killing was achieved. The treated bacteria kept pH in supernatant and biofilm above 5.5 without killing all the bacteria like the traditional oral rinse control did.

Conclusion
The success of selective killing of acid-producing bacteria using traditional broad-spectrum antimicrobial agents will significantly help to preserve microbial community and reduce the use of drug for preventing drug resistance. Such specific and local delivery of drug opens new avenues for using traditional drugs in dental applications.

References
1. R. H. Selwitz, A. I. Ismail, N. B. Pitts, Lancet. 369, 51–59 (2007).
2. N. Kip, J. A. Van Veen, ISME J. 9, 542–551 (2015).

Acknowledgements
We thank financial support from National Institutes of Health (NIH) (R01DE029479 and R21DE029925).

The detection of circulating tumor cells (CTCs) is very important for cancer diagnosis. CTCs can travel from primary tumors through circulation to form secondary tumor colonies via bloodstream extravasation. The number of CTCs has been used as an indicator of cancer progression. However, the population of CTCs is very heterogeneous. It is very challenging to identify CTC subpopulations with high metastatic potential, such as cancer stem cells (CSCs), which are very important for cancer diagnostic management.
We report a study of real-time CTC and CSC imaging in the bloodstreams of living animals using multi-photon microscopy and antibody-conjugated quantum dots. We have developed a cancer model for noninvasive imaging wherein pancreatic cancer cells expressing fluorescent proteins were subcutaneously injected into the earlobes of mice to form solid tumors. When the cancer cells broke from the solid tumor, CTCs with fluorescent proteins in the bloodstream at different stages of development could be monitored noninvasively in real-time. The number of CTCs observed in the blood vessels could be correlated to the tumor size in the first month and reached a maximum value of approximately 100 CTCs/min after five weeks of tumor inoculation. To observe CTC subpopulations, conjugated quantum dots were used. It was found that CD24+ CTCs can move along the walls of blood vessels and migrate to peripheral tissues. The accumulation of CD24+ cells on the sides of solid tumors was observed, which may provide valuable insight for designing new drugs to target cancer subpopulations with high metastatic potential. We also demonstrated that our system is capable of imaging a minor population of cancer stem cells, CD133+ CTCs, which are found in 0.7% of pancreatic cancer cells and 1-3% of solid tumors in patients.
With the help of quantum dots, circulating tumor cells with higher metastatic potential, such as CD 24+ and CD 133+ CTCs, have been identified in living animals. Using our approach it is possible to investigate the detailed metastatic mechanism, such as the extravasation of tumor cells to the blood vessels. In addition, the number of observed CTCs in the bloodstream could be correlated with the stage of the tumor.

Magnetic resonance imaging (MRI) is a leading non-invasive medical imaging technique due to its well established spatially resolved images. To aid this diagnostic tool further, contrast agents have been designed to improve the quality of the images, with nanostructured MRI contrast agents showing exceptional promise in image enhancement at extremely low doses.¹ Relaxivity is the term used to assess the effectiveness of an MRI contrast agent on signal enhancement. Taking advantage of their generally high surface areas, nanostructured contrast agents often host large numbers of paramagnetic centres thereby increasing sensitivity through increased local concentration. Importantly, their bulky size improves relaxivity by contributing to slower rotational correlation time, resulting in longer T₁ relaxation times.² There is also increasing evidence that nanoscale design features, such as pore size and surface chemistry can influence water mobility and hence affect the ultimate capability of these nanostructures as MRI contrast agents.^2,3 Surface modifications can not only impact water diffusion, but also directly affect the local tumbling rate of a chelated paramagnetic centre.^4,5 However, understanding the structure-property relationship of designed nanostructured contrast agents is still relatively poor and therefore a more thorough investigation is required in order to improve their potency.
The objective of this work is to explore how nearby surface modifications could influence the relaxation of Gd³⁺-chelates loaded in mesoporous silica nanoparticles (MSNs). We seek to gain a better grasp of how a gadolinium complex interacts with neighbouring functional groups, such as hydrophilic thiols or bulky phenyls, across a range of molar percentages present in the pores, to probe water diffusion and effects on local tumbling, and understand the resulting impact on relaxivity. As well as full structural characterisation, single-field and fast-field cycling relaxometry (SFR and FFC-NMRD, respectively) have been used to analyse the water diffusion/exchange behaviour within these composites. It was found that modifying the molar percentages of either functional group did not significantly affect the colloidal stability of the particles, nor their particle size, as determined by TEM. Functionalised particles displayed differing behaviour when analysed using SFR; the relaxivity of phenyl-functionalised MSNs did not exhibit a linear trend with an increasing number of phenyl groups present, indeed showing no influence from the bulky ligand, whereas the thiol-MSNs gave lower relaxivities as the thiol molar percentage increased. This is potentially due to the hydrophilic nature of the thiols and thus their interactions with water affecting the exchange rate. FFC-NMRD analysis revealed that both sets of functional groups influenced the paramagnetic Gd³⁺-chelate compared to non-functionalised MSNs. This work provides valuable insights into the importance of nanomaterial design features, in particular the location and nature of functional groups in MRI contrast agent design. An improved understanding of the interplay between these factors should prove useful in the development of such agents for diagnostics and sensing.

References
1. J. J. Davis, W.-Y. Huang and G.-L. Davies, J. Mater. Chem., 2012, 22, 22848-22850.
2. G.-L. Davies, I. Kramberger and J. J. Davis, Chem. Comm., 2013, 49, 9704–9721.
3. W.-Y. Huang, G.-L. Davies and J. J. Davis, Chem. Comm., 2012, 49, 60–62.
4. F. Carniato, L. Tei, A. Arrais, L. Marchese and M. Botta, Chem. Eur. J., 2013, 19, 1421–1428.
5. F. Carniato, L. Tei, M. Cossi, L. Marchese and M. Botta, Chem. Eur. J., 2010, 16, 10727–10734.

Nanofiltration is shown to provide a way to test and measure nano-bio interactions between the nanofilter material and biological nanoparticles (NP).
Nanofiltration is used in biotechnological and biopharmaceutical industries for separation and purification of biological molecules such as viruses, monoclonal antibodies, vaccines, blood plasma and therapeutic proteins. Other applications can be found in water purification, air filtration, biomaterial processing.. Membrane fouling limits use of nanofiltration in large low value applications such as wastewater treatment and has encouraged the development of better membranes. Nanofibers of polymers produced by electrospinning yield filters with higher flux and better mechanical stability. Ceramic membranes such as nanoporous zeolites improve selectivity. Recently Carbon nanotubes (CNT) and other nanotube materials have been explored and show promising properties. The interaction between nanofilter material and permeating biological nanoparticles determines the efficiency of the filtration process.
A theory for the efficiency and permeability of a nanomembrane is presented. The dynamic equations for flux and concentration profiles, derived from a kinetic theory of non-equilibrium statistical mechanics, are solved analytically. The penetration of the nanoparticles is determined by the ratio of the flux at the exit of the membrane to the flux at the entrance.
The theory is applied to two specific examples.
●Filtration of virus-like particles in air by a nanofibrous membrane with and without charge on fiber surfaces. The model treats the virus as a spherical particle of net surface charge and the polymer fiber as a neutral or charged line or plane. For like net charges on fiber and virus the electrostatic interaction between the NP and the fibers is shown to decrease penetration and impact NP aggregation, pertinant for the smallest NP sizes.

●Filtration of a polydisperse virus sample in water by a cylindrical CNT of radius H. The model demonstates a transition with increasing effective interaction from "hydrophobic" rejection of water molecules (diameter σ) for weak van der Waals forces with the carbon walls to notable penetrration with large flux and density, localized for σ/H =1 at the center of the tube. Interactions between water molecules play an important role. The virus interacts with the pore material principally by a Lennard Jones type interaction. Viruses with effective diameter greater than H are inhibited from entering the CNT by steric effects and pure water exits the CNT pore.




fl

Based on the laser-matter interaction in liquid ambiance with a solid target material or water powder dispersed, the ultrafast laser processing appears relevant approach to develop innovative nanoparticles for healthcare and wellbeing challenges. This method can lead naturally to the formation of functional engineered nanoparticles with adjustable physicochemical properties exempt of any contaminants compared to analogue nanoparticle formulations made from conventional synthesis methods. For instance, we have demonstrated the possibility to elaborate ultraclean and stable colloidal based on AuNPs and SiNPs with unique physicochemical properties for biomedical applications (F. Correard et al, Int. J. Nanomed., 2014, 9, 54152; T. Baati et al, Sci. Rep., 2016, 6, 25400). Moreover, the presence of high oxidation state on the NPs surface promises efficient interactions with many biological materials (A. Al-Kattan et al, J. Mater. Chem. B, 2016, 4, 78523). As one of the major result, we have shown that SiNPs can be exploited as significant sensitizers of radiofrequency (RF)-induced hyperthermia and the Two-Photon Photodynamic Therapy (K.P. Tamarov et al, Sci. Rep., 2014, 4, 7034; A. Al-Kattan et al, Nanomaterials, 2020, 10(8), 1462). Beside conventional additives mainly made-it by chemical way, we have also started to explore such bare laser synthesized nanoparticles as novel functional additives in electrospun-nanofibers for tissue engineering applications (A. Al-Kattan et al, IJMS, 2018, 19(6), 1563; A. Al-Kattan et al, Nanomaterials, 2021, 11,712).

Several experimental and theoretical challenges limit a more rational design of nanoparticles (NPs) with a specific target application, i.e., the preparation of NPs with different structures/properties for various final uses. The characterization of different nanoparticle suspensions in liquids has drawn significant attention in a wide range of engineering applications. Recently, many computational approaches concerning the interactions between soft materials and inorganic nanoparticles proved to be promising in guiding the experimental preparation of nano suspensions [1-3]. Due to their optical and electronic properties, gold nanoparticles (AuNPs) are interesting for several applications, ranging from energy (e.g., solar steam generation [4,5]) to medicine (e.g., cancer theranostics [6,7]). Regarding the latter, AuNPs often encounter biocompatibility and biodegradability issues that can be overcome by encapsulating them in a poly (lactic-co-glycolic acid) (PLGA) matrix. Understanding the self-assembly dynamics of PLGA on the AuNP surface is crucial to guide and optimize the design of AuNPs coated with a PLGA corona. In this work, we combine different computational techniques to understand the interactions of an AuNP with PLGAs, aiming at assessing the most efficient and effective AuNP shape for biological applications. Specifically, we first perform classical molecular dynamics simulations while tuning the PLGA concentration in an aqueous solution; second, relying on a recently developed unsupervised machine learning (ML) algorithm, we evaluate the time evolution and behavior of PLGA clusterization. Finally, we employ the umbrella sampling approach to explore the AuNP-PLGA free energy landscape; this, combined with a detailed analysis of the surface still accessible to the solvent, allow us to gain insight into the anisotropic adsorption behavior of PLGAs onto AuNP. Our results highlight that the shallow morphology, besides surface chemistry, can influence the adsorption phenomena: in particular, the tested AuNP topology present the Au {1 1 1} crystal planes as privileged adsorption sites. This modeling-based investigation offers a comprehensive methodological approach for the rational and functional design of PLGA-coated gold nanoparticles [8].

Acknowledgement: Support of the Italian National Project PRIN Heat transfer and Thermal Energy Storage Enhancement by Foams and Nanoparticles (2017F7KZWS) is acknowledged.

References
[1] T. D. Jorgenson, et al., Soft Matter, vol. 15, no. 37, pp. 7360–7368, 2019, doi: 10.1039/C9SM00426B.
[2] Z. E. Hughes, et al., Nanoscale, vol. 9, no. 1, pp. 421–432, 2017, doi: 10.1039/C6NR07890G.
[3] A. Cardellini, et al., Journal of Physics: Condensed Matter, vol. 28, no. 48, 2016, doi: 10.1088/0953-8984/28/48/483003.
[4] M. Morciano, et al., Scientific reports, vol. 7, no. 11970, 2017, doi: 10.1038/s41598-017-12152-6.
[5] E. Chiavazzo, et al., Nature Sustainability, vol. 1, pp. 763–772, 2018, doi: 10.1038/s41893-018-0186-x.
[6] E. Chiavazzo, et al., Nature Communications, vol. 5, no. 3565, 2014, doi: 10.1038/ncomms4565.
[7] A. Gizzatov, et al., Advanced functional materials, vol. 24, no. 29, 2014, doi: 10.1002/adfm.201400653.
[8] R. Cappabianca, P. De Angelis, A.Cardellini, E. Chiavazzo, and P. Asinari, ACS Omega, under review

Nanocomposite hydrogel is fabricated via γ-irradiation crosslinking of PAA, graphene oxide (GO), and cellulose nanofiber (CNF) to serve as a sensing substrate for non-invasive dual detection of urea in sweat. In this work, CNF helps to improve the mechanical properties of the hydrogel whereas GO plays a key role in enhancing the detection signal of urea in laser desorption/ionization mass spectrometry (LDI-MS) and increases the hydrogel functionalities. The hydrogel possesses high water-sorption capacity and transparency suitable to accommodate coloring reagents and enzymes for the colorimetric sensor. The sensor exhibited vivid color change towards the increase of urea concentration in a linear range of 40–80 mM covering for chronic kidney disease (CKD) indication. Furthermore, the hydrogel can be directly applied as a substrate for the direct quantitation of urea by LDI-MS. In LDI-MS, it verifies that GO/CNF/PAA hydrogel can act as a direct matrix for promoting urea ionization, and these results corresponded well with the colorimetric sensor. Hence, this hydrogel patch might be a potential material to be applied in the non-invasive dual detection of CKD in medical diagnosis.

African swine fever virus (ASFV) is a double-stranded DNA virus that is highly contagious and deadly to cause severe economic losses. As there is no commercial vaccine or treatment for this virus, the only countermeasure currently available is to isolate livestock in every event of an outbreak. For the fast decision-making process in the field, the significance of point-of-care technology (POCT) has been recognized to reduce the further spread and fatality rates. Conventionally, the polymerase chain reaction (PCR) has been employed in on-site diagnosis and is considered as the golden standard for detecting contagious diseases. However, conventional approaches have further challenges in improving management for point-of-care rapid diagnostic tests. PCR-based methods require complex procedures, expensive instruments, and skilled expertise. Here, we developed a chromatography-based microfluidic system for the optical detection of ASFV using a hybridization chain reaction (HCR). Our system does not require additional analytical apparatus or immobile instrumentation. This portable microfluidic system designed to detect ASFV can be used anywhere to test on-site within 30 min without transporting samples. A colorimetric assay was also highly sensitive in that it can detect up to 19.8 pM of target gene molecules. This robust and sensitive visual detection system is suitable for non-specialist personnel and point-of-care diagnosis in low-resource settings.

Spherical nucleic acids (SNAs) are composed of inorganic core materials in cooperation with nucleic acids shell as soft material. The nucleic acid can be densely conjugated to the surface of the core material depending on the type of the core material. Polyvalent SNAs help in biosensing development because they provide a higher opportunity to recognize target strands. However, despite the widely applicable potential of DNA sequences on SNA, the function of nucleic acids has been limited in very simple operations. For example, colorimetric detection using gold nanoparticle assemblies triggered by target analytes is a common method in nanostructured biosensing applications. Previously, nucleic acid sequences worked simply to capture target strands or form DNA-mediated hybridization for core material assemblies.
To extend the functionality of the SNA nanoprobe, DNA nanotechnology can be combined with the SNA nanostructure. Accordingly, the way to exploit SNA for biosensors is to define a new role of nucleic acids layer on it. Nucleic acids can perform well-defined functions such as signal conversion or target amplification itself as far as the sequence-specific operating role is concerned. Target sequence conversions are useful when the target strands require high selectivity. For example, single nucleotide polymorphisms (SNPs) are challenging as target nucleic acids because there is only one single base mismatch between the analytes to distinguish specific targets, and the concentration of SNPs in biological samples is low. Consequently, converting sequences in high-density SNA nanoprobes allows similar target sequences to be transmitted to noticeably different sequences via encoding strand amplification. According to the experimental results, one target strand was encoded about 1000 strands in a distinctly different sequence. To distinguish four multiple targets of SNPs i.e., wild and mutant types, toehold-mediated strands displacement reaction on hydrogel microstructure has been designed as following detection process. Target sequence converting SNAs are enzyme-free amplification of targets and increased selectivity.
Furthermore, massively target strands hybridized SNA nanoprobe can be employed for the target amplification probe itself. To increase the target strand amplification efficiency, the nanoparticle-mediated cycle reaction has been developed under enzyme-free conditions with naked-eye detection. In each cycle, target amplifying SNA can exponentially increase the number of target DNA strands by up to 174ⁿ folds during n cycles. The cycles can be repeated as enough strands are amplified. SNA-based target amplification showed four times higher detection efficiency than polymerase chain reaction (PCR), which is widely used for nucleic acid amplification with 2ⁿ folds for n cycles. In addition, it was possible to detect the target strands up to 100 zM of target strands with a convenient detection process.

Mesoporous silica nanoparticles (MSNs) have been demonstrated as an excellent platform for drug delivery carriers in cancer treatment where tumor targeting is normally achieved via the enhanced permeability and retention (EPR) effect. However, it remains challenging for MSNs to deliver chemical drugs, nuclear acids, or proteins to reach brain tumors due to the presence of the blood−brain barrier (BBB). Here, we propose a simple strategy to modify MSNs to target brain tumors. Our strategy was to optimize the size of PEG on the surfaces of MSNs to overcome BBB. We first tested different sizes of PEG coating on the MSNS in the in vitro BBB model, where the smaller size of MSNs with near neutral charged (RMSN₂₅-PEG-TA) possesses higher transport efficiency to cross the BBB-mimicking endothelial cell layer. To evaluate the circulation of MSNs, we utilized two-photon microscopy. We observed that the MSNs stayed long enough in the circulation system (over 24 h) and could be accumulated outside of the cerebrovascular in mouse brains. We also examined the EPR effect with various functionalized MSNs. A particular modification in MSNs led to their abundant accumulation in tumor tissue. In a drug delivery study, we explored the potential of using MSNs to deliver drugs (DOX@MSN) into the glioma tumor. It has been observed that the functionalized MSNs with DOX significantly suppress the growth of orthotopic glioma tumors and improved DOX’s severe side effects in vivo study. The biosafety result showed that the given dose of the functionalized MSNs appeared safe and decreased severe side effects caused by DOX in the animal models.

Wide bandgap semiconductor nanoparticles, such as zinc oxide (ZnO) and titanium dioxide (TiO₂) nanoparticles, have been widely used as ultraviolet (UV) blocking materials due to efficient UV absorption and excellent stability. However, the high chemical potentials of the photo-induced electrons and holes unavoidably generate reactive oxygen species (ROS) that can induce adverse chemical and biological damage. Synthetic polymer encapsulation has been commonly used to suppress photo-induced ROS generation, but recent studies continue to warn against the use of synthetic polymers in cosmetic and personal care products. Here we present a new method to effectively minimize the photo-induced toxicity of TiO₂ using tannic acid, a bio-inspired adhesive antioxidant polyphenol molecule, that can strongly bind to TiO₂ nanocrystal surface via ligand-to-metal charge transfer (LMCT). SiO₂-TiO₂ particles were prepared through the in situ TiO₂ nanocrystal synthesis within mesoporous SiO₂ particles to minimize the photochemical reactivity of TiO₂. TA was spontaneously deposited on the TiO₂ surface by Ti-catechol and Ti-pyrogallol coordination to synthesize SiO₂-TiO₂-TA hybrid particles. TiO₂ nanoparticles penetrated the cellular membrane by endocytic internalization and accumulate around the endoplasmic reticulum and nucleus. Accordingly, fibroblasts treated with TiO₂ nanoparticles exhibited lower cell viability under UV or HEV light irradiation due to highly reactive ROS generation. However, SiO₂-TiO₂-TA hybrid particles did not penetrate the cell membrane but efficiently protected the fibroblasts against UV and HEV damage through the effective scavenging of photo-generated ROS. Additionally, the LMCT from the TA HOMO to the TiO₂ conduction band allowed a new absorption pathway, enhancing the UV-to-HEV blocking performance, which significantly increased the sunscreen performance of an emulsion formulation containing SiO₂-TiO₂-TA hybrid particles. This work demonstrated a new promising strategy of plastic-free sunscreen agents with enhanced sunblock performance and suppressed photochemically induced toxicity.

Flow chemistry is a fast-advancing field involving the continuous combining of reactants which are fed into a reaction chamber, followed by the continuous output of product. When compared to batch methods, flow chemistry boasts better mixing, more efficient heat transfer and the ability to undergo self-optimisation.¹ Typically synthesised in batch, nanoparticles which display superior properties (e.g. chemical, thermal, optical) to their molecular counterparts are becoming increasingly in demand, however their large-scale synthesis, necessary for industry, is currently limited. One significant benefit to flow is the ease of scale-up whilst still retaining the desired particle properties. A range of nanoparticles from metal oxides to polymers have been produced via flow techniques, for example microfluidics.² Moreover, in flow the user has much greater control over the experimental parameters, i.e. reaction time can be fine-tuned much more easily than in batch which is useful for reactions which occur in a matter of seconds.

Continuous stirred tank reactors (CSTR) are commonplace in many large process reactions such as pharmaceutical manufacturing where they are predominantly used to synthesise organic compounds on the molecular level. Whilst CSTRs are generally involved in batch reactions they can be utilised in continuous flow processes too. The fReactor™ represents a versatile piece of flow equipment consisting of five connected CSTR modules, each of which form a discrete reaction zone. Each module has multiple ports making telescoping of reactions possible. Offering alternative routes of synthesis, this equipment can be used to conduct both single and multiphasic reactions. Additionally, the fReactor allows for the exploitation of traditional chemical and physical principles but provides that critical level of control not seen in batch, owing to its small size and modular design. Thus, bridging the gap between batch and classical flow/microfluidics.

Using the fReactor, this work describes the optimisation of poly(lactic-co-glycolic) acid (PLGA) nanoparticle synthesis by nanoprecipitation. This polymer presents itself as an ideal candidate for encapsulating active pharmaceutical ingredients owing to its biocompatible and biodegradable nature, coupled with its FDA approval for use in vivo.³ Initial optimisation experiments allowed the formation of spherical nanoparticles ~200 nm with polydispersity indices of 0.05, a significant improvement over the polydispersity observed when prepared using traditional bath methods. Furthermore, we describe a methodological design which was carried out as a systematic study to assess several parameters including type of PLGA, solvent, flow rate, residence time, agitation speed, use of surfactants, and encapsulation ability. Notably we found that as agitation speed within the fReactor was decreased in regular intervals from 1500 to 500 rpm during the synthesis, nanoparticles size increased linearly (R² = 0.98). However, for speeds lower than 500 rpm this control was lost and an increase in particle polydispersity was observed. A full comparison against PLGA prepared through batch nanoprecipitation demonstrated that this flow technique has the ability to tune particle properties readily, through greater control over process parameters and produced nanoparticles with a smaller size distribution.

We have further demonstrated the broad utility of this cascade of small volume CSTRs by optimising the synthesise of superparamagnetic iron oxide nanoparticles (8 nm diameter) and mesoporous silica nanoparticles with tuneable pore diameters, which can be used as medical imaging agents and drug delivery carriers, respectively. All particles made in the fReactor were comparable to the equivalent batch materials.

References
1 Chem. Rev., 2017, 117, 11796.
2 React. Chem. Eng., 2020, 5, 1619.
3 J. Mater. Chem. B, 2018, 6, 2065.

INTRODUCTION
Glioblastoma is a very aggressive type of cancer with a very poor life expectancy for patients and breast cancer often metastasizes into the liver, lungs, brain, and, in 70% of cases, to bones^1,2. Chemotherapy is largely used to treat cancer and it is based on the use of molecules targeting the high cancer cell proliferation metabolism³. Platinum (Pt) and three of its isoforms (cisplatin, carboplatin, and oxaliplatin) are some of the most successful metal-based drugs to cure breast cancer and glioblastoma^4,5. Despite Pt-based chemotherapeutics being effective, their side effects (high degradation before entering the cells, the off-target organs toxicity, and cell resistance) remain great drawbacks^6-9. In this work, it was developed a Graphene Oxide (GO) nanoplatform functionalized with Pt as a promising smart delivery system that could increase the Pt cellular uptake reducing the Pt amount needed for cancer treatment and consequently the side effects.
EXPERIMENTAL METHODS
GO nanoplatforms were treated with 8-arm polyethylene glycol-amine (PEG) that permits to load Pt on the platform (GO-PEG-Pt) and an extensive in vitro screening was performed on two breast cancer cell lines with aggressive nature that lead to metastatic behavior (MDA-MB 231 and MDA-MB 468) and two glioblastoma cell lines (U87 and U118). The bioactivity of GO-PEG-Pt compared to Pt-free (15 μM, 30 μM, and 60 μM) was analyzed looking at the effect on cellular uptake (ICP-OES), viability (MTT Assay), morphology (DAPI and actin staining), and migration up to 72 hours (Scratch Assay).
RESULTS AND DISCUSSION
The cell viability was significantly lower in MDA-MB 468 and U118 cells at 30 μM for GO-PEG-Pt group compared to Pt-free (<75%), and even the cell morphology seemed to be compromised. These results were highly related to the cellular uptake of GO-PEG-Pt which is significantly higher compared to Pt-free after 24 hours. This data confirmed that our nanoplatform promotes drug delivery directly inside the cells. In addition, GO-PEG-Pt mostly affected the cell migration compared to Pt-free, in particular, MDA-MB 231 showed a migration reduction of 60%, and this could be a great advantage in reducing the metastasis process.
CONCLUSION
This study demonstrated that the combination of Pt onto PEG-functionalized nano-sized GO provided numerous advantages for tumor therapy such as minimizing toxicity, enhancing the cellular uptake, and consequently we could reduce the side effects because a lower amount of Pt is necessary.
REFERENCES
1. Feng, Y. et al., Genes Dis., 5(2):77-106, 2018
2. Dymova, M.A. et al., Int. J. Mol. Sci., 22(12):6385, 2021
3. Schirrmacher, V., Int. J. Oncol., 54:407–19, 2019
4. Taghavi, M.S. et al., In Vitro Cell. Dev. Biol.-Animal, 49:465–472, 2013
5. Martín, M., Clin. Breast Cancer, 2(3):190-208, 2001
6. Bersini, S. et al., J. Biomaterials, 35:2454–61, 2014
7. Lei, S. et al., Cancer Commun., 12:4413, 2021
8. Rajaratnam, V. et al., Cancers, 12(4):937, 2020
9. Liang, Y. et al., Semin. Cancer. Biol., 60:14–27, 2020
ACKNOWLEDGMENTS
The authors would like to thank the Nano4Tarmed project (H2020-WIDESPREAD-2020-5, grant no: 952063) for providing financial support to this project.

In this report, we have prepared oxide derived Cu (od-Cu) nanofibril assembly exhibiting superior glucose detection ability. The morphological analysis evidenced the formation of rough islands or nanofibril structure formation on the Cu surface depending on initial thermal oxidation temperature at 200 °C (Cu-200), 300 °C (Cu-300) and 400 °C (Cu-400). The glucose detection performance of the od-Cu electrodes was investigated by performing cyclic voltammetry (CV) and chronoamperometry (CA) with varying glucose concentration. A high sensitivity (4131.57 μA mM⁻¹ cm⁻²), low detection limit (1.41mM), wider linear range (0 – 3.9 mM) and long-term stability (60 days) have been recorded for oxide derived Cu prepared at 400 °C. The sensitivity is almost three times higher in comparison to the planner Cu surface. The od-Cu also exhibit low glucose oxidation potential in comparison to the pure Cu. This significantly enhanced glucose sensing ability of r has been attributed to the nanofibril morphology, origination of Cu (111) facet and formation of a stable oxide layer evidenced by XRD and EDS analysis. Moreover, despite higher sensitivity, od-Cu electrode does not show any response to the chloride ion, dopamine (DP), ascorbic acid (AA) and uric acid (UA). These results indicate that the od-Cu nanomaterial can be an excellent candidate to be used as an electrode for glucose sensing application.

Atherosclerosis is characterized by the recruitment of monocytes to the subendothelial space which then mature into macrophages in the presence of macrophage colony stimulating factors and under the influence of their microenvironment to either M1 or M2 phenotypes. Early detection of atherosclerosis is challenged by a phenomenon known as positive arterial remodelling. This phenomenon is characterized by outward expansion of arterial walls in response to development of plaques, thus retaining the lumen diameter and demonstrating no stenosis. It is one of the major causes for missing out the detection of atherosclerosis by techniques that rely on lumenography. This leads to the need for imaging agents capable of targeting and imaging plaque components. The current study aims at targeting one such plaque component, the M2 macrophages, that are prevalent in higher numbers during early-stage atherosclerosis and to image these macrophages using magnetic resonance imaging (MRI) to aid early detection and facilitate timely therapeutic intervention of atherosclerosis. The study employs ferritin, an iron storage protein, with its natural ligand, iron, for MRI contrast. M2 macrophages are known to express mannose receptors on their surface, and we thus aim at using mannose conjugated ferritin nanocages for targeted MRI of the M2 macrophages in the atherosclerotic plaques. Mannose-conjugation is hypothesized to increase accumulation of ferritin nanocages in M2 macrophages and therefore improve contrast by virtue of targeting.

Diabetes, one of the leading causes of death worldwide, is responsible for one-seventh of deaths in the global population each year. Non-invasive methods for sensing and screening glucose level are highly desirable due to the more comfortableness, simplicity, and no risk of infection. However, the insufficient accuracy and ease of interference limit the non-invasive sensing technique from practical medical applications. Here, we develop a non-invasive glucose biosensor for measuring glucose in saliva based on ferrocene-chitosan (Fc-Chit) modified carbon nanotubes (CNTs) electrode through a simple drop-casting method. Quantum chemical calculations as well as comprehensive experiments were conducted to optimize the electro-mediated Fc-Chit, demonstrating sturdy immobilization of glucose oxidase (GOx) on the electrode and leading to a better electron transfer process. Superior glucose sensing sensitivity of 119.97 μA/mMcm² in phosphate buffer saline (PBS) solution and 108.21 μA/mMcm² in artificial saliva, respectively, can be achieved in a wide sensing range of 20–800 μM. In addition, the electrode shows high stability (remaining 95.0% after three weeks) and high selectivity toward glucose in the presence of various interferences, including uric acid (UA), ascorbic acid (AA), and lactic acid (LA), which is attributed to the specific sites enabling GOx to be sturdily immobilized on the electrode. The results show that the proposed non-invasive glucose biosensor can serve as a technological solution for regular and accurate screening of blood glucose levels by saliva tests.

Doxorubicin (Dox) is the most widely used chemotherapeutic agent and is considered a highly powerful and broad-spectrum for cancer treatment. However, its application is compromised by the cumulative side effect of dose-dependent cardiotoxicity. Because of this, targeted drug delivery systems (DDS) are currently being explored in an attempt to reduce Dox systemic side effects. In this study, DDS targeting hepatocellular carcinoma (HCC) has been designed, specifically to the asialoglycoprotein receptor (ASGPR). Dox-loaded albumin-albumin/lactosylated (core-shell) nanoparticles (tBSA/BSALac NPs) with low (LC) and high (HC) crosslink using glutaraldehyde were synthesized. Nanoparticles presented spherical shapes with a size distribution of 257 ± 14 nm and 254 ± 14 nm, as well as an estimated surface charge of −28.0 ± 0.1 mV and −26.0 ± 0.2 mV, respectively. The encapsulation efficiency of Dox for the two types of nanoparticles was higher than 80%. The in vitro drug release results showed a sustained and controlled release profile. Additionally, the nanoparticles were revealed to be biocompatible with red blood cells (RBCs) and human liver cancer cells (HepG2 cells). In cytotoxicity assays, Dox-loaded nanoparticles decrease cell viability more efficiently than free Dox. Specific biorecognition assays confirmed the interaction between nanoparticles and HepG2 cells, especially with ASGPRs. Both types of nanoparticles may be possible DDS specifically targeting HCC, thus reducing side effects, mainly cardiotoxicity. Therefore, improving the quality of life of patients during chemotherapy.

The Oxygen-enriched Photodynamic Therapy (Oxy-PDT) is one of the emerging tumor-treating approaches, where the perfluorocarbon as a high-capacity oxygen carrier is conjugated to the photosensitizer that converts the carried triplet oxygens into reactive singlet oxygens, which kill cancer cells. However, the efficacy of Oxy-PDT in the biological system remains challenging because it is difficult to obtain cytosolic delivery of the Oxy-PDT agent into cells due to its low cell permeability. To overcome the issue, we synthesized the perfluoroalkyl-pyrene (PP) as the Oxy-PDT agent, which was further incorporated into lipid bilayers (DSPC and DPPC) for enhancing the delivery of the agent into cancer cells. Our results showed that the PP formed a well-ordered structure within a hydrophobic region of the DSPC-DPPC bilayers (Fluoroscence spectroscopy, DLS). We also confirmed that the PP incorporated into the liposomal bilayers successfully exhibited an excimer emission at 450 nm in aqueous solutions (Fluoroscence spectroscopy, DLS) and produced singlet oxygens (¹O₂) (UV-Vis absorption spectroscopy). Then, we applied our new Oxy-PDT to the human patient-derived cancer cells (i.e., glioma, a type of brain cancer) to evaluate the therapeutic efficacy. Using the immunocytochemistry and confocal microscopy, we demonstrated that the PP-liposomes were localized only within cancer cells and significantly decreased the number of cancer cells when irradiated with light. In this study, we are introducing a new class of small organic molecules for biomedical applications. We expect that our approach incorporating oxygen carriers, photosensitizers, and liposomes in one system would make a significant contribution to the study of the Oxy-PDT modality by improving the localization and timing of cancer killing agent delivery.

Periodontitis is a highly prevalent infectious disease that causes the progressive destruction of teeth-supporting tissues: alveolar bone, cementum, and periodontal ligament. If left untreated it can lead to tooth mobility and eventually tooth loss, impairing oral function, aesthetics, and the patient’s overall quality of life. Bone Tissue Regeneration (BTR) is a surgical therapy to restore the alveolar bone around the tooth for reducing its mobility or, if the tooth was already lost, for future implant placement. This periodontal therapy involves the use of a resorbable membrane that selectively excludes the relatively rapid epithelial and fibroblastic down growth into the bone defect, allowing the repopulation of the defect sites with slower migrating endogenous bone cells and stem cells to regenerate the affected tissues. Two of the major reasons for clinical BTR failure are the bacterial colonization of the membrane-defect area and the fast biodegradation of the membrane, causing postoperative infections and a premature rupture of the membrane, limiting the regeneration process.
In this work, we present the development of biodegradable polymer-blended membranes functionalized with ZnO-NPs via electrospinning to prevent local bacterial colonization and, simultaneously, favor bone growth.
The developed membranes were synthesized based on a homogeneous polymer blend of polycaprolactone and gelatin (PCL-G) and modified, via electrospinning, with different concentrations (1, 3, and 6 wt.%) of ZnO nanoparticles (ZnO-NPs). The chemical composition, micro-morphology, hydrophilic character, biodegradation rate, and thermal and mechanical properties of the membranes were analyzed under conditions similar to the physiological environment. The antibacterial effect of the PCL-G membranes modified with ZnO-NPs was evaluated using five bacterial strains, two important periodontal pathogens: A. actinomycetemcomitans serotype b and P. gingivalis; and three aerobic pathogens causing prevalent nosocomial infections: S. aureus, E. coli, and S. epidermidis. We also investigated whether the developed membranes could stimulate osteogenic differentiation, and consequently bone regeneration. For this, the expression of osteoblast markers (osteocalcin and osteoprotegerin) and calcium deposition in human bone marrow-derived mesenchymal stem cells (BM-MSC) after exposure to the membranes, were analyzed.
The developed membranes presented appropriate physicochemical properties to be potentially used in clinical treatments, mainly, the mechanical properties and biodegradation rates were satisfactory. All the PCL-G membranes modified with 1, 3, and 6 wt.% of ZnO-NPs showed a significant reduction in the planktonic and biofilm formation of the five clinically relevant tested. However, only the membranes modified with the lowest concentration of ZnO-NPs (1 wt.%) stimulated the production of osteoblast markers and calcium deposits in human BM-MSC and were biocompatible with human bone cells and gingival fibroblasts cells.
These results suggest that the PCL-G membranes with 1 wt.% of ZnO-NPs are high-potential candidates for BTR treatments, as they were the most effective in terms of better antibacterial effectiveness at biocompatible NPs-concentration while creating a favorable cellular microenvironment for bone growth.

Introduction: The human eardrum or tympanic membrane (TM), is a thin, conical tissue of the middle ear that captures sound waves and transforms them into mechanical motion. Successful transmission of these nano-vibrations to the inner ear is attributed to its precise three-dimensional (3D) design [1]. In this work, we investigated the integration of tissue engineering with different nanotechnologies for an accurate modelling and reconstruction of the human TM. Hierarchical scaffolds were biofabricated in this regard, and validated based on their mechanical, acoustical, and biological response [2]. Subsequently, antibiotic-loaded nanoparticles along with anti-inflammatory nanofillers were incorporated to prevent infections or immune reaction post implantation [3, 4].

Methods: A Python script was developed for modelling the anatomical architecture of the human eardrum. Computational simulations were performed on COMSOL Multiphysics to identify dominant structural attributes within the generated TM models. The selected geometries were fabricated using a combination of poly(ethylene oxide terephthalate)/poly(butylene terephthalate) (PEOT/PBT) with chitin nanofibrils (CN). A hybrid biofabrication approach combining electrospinning and additive manufacturing was implemented in this regard. 3D patterns with varying radial and circumferential arrangements were deposited on the nanofibrous electrospun membranes to replicate the collagen fibrils of the native tissue. A co-electrospinning setup was introduced for the incorporation of ciprofloxacin-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles within these eardrum scaffolds. The mechano-acoustical response of the fabricated constructs was evaluated by applying the techniques of macroscopic indentation and laser Doppler vibrometry. Finally, human mesenchymal stromal cells (hMSCs) were cultured to assess their differentiation towards TM fibroblasts.

Results: Biomimetic eardrum scaffolds were fabricated using PEOT/PBT/CN nanocomposites. A three-fold reduction in the diameter of electrospun nanofibers was obtained upon the introduction of CN within the polymeric matrix. The co-electrospinning setup was successful in depositing and adhering PLGA nanoparticles onto the nanofibrous membranes. In silico investigation of the chosen TM models suggested a geometrical dependency of their mechanical and acoustical responses, which was further corroborated by the experimental measurements. In general, radially aligned constructs were noted to show a more comparable mechano-acoustical behavior with respect to the native tissue. In vitro studies performed with hMSCs revealed a favorable influence of 3D hierarchy on cellular alignment and extracellular collagen production. Moreover, a pronounced downregulation of pro-inflammatory cytokines was achieved with the inclusion of CN. Lastly, the ciprofloxacin-loaded TM scaffolds demonstrated the desired biocompatibility and drug release kinetics.

Conclusions and Outlook: The optimized nano-biofabrication strategies allowed the creation of biomimetic constructs within the anatomical dimensions of native eardrum. The addition of CN as a nanofiller within the PEOT/PBT matrix produced significant improvements in their mechanical and immunomodulatory capabilities. Besides, a tunable release of ciprofloxacin was achieved from the fabricated scaffolds. Finally, advanced 3D bioreactor platforms are currently under investigation to differentiate the cultured hMSCs toward TM-specific cells.

Acknowledgments: This project was funded by EuroNanoMed III under Horizon 2020 Research and Innovation Framework Programme of the European Commission and the Netherlands Organization for Scientific Research (NWO).

References:
[1] Anand S et al. Prog. Mater. Sci. 2022; 127: 100942.
[2] Anand S et al. Adv. Healthc. Mater. 2021; 10(11): 2002082.
[3] Günday C*, Anand S* et al. Drug Deliv. Transl. Res. 2020; 10(3): 706-720.
[4] Danti S*, Anand S* et al. Pharmaceutics. 2021; 13(9): 1440.

We argue that one of the key enabling steps for nanoscale materials to make a qualitative advance in medical sciences is that we understand ‘what the cell sees’ (1) when it comes in contact with the nanomaterial. This would move us from a phenomenological effort of trying many different nanomaterials to de novo designers of structures that convey the biological signals we wish to send.

We have therefore sought to understand how living organisms ‘recognise' the unlimited diversity of nanoscale materials. By ‘recognise’ we mean that cells (and higher organisations) are able to discern even quite subtle differences in nanostructure architecture (2), using mechanisms that transcend simple ligand receptor interactions. These mechanisms capture and interpret inputs at the cell membrane-nanostructure interface across some tens of nanometers. Progress is now being made in this problem, and we summarise some of the insights. (3)

1. J. Am. Chem. Soc. 2010, 132, 16, 5761–5768
2. PNAS Nexus, Volume 1, Issue 4, September 2022, pgac172
3. Nature Nanotechnology, 2021 Mar;16(3):229-242.

Amphiphilic functionalized gold nanoparticles (AuNPs) are able to translocate cell membranes both passively and non-destructively, making them important tools for medical applications like drug delivery. However, this translocation is absent in accompanying model membrane studies and molecular dynamics simulations, though both have used symmetric and homogeneous lipid compositions. It is thus possible that lipid asymmetry in model membranes is a driving force of AuNP translocation. Here, we use the droplet interface bilayer method to vary phospholipid leaflet composition and form planar asymmetric membranes, then subsequently inject amphiphilic AuNPs into one of the aqueous droplet reservoirs. Passive translocation across the asymmetric bilayer is monitored by the presence of membrane-impermeable carboxyfluorescein in the opposite droplet, which becomes systematically quenched upon AuNP translocation due to the unique surface plasmon resonance of the gold core. We vary both the lipid head group type and tail group saturation, as well as the amount of hydrophobic functionalization on the AuNPs, to discern how changes in the membrane energy landscape affect translocation. We further use integrated electrodes to couple visual observations of translocation with changes in bilayer capacitance, resistance, and surface tension. The simultaneous optical and electrical monitoring reveal the importance of lipid asymmetry in nanoparticle translocation and enable increased biological relevancy of in vitro systems.

With their ability to passively enter cells, amphiphilic gold nanoparticles (AmNPs) functionalized with a striped pattern of hydrophilic sulfonate and hydrophobic octanethiol ligands show promise for enhanced drug delivery. However, the specific mechanisms of their passage through cellular membranes remain unclear, in part due to a lack of appropriate experimental tools. Ongoing work in the Sarles group at UTK seeks to reveal these interactions by leveraging the droplet interface bilayer (DIB) technique for model membrane formation and electrophysiological characterization. The advantages of the DIB method for assembling a lipid bilayer include the ability to independently control droplet and lipid leaflet compositions and membrane area. The DIB technique also permits the use of electrophysiology measurements to monitor changes in bilayer structure and transport properties, both of which may aid in the disclosure of NP-membrane interactions.
Herein, we utilize micro-injection to incorporate AmNPs into one droplet of a droplet interface bilayer after bilayer formation occurs and use electrophysiological measurements as well as brightfield imaging to assess NP-induced changes in bilayer properties. Post-bilayer-formation direct micro-injection of NPs allows for maintaining stable membranes needed to study NP-membrane interactions and permits before-and-after comparisons to be made on the same membrane. In this study, DPhPC model membranes are formed between 300 nL droplets in hexadecane. A pulled micropipette connected to a pneumatic injector is used to inject AmNPs without disrupting the membrane. Before injecting AmNPs, the electrical resistance and capacitance of the membrane are electrically tested using wire-type electrodes to establish baseline bilayer characteristics and, thereby, quantify NP-induced changes to the membrane after injection. This procedure reveals that AmNPs with 15 mol% OT ligands decrease the area-normalized capacitance of the bilayer by up to 20%, where the amount of reduction depends on the final AmNP concentration. When combined with other electrical measurements, this trend indicates that AmNPs spontaneously embed into the hydrophobic center of the bilayer, increasing its average thickness and reducing its capacitance per unit area. In contrast, no discernible changes in the bilayer's specific capacitance were observed after adding hydrophilic NPs lacking hydrophobic ligands. This implies that the hydrophobic ligands are responsible for the insertion of AmNPs into the bilayer. Moreover, AmNPs with 30 mol% hydrophobic ligands showed larger decreases in specific capacitance that occurred at a lower AmNP concentration) compared to 15 mol% OT AmNPs. Finally, we observed that AmNPs lowered the membrane resistance, resulting in increases in average ion current through the bilayer under an applied voltage. These changes also coincided with transient, discrete current spikes with durations of 3 and 12 ms. Unlike many works which leveraged qualitative experimental measures, our findings demonstrate how direct microinjection and electrophysiology measurements that specifically incorporate capacitance monitoring can be used to study NP-membrane interactions.

Due to their unique physicochemical properties nanomaterial (NM)-based technologies are growing exponentially in scope and economic importance. Additionally, due to their electric and antibacterial attributes silver NMs (AgNMs) are integrated into electronic, sensing, and consumer applications. This surge has resulted in significant degrees of NM waste and increased rates of human exposure. This has created a vital need to fully understand the potential biological consequences of NM exposure, characterize resulting NM-biological interfaces, and determine subsequent toxicological effects. NM safety assessments are currently being carried out in both cell-based in vitro and animal-based in vivo models, with limited correlation between the two models due to the fact that NM behavior is dependent upon environmental and exposure factors. Therefore, there exists a need for the development of an enhanced cellular model that preserves the advantages of in vitro systems while incorporating in vivo influences to produce an efficient, realistic, and relevant means for NM exposure and evaluation.

As such, the goal of this study was to design, optimize, and implement an enhanced in vitro microenvironment model to create a rapid, more realistic mechanism to evaluate the safety and nano-cellular interface of experimental NM constructs. Using perfusion plates, this model was comprised of three cellular compartments, dynamic flow to represent the cardiovascular system, and a combination of tissue-based and immune cell lines. The set-up selected for this study includes 1) initial NM exposure into an alveolar model, followed by 2) transport into liver then 3) skin compartments: representing initial inhalation, movement into the liver for waste removal, and relocation to the skin. AgNMs were incorporated into for this study, which are renowned for their ability to induce stress, genetic modifications, immune activation, and cytotoxicity. Furthermore, to effectively correlate NM deposition and physicochemical properties to bioresponses, two different AgNM sizes and surface chemistries were evaluated.

The results of this work demonstrated that the nano-cellular interface varied as a function of several influences, predominantly the presence of fluid dynamics and both primary size and surface chemistry of the AgNPs. One unique aspect of this study was the development of kinetic profiles of the nano-bio interactions within each, interconnected cellular compartment. Polymer coated AgNMs proved to be more adept in traveling between cellular compartments than their citrate coated counterparts, with a more evenly distributed. Looking at the toxicological profile following AgNM exposure, the cellular immune response was substantially decreased under dynamic conditions, as assessed via pro-inflammatory cytokine secretion rate. The degree of nano-bio interactions was directly linked to observed cellular outcomes, including intracellular stress and activation of signal transduction pathways; both of which were dependent upon exposure conditions and AgNM physicochemical properties. In conclusion, the enhanced in vitro model, which successfully incorporated multiple cellular components and fluid dynamics, resulted in a modified nano-cellular interface from a static, mono-cellular control. The evaluation of kinetic deposition rates, which varied with NM surface chemistry and primary particle size, were correlated to observed nanotoxicological outcomes. This work demonstrates that by including physiologically relevant modifications, in vitro models can be an effective tool in predicting nano-bio interactions, particle fate, and safety assessments within a biological system.

The vast majority of new drug candidates are "badly behaved", either poorly soluble, poorly permeable, or both. The pandemic has increased the expectation from patients and investors that we develop medicines more quickly. So, how can we accelerate timelines while also giving drug candidates the best chance of success in preclinical and clinical studies? We will discuss case studies demonstrating how nano-enabled approaches can enable you to formulate fast while also futureproofing your products.

Bio-textiles are primarily engineered for specific biomedical end-uses like textile-based drug-delivery carriers for appropriated in-vivo target sites while maintaining somatic harmony. The use of nanotechnology for fabricating such bio-textiles via electrospinning gained importance because of controllable nanoscale diameters, the encapsulation amount of active agents, and overall efficacy in targeted delivery overcoming first-pass metabolism barriers. Fine-tuning such parameters positively affects the morphology interface, imparts enhanced physiochemical properties, and facilitates bio-nano-interface construction. Responsive polymeric base materials as encapsulation agents for electrospun nanofibers for active agents like medicaments are preferred for their biocompatibility and homeostasis during interaction with bio-compounds. The large surface area and highly porous structure of the nanoparticles allow easier disintegration upon subjection to proximal physiological fluids. The protein corona expedites the stable transition of the nanoparticles to the target delivery site via endocytosis or direct penetration. The amorphized state of the active agent within the nanofibrous matrix allows easier adsorption into target organs. Apart from polymeric bases, cyclodextrins are a safe choice for nanofiber matrices to confine active agents via inclusion complexation (IC) within the hydrophobic truncated cone for drug delivery systems by amorphization of the crystalline active agents and enhancing its solubility, bioavailability, and stability. Cyclodextrins are more water soluble than polymers and become a better choice as an encapsulation agent because solubilizing polymers need toxic solvents sometimes. Cyclodextrin help in the fast or slow, or controlled release of the encased active agents leading to drug delivery in a similar fashion as the polymeric nanofibers. Cyclodextrin and active agent inclusion complexes can be electrospun into nanofibers in the form of strips or onto textile substrates to form bio-textiles. In this study, Lidocaine (Lid), a crystalline and poorly water-soluble amino-amide drug, was encapsulated within Hydroxypropylated Beta Cyclodextrin (HPβCyD) nanofiber matrices to enhance its topical bioavailability and solubility. Aqueous solutions of Lid/HPβCyD-IC in different molar ratios were electrospun into nanofibrous (NFs) strips and checked for their physiochemical properties to ascertain IC formation and understand the efficacy of encapsulation and amorphization of Lid in HPβCyD nano matrix through 1H-NMR, FTIR, XRD, DSC, and TGA. The Lid/HPβCyD-IC NFs were deposited on a non-woven cotton patch to create a bio-textile patch for topical administration. The in-vitro release performance was examined, and the findings corroborated the fast-release corollary.

Transdermal drug delivery (TDD) exhibits high drug efficacy and minimized side effects over oral administration because it bypasses first hepatic metabolism and gastrointestinal tract. However, the outermost layer of the skin, the stratum corneum (SC; composed of thousands of lipid layers), is recognized as the major barrier in TDD.
With the recent FDA approval case, Microneedle (MN) is recognized as an effective solution for TDD. MN, however, also has an issue with remaining physical damage up to the dermis, where abundant immune cells reside. Therefore, MN can cause external infection and induce the hypersensitivity that can be fatal for children.
Here we devised a needle-free TDD based on lipid as a chemical penetration enhancer. Specifically, we designed structure of lipid nanoparticles with different fusogenicity (liposome < cubosome < hexosome). With structure engineered lipid nanoparticles, Structure Optimized Lipid-based Intradermal Delivery (SOLID) patch was fabricated. Our in vitro test revealed that cubosome- and hexosome-SOLID patch outperforms that of liposome in SC penetration. To understand behind principle of outstanding performance, we conducted in situ synchrotron SAXS study and found out both cubo- and hexo-some show much faster kinetics in SC lipid layer disruption over liposome. Our study indicates that structure engineering of lipid nanoparticle can be an effective approach for the development of needle-free TDD. We believe needle-free TDD can be an effective strategy for not only drug delivery, but many other applications including mRNA intradermal vaccine to prevent pandemic.

Nitric oxide (NO) is a potent biological molecule that contributes to a wide spectrum of physiological systems, including cardiovascular system, immune system, central nervous system, and outflow physiology. However, NO delivery technology remains severely limited due to the physiological properties of NO: 1) NO has a short half-life in human tissues (seconds); 2) NO can only diffuse over short distances (~100 µm), thus limiting its action to only areas near the source of delivery; and 3) NO can exert protective or deleterious effects depending on its concentration. Current strategies for NO delivery focus on encapsulation of NO donors into pre-fabricated scaffolds or an enzyme-prodrug therapy approach. The former is limited by the finite pool of NO donors available, while the latter is challenged by the inherent low stability of natural enzymes. Enzyme mimics are attractive substitutes for their natural counterparts in diverse biomedical applications because they have excellent stability against biological degradation, high temperature, and extreme pH conditions compared with natural enzymes. In this work, we present nanoparticles with innate glutathione peroxidase and glycosidase activities that catalytically decompose endogenous and exogenous NO donors (e.g. S-nitrosoglutathione, S-nitrosocysteine, and β-gal-NONOate) to generate NO at physiological conditions. Through the nanozyme approach, we envision that sustained NO delivery could be achieved by relying on life-long pools of endogenous NO donors, and when needed, on-demand NO delivery at the desired levels of NO could be realized by externally administered exogenous NO prodrugs. By tuning the concentrations of particles and NO prodrugs, physiologically relevant NO levels were generated. These materials preserved their catalytic property to generate NO for at least 6 months. We further demonstrated the therapeutic activity of NO generated by nanozymes to inhibit cancer cell proliferation and to disperse bacterial biofilms. Our findings may open new routes to the next generation of NO-releasing biomaterials and devices in diverse biomedical applications.

Numerous advances and innovative therapies have been developed for interventional cardiology over the recent years, since the first introduction of balloon angioplasty. Among these, bioresorbable vascular scaffolds (BVS) represent a breakthrough technology, heralded as potential candidates to treat atherosclerosis (a cardiovascular disease related to the build-up of hypercholesteremic plaque in the dysfunctional arteries). Compared to permanent metal stents, BVS brings the promise of complete bio-sorption after regaining the normal blood flow through arteries, restoration of natural vasomotion, and the possibility of restenting at the same site (if needed) without the interference of previous treatments. However, this breakthrough technology is facing a serious issue of late-stent-thrombosis. The underlying causes of failure of this technology could be summarized as (1) delayed endothelialization, (2) recoiling after the implantation, and (3) ineffective, and uncontrolled release of cytotoxic drug which not only stops the proliferation of vascular smooth muscle cells but also affects the normal functioning of endothelial cells.
In this study, to address these key shortcomings, we introduce a unique platform for effective drug delivery only to the lesion site, through the integration of nanoneedles (NNs) within a poly L lactic acid (PLA) BVS.
The planar surface (metal or polymeric) of stents usually result in the non-specific burst release of the cytotoxic limus drug towards the vessel wall as well as to the lumen, leading to less efficient drug delivery and disruption of normal functions/tight junctions of endothelial cells. In contrast, the NNs can penetrate the vascular tissue in a minimally invasive way and precisely target and modulate the release of drugs, thus selectively treating the atherosclerotic vessel wall and minimizing systemic dispersion. As a proof of concept, here we demonstrated the interfacing of NNs with primary human vascular smooth muscle cells (HVSMCs: the cells of interest and the primary cause of in-stent-restenosis) and the capacity of NNs to deliver the GFP-mRNA to these cells.
The biocompatibility of the fabricated NNs platform has been evaluated using human vascular endothelial cells (HUVECs). Results demonstrated no significant impact on cell viability, adhesion, spreading, proliferation, and most importantly on the formation of the tight junction between the endothelial cells.
Furthermore, we evaluated the bio-interfacing of NNs with vessel wall tissue compared to the plane PLA surface to estimate the impact on recoiling. The cells are known to grab and pull on individual nanoneedles, yielding significantly enhanced adhesion which can thus enhance the apposition to the vessel wall and minimize the issue of BVS recoiling The ex vivo interfacing experiments, performed using porcine artery wall and analyzed using histological assessment of the interfaced tissue specified an overall effect of nanoneedles on underlying and surrounding tissue.

The developed degradable platform can be potentially used to deliver the drugs to the target site with minimal side effects and also can help to solve the recoiling issue that exists with BVS technology. With directional and respective modifications, this platform can also be used to treat other peripheral blockage conditions where we need to open up the lumen and at the same time need to deliver the drug/s efficiently to cure the condition.

Most conventional chemotherapeutics have narrow therapeutic windows, and thus their delivery remains challenging and often raises safety and efficacy concerns. Theranostic platforms, with simultaneous encapsulation of therapeutic and diagnostic agents, have been proposed as next-generation formulations which can overcome this issue. We have shown in recent studies that co-encapsulation of superparamagnetic iron oxide nanoparticles (potent magnetic resonance imaging [MRI] contrast agents) and chemotherapeutic active ingredients into nanoscale fibers and nano-microscale particles produces formulations from which drug release can be directly quantified from the MRI signal. We have generated systems appropriate for both oral and implant delivery. This presentation will summarize our recent findings in this research, exploring the effect of formulation composition and morphology on the functional performance.

Pancreatic cancer is one of the most lethal and aggressive tumors with a 5-year survival rate of 5%. Due to the complex and surgically inaccessible anatomical position of the pancreas, most cases are treated using chemotherapeutics. However, these drugs have several limitations such as low targeting specificity, high instability, severe side effects from the use of high doses, inability to bypass cell membranes, and poor pharmacokinetics. One strategy to improve the efficacy of chemotherapy drugs is their encapsulation into nanoparticle systems. Among different nanoparticle systems, metal-organic frameworks (MOFs) represent a promising opportunity for the treatment of cancer. MOFs are a new class of biocompatible nanoporous materials with exceptionally high surface area (>8,000 m²/g) and drug loading capabilities (>70% drug weight), surpassing that of alternative drug delivery systems. Their chemical flexibility allows them to host virtually any therapeutic payload, including small molecules and macromolecules, and to be functionalized with different surface molecules (e.g., PEG), offering a platform with the potential to ultimately become a universal “plug-and-play” system.

In this work, the drug loading efficiency of the most common chemotherapeutic drugs for pancreatic cancer (gemcitabine, paclitaxel, and SN38) was assessed using a MOF named PCN222. PCN222 was first synthesized and characterized by DLS and SEM to confirm a size between 120-150 nm that ensures its ability to interact at a cellular level. PXRD and N₂ adsorption were used to confirm the crystallinity and the porosity of the material. The three drugs were then loaded independently into PCN222 followed by surface functionalization with PEG chains to increase both stability and biocompatibility of the drug-MOF complex. The drug loading efficiency was measured using UV-vis and HPLC while PEGylation and drug content were confirmed by ζ-potential, DLS, FT-IR, and TGA. Following the material characterization, the three drug-loaded PCN222 were tested for in vitro toxicity in pancreatic cancer cell lines (BxPC-3, Mia-Paca-2, and PANC-1) using live-imaging cell analysis and MTS end-point viability assays. Cell internalization was further studied using confocal microscopy. Subsequently, the most effective formulation was evaluated in vivo using a subcutaneous xenograft mouse model of human PDACs of BxPC-3.

The viability analysis showed that different pancreatic cancer cells tolerated high concentrations of the empty PCN222, highlighting its biocompatibility in vitro. The PEG coating improved the stability and the sustained drug-release capability of loaded PCN222 in vitro. In addition, PCN222 showed a high cell internalization efficacy in BxPC-3, Mia-PaCa2, and PANC-1 cells. The in vivo studies using human pancreatic cancer xenograft mouse models showed that the delivery of chemotherapeutics loaded in PCN222 led to enhanced antitumor efficacy when compared to the free drug.

PCN222 is a promising drug delivery system able to increase the efficacy and safety of current standard-of-care chemotherapeutics such as gemcitabine, paclitaxel, and SN38, paving the way toward the clinical translation of MOFs in pancreatic cancer and other hard-to-treat cancers.

Therapeutics that can be activated by radiation in situ to enhance the efficacy of radiotherapy are highly desirable. Herein, 7-Dehydrocholesterol (7-DHC), a biosynthetic precursor of cholesterol, is engineered in a liposome nanoparticle as a targeting delivered radiation-induced radiosensitizer (RIRS) towards non-small cell lung cancer (NSCLC). The studies show that 7-DHC can be activated and react with radiation-induced reactive oxygen species (ROS) and in turn promote lipid peroxidation, subsequently induce ferroptosis. For efficient delivery, 7-DHC is encapsulated into a liposome nanoparticle, and been tested in tumor bearing mice, results showed a significantly enhanced the efficacy of radiotherapy. After treatment, 7-DHC is converted to cholesterol, causing no detectable side effects or hypercalcemia. This new method represents a nature-inspired, safe RIRS with great potential in clinical translation.

Piezoelectric nanomaterials, which are capable of generating reactive oxygen species (ROS) via piezocatalytic redox reactions under mechanical stress have emerged as promising nanoplatforms for efficient cancer treatment. Herein, piezoelectric nanoparticles such as ZnO nanorods and metal sulfide nanoparticles were functionalized with poly(ethylene glycol) (PEG) and loaded with chemodrugs for ultrasound (US)-triggered combination chemo-piezocatalytic cancer therapy. The drug-loaded piezoelectric nanoparticles can efficiently induce piezoelectric polarization for the generation of ROS under US irradiation. In addition, the drug-loaded piezoelectric nanoparticles not only generated ROS under US irradiation but also improved the intracellular delivery of chemodrugs. In vivo study showed that drug-loaded piezoelectric nanoparticles effectively accumulated in the tumors and significantly suppressed the tumor growth under US irradiation without systemic toxicity. This study demonstrates the feasibility of piezoelectric nanoparticles as US-triggered piezocatalytic agents that can selectively and effectively eradicate tumors via chemo-piezocatalytic combination therapy.

Hepatocellular carcinoma (HCC) is commonly diagnosed in the late stages which restricts treatment options to the FDA approved drug sorafenib. However, sorafenib’s low efficacy, poor solubility, and toxic side effects limit its performance to only 30% of patients. In addition, the lack of a proper diagnostic tool for either detecting the tumour in the early stages or to monitor the disease progression represents another barrier. ^1-3

This work aims to solve these problems by developing theranostic mesoporous silica nanoparticles (MSNs) that can enhance the therapeutic and diagnostic performance through combination therapy of doxorubicin.HCl and sorafenib tosylate as well as magnetic resonance imaging (MRI) contrast by loading of MRI-active gadolinium 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid (Gd³⁺-DOTA) chelate. Therapeutic MSNs have been prepared and the effect of the pore size, internal pores’ chemistry and solvent polarity (DMSO, DMF, ethanol, THF, acetone) on both drug loading and entrapment efficiency of sorafenib tosylate and doxorubicin.HCl has been studied. In term of diagnosis, MRI-active MSNs have been optimised by incorporating the MRI contrast agent (Gd³⁺-DOTA) chelate to internal surfaces, at different locations where water gating can be exploited to provide an ‘on/off’ MRI signal switch for disease diagnostics. ⁴ In order to cap the pores, different molecular weights of UCST thermo-responsive polymers (poly(acrylamide-co-acrylonitrile)) were synthesized using reversible addition−fragmentation chain-transfer polymerization (RAFT); where design of experiment (DOE; central composite design) was applied to optimise the temperature at which the polymer will change its conformation from dehydrated to hydrated, allowing water access to the internally located paramagnetic species (turning ‘on’ the MRI contrast) and concurrent controlled drug release. ^5,6

Sorafenib tosylate loading capacity into MSNs has been highly affected by solvent polarity and pore size variation; where maximum drug loading was achieved upon using THF as a solvent and MSNs of narrow pore diameter of 3.5 nm. In the case of doxorubicin.HCl, the loading capacity was decreased 5 times upon scaling up, however other parameters showed no significant effect on its loading. The dual loaded optimised MSNs showed loading capacity and entrapment efficiency percentages of 29.1 % and 27.1 % for sorafenib tosylate and 17.4% and 9% for doxorubicin.HCl, respectively. MRI-active MSNs showed relaxivity values (r_{<span style="font-size:10.8333px">1</span>}) of 60.1 mM^-1 s ^-1 at 0.47 T for internally located Gd³⁺ chelates on MSNs-Gd, compared to the commercially available Gd³⁺-DOTA chelate (Dotarem®) of r_{<span style="font-size:10.8333px">1</span>} 3.4 mM^-1 s ^-1 at 1 T. The molecular weight of the synthesised UCST thermo-responsive polymers (poly(acrylamide-co-acrylonitrile)) ranges between 84600- 164100 g/mol and their cloud points were characterised using dynamic light scattering (DLS) as well as turbidimetry, and found to range between 36.6–85.5 ^oC. As a final step, the behaviour of the optimised thermo-responsive polymer grafted onto the theranostic MSNs will be described, including studies on the efficacy and biosafety of the developed system on Hep-G2 cell lines.

References

1. Galun, D., Srdic-Rajic, T., Bogdanovic, A., Loncar, Z. & Zuvela, M. J. Hepatocell. Carcinoma 4, 93–103 (2017).
2. Wang, C. et al. Drug Dev. Ind. Pharm. 42, 1938–1944 (2016).
3. Zhang, J. et al. Nanomedicine (Lond) 12, 911–925 (2017).
4. Jason J. Davis,* Wen-Yen Huang and Gemma-Louise Davies. J. Mater. Chem. 22, 22848-22850 (2012).
5.Summers, M. J., Phillips, D. J. & Gibson, M. I. Chem. Commun. 4223–4225 (2013).
6. Gibson, M. I. & O’Reilly, R. K. Chem. Soc. Rev. 42, 7204–7213 (2013).

Radiolabeled nanomaterials have gained tremendous interest over the last 2 decades, which can play diverse roles in imaging, image-guided drug delivery, as well as theranostics of a number of diseases such as cancer. Some recent examples of radiolabeled materials from our recent work will be briefly described in this talk.

Although chelator-based radiolabeling techniques (commonly used for labeling nanomaterials with radiometals such as ⁶⁴Cu/⁸⁹Zr) have been used for decades, concerns about the complexity of coordination chemistry, possible alteration of nanomaterial pharmacokinetics, and potential detachment of radioisotopes have driven the need for developing a simpler yet better technique for future radiolabeling, which may facilitate future clinical translation.

The emerging area of intrinsically radiolabeled nanomaterials can take advantage of the unique physical and chemical properties of well-selected inorganic or organic nanomaterials for radiolabeling, and more importantly, offer an easier, faster, and more specific radiolabeling possibility to facilitate future clinical translation. Generally speaking, the four major categories of intrinsically radiolabeled nanomaterials include: 1) hot-plus-cold precursors, 2) specific trapping, 3) cation exchange, and 4) proton beam activation.

Representative examples of these strategies will be briefly illustrated in this talk, with the main focus on our own work that involves the radiolabeling of a variety of nanomaterials via “specific trapping”. The nanomaterials investigated in our laboratory include silica/carbon-based nanomaterials, COVID-19 nano-vaccines, multifunctional/multimodal hybrid nanomaterials, iron oxide nanoparticles, micelles, DNA nanostructures, etc. [1-10].

References
1. Goel S, Ferreira CA, Chen F, Ellison PA, Siamof CM, Barnhart TE, Cai W. Advanced Materials, 2018, 30, 1704367. (PMCID: PMC5805572)
2. Ni D, Jiang D, Ehlerding EB, Huang P, Cai W. Accounts of Chemical Research, 2018, 51, 778-788. (PMCID: PMC5878690)
3. Jiang D, Ge Z, Im H-J, England CG, Ni D, Hou J, Zhang L, Kutyreff CJ, Yan Y, Liu Y, Cho SY, Engle JW, Shi J, Huang P, Fan C, Yan H, Cai W. Nature Biomedical Engineering, 2018, 2, 865-877. (PMCID: PMC6258029)
4. Ni D, Ferreira CA, Barnhart TE, Quach V, Yu B, Jiang D, Wei W, Liu H, Engle JW, Hu P, Cai W. Journal of the American Chemical Society, 2018, 140, 14971-14979. (PMCID: PMC6310174)
5. Ni D, Ehlerding EB, Cai W. Angewandte Chemie International Edition, 2019, 58, 2570-2579. (PMCID: PMC6314921)
6. Ferreira CA, Ni D, Rosenkrans ZT, Cai W. Angewandte Chemie International Edition, 2019, 58, 13232-13252. (PMCID: PMC6698437)
7. Ni D, Wei H, Chen W, Bao Q, Rosenkrans ZT, Barnhart TE, Ferreira CA, Wang Y, Yao H, Sun T, Jiang D, Li S, Cao T, Liu Z, Engle JW, Hu P, Lan X, Cai W. Advanced Materials, 2019, 31, 1902956. (PMCID: PMC6773480)
8. Jiang D, Rosenkrans ZT, Ni D, Lin J, Huang P, Cai W. Accounts of Chemical Research, 2020, 53, 1869-1880. (PMCID: PMC7494607)
9. Wang H, Guo J, Lin W, Fu Z, Ji X, Yu B, Lu M, Cui W, Deng L, Engle JW, Wu Z, Cai W, Ni D. Advanced Materials, 2022, 34, 2110283. (PMCID: PMC9012683)
10. Li S, Wang Y, Wu M, Younis MH, Engle JW, Zhu X, Cai W. Advanced Materials, 2022, 34, e22049763. (PMID: 35973230)

Each year, more than two million women worldwide are diagnosed with breast cancer [1]. In the typical surgical treatment of this cancer the primary tumor is removed, together with the so called sentinel lymph nodes (SLNs), these are the lymph nodes that have the highest probability of being invaded by cancer cells. A combination of two methods has been established as the gold standard for the detection of SLNs. Metastable radioactive Technetium-99m (^99mTc) labeled nanocolloids are either peritumoral or periareolar injected several hours before surgery and accumulate in the SLNs. A preoperative SPECT/CT is made to identify the exact anatomic location of the SLNs and during surgery, a handheld gamma counter is used as confirmation. SLN imaging is often supplemented by an intraoperative injection of a blue dye to visually guide the surgeon. Unfortunately, the current standard has several downsides; the radioactive nanocolloids have a short half-life (i.e. 6 hours), SPECT imaging has a spatial resolution in the mm-range and both the patient and the surgical team are exposed to ionizing radiation. In addition, the blue dye can only be detected at a depth of a few millimeters (increasing the risk of missing the SLN), is prone to leach from the lymphatic vessels, occasionally cause (severe) allergic reactions, and may cause a long-lasting blue stain remaining on the breast for several months. Therefore, there is a need for alternative imaging methods to identify SLNs.
As an improved alternative to the current clinical standard, we have developed dual-modality nanocrystals (NCs) for the detection of SLNs using X-ray Computed Tomography (CT) and near-inrared (NIR) fluorescence. By removing radioactivity from the equation, we could reduce overall patient radiation exposure and remove the need for high-cost SPECT scanners, and instead use more widely available and faster imaging techniques like CT or conventional radiography to identify SLNs. The second imaging modality, NIR-fluorescence, is part of the same imaging probe and as such does not suffer from undesired tissue extravasation like the currently used small molecule dyes do. To mimic the behavior of the currently used clinical nanocolloids, we synthesized high-density bio-inert nanocystals that are approximately the same size after surface functionalization (5 - 10 nm). Next, we functionalized the NCs with our recently developed catechol-derived ligands, providing colloidal stability in relevant biological buffers, such as phosphate buffered saline at concentrations up to 300 mg NCs/ml. In the following step, we further improved the surface chemistry of the NCs by synthesizing an azide-terminated catechol ligand and apply strain-promoted click chemistry to covalently link fluorophore molecules to the NCs to create a dual-modality imaging-probe. Following this, we performed an in vivo evaluation of the dual-modality NCs in mice, imaging the lymphatic system using CT and NIR-fluorescence. We found that the NCs drain to the SLN shortly after injection and provide high in vivo contrast enhancement and NIR-fluorescence. Contrast enhancement and fluorescence remain high over several hours, which could make the NCs useable for extended surgical procedures. We further confirmed our findings by performing a longitudinal statistical study between a test and control group. Finally, we directly compared the NCs in terms of lymphatic drainage, spatial resolution and image quality to ^99mTc-Nanocoll, the most used radiographic compound for SLN identification in Europe, and found that the NCs show similar drainage behavior as the clinical standard while allowing for faster scan times at higher scan resolution.


[1]: Sung, H.; Ferlay, J.; Siegel, R. L.; Laversanne, M.; Soerjomataram, I.; Jemal, A.; Bray, F., Global cancer statistics 2020: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries. CA: A Cancer Journal for Clinicians 2021

Metastatic cancer has remained one of the most lethal diseases worldwide for decades because of its complex pathophysiology. Given the great efforts and investment devoted, the remaining high mortality of metastatic cancer patients is certainly frustrating. Yet in recent years, cancer immunotherapy has been considered a promising cancer treatment regulating the immune system and stimulating innate immune responses to fight tumor cells. There are several strategies that achieved a certain level of clinical success. Even so, restrained by the complex tumor microenvironment, these strategies are still limited by the insufficient activation of the immune system, poor infiltration to the tumor microenvironment, and the inability to track the distribution of the anticancer ingredients. Consequently, combining treatments for metastatic cancer to enhance the infiltration to the tumor microenvironment and immune response has been paid noteworthy attention. Considering the severe side effects caused by radiotherapy or chemotherapy and the limited penetrating ability of near-infrared light, magnetic hyperthermia therapy (MHT) becomes a promising treatment to induce and promote an immunological response in the tumor microenvironment safely and effectively. Such a remote-controlled therapeutic system affords triggered release for high local effectiveness of the anticancer process with excellent tissue penetration and minimal damage to healthy tissue.

Hyperthermia is a cancer therapy raising the local tumor temperature and maintains 41 - 45 °C for a period to kill the tumor cells while sensitizing them to other treatments. For iron oxide nanoparticle-based MHT, the heat will be generated by the MNPs while an alternating magnetic field (AMF) was applied. By harnessing the unique property of superparamagnetism, the MNPs will be well-dispersed in the tumor microenvironment while avoiding the high cost and long preparation time of the regular methods for targeted drug delivery including the cell-specific ligands and pH-responsive. Additionally, the particles manipulated by a magnetic field indicate that precise targeting delivery and MHT cancer treatment can be realized at the same time.

In this study, we designed and synthesized the superparamagnetic copper iron oxide nanoparticles (SCIONs) and engineered them into a monodisperse multifunctional anti-cancer SCION complex, programmed for targeting delivery, hyperthermia therapy, and immune therapy of metastatic cancer treatments. The porous structure of our SCIONs provides multiple Cu²⁺ sites. When loading sodium diethyldithiocarbamate trihydrate (DDC-Na), the [Cu(DDC)₂] complex will be self-assembled on the surface, which has been wildly proven as an effective anticancer ingredient. Compared to common combined magnetic hyperthermia and immune therapy where the high-performance-hyperthermia magnetic nanoparticles and the programmed checkpoint blockade therapy ingredients were treated to the tumor environment separately, each SCION complex is a multifunctional tumor cell treatment.

In the pre-clinical study of 4T1 tumors (murine breast cancer cells) on BALB/c mice, the MHT and anti-cancer immune therapy collaborate simultaneously. The inherent mechanism and the process of the anti-cancer effect are proposed following. Firstly, the SCION complex generates a considerable amount of local heat to eliminate tumor cells when AMF is applied. Meanwhile, the anti-cancer ingredients will continuously function in the tumor microenvironment inducing tumor cell death and apoptosis. Then, combined MHT and [Cu(DDC)₂] complex treatment ablation of tumor cells could generate tumor-associated antigens, The antigens were uptaken by dendritic cells (DCs), which would lead to the activation of immunological cell death (ICD). Furtherly, the anti-cancer ingredients loaded on the surface of the SCION complex keep functioning to inhibit epithelial-mesenchymal transition (EMT) to prevent cancer metastasis from happening.

Breast cancer (BrCa) is the most common cancer worldwide and approximately 70% BrCa patients eventually develop bone metastasis. 80-90% of breast cancer (BrCa) patients die because of the skeletal complications due to the bone metastases. Therefore, the presence of bone metastases plays an important role in cancer patient’s prognosis, quality of life, and the planning of the treatment. To better understand cancer metastases, it is critical to find an effective method of detecting the status of bone metastases and investigating the dynamics of breast cancer metastasis to bone in a timely and cost-effective manner. Current techniques including imaging techniques such as CT, MRI, particular skeletal scintigraphy, have been developed and used as an initial work-up for the detection and management of bone metastases from breast carcinoma. These techniques are accurate but cause concerns about high dose of radiation exposure, comprehensive operation, and expensive cost. The development of 3D models for cancer metastasis using scaffolds provide a way to recapitulate native microenvironment for the metastasis to bone. However, imaging techniques and 3D models using scaffolds both can not real-time capture and evaluate the circulating process of cancer cells to cancer tumor at the bone site.

This presentation focuses on developing a new MXene based 3D printed scaffold sensors to 1) real-time capture and evaluate the circulating process of cancer cells to cancer tumor at the bone site; 2) control tumor formation; and 3) find solutions of improving new drug response and delay metastases. We will take a two-pronged approach: (1) the 3D bone mimetic scaffold seeded with cancer cells, placed in a bioreactor to mimic physiological flow conditions, with embedded sensors for real-time monitoring will capture the chemical and biological signals during tumor formation, (2) keeping the same conditions as in the previous approach, anti-cancer treatments will be introduced in the bioreactor, and real-time monitored as the treatment inhibits tumor formation. These experiments, along with characterization techniques such as gene and protein expressions, and imaging will supplement the sensor data to develop the roadmap of tumor formation and assist in developing the design rules. This work will be to initialize a new research area of developing new functionalized sensing techniques that can sense the impact on osteogenesis of bone in tumor proximity and monitor new drug response to limit tumor formation and cancer metastases. In particular, this work will expect to design multifunctional 3D scaffolds as novel biomaterials with sensing capability and tissue-engineering performances.

INTRODUCTION
Tuberculous meningitis (TBM) is the most severe form of tuberculosis infection with very high mortality and accounts for 2-5% of all
tuberculosis cases among children and HIV-positive adults, causing permanent neurological consequences and disability.¹
TBM arises from mycobacterium tuberculosis (M.tb) release into the brain, which triggers an inflammatory cascade. TBM treatment is currently based on the treatment of pulmonary tuberculosis with combinations of antibiotics including first-line antibiotics drugs, such as rifampicin (RIF). Therapy using these drugs has poor outcomes because suboptimal drug levels reach the brain due to poor blood brain barrier (BBB) penetration. There is an urgent clinical need for alternative vehicles to deliver antibiotics and anti-inflammatory drugs inside the brain to treat TBM locally. In this work a biodegradable and monodisperse mesoporous silica nanostars (MSNS) have been proposed as a carrier of RIF (antibiotic) and cerium oxide nanoparticles (nanoceria, anti-inflammatory) with the aim of using the system to treat TBM.
EXPERIMENTAL METHODS
MSNS were synthesized using a sol gel single-micelle epitaxial growth approach². In a typical synthesis CTAB is used as mesoporous template, NaOH as catalyst, n-hexane as co-solvent and TEOS as silica source. Temperature, aging time and stirring rate effects on MSNS diameter and spike length were investigated. The drugs, RIF and nanoceria, were encapsulated into MSNS using a passive diffusion method and post-synthetic impregnation respectively.
The MSNS physicochemical properties were determined by using transmission electron microscopy (TEM), dynamic light scattering (DLS), Brunner-Emmett-Teller (BET) analysis and X ray diffraction spectroscopy (XRD). Encapsulation of RIF and cerium oxide were confirmed using high performance liquid chromatography (HPLC) and inductively coupled plasma mass spectrometry (ICP-MS).
The toxicity and immunogenicity of MSNSs were evaluated in PBMC, astrocyte, pericyte and microglia cells by MTS and Luminex assays. An in vitro BBB model was used to assess the BBB permeability to MSNS in comparison to spherical mesoporous nanoparticles (MSNP).
RESULTS AND DISCUSSION
The synthetic approach used in the present work to produce virus like shape nanoparticles allows to tune the size and the spike length of MSNS. Two types of nanoparticles, MSNS-1 with size of 83 ± 9 nm (spike length: 9 ± 2nm) and MSNS-2 72 ± 11 nm (Spike length:18 ±4 nm) were chosen for further experiemnts. XRD analysis reveals their amorphous structure while the BET demonstrates a high surface area of ~200 m²/g which allows a high drugs encapsulation. RIF was successfully incorporated in both type of MSNS at concentration of 70 mg/300mg MSNS-1 and 220mg/300mg of MSNS-2. Furthermore, XRD and ICP-MS analysis show the successful incorporation of nanoceria into MSNS. MSNS Cellular toxicity was measured and the 1 µg/ml of MSNS was set do not induce any cellular toxicity and any immunogenic effect in PBMC cells and in the four types of cells that make up the BBB (astrocytes, pericytes, endothelial cells, and microglia). Moreover, the capability of MSNS to cross the BBB was assessed in a unique 3D in vitro model showing MSNS better crossing the BBB respect to the spherical MSNP.
CONCLUSION
The present work shows we can tune the size and the morphology of MSNS, RIF and nanoceria drugs were successfully incorporated into MSNS without producing any modification in the silica structure. MSNS tdid not induce any cellular toxicity and immunogenic effect and are able to better cross the BBB respect to the spherical counterpart. The preliminary results pave the way to a new therapy for TBM.
References
1- Seddon J.A, Wilkinson R, van Crevel R, Figaji A, Thwaites G.E. (2020) Wellcome Open Res. 4: 1-18.
2- Wang W, Wang P, Tang X, Elzatahry A.A, Wang S, Al-Dahyan D, Zhao M, Yao C, Hung C.T, Zhu X, Zhao T, Li X, Zhang F, Zhao D. (2017) ACS Cent. Sci. 8: 839–846.

Renin is an enzyme with the function to produce angiotensin I in plasma triggering a cascade of reactions that regulate blood pressure homeostasis. It is a useful marker of tissue perfusion plasma renin activity (PRA), but it was not well exploited in terms of electroactivity in human blood while evaluating the renin-angiotensin-aldosterone system. To quantify the renin levels in human plasma samples, a novel screen-printed carbon electrode (SPCE) sensor modified with doped multi-walled carbon nanotubes (MWCNTs) and polyethylene glycol (PEG) is proposed and experimentally demonstrated. PEG is a biopolymer commonly used to coat the surface of nanostructures to reduce nonspecific interactions and minimize aggregation promoting colloidal stability. The functionalized MWCNTs were first evaluated with Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) images. The structural analysis proved that there were no further effects on the size and shape of the carbon nanostructures. The doping was confirmed with the three-electrode cyclic voltammetry (CV) technique where the peak currents were amplified by almost 6.5× after the functionalization step. Afterward, the Human Renin Antibody Pair is immobilized on the nanocomposite film for 1 hour before the performance of the electrochemical measurements with the samples containing the enzyme. Differential pulse voltammetry (DPV) measurements were performed to quantify the Renin (0 ~ 2,000 pg/mL) in human plasma samples (<20 μl) that are injected into the device. The variation of the current peaks presented high linearity (linear regression coefficient (R²) of 0.9890) with the levels of renin enzyme. The validation was obtained while comparing the results of the SPCE device with the gold standard method, Enzyme-Linked Immunosorbent Assay (ELISA), using the Bland–Altman plot with a good agreement between the two methods within a 95% confidence interval. Further studies involve the combination with the other inflammation-related markers already evaluated with our multiplexed electrochemical sensing device.

Cellular communication is an essential process to maintain cellular bio-function. Communication between cancer cells and immune cells has been investigated for decades. One of immune checkpoint cancer therapies is developed after fully understanding the communication between programmed death ligand 1 (PD-L1) from cancer cells and programmed death 1 (PD-1) on T cells. Cancer cells can remotely deactivate T cells by secreting soluble PD-L1 proteins and secreting extracellular vesicles (EVs) with exosomal PD-L1. Commercial immunoassays, such as enzyme-linked immunosorbent assay (ELISA), have been utilized to measure concentrations of PD-L1, IL-2, and IFN-γ for the demonstration of cellular interaction between cancer cells and T cells. However, commercial immunoassays cannot detect a diffusion path of proteins. A diffusion map of proteins is also significant information to understand how cells secrete proteins. Here, a specially designed on-chip device consists of cell isolation chambers and a gold nanosphere-based nanoplasmonic digital immunoassay, rendering in situ remote cell communication to visualize a diffusion map and quantify a concentration of proteins. A machine-learning-based image process method was utilized to generate a signal map translating a PD-L1- exosome-mediated communication between breast cancer cells and T cells. This developed platform provides new methods for visualizing cell-cell remote communication that has high potential as a characterization method for monitoring cellular progression.

Over 10million people have disabilities due to nervous system disorders. Alzheimer's, a representative degenerative brain disease, is characterized by irreversible cognitive dysfunction and occurs when amyloid plaque accumulates even before symptoms occur. Therefore, it is more important to prevent it through early diagnosis than to treat the disease. One of the early diagnosis system is Liquid biopsy that diagnoses using blood, urine, spinal fluid, etc. The aqueous humor is body fluid which fills the space between the lens and the cornea of the eye. The aqueous humor contains biomolecules come from central nervous system. Diagnosis platform using aqueous humor can be a promising platform for early diagnosis of neurodegenerative diseases.

Here, we made fluorescence aptamer conjugated inverse opal hydrogel lens (FAIOL). Intraocular lens are implanted for vision correction or cataract surgery at eye chamber which is filled with aqueous humor. FAIOL is aptamer conjugated intraocular lens system. When the biomarker approaches at FAIOL, quencher modified aptamer combines biomarkers and dissociates from fluorescence modified complimentary DNA. To raise specificity of FAIOL, AFIOL is made by MMA (methyl methacrylate) which is well known hydrophobic monomer. And for sensitivity of FAIOL, we applied inverse opal system that makes fluorescence signal amplification by photonic band gap. FAIOL can be a target independent sensor such as protein sensor by, DNA sensor, or RNA sensor. Early diagnosis of various neurological diseases will be possible through FAIOL

The development of smart bio-responsive drug delivery systems based on the features of cancer cell environments are emerging as a potentially efficient strategy to overcome the limitations of chemotherapy. Here in, a novel dual carbon dioxide– and pH– responsive supramolecular drug delivery system was successfully developed. A potent anticancer amino functionalized highly conjugated rhodamine 6G (A-R6G) material entrapped by a difunctional uracil-terminated polyethylene glycol (BU-PEG) supramolecular polymer via non-covalent interaction. The resulting A-R6G loaded BU-PEG spherical nanogel was colorless and weakly or non-fluorescent. However, simple CO₂ bubbling caused hydrophobic to hydrophilic phase transition of A-R6G and resulted pink colored and highly fluorescent solution due the interaction of amino moiety of carbon dioxide. Interestingly, the in vitro drug release study confirmed that A-R6G loaded BU-PEG nanogel was dual carbon dioxide– and pH–responsive system. Moreover, compared to the corresponding nanogel in untreated medium, the use of carbon dioxide treated medium in the in vitro studies significantly increased the internalization and accumulation of A-R6G loaded BU-PEG nanogel inside cancer cells via endocytosis and subsequently led to the induction of massive apoptotic cell death. Thus, using carbon dioxide gas and pH as triggers could open up a new pathway and significantly increase the selectivity, safety, and efficacy of cancer chemotherapy.

Sonodynamic (SDT) has the advantage of localized anti-cancer treatment on the targeted tumor region and, can minimize the side effects for normal tissues. SDT is usually operated by ultrasound of 20 kHz or higher frequencies. However, biomedical research on audible soundwaves below 20kHz to control SDT were vailed. Herein, we report audible soundwaves that triggering the aggregation of the nanoparticles and, the aggregation behavior of the nanoparticles subsequently influenced the intracellular autophagy formation. Thus, the amplified autophagy by audible soundwave responsive nanodrug effectively increased apoptosis in cancer cells. In conclusion, obtained result clearly demonstrated the anti-cancer therapy using sub-audible ranges of frequency and suggested novel strategy for the treatment of anti-cancer therapy with noninvasive manner.

Gold nanorods (GNRs) have received broad attention due to their tunable surface plasmon modes, which make them attractive candidates for applications in drug and gene delivery, biological imaging, and cancer treatments. In this study, we highlight the interactions of four different aspect ratios (ARs), 2.6, 3.2, 5.4 and 11.5, of GNRs with HeLa cells. Specifically, we study the uptake of the particles by HeLa cells while also considering the effects of other parameters such as the surface stabilizer, supernatant, and serum proteins present in the medium. From this work, it was determined that the cell viability depended on the chemical composition of the supernatant especially the amount of excess surfactant, hexadecyltrimethylammonium bromide (CTAB), used for the synthesis of GNRs; thus, the effect of aspect ratio of GNRs on endocytosis could not be directly discerned. For example, when exposed to GNRs of aspect ratio 11.5, HeLa cells showed higher cellular uptake compared to smaller aspect ratios, and also exhibited lower cytotoxicity due to the lower concentration of CTAB used in their synthesis. Gentler purification methods (sedimentation) appeared to be a factor in lowering the free CTAB concentration for experiments containing GNRs of aspect ratio 11.5. Overall, the synthesis protocols functionalization, purification processes, and the stability of GNRs in media have an effect on cellular uptake and viability. Our results suggest that the AR of GNRs may a role in endocytosis when mPEG, instead of CTAB, is used as a stabilizing ligand although an overall trend could not be unequivocally established. In future studies, sedimentation, contact time, and internalization kinetics need to be probed further using more biocompatible ligands and less inert ligands (mPEG) to determine the effect of AR on GNR internalization in HeLa cells.

Currently, the survival rate of pancreatic tumors has not been improved despite development of therapeutic agents for other tumors, such as breast cancer, liver cancer, lung cancer, and stomach cancer. This is because ligand-antibody binding strategies cannot be applied for pancreatic tumors, and thus, targeting pancreatic cancer is not available yet. Due to the unique ability of stem cells for targeting the specific tumor environment, stem cell membranes (stemsome) with nano-encapsulated mediators can target tumor and can load active anticancer agents. In this study, a specific cancer targeting strategy for stemsomes prepared by extracting ectosomes from stem cells with improved pancreatic cancer targeting ability was demonstrated. Stem cell membranes with enhanced targeting ability to pancreatic tumor cells were encapsulated with doxorubicin-loaded PLGA nanoparticles, successfully targeted and reduced pancreatic deep tumor tissue. Considering that there are no known target proteins in pancreatic tumor cells, the proposed platform technology can utilize for targeting various malignant tumor possessing unknown surface target receptors on cancer cell membranes.

Even though chemotherapy is most commonly applied to treat cancer, the insufficient locoregional retention and systemic toxicity has remained to be solved. Naturally derived chitosan is a promising biomedical material due to its biocompatibility. However, pH and concentration-dependent solubility of chitosan has been restricted further applications to clinical settings. Here, we propose chitosan-based nanodepots containing Fe(III)-catechol complexes (Cat-CS NPs) as a tumor-activatable therapeutics delivery system to accomplish highly site-directed administration while minimizing adverse effects towards surrounding normal tissues, inspired by intriguing adhesion mechanism of marine mussels. The Cat-CS NPs fabricated through electrospray exhibited Spherical uniform size nanoparticles. Furthermore, they indicate improved adhesiveness on glass and porcine skin tissue model in aqueous conditions. The pH-dependent stoichiometry of Fe(III)-catechol coordination in the doxorubicin-loaded Cat-CS NPs (Cat-CS@DOX NPs) allows the triggered release of DOX in response to the acidic conditions around the tumor tissues. The Cat-CS@DOX NPs showed a significant inhibition of growth of cancer cell in vitro while exhibiting a good biocompatibility towards normal cells. In addition, they demonstrated superior adhesion ability to tissue substrates after local spray process in vitro and in vivo. Taken together, our polysaccharide-based sticky nanoparticles can be applied to open new avenues as a topical delivery system to adjuvant cancer therapy.

Recently, artificial liposomes were developed as an effective carrier for the COVID-19 vaccine. However, liposomes are not sufficient to use for the treatment of diverse diseases due to the absence of the ability for targeting pathophysiological sites. In this regard, ectosomes, a type of nano vesicles composed of cell membrane can be endowed with target ability, is a promising drug delivery vector. In this study, macrophage derived ectosome shows greater cancer targeting efficacy. Macrophages can migrate to the cancer cells and additionally can release pro-inflammatory cytokines, such as TNF-a, IL-1b, and IL-6. Macrophage-derived ectosomes fused with liposomes, hybrid nano formation (ecto-liposome), enhanced the anticancer efficacy of delivery to malignant tumor tissues. Specifically, a mRNA, regulating signaling pathways involved in cancer, was encapsulated in ecto-liposome inhibited cancer cell growth and suppressed chance of metastasis. Obtained results in this study clearly suggested that the mRNA encapsulated ecto-liposome is highly effective and thus, represents a novel strategy for the treatment of anti-cancer therapy.

For several decades, to maximize the therapeutic efficacy of drugs, various drug delivery systems that target various cells or subcellular organelles (e.g., nucleus, mitochondria, lysosomes, endoplasmic reticulum, Golgi apparatus, etc.) have been developed. However, most targeted drug delivery systems use methods to directly conjugate the targeting moiety to the drug or to decorate the nanoparticle surface.
In this study, an ε-poly(_L-lysine)-based mitochondrial targeted drug delivery system (i.e., REPL-NG) was developed by introducing hydrophobic and biodegradable disulfide bonds into a hydrophilic polymer without a mitochondrial targeting moiety. REPL exists in the form of nanogels in aqueous solution due to hydrophilic primary amines on the surface and hydrophobic disulfide bonds inside the core. Thus, hydrophobic drugs such as doxorubicin could be encapsulated into REPL-NG (i.e., DOX@REPL-NG) by hydrophobic interactions.
In HCT116 cell line, a human colorectal cancer cell line, DOX@REPL-NG was internalized by endocytosis and was able to escape the endo/lysosomes by the proton-buffering effect of the primary amine of REPL-NG. After internalization, DOX@REPL-NG favored mitochondria over the nucleus, and as a result, a greater amount of DOX was uptaken into mitochondria rather than the nucleus. In addition, in HCT116-xenografted nude mice, DOX@REPL-NG exhibited superior antitumor effect than free DOX-HCl by tumor accumulation and retention of DOX. In conclusion, DOX@REPL-NG could target mitochondria by modulating the hydrophobicity of lysine-based polymers without commonly used mitochondrial targeting moiety.

Therapeutics used in the treatment of various types of cancer and respiratory diseases present significant drawbacks such as limited efficacy and severe off-target toxicity. These issues hinder their success and support the current need to develop enhanced formulations to improve the prognosis of patients. Metal-organic frameworks (MOFs) have attracted much attention for biomedical applications since they can encapsulate and thus enhance the safety and efficacy of therapeutics. MOFs are a class of biocompatible nanoporous materials with exceptionally high surface area (>8,000 m²/g) and drug loading capabilities (>70% drug weight).

In this work, molecular simulations were performed to find a MOF structure with a porosity compatible with different chemotherapeutics. PCN-222, a zirconium-based MOF with mesopore size (> 2 nm), was selected due to its high porosity and biocompatibility. Chemotherapeutics used to treat breast and lung cancer (fulvestrant and temozolomide, respectively) were then loaded into PCN-222. Subsequently, a PEG coating was applied to drug-loaded PCN-222 to improve stability and slow-release profile. The resulting PEGylated drug-loaded MOFs were characterized for drug loading capacity and physiochemical properties, including size, aqueous stability, crystalline structure, and porosity. Drug loaded-PCN-222 was tested using in vitro models of breast and lung cancer (MCF7 and A549 cells, respectively). The effects of this nanomaterial’s characteristics (including size, composition, and surface characteristics) on toxicity were assessed by metabolic activity. Live-cell imaging and confocal microscopy were used to analyze internalization and cellular interactions of PCN-222.

PCN-222 characterization showed nanoparticles of 120-150 nm in a homogenous dispersion. Drug loading of fulvestrant and temozolomide into PCN-222 was successful for both chemotherapeutics, achieving a loading efficiency of more than 30%. The effect of this nanomaterial on cell toxicity was assessed by a metabolic activity assay and live cell imaging, showing that breast and lung cancer cells tolerated high concentrations of PCN-222. These results highlight the biocompatibility of PCN-222. The PEG coating improved intracellular stability and delayed drug-release capability. PCN-222 showed a high cell internalization efficacy in MCF7 and A549 cells, as seen by confocal microscopy.

PCN-222 showed biocompatibility, high loading capabilities, delayed drug-release, and efficacious cell internalization. Further works using in vivo mouse models are expected to confirm the previous in vitro data. Finally, PCN-222 is a promising nanocarrier able to increase the efficacy and safety of current standard-of-care chemotherapeutics and facilitate the progress of nanomaterials for medical applications.

Nano-corona is induced by the interaction of nanoparticles with plasma proteins. Although the immune toxicity aroused by nano-corona has been intensively studied for the past decade, there were no reports on immunotherapy using nano-corona. It is widely believed that nano-corona invoke intrinsic and adaptive immune responses by conformation changes in the protein structures. In this study, the anti-cancer efficacy of nano-corona was analyzed in the tumor microenvironment in which the immune response was suppressed by cancer cells. Surprisingly, nano-corona significantly induced M1 differentiation from the M2 phenotype in the tumor microenvironment with a stimulated innate immune response. In addition, to examine the removal of the tumor tissue, combination therapies using nano-corona, photothermal therapy, and anti-cancer immune-therapy was conducted. Combinational therapies inhibited the growth of tumor tissues. Activation of NK cells and cytotoxic T cells that directly destroyed tumor cells and importantly, T_reg cells are reduced at the tumor microenvironment. Obtaimed results represent that the anti-tumor immune response enhanced by nanocorona. Importantly, the study suggested evidence that controlling of immune responses using nano-corona significantly influences the efficacy of anti-cancer therapy by switching immune regulation at the tumor environment.

Nanoparticles (NPs) have attracted significant attention in the field of gene therapy in recent years. Despite the many advances in NP-mediated non-viral gene delivery, the stability of the NPs, successful internalization of nucleic acids, and efficacy in delivery and transfection in cells remains an obstacle to their clinical translation. This work explores the surface-stabilization of a synthetic protein nanoparticle (PNP) with a polycation for improved NP stability and pDNA transfection in vitro and in vivo. Utilizing electrohydrodynamic (EHD) jetting, PNPs were used to encapsulate a large plasmid followed by stabilization by a polycation. The stabilization of the PNP in solution is enabled by the electrostatic interactions between the polycation and the protein. Electron microscopy, dynamic light scattering (DLS), and nanoparticle tracking analysis (NTA) confirm that the surface-stabilized PNPs (ssPNPs) have sub 200 nm diameters in their dry and hydrodynamic states. Additionally, it was determined that the ssPNP size and positive charge are stable in aqueous conditions for extended periods of time, without the addition of stabilizing agents. Utilizing NTA and UV-vis absorbance data, a method was established to determine the DNA amount per ssPNP, indicating an overall yield of 75-80%. In human HepG2 cells, more than 90% of cells take up the ssPNPs, partly due to the positive surface charge. Moreover, transfection of ca. 50% can be achieved while varying the amount of DNA and NP dosing, with negligible cytotoxicity. In a mouse glioblastoma model, ssPNPs demonstrated transfection effectiveness higher than JetPEI®, a commercially used product. This platform shows that using a polycation as a surface stabilizer allows for successful pDNA internalization, NP stability, and transfection efficacy. These findings demonstrate the capability of this new gene delivery system to overcome challenges that hinder the clinical translation of NPs, with the potential for the treatment of various cancers and diseases.

Unfortunately, conventional therapy for rheumatoid arthritis (RA), which is an autoimmune and inflammatory disease, was not enough to attenuate the RA patient with severe inflammatory symptoms. Mesenchymal stem cells (MSCs) are considered as a promising regenerative therapy for the treatment of RA due to their regenerative activity and ability to migrate toward damaged tissues, but the insufficient anti-inflammatory efficacy limited MSC application in various stages of RA patients. In this aspect, the combination of nano-drugs and MSCs can increase the anti-inflammatory response at the inflamed joints, and the severe stages of RA can be recovered. In this study, the inflammation-mediated education process without genetic engineering enhanced the migration ability of MSCs to inflamed joints. Star-shaped gold NPs (AuStar: AuS) were synthesized with the conjugation of Triamcinolone (TA), a glucocorticoid widely used for inflammatory disease. AuS-TA stably conjugated on the surface of MSCs, and inflammation-educated MSCs with conjugation of triamcinolone-loaded gold nanostar (Edu-MSCs/AuS-TA) elicited remarkable attenuation of RA in collagen-induced arthritis (CIA) mouse model. Furthermore, photothermal therapy (PTT) with the irradiation of near-infrared (NIR) laser on inflamed joints showed the maximized efficacy of the anti-inflammatory response for the treatment of the severe stage of the CIA model. Specifically, Edu-MSCs/AuS-TA promoted the repolarization of macrophages from the M1 to the M2 phenotype and decreased the recruitment of neutrophils in joints. Additionally, Edu-MSCs/AuS-TA significantly decreased pain and increased general locomotor activity levels and cartilage regeneration.

Since the silica surface is generally composed of hydroxyl groups and ether bonds, it is considered to have a negatively charged surface that readily adsorbs oppositely charged molecules. The heparin-binding domain (HBD), mainly composed of positively charged residues, is present in many growth factors (GFs). It plays an essential role in the binding with the anionic sulfate of heparin/heparan sulfate. Based on this, GFs containing HBD may have an affinity for the anionic silica surface. We hypothesized that the silica coating would increase the association for the growth factors. To identify this, hydroxyapatite, currently used as a bone graft material and BMP2 carrier, was coated with bio-silica on the surface using a silica-forming peptide. By atomic force microscopy, we measured the binding force between GF, BMP2, and the silica surface, demonstrating that the biosilica surface showed an 8-fold higher binding strength than the HA alone. While the loading efficiency was increased due to the strong binding force, there was a problem in that the release rate was low. For effective delivery of GF by increasing diffusion rate, collagen was introduced. HA was coated with collagen and biosilica layer by layer according to collagen concentration and the number of coating layers. In the final biosilica-coated surface, the diffusion rate of two successive coatings of collagen and biosilica was higher than the one-time coating. Meanwhile, triple layers lowered the loading efficiency (LE%) and diffusion rate than the former coating. Double successive coatings of collagen and biosilica with 0.01% collagen displayed the highest LE% and diffusion rate. Hence, this formulation was selected as an optimal carrier for GFs. The carrier above demonstrated increases in cell proliferation, alkaline phosphatase activity, osteogenic gene expression, and calcium mineral precipitation in the osteogenesis of MC3T3 E1 cells compared to those of HA and one-time biosilica-coated HA. Therefore, the biosilica/collagen-coated HA can be an effective carrier for GF-employed therapy in bone regeneration.

Controlling the bone formation and resorption processes by osteoblast and osteoclast is crucial for bone regeneration. Previously, it was solely reported that osteoblast secretes receptor activator of nuclear factor kappa-B ligand (RANKL) to differentiate osteoclasts. However, it is recently reported that RANKL reverse signaling mechanism which induce the bone formation by osteoclastic exosomes possessing RANK. Bioinspired by the RANKL reverse signaling pathway, we fabricated artificial osteoclastic exosomes to induce enhanced bone formation. In detail, we extracted osteoclast-derived cell membrane vesicles (OCMVs) which were functionalized on PLGA nanoparticle core. We successfully confirmed the synthesis of the OCMVs by the analysis of dynamic light scattering, zeta potential, and TEM imaging. In addition, the presence of RANK on OCMVs was verified via confocal microscopy and western blot. Finally, we validated the enhanced bone regeneration process by OCMVs using alkaline phosphatase (ALP) assay. The results show that the degree of bone regeneration by OCMVs significantly increased compared to that of bone morphogenic protein-2 (BMP-2). Our findings suggest that OCMVs have a potential to be utilized in biomedical application of bone regeneration.

Sub-nanometer-precise DNA origami structures may serve as versatile high-resolution templates for engineering inorganic materials [1] and as components for bridging molecular and macroscopic scales [2]. For biomedical applications, DNA origami could be integrated into robotic devices [3], gene-editing tools [4], delivery vehicles [5], and diagnostic platforms [6]. However, under physiological conditions these structures may suffer from poor stability due to low-cation-induced denaturation and enzymatic degradation. Here, I will present some of our very recent results in the following topics:
(1) Structural design governs the folding [7] and environment-dependent stability of DNA origami [8].
(2) Superstructure of DNA origami can be harnessed in rational design of drug release profiles [9].
(3) Customized static [10-12] and stimuli-responsive [13] coatings can be used for targeting, for protecting DNA origami from degradation, and for increasing the immunocompatibility of DNA-based delivery systems.

References
[1] Heuer-Jungemann & Linko ACS Cent. Sci. 7 (2021) 1969
[2] Xin et al. Chem. Eur. J. 27 (2021) 8564
[3] Nummelin et al. ACS Synth. Biol. 9 (2022) 1923
[4] Piskunen et al. iScience 25 (2022) 104389
[5] Seitz et al. Macromol. Biosci. 21 (2021) 2100272
[6] Keller & Linko Angew. Chem. Int. Ed. 59 (2020) 15818
[7] Ijäs et al. Biophys. J. (2022) in press
[8] Xin et al. Small 18 (2022) 2107393
[9] Ijäs et al. Nucleic Acids Res. 49 (2021) 3048
[10] Shaukat et al. Chem. Commun. 56 (2020) 7341
[11] Julin et al. Angew. Chem. Int. Ed. 60 (2021) 827
[12] Seitz et al. under review
[13] Seitz et al. ACS Appl. Mater. Interfaces 14 (2022) 38515

Antimicrobial surface coatings can be used to reduce the transmission of infectious diseases that are spread by contact. An effective coating should kill microbes in the time between users, which is minutes or less, and also continue to operate for an extended period. Fast killing is a transport problem, and our solution is a porous coating with the active material inside the pores. We use hydrophilic pores of dimensions 5-100 µm such that they infiltrate liquid droplets in seconds, and from there transport distances and times are short, defined by the pore size, rather than the droplet size. Our coating has two levels of structure: (A) a porous scaffold and (B) an antimicrobial coating within the pore structure containing the active ingredient. Two scaffolds are studied: stainless steel and poly(methylmethacrylate) (PMMA). The active ingredient is electrolessly-deposited copper. To enhance adhesion and growth of copper, a layer of polydopamine (PDA) is deposited on the scaffold prior to deposition of the copper. This porous copper coating kills 99.8% of Pseudomonas aeruginosa within three minutes, which is highly effective. Killing on this fast scale is appropriate for antimicrobial applications to prevent disease.

Researchers are concentrating their efforts on discovering reducing treatments for bacterial infections due to the worrisome and quick rise of drug-resistant microbial-related illnesses. Escherichia coli (E. coli) causes post-surgical infections and wound infections, the most serious and drug-resistant diseases in the world. Anatomical sites with insufficient bone tissue due to illness or revision surgery are referred to as having bone defects. Severe bone defects can cause disability, limit an individual’s ability to live and work and impose significant social and economic burdens. composite silver-cerium co-doping mesoporous bioactive glass (MBG) can defend against drug-resistant pathogens of Escherichia coli (E. coli) infection of wounds and solve issues with bone deformities. In this study; un-doped MBG and silver-cerium co-doped mesoporous bioactive glass based on the composition of 80SiO₂-(16-x) CaO-4P₂O₅- xAg₂O- xCeO₂ (x=0, 0.35, 0.71, and 2.87 mol%) co-doped have been successfully synthesized by spray pyrolysis method. Various mesoporous bioactive glass powders were produced and characterized in this research. The phase compositions, chemical bonds/functional groups, surface morphologies, chemical compositions, inner structure morphologies, specific surface areas, and elemental compositions on the surface were investigated using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), nitrogen sorption isotherm analysis, and X-ray photoelectron spectroscopy (XPS), respectively. When the glasses were exposed to simulated bodily fluid (SBF), they quickly formed HA on their surfaces, which caused Ag and Ce to be deposited on the surface of the MBG, and no negative effects were seen in the MTT assay test. Furthermore, antibacterial activity against E. coli was determined using the colony count method, and all silver-cerium co-doped MBG were very effective against E. coli and intriguing candidates for use in improving the filling of bone defects. According to our literature analysis, the 80S- Ag-Ce- was the first silver-cerium co-doped mesoporous bioactive glass, however, additional functional studies are required for its advancement.
Keywords: Mesoporous bioactivity glass (MBG), Silver (Ag), Cerium (Ce), Antibacterial activity, In vitro bioactivity.

The development of novel biomaterials that provide electrical potentials generated through bioactive scaffolds with respect to their appropriate effects on cell behaviors is essential for tissue engineering. In particular, piezoelectric biomaterials are attractive due to the possibility to produce electrical potentials for stimulation via cell motility. Despite their capacity to promote tissue regeneration through cell stimulation, synthetic piezoelectric biomaterials still face issues with poor biocompatibility and inflammatory response. Here, we designed a scaffold that supports cellular activity without eliciting any toxic effect on the host immune response by using a nature-derived piezoelectric protein and mimicked extracellular matrix microenvironment topologies using electrospinning to enhance cell adhesion. The scaffold enhanced piezoelectricity to overcome limited electrical signaling pathways of the nanofibrous membrane via alpha-helix to beta-sheet transition, and this led to elevated mechanical properties and wettability according to the morphological modification. In addition, the hierarchical structure of the scaffold induced a sequential release of hydroxyapatite and simvastatin by gradual biodegradation of the protein to accelerate homogenous growth in a higher local ion concentration during mineralization. Our scaffold is a promising candidate for tissue engineering and mechanoelectrical transduction platform due to its phased functionality in electrophysiological activity, biodegradability, and mineralization. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. 2021R1C1C2011542) and NRF-2017-Fostering Core Leaders of the Future Basic Science Program/Global Ph.D. Fellowship Program.

In this study, we explored the sinterability of MgO-SiO2-P2O5-CaO-CaF2 glass compositions created through spray pyrolysis and the relationship between their microstructures and bioactivity after various immersion times in simulated bodily fluid (SBF). We evaluated the bioactivity of the materials by immersing them for 3, 5, 7, 14, and 21 days at 37°C in SBF and found that bioactivity was correlated with sintering temperature and soaking time. The material's pH value during immersion in SBF was in the range of 7.4-8.2, which is below 8.5 and contributes to its improved compatibility and reduced toxicity in biological applications. We used X-ray diffraction and scanning electron microscopy to determine the phase compositions and morphologies of the samples and found that the 1100°C sintered A-W GC sample exhibited the highest bioactivity after soaking in SBF. This sample was dominated by fluorapatite, wollastonite, and whitlockite crystals scattered throughout the glass matrix. The crystallinity (%) of the A-W GC increased as its bioactivity improved, making it more suitable for use in pharmaceutical applications. Wollastonite, with its aspherical particle shape, whiteness, and lack of volatile components, enhances the performance of the ceramics production process. The P and Ca ions released into the SBF medium during soaking caused the amorphous phase and wollastonite phase to continually disintegrate. We also conducted a cytotoxicity test on A-W GC samples sintered at 700, 800, 900, 1000, and 1100°C using extraction concentrations of 250, 200, 150, 100, and 50 mg/ml and incubating for 48 hours. The results showed that the glass-ceramics were non-toxic to MC3T3-E1 cells at all extraction concentrations, except for those sintered at 700°Cat concentrations of 250, 200, and 150 mg/ml where cell viability (%) was below the threshold of 70%.
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INTRODUCTION
Osteosarcoma is the most common type of bone cancer diagnosed especially in children and young adults¹. A combination of chemotherapy, radiotherapy and surgery is commonly used to treat this type of cancer^2,3. In detail, chemotherapy is based on the use of molecules targeting the high cancer cell proliferation metabolism such as Platinum (Pt)-based drugs that binds nuclear DNA upon overpassing the cell membrane, causing its damage and the arrest of the cancer cell cycle at G2/M transition phase, leading to apoptosis^4-7. Despite Pt chemotherapeutics are the most potent used anticancer drugs, their side effects (high degradation before entering the cells, the off-target organs toxicity, and cell resistance) remain great drawbacks^8-11.

EXPERIMENTAL METHODS
In this study, we synthetized Graphene oxide (GO)-based nanoplatforms as smart delivery systems of Platinum-based drug. In order to reduce GO cytotoxicity in health cells while promoting its cellular uptake in cancer cells, and to allow Pt loading on GO, 8-arm polyethylene glycol-amine (PEG) was used. The bioactivity of GO-PEG-Pt platforms were compared to Pt-free (15 μM, 30 μM, and 60 μM) on three osteosarcoma cell lines (MG63, U2 and SAOS-2). The in vitro analysis of cellular uptake (ICP-OES), viability (MTT assay), morphology (actin and DAPI staining) and migration (scratch test) was performed.

RESULTS AND DISCUSSION
A preliminary study showed that GO-PEG was not toxic for cells at any concentration tested compared to cells only. A significant cell viability reduction was detected at 30 μM GO-PEG-Pt for all cell lines compared to Pt-free, reaching 70% cell mortality in MG63 (p value ≤ 0.0001) and SAOS-2 (p value ≤ 0.001). Morphological analyses showed a round-shape cell morphology and cell number reduction in the presence of GO-PEG-Pt respect to Pt-free in a dose dependent trend. Cellular uptake of GO-PEG-Pt was significantly higher after 24h for SAOS (p value ≤ 0.05) and MG63 (p value ≤ 0.0001) cell lines than Pt-free. The cell migration was lower in Go-PEG-Pt than Pt-free in MG63 and U2 with overall more than 60% migration inhibition over time at 30 µM concentration.

CONCLUSION
The results confirmed that GO-PEG-Pt platforms work as promising anticancer delivery systems. In fact, all the three osteosarcoma cell lines showed higher susceptibility to GO-PEG-Pt in terms of lower metabolic activity and lower migration rates due to the higher GO-PEG-Pt uptake compared to Pt-free.

REFERENCES
1. Tang, Q.L. et al., Cancer Lett., 113:121, 2011
2. Xiao, X. et al., J Exp Clin Cancer Res, 37:201, 2018
3. World Health Organization – Cancer, 2021
4. Hulvat MC., Cancer Incidence and Trends. Surg. Clin. North Am. W.B. Saunders, 2020
5. Schirrmacher V., Int J Oncol., 54:407–19, 2019
6. Johnstone TC, et al. Chem. Rev. American Chemical Society, 3436–86, 2016
7. Gmeiner WH et al., Nanotech. Rev., 3:111–22, 2014
8. Bersini S, et al. J Biomaterials 35:2454–61, 2014
9. Lei S et al., Cancer Commun. 1–12, 2021
10. Rajaratnam V. et al., Cancers, 2020
11. Ottaviani G. JN., Cancer Treat Res., 152:33, 2019

ACKNOWLEDGMENTS
The authors would like to thank the Nano4Tarmed project (H2020-WIDESPREAD-2020-5, grant no: 952063) for providing financial support to this project.

Introduction: Gliotoxin, a secondary metabolite isolated from the fungi, Aspergillus fumigatus has shown cytotoxic activity against neuroblastoma (1), a type of cancer accounting for 15% of all childhood cancer-related deaths (2). But as with all other chemotherapeutic agents, this compound is toxic to both tumour cells and healthy cells. To minimize toxicity towards the healthy cells, a biocompatible nanoparticulate system is needed. For this reason, our study has explored the use of nanosized metal organic frameworks (MOFs) – a class of organic-inorganic hybrid materials made up of metal nodes held together by organic bi or tridentate linkers, as drug delivery systems with the goal of achieving controlled delivery of gliotoxin to neuroblastoma cells. Amongst the MOF systems we have investigated, Cu-MOFs with RAWYAS and GIFKUC phases showed interesting results and are the focus of this contribution. By means of microwave-assisted solvothermal method, we synthesized some Cu-based MOFs at 1 (MOF1Cu), 5 (MOF5Cu), and 30 (MOF30Cu) minutes, using copper (ii) nitrate trihydrate as the metal ion and 5-aminoisophthalic acid as the ligand, and studied their structural characteristics by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD). We also explored their adsorption capacities using high performance liquid chromatography (HPLC) and investigated their cytotoxic effect against the SHSY-5Y neuroblastoma cell line by means of 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT) assay. To rationalize our findings from the MTT assay, we sought to understand the nature of the intra-and inter-molecular interactions between gliotoxin and the synthesized Cu-MOFS by measuring the K-edges of Cu, C, N, O, and S of the MOF-gliotoxin complexes by means of soft and hard x-ray absorption spectroscopy (XAS) and x-ray photoelectron spectroscopy (XPS) in an ex-situ fashion.
Results: The MTT assay showed that upon immobilization of gliotoxin within the synthesized MOFs, its cytotoxic effect was increased. This enhanced cytotoxicity suggests that not only do the MOFs act as carrier systems, but they also provide a synergistic effect. The changes in the near edge x-ray absorption fine structure (NEXAFs) spectra on immobilization of gliotoxin within the synthesized Cu-MOFs showed that there is an interaction between the drug and the MOF systems. This is particularly evident in the N K edge spectrum of the MOF sample after immobilization of gliotoxin 1:5 ratio with a shift of the 1s→p* transition of the amino group of MOFs to higher energy. Moreover, the ratio between the 1s→p* and 1s→s* in the OK edge changes significantly upon immobilization of gliotoxin, indicating a significant structural modification of the MOFs. Also, marked changes can be seen in the S2p XPS spectra upon gliotoxin immobilization, which suggests a direct co-ordination between the sulphur of gliotoxin and the Cu metal sites of the MOFs. Based on these results, we posit that the interaction of the gliotoxin with the MOFs involves mainly the N site of the ligand. More investigations on the S L edge XAS will clarify any modification on the structure of the gliotoxin.
Conclusion: Taken together, our findings highlight an approach to enhancing the pharmacological activity of gliotoxin. As an outlook, we would further explore the nature of the host-guest chemistry between gliotoxin and the synthesized Cu-based MOFs from a computational viewpoint using molecular dynamic studies.

References
1. Axelsson V, Holback S, Sjögren M, Gustafsson H, Forsby A. Gliotoxin induces caspase-dependent neurite degeneration and calpain-mediated general cytotoxicity in differentiated human neuroblastoma SH-SY5Y cells. Biochem Biophys Res Commun. 2006 Jul 7;345(3):1068–74.
2. Maris JM, Hogarty MD, Bagatell R, Cohn SL. Neuroblastoma. Vol. 369, Lancet. Elsevier; 2007. p. 2106–20.

We report the evaluation of lactosylated graphene oxide (GO-AL) as a potential drug carrier targeted at an asialoglycoprotein receptor (ASGPR) from hepatic cancer cells. Structural-modification, safety evaluation, and functional analysis of GO-AL were performed. The structure and morphology of the composite were analyzed by atomic force microscopy (AFM), while Raman and FTIR spectroscopy were used to track the chemical modification. For the safe application of GO-AL, an evaluation of the cytotoxic effect, hemolytic properties, and specific interactions of the glycoconjugate were also studied. SEM and AFM analysis of the GO showed graphene sheets with a layer size of 2–3 nm, though a few of them reached 4 nm. The Raman spectra presented characteristic peaks of graphene oxide at 1608 cm⁻¹ and 1350 cm⁻¹, corresponding to G and D bands, respectively. Besides, Si–O peaks for the APTES conjugates of GO were identified by FTIR spectroscopy. No cytotoxic or hemolytic effects were observed for GO samples, thus proving their biocompatibility. The cytotoxicity in cancer cells of GO, GO-A or GO-AL was evaluated at different concentration by MTT (0.25 to 100 ug/mL). The interaction of Ricinus communis lectin confirmed that GO-AL has a biorecognition capability and an exposed galactose structure. This biorecognition capability was accompanied by the determination of the specific absorption of lactosylated GO by HepG2 cells mediated through the asialoglycoprotein receptor. The successful conjugation, hemolytic safety, and specific recognition described here for lactosylated GO indicate its promise as an efficient drug-delivery vehicle to hepatic tissue.

Manganosite (MnO) nanocrystals are used as a spin lattice contrast agent in magnetic resonance imaging for their improved relaxivity and low cytotoxicity compared to the standard gadolinium contrasting agent. Besides, MnO nanocrystals have promising applications in cancer treatment as a delivery mechanism for chemotherapeutic drugs and in imaging-guided photothermal therapy to target tumor cells. The interaction of nanoparticles in the biomedical environment at the nano-bio interface remains of significant interest, both to improve efficacy of nano-based treatments as well as reduce toxicity. This interface is governed by several properties that are of particular interest to MnO nanocrystals, such as valence states, crystallinity, defects, and surface charge and energy. Additionally, cellular uptake of nanocrystals is impacted by nanocrystal size, shape, and surface chemistry. Manganese is a naturally occurring element in the human body, found in a variety of cells and proteins. As such, MnO has the potential to be biocompatible in many novel applications. By developing a deeper understanding of how these properties are related, the MnO nanocrystals could be enhanced and designed such that they are optimized for specific biological responses.
MnO nanocrystals ranging from 22 to 36 nm have been prepared by reducing hausmannite (Mn₃O₄) nanocrystals with hexamethylenetetramine C₆H₁₂N₄. X-ray Diffraction analysis indicates that the lattice parameter decreases by up to 0.18% (4.4379 Å) as the crystalline diameter decreases to 23 nm. This is the opposite of the lattice expansion with decreasing size of five other nano-oxides show due to surface adsorbents and cation reduction. X-ray Absorption Near Edge Spectroscopy demonstrates increasing Mn³⁺ fraction from 8.9% for 36 nm diameter crystallites to 14.5% for 23 nm diameter crystallites. Thus, the lattice contraction could be due in part to the decrease of the relative cation radii from Mn²⁺ to Mn³⁺. Yet, straight calculations of lattice parameter from the Mn³⁺ concentrations yield a 10x larger lattice contraction. We suspect the magnetic properties of the nano-MnO plays a role. Though it is expected that the band gap should increase with decreasing size, the increasing concentration of Mn³⁺ would result in states inside the bandgap, potentially giving the appearance of a smaller bandgap. Further, the increased concentration of Mn³⁺ has potential antioxidant properties due to the dual oxidation state as observed in nanocrystals of Mn₃O₄ and CeO₂ in other studies. With respect to nano-oxides, lattice expansion is usually observed. In the case of nano-MnO, lattice contraction is observed which has only previously been reported before in α-Fe2O3 and NiO nano-oxides. Additionally, the ratio of oxidation states in nano-MnO are size dependent as well, which has potential antioxidant applications as nano-ceria.
Supporting publications:
Precision Nanomedicine DOI: 10.33218/001c.56898
Materials Chemistry and Physics DOI: 10.1016/j.matchemphys.2021.125091
Accessing the genomic effects of naked nanoceria in murine neuronal cells
Nanomedicine DOI: 10.1016/j.nano.2011.08.005
Cerium and yttrium oxide nanoparticles are neuroprotective; Biochemical and Biophysical Res. Comm. DOI: 10.1016/j.bbrc.2006.01.129

Nucleic acid technologies, including plasmids, ASO, siRNA and mRNA, are a suite of well-studied and emerging tools to study living systems and target genetic disorders in vivo. Controlling nucleic acid technologies by external stimulus has become a vital requirement in biotechnology and gene therapy. Among the external stimulus that can be used, temperature is an ideal candidate due to its reversibility and high tissue penetration, when combined with ultrasound¹. Temperature control can be achieved by using thermoresponsive polymers. Thermoresponsive polymers are “Smart Materials” that can switch between globule and coil states when changing the temperature. They are divided into 2 categories; polymers with a lower critical solution temperature (LCST) aggregate when temperature is above a critical temperature, and polymers exhibiting an upper critical solution temperature (UCST) become soluble above their critical temperature. Poly(N-isopropylacrylamide) (PNIPAM), which exhibits a LCST of 32○C, has been previously coupled to DNA² and preliminary studies have shown it can be used to regulate gene expression when polymerized with antisense oligonucleotides (ASOs)³. ASOs are short ssDNA that can bind to complementary mRNA then allow their cleavage in the presence of RNAse H enzyme, and have been used to control protein production in cell-free and living systems. In this project, we are exploring the conjugation the LCST and UCST (co)polymers onto DNA template and ASOs to produce a platform for temperature control.
Here, different (co)polymers (PNIPAM and P(NIPAM-co-AAm)) with LCSTs in the range of 32-38○C were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization and conjugated to functional DNA and ASO by click chemistry to produce defined polymer-nucleic acid species. These conjugates aggregated upon heating, as expected, and were used to control cell free protein synthesis (CFPS). In the first instance, we conjugated PNIPAM to a DNA template, encoding a fluorescent protein. The expression from DNA-PNIPAM was significantly decreased upon heating above the LCST, compared to the non-modified DNA template. We have also generated defined conjugates of ASOs with PNIPAM, unlike the previously example that employed free radical polymerisation³. In preliminary results, these ASO-PNIPAM conjugates were able to degrade mRNA below the LCST, but exciting, showed no degradation above the LCST.
These results demonstrate that it is possible to use thermoresponsive polymers to control both large (DNA template) and small (ASOs) nucleic acid technologies, using bioconjugation. Creating these bioconjugates, rather than the polydisperse nanoparticle aggregates, allows for the formation of a distinct, single molecular species, which simplifies synthesis, analysis, and pharmacokinetics. Our future aim is to attach LCST and UCST (co)polymers, which can be activated by mild hyperthermia, to many nucleic acid technologies and demonstrate their ultrasound-targeted application in biology and medicine.
ACKNOWLEDGEMENTS
This work was supported by funding from The Royal Society and EPSRC.
REFERENCES
[1] Gomes, I. P. et al., Pharm., 12(4), 2019.
[2] Li, S. et al., ACS. Macro. Lett., 7, 281-286, 2018.
[3] Murata, Masaharu et al., Chem. Lett., 32(11): 986-987, 2003.

Metal oxide nanoparticles (NPs) are widely used in different biomedical fields, such as tissue engineering [1], MRI contrast enhancement [2], and the detection of proteins [3]. In the current study, we are focusing on synthesizing metal nanoparticles (core size <50 nm). In comparison with their oxide counterparts, metal NPs with improved magnetic properties could be used as MRI contrast agents. Our metal NPs were synthesized using metal oxide NPs, which have been synthesized beforehand by using simple one-pot pyrolysis [4]. Metal hydrate salt and polyvinylpyrrolidone (PVP) in DMF were used as starting materials. The reaction is carried out in a Teflon tube that is heated in a furnace (< 200oC). The metal oxide NPs were covered with SiO2 and reduced using CaH2 in a vacuum-sealed tube [5]. Therefore, NPs with a cubic metal core and a SiO2 shell coating were obtained. The crystal structure and morphology of the NPs were analyzed using X-ray diffraction (XRD) and transmission electron microscope (TEM). Using the physical properties measurement system (PPMS), we studied the magnetic properties of the NPs at room temperature. As far as biomedical applications are concerned, we improved the solubility of the NPs in water. For this purpose, zwitterionic dopamine sulfonate (ZDS) [6] was synthesized and used as a coating material for the NPs. Cytotoxicity studies showed that the synthesized NPs were not toxic to liver cells in vitro even at 100 mg/L, revealing them to be biocompatible. The cubic core Fe NPs0 Ms value of as much as 180 emu per g-Fe is quite close to that of bulk iron, 218 emu per g-Fe, and results in high MRI relaxivity r2. We have indeed determined that the cubic core Fe NPs0 r2 value was larger than for maghemite NPs, 109 s-1mM-1 compared to 55 s-1mM-1.[7]
[1] Sabine van Rijt and Pamela Habibovic. J R Soc Interface. 2017, 14, 129, 20170093.
[2] Shen Z, Wu A, Chen X. Mol Pharm. 2017,14, 5, 1352-1364.
[3] Li-Jun Zhao, Ru-Jia Yu, Wei Ma, Huan-Xing Han, He Tian, Ruo-Can Qian, Yi-Tao Long. Theranostics, 2017, 7, 876-883.
[4] Maria Volokhova, Anna Shugai, Masahiko Tsujimoto, Anna-Liisa Kubo, Sven Telliskivi, M. Nigul, Peep Uudeküll, Heiki Vija, Olesja M, Bondarenko, Jasper Adamson, Anne Kahru, Raivo Stern, Liis Seinberg, Materials, 2022, 15, 2228.
[5] Kaori Kohara, Shinpei Yamamoto, Liis Seinberg, Tatsuyama Murakami, Masahiko Tsujimoto, Tetsuya Ogawa, Hiroki Kurata, Hiroshi Kageyama, Mikio Takano, Chemical Communications, 2013, 49, 2563−2565.
[6] He Wei, Numpon Insin, Jungmin Lee, Hee-Sun Han, Jose M. Cordero, Wenhao Liu, and Moungi G. Bawendi, Nano Lett. 2012, 12, 22−25.

Infections caused by bacteria are among the most serious physiological conditions that threaten human health. The swift emergence of resistant bacteria is jeopardizing the efficacy of most antibiotics, highlighting the importance of finding non-invasive theragnostic systems to treat bacterial infections. Currently, different antimicrobial systems used in the field include metal-ion nanoparticles (NPs) (e.g., Ag NPs), semiconductor photocatalytic materials (e.g., TiO₂), and antibacterial-nanocarrier composites. However, these systems face several shortcomings such as very low efficiency, short-term effect, and fast release of the antimicrobial agent. To overcome these issues, metal-organic frameworks (MOFs) have emerged as a promising theragnostic system. MOFs are nanoporous crystalline materials made by the self-assembly of metal clusters and organic linkers. They have shown high biocompatibility, high drug loading capacity, slow release of their cargo, and a surface that is easy to functionalize. Despite the potential of these materials as nanocarriers, hardly any research has been carried out using MOFs for antimicrobial delivery.
In this work, a novel MOF named PCN-222 was functionalized with aptamers (apt@PCN-222), short oligonucleotide sequences that selectively bind to bacteria, to deliver doxorubicin and antimicrobial peptides (apt@dox@PCN-222) to bacterial targets. PCN-222 is a photoluminescent Zr-based nanomaterial that has shown great potential for bio-applications due to its large porosity, high stability, and biocompatibility. Growth assays for Gram-positive (Bacillus subtilis) and Gram-negative (Escherichia coli) bacteria were used to determine bacteria growth with bare PCN-222, free doxorubicin, apt@PCN-222, and apt@dox@PCN-222. Different characterization techniques were used to assess the physico-chemical properties of the NPs. High resolution transmission electron microscopy (HR-TEM) was used to confirm the crystallinity NPs. Scanning electron microscopy (SEM) and dynamic light scattering (DLS) were carried out to determine the particle size of the NPs and their colloidal stability, respectively. Ultraviolet-visible spectroscopy (UV-vis) was used to determine the drug loading content and inductively coupled plasma mass spectrometry (ICP-MS) was utilized to quantify the binding of aptamers into the surface of PCN-222. Finally, the binding of apt@PCN-222 NPs to the different types of bacteria was assessed by structured illumination microscopy (SIM).
Crystalline PCN-222 NPs with a size of 145 ± 7 nm and a BET area of 1980 m²/g were successfully synthesized. Doxorubicin was successfully encapsulated into PCN-222, obtaining a drug loading greater than 40%. This result confirms the expected high porosity of this NP. Enhanced binding of PCN-222 to the bacteria was corroborated by measuring the overlapping region by SIM since GFP-expressing E. coli are green and the PCN-222 NPs are red. The increase in binding levels was obtained by exploiting the synergistic effect of two binding mechanisms: electrical binding due to the positive charge of PCN-222 and selective binding by the addition of aptamers to the surface of the MOF. The phosphate ions present in PBS destroyed the porous matrix of PCN-222, thus releasing the doxorubicin in a slower manner than the current antibacterial-nanocarrier composites. The slow release of the drug, together with the selective binding of the apt@PCN-222 conjugate to the bacteria resulted in an increased reduction of bacteria growth when compared to free doxorubicin.
PCN-222 has shown promising physico-chemical properties for the effective delivery of antimicrobial agents to bacteria. Further studies will examine the effect of using larger aptamers or cationic polymers to increase its targeting effects. This study represents the first systematic attempt to target bacteria using aptamer-functionalised PCN-222, promoting the use of nanomaterials against antibiotic resistance.

Ultrasmall gold nanoparticles (diameter 1-2 nm) are smaller than most proteins and therefore well suited to elucidate particle-protein interactions after suitable surface functionalization. siRNA and fluorescing dyes (e.g. FAM, Cy5, Alexa647) were attached by copper-catalyzed azide-alkyne cycloaddition (click chemistry) to azide-terminated gold nanoparticles. Peptides of different length were directly attached via cysteine, taking advantage of the strong gold-sulfur bond. The particles were characterized by high-resolution transmission electron microscopy, differential centrifugal sedimentation, and ultraviolet spectroscopy. Extensive NMR spectroscopic investigations of dispersed particles were possible due to the ultrasmall nature of the particles. By combining the results of all these analytical techniques, a full image of the particles was gained, including the number of ligands (typically 5-10 per nanoparticle) and the details of the ligand-gold bond.
The nanoparticles were surface-decorated with biomolecules and synthetic receptor molecules to interact with the surface of model proteins as probed by NMR spectroscopy, isothermal titration calorimetry, and fluorescence polarisation. Such particles are easily taken up by cells as demonstrated in classical two-dimensional cell cultures and in three-dimensional organoids. Notably, the particles were able to enter the cell nucleus and also to cross the blood-brain barrier in brain organoids that exhibit a functional blood-brain barrier in vitro. We also demonstrated how they were taken up by bacteria.
In conclusion, covalently functionalized ultrasmall gold nanoparticles have a strong potential for specific interaction with proteins, for imaging and as drug carrier into cells and organoids.

Mesoporous Silica Nanoparticles (MSNs) have been considered promising for in vivo biomedical applications, such as targeted therapy and diagnostic imaging. However, once nanoparticles are exposed to the biological system, biomolecular corona formed around the nanoparticles can result in unexpected outcomes in terms of therapeutic efficiency, biodistribution, and pharmacokinetics. Therefore, understanding the composition and functionality of protein corona is crucial for nanomedicine development. Nowadays, cancer nanomedicines are widely applied to overcome the low tumor-targeting efficiency of the conventional drug, but the elimination processes of nanoparticles are still unclear. Kidneys, with a filtration threshold of 6 nm for metal-based nanoparticles or proteins defined by the previous investigation, are the major excretion organs in metabolism to remove excess waste in the body.
In this study, we employed LC-MS/MS, SDS-PAGE, DLS, and Zeta potential measurements to identify the protein corona after the in vitro incubation of 25 nm cationic PEGylated MSNs with human plasma and intravenous injection of nanoparticles into the mice. Additional bioinformatics analyses using ClueGo and Ingenuity Pathway Analysis (IPA) revealed altered regulation in crucial pathways. The biodistribution of MSNs in 4T1 breast tumor-bearing BALB/c mice was investigated using immunofluorescence microscopy and a non-invasive in vivo imaging system (IVIS). Our results demonstrated that superior tumor-targeting efficiency could be achieved more simply by reducing protein adsorption but not manipulating protein type on the surface of MSNs. On the other hand, immunofluorescence and TEM visualization showed the localization of PEGylated MSNs in the glomerular basement membrane and mesangial cells. Notably, intact 25 nm cationic PEGylated MSNs were observed in the collective urine. A comprehensive evaluation revealed that the biomolecular mechanisms involved in the excretion of MSNs are through the proximal tubular epithelial cells by caveolae-mediated albumin transcytosis.

The utility of noble metal species in catalysis has been further broadened by investigations into their complex substrate interactions (catalyst-substrate/support effects). Such studies highlight the impact of chemical environment on material character as emergent phenomena (e.g. varied plasmon character, unique reaction selectivity (reactivity)). In the presented study, noble metal silver’s limited solubility in and surface-phase formation on redox-active cerium oxide nanoparticles is overcome by manipulating the unique chemistry of ionic silver in aqueous solution. In particular, the oxidation of silver and, thereby, the final nanomaterial synthesis products, are nanoengineered by top-down chemical etching process to remove contaminant silver (oxide) phases post-synthesis (utilizing Tollen’s reagent, [Ag(NH₃)₂]⁺, formation from silver (oxide)) (AgCNP1) or selective-oxidation of Ce³⁺ over silver by hydrogen peroxide (H₂O₂+Ag⁰,Ag₂O → Ag⁺+H₂O+(radical oxygen species)), bottom-up process, to preclude silver (oxide) particle phase formation (AgCNP2). Each synthesis produces surface/near-surface silver-phases of varied oxidation states (evidenced by x-ray photoelectron spectroscopy) due to the unique crystal environments evolved by each synthetic route (evidenced by transmission electron microscopy, x-ray diffraction, electroanalysis). Further, synthesis conditions and product silver phase character strongly impact cerium site reduction in each formulation (25.8 and 53.7 %Ce as Ce³⁺ for AgCNP1 and 2, respectively). Biomedically-relevant, reactive oxygen species modulating enzyme-mimetic catalysis assays (peroxide-degrading: catalase, superoxide radical scavenging: superoxide dismutase) were performed for each formulation, which correlate catalytic redox activity with extent of cerium reduction in the formulations. The complex nature of the silver surface phase character and silver/ceria-mediated surface catalysis activity of each formulation were further highlighted in studies demonstrating their unique efficacy towards inactivation of enveloped (OC43 coronavirus) and/or non-enveloped (RV14 rhinovirus) viruses. Specificity towards virus character is further studied through electroanalytical methods (electrochemical impedance spectroscopy, circuit modeling) and adsorption studies.

Nanomedicine represents one of the fastest growing fields of research in recent years, encompassing both therapeutic and diagnostic medicine. Global impacts across several wide-ranging disease conditions have been achieved, for example Doxil/Caelyx and Myocet for cancer chemotherapy, Macugen for macular degeneration, Fosrenol for renal disease and Endorem for magnetic resonance imaging. Critically, all advances in nanomedicine are driven by material development on the nanoscale, with many applications established through fundamental research and design of novel nanomaterials. Thus, in order to discover next generation technologies, next generation nanomaterials must be developed.
The success of current clinical nanomedicine is borne out of advances in both inorganic and organic nanomaterials. The Inorganic/Organic Nanocomposite Particles (I/O-NP) platform technology is composed of organic, polymeric nanoparticles that incorporate and functionalise various inorganic nanoparticles. The aim is to harness the versatility of both inorganic nanoparticle (I-NP) and organic nanoparticle (O-NP) technologies to develop a highly versatile platform with multiple opportunities in varied healthcare applications possible through variation in nanocomposite structure and composition. Through advanced materials design and collaborative research approaches, the scientific objective is to apply the versatility of the I/O-NP platform across several emerging healthcare applications, both diagnostic and therapeutic. Herein an overview of synthetic approaches towards composite material developments aimed at several healthcare applications will be presented:
1. Superparamagnetic Iron Oxide Nanoparticle based tracers for Magnetic Particle Imaging (MPI)
2. Gold nanoparticle based radiosensitisers for Proton Beam Therapy
3. Lanthanide Upconversion Nanoparticles as Optical Imaging Probes
4. Polymeric nanocomposites as theranostic agents for Magnetic Resonance Imaging (MRI)

Considerable strides continue to be made in the design of nanoparticles as highly specialized therapeutics for improving treatment outcomes and overcoming limitations that may be observed with standard pharmacologic agents. Novel emerging paradigms that lead to durable response rates in combination with other classes of therapeutics are also critically needed. One promising strategy exploits the unique self-therapeutic capabilities that may be exhibited by the nanomaterials themselves, which do not require attachment of a cytotoxic drug. These capabilities are governed by the physico-chemical properties of these materials, which can disrupt signal transduction pathways, cell cross-talk or invasion, induce cell death programs, or mediate other biological properties within the melanoma tumor microenvironment (TME), thereby providing unprecedented opportunities for combating disease. We find that an ultrasmall fluorescent core-shell silica nanoparticle, Cornell prime dots (C’ dots), exhibits multiple distinctly separable intrinsic therapeutic properties, including their ability to (1) specifically induce regulated cancer cell death programs, such as the iron-dependent process, ferroptosis; (2) selectively modulate expression profiles with activation of multiple gene classes and proinflammatory cytokines, in addition to their ability to (3) directly activate immune cell populations towards an anti-tumor pro-inflammatory phenotype in syngeneic models. Our future work will continue to explore the nature/type of interactions among TME populations exposed to C' dots, probing mechanisms by which these particles engage pro-inflammatory anti-tumor and cytotoxic responses. Such information, in turn, can be used to develop novel treatment paradigms for clinical cancer care.

Multifunctional biomaterials which exhibit well-defined physicochemical properties and encode spatiotemporally controlled biological signals have the potential to act as next generation advanced systems modulating cellular behaviour. Within tissue regeneration field one of the commonly arising themes is impaired regeneration associated with the compromised immune system.¹ One solution to tackle this issue is to design immunomodulatory biomaterials that temporally control the overall level of inflammation.¹ For example, it has been shown that molecular weight of hyaluronic acid (HA) directly influences the polarization state of macrophages.² Designing functional materials that incorporate immunomodulatory effects, biocompatibility and that allow stable long-term polarization of macrophages is therefore of high interest in tissue engineering and 3D bioprinting.¹
Self-assembling β-sheet forming peptides and tyramine-modified HA (THA) are two examples of biopolymers that have been shown as vital biomaterials spanning advanced cell culture systems up to effective minimally complex microenvironments for the generation of organoids.^{3, 4} The role of these materials interfacing immune cells is not yet fully uncovered, therefore here we designed a selection of hydrogels built from self-assembling β-sheet forming peptides⁵ and THA,⁶ that can be processed by 3D micro-extrusion printing. A selection of peptide sequences was based on the alternation of hydrophobic and hydrophilic amino acids: DABACABACD (A: hydrophobic residue: F phenylalanine or Y tyrosine, B/C: hydrophilic residue e.g.: K lysine or E glutamic acid). THA of two molecular weights (280 kDa and 1640 kDa) were synthesized as previously described.⁶
A parametric study was carried out on the designed selection of DABACABACD peptides to verify the effect of rational peptide sequence modification on final physicochemical properties of peptide alone and peptide-THA composite hydrogels. D residues were rationally varied between hydrophobic (Y) or hydrophilic (E) amino acids to modulate the interactions' ability of formed β-sheet edges and shell with other peptide fibres and THA. All parental peptides self-assembled into semi-flexible networks and hydrogels above critical gelation concentration in the region of 2.5-5 mM and display characteristic high β-sheet content. Self-assembly, rheological properties and printability of both peptide and peptide-THA hydrogels can be controlled by the choice of primary peptide sequence, fabrication technique and final crosslinking mechanisms including enzymatic (horseradish peroxidase, H₂O₂) and visible green light crosslinking using Eosin. For the first time we also demonstrate the polarization effects of the supplemented THA on macrophages differentiated from human peripheral blood mononuclear cells over 5 days. M1 and M2 polarization modulated by the supplementation with low and high molecular weight THA were unravelled by the semi-automated image analysis from confocal microscopy, gene expression analysis and ELISA.
In summary here we uncover the link between basic molecular interactions driving self-assembly of functional tyramine modified peptide-based and hyualuronic acid-based biomaterials and demonstrate their capabilities as extrudable platforms for immunomodulatory tissue engineering.
Acknowledgements
This work was supported by the European Union’s Horizon 2020 (H2020-MSCA-IF-2019) research and innovation programme under the Marie Sklodowska-Curie grant agreement 893099 — ImmunoBioInks.
References
1. C. M. Walsh, et al., Pharmacology & Therapeutics, 2022, 234, 108043.
2. J. E. Rayahin, et al., ACS Biomaterials Science & Engineering, 2015, 1, 481-493.
3. A. Schwab, et al., Materials Today Bio, 2020, 7, 100058.
4. N. J. Treacy, et al., Bioactive Materials, 2023, 21, 142-156.
5. J. K. Wychowaniec, et al., Biomacromolecules, 2020, 21, 2285-2297.
6. C. Loebel, et al., Biomacromolecules, 2017, 18, 855-864.

The incorporation of nanotechnology into medicine (termed nanomedicine) has often been criticized for a lack of human clinical translation. While numerous studies have shown the ability of nanomaterials to improve tissue growth (such as bone, cartilage, nervous system tissue, etc.), fight infection, limit inflammation, and kill tumors in in vitro or animal studies, it has been largely speculated that few nanomaterials have been commercialized into real products helping human health. This talk will show for the first time human data in which spinal implants were modified to possess nanotextures and have been implanted into humans over the past 5 years. Impressively, out of approximately 14,000 patients, there have been no cases of implant failure including no cases on implant infection. Mechanistic studies have demonstrated that nanotextured implants not only mimic the natural roughness of bone itself but also possess altered surface energy to adsorb endogenous proteins known to promote osteoblast (bone forming cell) functions while inihibiting bacteria functions. Such results represent some of the only results available demonstrating the successful use of nanotextured spinal implants in humans and further demonstrate that bacteria infection can be stopped through the use of nanotextures alone, and not antibiotics which are causing the emergence of harmful antibiotic resistance bacteria.

Here we inrtoduce a new approach for generating immunotherapeutic nanoparticles of dendritic cell (DC)-derived exosomes (DC-Exos) on a large-scale for the clinical translation. Exosomes denote a family of nanoparticles (30–120 nm in a diameter) secreted by most cell types. Secreted exosomes consist of a surrounding lipid bilayer containing various proteins, lipids, and nucleic acids in donor cells. The use of DC-derived exosomes was recognized to address the technical challenges associated with DC-based immunotherapy, leading to multiple clinical trials. However, the workload required to upscale the production of DC-Exos is currently not suitable for their major clinical use. Our lab has been showing that a peptide (NapFFK(NBD)Yp) self-assembles in fiber networks in the cytoplasm of donor cells, catalyzed by alkaline phosphatases (ALPs), and such peptide self-assembly can increase the secretion of exosomes in various cancer cells, reaching in some cases a 10-fold increase. We observed that the peptide self-assembly was triggered by ALP in DCs, in which the expression of required enzyme was induced by specific growth factors, and this assembly stimulated mass production of DC-Exos; the production of exosomes from bone marrow-derived DCs was amplified 7-folds by the self-assembled peptide without inducing major toxicity. We also showed the potential that the self-assembled peptide could activate DCs to become strong stimulators of the immune response by triggering pro-inflammatory recognition mechanisms via proteomic analysis and flow cytometry. With proteomics, the heatmap of protein expression of exosomes with the peptide treatment indicates the packaging of exosomes is not affected by self-assembled peptides in parental cells, an important condition for their clinical applications. The proteomics could also suggest possible biogenesis and mechanism of amplified generation of exosomes.
The outcome could advance scientific knowledge for precision medicine as proposed exosomes can be applied as intercellular vectors for personal RNA-based therapy (both miRNAs and siRNAs) with capability of individualized-specific targeting of cancers and suppression of immunogenic response. It will also lay the foundations for future studies implementing DC-Exos as delivery systems in mRNA vaccine, cardiovascular diseases-related RNA therapeutics that can be regulated through exosomes.

Vaccines have been providing humankind with the ability to defend against infectious diseases. However, existing vaccines face obstacles such as a risk of adverse effects and limited immunogenicity. In the present work, we developed a self-assembled vaccine (SAV) platform based on antigen conjugated with an amphiphilic block copolymer, mPEG-b-PLA-NHS. To improve subunit vaccine immunity, SAV was designed to be nanoscale for effective antigen transport and to display repetitive antigens on its surface to trigger immune cells via multivalent recognition. SAV demonstrated improved cellular uptake by dendritic cells (DCs), hence promoting an efficient activation of the adaptive immune system. In vivo study revealed that SAV induced high levels of IgG, IgG1, and IgG2, indicating effective B cell activation and T cell-mediated immunological response. In addition, we confirmed that SAV containing hemagglutinin (HA) effectively prevented mice from mortality due to influenza virus infection. These results imply that the self-assembled nanosystem constituted of antigen-polymer conjugate can serve as an effective and versatile vaccine platform.

Prevention and curing of various neurodegenerative diseases require inhibition of protein fibrillation under extra-/intra-cellular space, clearance of aggregated protein plaques from brain and lowering of protein aggregate-induced toxicity. Towards this direction chemists and materials scientists have identified various anti-amyloidogenic molecules (e.g. polyphenols, sugars, osmolytes and peptides) that can inhibit protein aggregation.
We show that performance of these anti-amyloidogenic small molecules can be enhanced as high as 100 000-times if they are transformed into appropriately designed colloidal nanoparticles.^1-7 We explain that such enhanced performance of anti-amyloidogenic molecules is due to increased bioavailability at intra/extracellular space, modular binding property with protein, and higher brain delivery option in nanoparticle form.
We have adapted different strategies for the preparation of colloidal nanoparticle where anti-amyloidogenic molecules are terminated or loaded with nanoparticle and polymer micelle and a wide variety of colloidal nanoparticles are designed either for inhibiting protein aggregation or disintegrating protein fibrils or clearing of protein aggregates from cell. In particular, these designed nanoparticles are shown to inhibit protein fibrillation under extra-/intra-cellular condition, block aggregation of polyglutamine-derived mutant huntingtin protein in Huntington mouse brain and increases life span of Huntington mouse.
This talk will summarize our effort in this area and highlight the importance of nanoparticle form of anti-amyloidogenic molecule for efficient performance in prevention/curing of neurodegenerative diseases.
References:
[1] Koushik Debnath, S. Shekhar, V. Kumar, Nihar R. Jana, Nikhil R. Jana, Efficient Inhibition of Protein Aggregation, Disintegration of Aggregates and Lowering of Cytotoxicity by Green Tea Polyphenol-Based Self-Assembled Polymer Nanoparticle. ACS Appl. Mater. Interfaces, 2016, 8, 20309–20318.
[2] Koushik Debnath, Nibedita Pradhan, Brijesh Kumar Singh, Nihar R Jana, Nikhil R Jana, Poly (trehalose) Nanoparticles Prevent Amyloid Aggregation and Suppress Polyglutamine Aggregation in a Huntington’s Disease Model Mouse. ACS Appl. Mater. Interfaces, 2017, 9, 24126-24139.
[3] Nibedita Pradhan, Koushik Debnath, Suman Mandal, Nihar R. Jana, Nikhil R. Jana, Anti-amyloidogenic Chemical/Biochemical-Based Designed Nanoparticle as Artificial Chaperone for Efficient Inhibition of Protein Aggregation. Biomacromolecules (Perspective), 2018, 19, 1721–1731.
[4] Koushik Debnath, Nihar R. Jana, Nikhil R. Jana, Designed Polymer Micelle for Clearing Amyloid Protein Aggregates via Up-Regulated Autophagy. ACS Biomater. Sci. Eng., 2018, 5, 390-401.
[5] Suman Mandal, Prasanta Panja, Koushik Debnath, Nihar R. Jana, Nikhil R. Jana, Small-Molecule-Functionalized Hyperbranced Polyglycerol Dendrimers for Inhibiting Protein Aggregation. Biomacromolecules, 2020, 21, 3270-3278.
[6] Suman Mandal, Koushik Debnath, Nihar R. Jana, Nikhil R. Jana, Trehalose-Conjugated, Catechin-Loaded Polylactide Nanoparticles for Improved Neuroprotection against Intracellular Polyglutamine Aggregates. Biomacromolecules, 2020, 21, 1578-1586.
[7] Koushik Debnath, Ankan Kumar Sarkar, Nihar R Jana, Nikhil R Jana, Inhibiting Protein Aggregation by Small Molecule-Based Colloidal Nanoparticles. Acc. Mater. Res. 2022, 3, 54-66.

Neuromodulation techniques, such as electrical deep-brain stimulation and optogenetics, are capable of selective activation or inhibition of certain subgroup of neurons, thus providing unprecedented opportunities for the dissection of complex neural circuitry and the treatment of neurological disorders such as Parkinson’s disease. The electric field or visible light used in the current predominant neuromodulation approaches, however, is strongly attenuated by the brain tissue, thus necessitating invasive implantation of stimulation electrode or optical fiber. Such invasive brain implants inevitably cause acute brain damage, chronic immune response, and physical tethering that interferes with the animal’s natural behavior. Therefore, it is desirable to develop new methods that can modulate neural activities with an implant-free and tether-free interface.
To address these challenges, we designed a nanomaterial-based bio-interface in one of the biological transparence windows, the second near-infrared window (NIR-II, 1000-1700 nm), for remote and non-invasive deep-brain stimulation. NIR-II light exhibits reduced scattering than visible light and lower water absorption than longer wavelength NIR light, and is thus the optimal wavelength for deep-brain neuromodulation. Although no existing opsin responses to NIR-II photons, we got inspiration from the findings of Nobel laureate David Julius that rattlesnakes sense infrared irradiation through its thermal effect using transient receptor potential (TRP) channels. We hypothesized that TRP channels can also be used as NIR-II receptors in mammalian neurons. However, to activate deep-brain TRP channels, a high laser power is required, which inevitably leads to a high temperature increase on the brain surface, and as a result, altering the neural behaviors and even causing brain damage. To overcome this challenge, we designed nanotransducers named MINDS (macromolecular infrared nanotransducers for deep-brain stimulation) that strongly interact with NIR-II light. Specifically, MINDS consist of a NIR-II absorbing semiconducting polymer core with a photothermal conversion efficiency of 71% in the NIR-II window, and an FDA-approved amphiphilic polymer shell to facilitate water solubility and biocompatibility. As a result, through-scalp wide-field NIR-II illumination creates a local hotspot around MINDS up to a depth of 5-mm in the brain, while largely sparing the brain surface from heating. Consequently, MINDS act as an NIR-II sensitizer to remotely activate deep-brain TRP-expressing dopaminergic neurons in freely behaving mice without any brain implant or physical tethering, producing significant behavioral changes in a conditioned place preference test.
The utility of this NIR-II neuromodulation technique sits between optogenetics and chemogenetics: it eliminates the chronic brain implants and fiber tethering required for optogenetics and features a more precise temporal control of activation and inactivation than chemogenetics. Therefore, the NIR-II neuromodulation approach reported here allows timely behavioral modulation of freely moving subjects with minimal chronic gliosis in the neural tissue and no interference to natural animal behaviors. With complete elimination of any brain implant and head tethering, our approach could afford wide applications in dissecting the complex neural circuits of normally behaving animals in a natural interaction environment, such as in the IntelliCage, in the future. This work was recently published in Nat. Biomed. Eng. (Wu, X. et al. Tether-free photothermal deep-brain stimulation in freely behaving mice via wide-field illumination in the near-infrared-II window. Nat. Biomed. Eng. 6, 754-770 (2022)).

The injection of organic photo-responsive nanoparticles (NPs) of poly(3-hexyltiophene) (P3HT) into rat models of retinitis pigmentosa was proposed as a “liquid retina device” to treat degenerative blindness, inducing a light evoked retinal neuron response (Maya-Vetencourt et al., 2020; Francia et al., 2022). Although the efficiency of organic polymer-based retinal devices in vivo has been proven, the interpretation of the working mechanisms that grant photostimulation at the polymer/neuron interface is still a matter of debate.

In our work, we focus on understanding the mechanisms which may play a role at the bio-hybrid interface, decoupling them into: (i) a photochemical effect, which in our case consists in the photocathodic behavior of P3HT in watery oxygenated environment; (ii) an electrostatic effect, due to light induced capacitive charging of the NP, known as Photo-Dember effect. With mathematical modeling and electrochemical studies, we are able to identify the relative importance of each mechanism as a function of light intensity impinging onto the substrate, cleft size and cleft resistive properties.

The photo-chemical mechanism, connected to the production of O₂^- in the cleft, appears to be relevant solely when light intensity increases above the physiological ranges and under conditions of strict proximity to the neuron membrane (<50 nm). The capacitive effect induced by the electrostatic charging of the nanoparticle is instead appreciable only in the presence of a highly resistive medium, where ionic screening can be assumed as negligible (Debye Length>>cleft thickness): if this condition is verified by the system, even physiological light intensities (0.2 W/m²) are able to induce appreciable depolarization of the neurons. The highly resistive medium in the model is accounted for by the presence of adhesion proteins in the cleft. Therefore, the formation of “proteic islands” is suggested by the model as a fundamental ingredient to ensure the coupling among neuron and nanoparticle at reduced light intensity.

A preliminary confirmation of our simulation results comes from ex vivo experiments on retinal explants that received P3HT-NPs in the subretinal space either acutely after the explantation or that were taken from rats which had been subretinally injected in vivo with P3HT-NPs one month before. The recordings of retinal ganglion cell firing on acutely injected explants displayed a significantly reduced response with respect to the retinas which experiences a prolonged in vivo contact with the NPs before explantation.
The combined use of modeling and physiological experiments suggests that, in vivo, NPs are engulfed by the neuronal membrane with a highly resistive medium which ensures an efficient electrostatic coupling. While at the high light intensities used in in vitro experiments both phenomena may take place, at the lower light intensities used in vivo the sole electrostatic effect is responsible for the photostimulation. The results also suggest that in vitro experiments do not faithfully reproduce the in vivo condition and that a prolonged in vivo contact between NPs and the neurons, occurring in vivo, is necessary to fully elicit the physiological effects.

Optogenetics has revolutionized neuroscience understanding by allowing spatiotemporal control over cell-type specific neurons in neural circuits. However, visible light cannot be directly delivered to deep brain tissue, due to the severe dissipation and scattering of photons. As a result, invasive craniotomy is usually required to implant optical fibers in the brain for in vivo optogenetic stimulation, resulting in permanent damage and chronic gliosis in brain tissue. To achieve non-invasive optogenetics with high temporal resolution and excellent biocompatibility, we have developed focused ultrasound triggered liposome-based light sources (Lipo@IR780/L012 nanoparticles) for deep brain photon delivery. Synchronized and stable blue light emission was generated under ultrasound irradiation due to the activation of chemiluminescent L012 via nearby reactive oxygen species generated by IR780. In vitro tests revealed that Lipo@IR780/L012 nanoparticles could be triggered by ultrasound for light emission at different frequencies and hence activate opsin-expressing spiking HEK cells under the ultrasound irradiation. In vivo optogenetic stimulation further demonstrated that motor cortex neurons could be noninvasively and reversibly activated under the repetitive ultrasound stimulation after i.v. injection of Lipo@IR780/L012 nanoparticles to achieve limb motions control.

Modern medicine is currently transitioning to a new paradigm of precision and personalized care, where patients will be comprehensively screened and monitored for the detailed molecular abnormalities that characterise their specific disease. In the past decade, nanotechnology has provided new tools with unprecedented power to comprehensively interrogate genetic, transcriptomic and epigenetic information. The Centre for Personalised Nanomedicine at UQ is focused on translating these new technologies into a clinical setting, whilst simultaneously developing the next generation of point-of-care diagnostic and therapeutic technologies to further empower the personalised and precision medicine approach. As part of a major National Collaborative grant funded by the National Breast Cancer Foundation (“Enabling clinical epigenetic diagnostics: The next generation of personalized breast cancer care”, CG-12-07), our consortium recently published hundreds of epigenetic regions that are highly informative in cancer, as well as a unique (and simple to detect) epigenetic marker that appears to be universal for cancer^1-3. These are now being validated in a real-time clinical setting, where comprehensive DNA, methyl-DNA and RNA information is collected in tandem and analysed. In this talk we will present data on the clinical translation of this approach, highlighting some of the positive impacts that such an approach can make on the “recovery trajectory” of cancer patients. Along with comprehensive DNA/RNA/methylated-DNA sequencing methodologies, several point-of-care nanotechnologies recently developed by our lab will be presented.^e.g.,4-7. These include novel technologies for detecting circulating free DNA/RNA/methyl-DNA, circulated tumour cells, exosomes and protein biomarkers, as well as single-molecule read-out systems to monitor the immune system in real time.
Refs:
Sina et al., Nat. Comm. (2018)
Stone, et al., Nat. Comm. (2015)
Stirzaker, et al., Nat. Comm. (2015)
Koo, et al., Nat. Rev. Ur., (2019)
Tsao, Wang, et al., Nat. Comm. (2018)
Wang, et al., Sci. Adv. (2020)
Li, et al., Nat. Comm. (2021)

Of various methods that have been developed for the diagnosis of diseases, molecular diagnostic approaches have proven to be of great significance and thus have been developed to a great extent. Of these approaches, nanoparticle-based systems for nucleic acid detection have gained much attention due to the remarkable features of the nanoparticle platform (large surface area, electrochemical catalysis, biocompatibility, etc.). These methods produced notable results for detection of disease-related genetic material, which suggested the potential to overcome the critical drawbacks of conventional PCR-based diagnosis. However, the acquisition of both high sensitivity and short detection runtime in a single method remain a challenge as methods with high sensitivity demand lengthy procedures while faster methods require higher concentrations of genetic material for detection. In response to this matter, we propose an innovative nanoparticle-based system composed of a nucleic acid amplification method paired with electrochemical assay for rapid and ultrasensitive detection of genetic biomarkers. Termed “nanoparticle surface localized amplification (nSLAM)”, the method uses DNA functionalized Fe₃O₄−Au core−shell nanoparticles as a platform for nucleic acid amplification and accumulation. The surface-anchored DNA act as primers that bind and amplify target DNA directly on the nanoparticle surfaces using conventional PCR procedures. The surface-accumulated amplicons are subsequently subjected to electrochemical detection, which induces significantly amplified current signals that identify the presence of the target material. The nanoparticles function as dispersible nanometer-sized electrodes that significantly improve the biochemical contact efficiency between the primers and target gene of interest, further enabling amplification and collection of extremely low concentrations of target material. Furthermore, multiple measurements of electrochemical detection induce rearrangement of the dispersible nanoparticles, substantially enhancing the current signals for both ultrasensitive and rapid detection of target genes. The detection performance was tested using the COVID-19 model, which produced a remarkable sensitivity of ~1 RNA copy/μL using 35 PCR cycles. This ultrasensitivity enabled the reduction of amplification cycles to as low as 4 cycles (~7 min runtime) using 1 fM COVID-19 cDNA, which demonstrated the system’s capacity for rapid detection. These results suggest the potential for the system to overcome critical drawbacks of conventional COVID-19 molecular diagnosis by speeding up the detection process to enable expeditious treatment-related measures taken by medical personnel during emergency situations. The nSLAM system was also tested using the estrogen receptor 1 (ESR1) gene model, a ctDNA biomarker from metastatic breast cancer, which resulted in a successful detection of as low as ~1 aM concentration using 40 PCR cycles and reduction to 10 PCR cycles (~18 min runtime) for 1 fM ESR1 detection. The detection results provide a solution to the crucial shortcomings of detecting ctDNA for liquid biopsy, as the short half-life and extremely low abundance of ctDNA in blood are supplemented by the rapid and ultrasensitive detection properties of the system. The system is a promising platform that can be used to detect cancer- and infectious disease-related genetic material in an ultrasensitive and rapid manner. The system also demonstrates great versatility that can be tailored to specific diseases by designing and substituting the primers used for amplification. We plan to further develop the system as a multiplex platform for simultaneous detection of various diseases.

Unpredictable pandemic caused by Infectious viruses raised the need for simple, accurate, reliable and rapid detection which plays a crucial role in the efficient and timely management on site. Herein, we designed advanced colorimetric immunoassay for influenza A (H1N1) virus detection with layer-by-layer signal amplification based on avidin & biotinylated Gold Nanoparticles (BGNPs) complex. To accomplish this system, we fabricated BGNP using Au-S covalent bonding between SH-PEG-biotin and Gold Nanoparticles (GNPs). We identified that it recognizes influenza virus captured by specific antibody immobilized on to a microplate. In the presence of virus, red color appears on the plate and the intensity of the color is proportionate to the number of avidin-BGNPs binding which is accumulated by repetitive cycles. Furthermore, enzyme mimicking property of BGNPs that catalyzes the chromogenic substrates(3,3',5,5' Tetramethylbenzidine) with H₂O₂ offers another signal amplification that leads to enhanced color intensity and the red color becomes blue. Finally, we successfully verified the amplification of color intensity for naked-eye detection of influenza virus within 55 min, shorter than that of conventional immunoassay, ELISA. And we confirmed that its sensitivity is higher than rapid kit assay. Thus, the designed system not only suggests alternative way to conventional colorimetric immunoassays but serve as promising tool for field diagnostic tests.

Specific interactions between viruses and host cells provide essential insights into material science-based strategies to defeat emerging viral diseases. Viral fusion is ubiquitous to enveloped virus and is important for understanding the viral infection cycle. Inspired by this process, virus detection has been achieved using nanomaterials with host-mimetic membranes, enabling fusion activities with viral membrane via fusion protein activation. In this study, sialic acid expressing liposomes with tunable responsiveness to external stimuli is developed for rapid and straightforward detection of an infectious virus. Membrane fusion between the liposome and virus can be readily controlled by varying the membrane stiffness determined by cholesterol ratio, giving rise to fluorescence signals within 30 min and detection of various influenza viruses even with avian fecal samples. Therefore, the designs demonstrated in this study propose underlying approaches for utilizing engineered liposomes toward bio-mimicking tactics for direct and sensitive identification of infectious viruses.

Significant efforts are being made to develop nanoscale electronic devices integrated into neuromorphic circuits capable of emulating the dynamics of natural synapses. The coupling between neuronal populations via artificial synapses bears great potential for therapeutic strategies focused on the monitoring and control of neuronal electrical activity. Such hybrid systems, effectively coupling biological and electrical components, are important milestones for the development of a new generation of neuroprosthetic devices aimed to address a number of challenging neurologic disorders [1]. Consequently, therapeutic strategies based on the direct modulation of neuronal electrical activity have been producing remarkable results, with successful examples ranging from cochlear implants to deep brain stimulation. Developments in these implantable devices are hindered, however, by important challenges such as power requirements, size factor, signal transduction, and adaptability/computational capabilities. Memristors, neuromorphic nanoscale electronic components able to emulate natural synapses, have gained attention as a core component is these hybrid systems, mainly because of their neuromorphic properties, small size and low power signature [2]. They are nanoscale two-terminal electrical components whose present conduction state depends on the electrical stimulus that has been previously applied to them. The dynamics of a memristor’s response to stimulation is analogous to that of synapses, presenting learned transitions from low to high conductivity states, and vice versa. Importantly, the timescale of these transitions can be made analogous to the plasticity timescale of learning mechanisms in the brain, such as synaptic short-term plasticity (STP), which acts on the range from seconds to minutes. Relevant proofs of concept have already been presented in the literature [3], but we argue that crucial aspects have not yet been demonstrated on how these memristor-based hybrid systems can effectively operate in a meaningful way. Here we show, for the first time, how biological in vitro hippocampal neuronal populations can be dynamically coupled with a memristive device acting as a synapstor, forming a hybrid bio-electronic system [4]. We demonstrate that the conductance state of a memristor can be changed by the electrical activity of biological neurons and mediate a dynamic connection between isolated spiking neuronal populations. Our system connects biological neurons to microelectrodes, amplifier, memristor, stimulator, microelectrodes, and back to biological neurons, in an effective real-time configuration that does not use software nor simulations. Using our system, we can have neuronal population B being effectively activated if, and only if, there is a consistent firing pattern of activity in population A (network bursting activity). Importantly, we demonstrate that our artificial synapse is capable of short-term plasticity, dynamically changing its conductance level in both directions. Our results pave the way for further implementation of elements able to perform more complex modulatory operations in neuronal populations. We envision very similar systems being used for the automatic detection and suppression of seizures in epileptic patients.

References
[1] V. L. Feigin et al. Lancet Neurol. 18(5), 459–480 2019.
[2] A. Mikhaylov et al. Front. Neurosci. 14, 1–14 2020.
[3] E. Juzekaeva et al. Adv. Mater. Technol. 4, 1800350, 2019.
[4] C. Dias et al. ACS Appl. Electron. Mater. 4(5), 2380–2387, 2022.

This talk will provide an overview of our work in the design of self-assembled, functionalised peptide and protein nanoparticles, hydrogels and bio-interfaces for applications in healthcare. These hybrid materials are of growing importance with potential applications including drug delivery and disease detection. We are developing high-throughput synthesis techniques to diversify peptide libraries and quickly survey properties of interest such as fluorescence and supramolecular behaviour [1]. Using molecular dynamics simulation, we can rationalise the different self-assembly behaviours across length scales and to understand the interplay of membrane-curvature and nanotopography at the biointerfaces to aid in the development of cell-active substrates [2]. With the design of peptide-polymer hybrid hydrogels, we are incorporating tailorable mechanical properties to self-healing injectable scaffolds with exciting applications in regenerative medicine [3]. We are exploiting the sensing capabilities of functionalised nanoparticles to engineer nanoprobes for in vivo disease diagnostics that produce a colorimetric response ideal for naked eye read-out [4] and for CRISPR-based preamplification free detection of ncRNAs (CrisprZyme) [5]. I will talk about how we integrate our portfolio of nanoparticle-based sensing probes for diagnosing and monitoring infectious and non-communicable diseases with integration to smartphone technology for mHealth approaches [6]. This talk will also provide an overview of our recent advances in Raman spectroscopy-based characterisation techniques for tracking the functionalisation in single nanoparticles [7]. Finally, I will discuss how we are actively engaging in efforts towards the democratisation of healthcare innovations [8].

[1] Y. Lin, … M. M. Stevens. “High-throughput peptide derivatization toward supramolecular diversification in microtiter plates.” ACS Nano. 2021. 15(3); 4034-4044.
[2] A. Belessiotis-Richards, … M. M. Stevens. “Coarse grained simulations suggest the epsin N-terminal homology domain can sense membrane curvature without its terminal amphipathic helix.” ACS Nano. 2020. 14(12):16919-16928.
[3] D. E. Clarke, … M. M. Stevens. “Self-healing, self-assembled β-sheet peptide–poly(γ-glutamic acid) hybrid hydrogels.” Journal of the American Chemical Society. 2017. 139(21): 7250-7255.
[4] C. N. Loynachan, … M. M. Stevens. “Renal clearable catalytic gold nanoclusters for in vivo disease monitoring.” Nature Nanotechnology. 2019. 14: 883-890.
[5] M. Broto, … M. M. Stevens. “Nanozyme-catalysed CRISPR assay for preamplification-free detection of non-coding RNAs.” Nature Nanotechnology. 2022. 10: 1038.
[6] C. S. Wood, … M. M. Stevens. “Taking connected mobile-health diagnostics of infectious diseases to the field.” Nature. 2019. 566: 467-474. 10: 1038.
[7] J. Penders, … M. M. Stevens. “Single particle automated Raman trapping analysis.” Nature Communications. 2018, 9: 4256.
[8] A. T. Speidel, … M. M. Stevens. “Ascendancy of semi-synthetic biomaterials from design to democratization.” Nature Materials. 2022. DOI: 10.1038/s41563-022-01348-5.

Neovascular age-related macular degeneration (nAMD) is a progressive condition that is common in individuals over 50 years of age and cannot be cured in 90% of patients, and is one of the most common causes of blindness affecting more than 200 million people worldwide. Current therapeutic approaches include periodic intravitreal injections of monoclonal antibody-based anti-VEGF (anti-Vascular Endothelial Growth Factor) drugs. In spite of successful progress in neovascular AMD therapy in recent years, anti-VEGF therapies have some limitations such as the high cost and limited half-lives of protein drugs, need for frequent intravitreal injections, intravitreal injection-related complications and inadequate response to some anti-VEGF drugs. Because of these drawbacks, new approaches need to be developed for long-lasting anti-VEGF drug delivery. Peptide drugs offer ease of production and storage, extended drug shelf life and reduced costs. Currently, a drug using anti-VEGF peptides in the treatment of nAMD is not available and several anti-VEGF peptides in the literature are waiting to be evaluated for their efficacy in nAMD therapy. This project aimed to develop a composite drug delivery system consisting of poly(glycerol sebacate) (PGS) nanoparticles and cross-linked hyaluronic acid hydrogel that reduces the frequency of intravitreal administration by providing sustained release (up to 6 months) of anti-VEGF peptide drugs as a new generation treatment method.
In this study, PGS nanoparticles obtained by solvent evaporation method have high encapsulation efficiency (93,7%) and their size was around 200 nm. HA-DVS crosslinked hydrogel was synthesized by Oxa-Michael addition reaction and successful crosslinking was confirmed by FTIR spectroscopy. Drug delivery system was formed by incubating anti-VEGF peptide loaded PGS nanoparticle solutions with crosslinked HA-DVS hydrogel to have 25% (v/v). The in-vitro drug release from drug delivery system was less than 20% in the first month, consistent with the targeted long-term release profile. It was demonstrated by calculating cell viability that the anti-VEGF peptide loaded drug delivery system does not cause cytotoxic effects on human retinal pigmented epithelial (ARPE-19) cells for up to 72 hours. The inhibition effect of anti-VEGF peptide on angiogenesis was determined by calculating cell viability and examining tube formation by incubating human umbilical vein endothelial cells (HUVEC) with anti-VEGF peptide-loaded drug delivery system.
Developing new generation biomaterials for the storage and preservation of therapeutic peptides and improving their bioavailability with prolonged release will significantly improve the efficiency of long-term treatment strategies for neovascular AMD.

The cornea is the transparent, avascular, watch-glass-shaped tissue at the outermost part of the eye. It is effective in good vision as it allows the light coming into the eye to be transmitted to the lens. The cornea consists of five distinct layers, which are the epithelium, Bowman's membrane, stroma, Descemet's membrane, and endothelium. The epithelium layer is the outermost layer of the cornea and is in direct contact with the outer environment. It has important functions such as water intake from tear and protection of the cornea from external factors. The corneal epithelium layer consists of 5-7 layers of corneal epithelial cells connected by tight junctions. Thus, selectivity is ensured in the intake of water and minerals from outside. The limbal epithelial stem cells in the limbus layer, which are located next to the cornea differentiate, and form corneal epithelium. By this stem cell source, corneal epithelium layer can be regenerated. The corneal epithelium is located on a thin layer consisted of collagen fibrils called Bowman's membrane. Bowman's membrane is a cell-free corneal layer and does not regenerate. Due to reasons such as keratoplasty being the only treatment method for corneal diseases, limited donor for transplantation and high donor age, corneal tissue engineering studies are of great importance.
In this study, it was aimed to mimic the corneal epithelium layer. Accordingly, corneal epithelial cells immortalized after being isolated from the human donor cornea were cultured on PGS films. The most suitable PGS films produced by different length pre-polymers were selected and the ability of the cells to show their properties on Bowman's membrane was examined. According to the MTS assay results, PGS membrane with longer pre-polymer chains provided better corneal epithelial viability. In addition to this, cytokeratin-3, which is the main corneal epithelial marker, was expressed in higher amounts in the cells cultured on PGS membrane produced with longer pre-polymers. This study presents a recent innovation for cornea tissue engineering and makes a significant contribution to the literature.

This work is funded by 2232 International Fellowship for Outstanding Researchers Program of TUBITAK (Grant number 118C371). The funder had no role in study design, data collection or analysis, the decision to publish, or the preparation of this abstract.

The development of new chemical methods for the next generation of nanoparticles with very high magnetic moment, fine tuning Au nanorods and novel hybrid and multifunctional nanostructure is presented.
Detailed mechanistic studies of their formation by sophisticated and advanced analysis of the nanostructure allows tuning of the physical properties at the nanoscale; these can subsequently be exploited for diagnosis and treatment of various diseases. The studies are conducted to provide insight for future material design approaches. It will also help to identify the critical process parameters that can be manipulated in order to obtain the suitable physical properties for the intended applications.


^Ref:
Storozhuk, L., Besenhard M. O., Mourdikoudis, S., LaGrow, A. P., Lees, M.R., Tung, L. D., Gavriilidis, A., Thanh, N. T. K* (2021) Simple and Fast Polyol Synthesis of Stable Iron Oxide Nanoflowers with Exceptional Heating Efficiency. Journal of Applied Materials and Interface. 13: 45870−45880)
See more publicaiton here: https://scholar.google.com/citations?user=pK_qvc0AAAAJ

Cancer cells can be distinguished by tumor-associated antigens (TAAs) from healthy cells. Evidence showed that the tumor-specific cytotoxic T lymphocytes (CTLs) can be isolated from the peripheral blood or tumor of patients with various types of cancer, which demonstrated CD8 T cell-mediated anti-tumor immunity. CD8 T cells play an important role in anti-tumor immunity response by recognizing TAAs presented on major histocompatibility complex class I (MHCI) by T cell receptor (TCR). However, tumor could often evade immune surveillance by deactivating antitumor T cell responses. A lot of promising clinically applicable therapies aim to enhance tumor-specific CD8 T cell response including adaptive cell transfer (ACT), such as CTL clones of tumor infiltrating lymphocytes or chimeric antigen receptor (CAR) T cell therapy, and immune checkpoint blockage (ICB) such as anti-PD-1 or anti-CTLA-4. Though the great success of these therapies, a great amount of patients still have a low response rate to CAR T cell therapy due to insufficient T cell priming or activation, which results in exhaustion and functional impairment of T cells. Ionomycin (ION)/phorbol 12-myristate 13-acetate (PMA) combination is commonly used to activate T cell. Research shows that ION (a Ca²⁺ carrier through cell membrane) activates the calcineurin-NFAT signally pathway, while PMA activates protein kinase C (PKC) and NF-κB pathway. This stimulator cocktail mimics the full activation by TCR signaling and co-stimulation of T cell. However, no evidence showed that ION/PMA could bring clinical benefits when applied in vivo due to its systematic toxicity and off-targets effect.
Herein, we designed a CaCO₃-based nanoparticle and optimized its structure so that it can be easily dispersed in aqueous solution with PEG conjugated to the outer layer for longer circulation time in system. We also conjugated anti-PD-1 to the nanoparticles to ensure the targeting ability to T cells. PMA is loaded into the nanoparticles due to the hydrophobic interaction. This CaCO₃-based nanoparticle could bring Calcium and PMA into T cell specifically through its targeting ability and thus activate T cell and enhance its anti-tumor immunity. This salt-based nanoparticle is also non-toxic to the body system and can be easily excreted.
Our results indicate that we successfully synthesized these nanoparticles (finally formulation namely PMA@CCNP-Ab) with favorable size and zeta potential. Our in vitro data indicates that PMA@CCNP-Ab can be internalized by T cell compared with particles without antibodies. Meanwhile, the intracellular calcium ion concentration was increased which confirms the successful delivery of the nanoparticles. We also observed a significant increase of several activation markers such as CD69, TNF-α, and IFN-γ on OT-1 cells which proves that PMA@CCNP-Ab could induce T cell activation. In vivo tumor-infiltrating T cell profile analysis demonstrates the nanoparticles’ ability to convert the tumor immunosuppressive environment to immunostimulant. Finally, the PMA@CCNP-Ab can also be combined with radiation therapy and immunotherapy and showed significant tumor inhibition rates. These nanoparticles have great potential to be applied in clinics to enhance T cell immunity against tumor.

Biological condensates (membraneless organelles) are liquid droplets consisting of proteins and nucleic acids that form within cells via liquid-liquid phase separation. These droplets are dynamic, have been shown to coalesce within cells, and can form and dissipate in response to biological and environmental signals. Many condensates have multiphase structure where different cellular components are sequestered into different layers, each with their own function. Here we discuss designing synthetic condensates to understand the role of diverse molecular interactions within proteins on biological phase separation, investigate the encapsulation of small molecules and enzymes, and establish design rules for multiphase formation. The synthetic condensates are formed via complex coacervation of oppositely charged polypeptides. Complex coacervation is a liquid-liquid phase separation that occurs via enthalpic charge interactions and entropic effects from the release of counterions and hydration water. We have created a library of different polypeptide sequences that incorporate various charge patterns, hydrophobic amino acids, and aromatic amino acids in the sequence. In addition, our sequences incorporate different chiral patterns of amino acids that bias the formation of liquid complex coacervates by preventing hydrogen bonding between the polypeptides know to form solid polyelectrolyte complexes. With this library we aim to explore the effects on the stability, encapsulation selectivity, and materials properties of the coacervate phase. Moreover, we mix coacervate phases with different interfacial tensions to create multiphase droplets.

Materials that cause apoptosis of cancer cells should potentially be candidates for future anti-cancer drug. Apoptosis cell classification using AI will be an effective method to evaluate the effect. Characteristics of apoptosis cells are effectively identified from the fluorescence-stained images. The effectiveness will increase if the classification could be performed without stains.
γ secretase inhibitor (GSI) is reported to cause apoptosis of K562, a human chronic myelogenous leukemia cell line. We found that AI-based classification results of phase-contrast images of the cells were quite similar to those of fluorescence images. Factors that AI identified, but naked eyes could not identify, were examined. Biochemical change inside cells were studied in connection with morphological characteristics.

Molecular recognition is an essential function in developing advanced materials, including biomaterials. The precise design of molecular recognition functionalities, such as selectivity, affinity, and stimuli-responsibility, is the most important challenge in this research field. There are many studies on the design of molecular recognition elements using macrocyclic molecules, metal-organic complexes, and biomolecules. The designed recognition elements can capture guest molecules based on specific interactions. In addition, developing characterization tools is equally important to understand molecular-recognition functionalities and apply the advanced materials to various fields. Depending on their application, the designed recognition elements are often fixed on material surfaces. We easily imagine that the functionalities of the fixed recognition elements are influenced by their orientation and distribution on the material surfaces. However, a molecular scale understanding of the functionalities of the fixed recognition elements is still challenging due to the lack of analytical methods. Although the functionalities, such as the amount of capturing guest molecules, can be investigated with conventional analytical techniques, understanding the functionalities of each recognition element at a single molecular scale is difficult due to the averaging over numerous elements in conventional methods.
To overcome the limitation of conventional analytical methods, a method based on frequency modulation atomic force microscopy (FM-AFM). The FM-AFM technique is known to have the capability to visualize subnanometer-scale structures of various molecules and materials in liquid. The subnanometer resolution of the FM-AFM technique in liquid is based on the high sensitivity for interaction forces acting on the tip apex (the detectable theoretical limit is four pN). Moreover, conservative and non-conservative (dissipative) forces are measured separately in FM-AFM imaging. The characteristics of the FM-AFM technique suggest establishing a novel analytical method to investigate the recognition functionalities at a single molecular level based on the FM-AFM.
In this study, molecular-scale investigation of recognition events was demonstrated by FM-AFM imaging with a guest molecule-modified tip. Metal-salen complexes were fixed on a Si substrate as a model of molecular recognition elements. Amino-terminated AFM tips were prepared in this study because the metal-salen complexes have reported the capture of amino-containing molecules through the formation of coordination bonds. The FM-AFM experiments were performed with the amino-terminated AFM tips and the metal-salen complex fixed substrate. As a result, the fixed metal-salen complexes were visualized in the height images constructed by the measured signal of conservative forces. In contrast, energy dissipation images showed that dissipative interactions occurred in only a part of the fixed metal-salen complexes visualized in the height images. The results indicate that only a part of the fixed metal-salen complexes can recognize the amino group at the tip apex. The difference in the recognition function between the fixed metal-salen complexes is most likely caused by their orientation and dynamics. Our results demonstrate that the proposed analytical method based on the FM-AFM techniques with guest molecule-modified tips has the potential to investigate the recognition functionalities of the fixed recognition elements at the single molecular level, indicating future contributions to the development of advanced materials with recognition functions.

In traditional drug delivery systems, nanoparticles tend to accumulate at tumor sites due to the enhanced permeability and retention (EPR) effect, resulting in therapeutic efficacy. However, in the process of transporting through the blood, there is inevitable diffusion of drug to the normal tissue, causing side effects and reducing efficacy at the tumor site. An approach for such problems is to selectively release the drug at the tumor site through localized drug administration.
Silk protein hydrogels are inherently suitable for biological applications due to their permeability, high water content, and structural properties compatible with cell membranes. Its biodegradability can also be modified and subsequently utilized to control the drug release behavior, making silk hydrogel a potential drug-loading material.<span style="font-size:10.8333px"> </span>In vivo, hydrogels can be broken down by proteases. By changing the properties of the hydrogel, the degradation rate of the silk hydrogel can be tuned, therefore achieving controllability over the drug release. The study of injectable silk protein hydrogels as drug delivery systems has achieved good results in research for breast and liver cancers, but the research focus of controlling water-insoluble drug loading and drug release properties of hydrogels has not yet been realized. The aim of this study is to fabricate silk protein hydrogels that could be used as nano-prodrug carriers.
To this end, systematic changes in silk hydrogel preparation conditions were screened, and the obtained hydrogels were then used to load and release various types of drugs. Changes in dissolution conditions and gel parameters such as temperature, sonication time, shaking, stirring time, etc., during the preparation of hydrogels are considered to be factors that affect the performance of hydrogels. The properties of silk protein hydrogels were analyzed by gel fraction, swelling ratio, degradation rate, FT-IR, XRD, rheometer and so on.
In this report, calcium chloride solution was used to dissolve fibroin to obtain hydrogels with gelation times ranging from 1 to 4 days. By changing the gelation conditions, hydrogels with different properties were obtained. In addition, the loading of nano-prodrugs (NPDs) has been preliminary investigated. The in vitro drug release behavior of drug-loaded hydrogels will be studied. We expect to create an injectable hydrogel in which degradability can be controlled in vivo. This means that drug release can be manually controlled.

Adoptive transfers of macrophages have been explored for treating diseases since 1970s. The infused macrophages, which are polarized to a desired phenotype pharmaceutically prior to administration, can infiltrate into the diseased tissue and function as a cellular therapeutic by modulating the microenvironment in a good way. This approach shows promise in treating chronic diseases associated with suppressed immune surveillance, like cancer, with cytotoxic macrophages or those which are associated with a pronounced inflammation, like Type I diabetes and obesity, by using immunomodulatory macrophages. One major hurdle, learned from the initial unsuccessful clinical trials since 1980s, is that, because of the great plasticity and flexibility, the infused macrophages can be reprogrammed in response to the cues present in the diseased tissue and lose their therapeutic function as a consequence.
One emerging strategy is to reprogram macrophages with nanoparticles for adoptive cell therapy use. During this process, macrophages are loaded with certain nanoparticles, which provide necessary stimuli to guide and maintain the functional status of macrophages during the whole course of treatment. This can be done by using therapeutic nanoparticles, which tune the macrophage phenotype by themselves, or drug loaded nanocarriers, which affect macrophages with the progressively released drug payload. The advance in nanotechnology in the past few decades provides us with a large arsenal of nanoparticles for therapeutic and diagnostic uses, and potential nanoparticle candidates as well as some of their working mechanisms in shaping the macrophage phenotype have been discussed in previous reports.
Immunogenic cell death is defined by the ability of dying cancer cells to elicit immune response through upregulated releasing or expressing of damage-associated molecular patterns (DAMPs). Calreticulin (CRT), adenosine triphosphate (ATP) and high-mobility group box 1 (HMGB1) are there common DAMPs as a hallmark of ICD. A lot of anticancer therapeutics were investigated to induce ICD of cancer cells. However, not all of them could induce strong ICD. Here, we are proposing that reprogramed macrophage by nanoparticles could be the foundry of DAMPs, boosting ICD immunotherapy’s anticancer efficacy. We have tested that macrophage treated with iron oxide, zinc oxide and aluminum oxide can release multiple types of DAMPs in vitro and retard tumor growth in vivo.

A novel electrochemical biosensor platform based on graphene conductive polyaniline ink and laser-engraved Kapton sensor has been developed for the detection of dopamine and IL-6. Dopamine is an important catecholamine neurotransmitter, and the abnormal concentration of dopamine has been linked to several neurological diseases. IL-6 acts as an important biomarker for prostate cancer detection. We have developed graphene-conductive Polyaniline ink (G-PANI) and laser-engraved Kapton sensor in this work. For the fabrication of the laser engraved sensor, CAD design has been utilized and the parameter of the laser system has been modified. We have used silver ink as contact pads and Autolab Potentiostat for the electrochemical analysis. Due to the superior electrical conductivity, graphene is an appealing sensing material. Conductive Polymers coupled with graphene exhibit better conductivity, tunable surface properties, superior biocompatibility, and stability. Polyaniline incorporated in graphene improves solubility in aqueous solutions and shows improved conductivity and stability. Doping with acids enhances and improves the electroactive behavior of Polyaniline, and so we have created a homogenous mixture of phytic acid, polyaniline, and graphene with a planetary mixer. The SEM images depict that the surface of G-PANI is smoother with the nanoporous structure with around 1 μm diameter. To evaluate the effectiveness of the developed electrode in detecting dopamine and IL-6, we have investigated electrochemical techniques (Cyclic voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS)) with Fe²⁺/Fe³⁺ redox pair. The Nyquist plots obtained from EIS are almost perfect semicircles (a characteristic of non-diffusion-limited electrochemical processes), with the diameter substantially dependent on charge transfer resistance(R_ct). The diameter of the Nyquist semicircle decreases with the increase of conductivity of the electrode surface and a shift to lower R_ct values. From the obtained equivalent circuit, G-PANI ink has a very low Rct value (13.5Ω), compared to the unmodified one (58.7 kΩ). We have analyzed the sensitivity of our proposed inks by using Cyclic Voltammetry with 3 µM dopamine in a basic medium (pH 7.4) with a scan rate of 0.08 V s^-1. The anodic peak current of the cyclic voltammograms (CVs) is 22.17 times higher than the unmodified laser-engraved Kapton sensor. The limit of detection (LOD) of the unmodified and modified sensor has been calculated over the range from 0.5 µM to 5µM dopamine. The G-PANI modified sensor has a much lower LOD (0.4084 µM) compared to the unmodified one (1.441 µM). The calibration curve shows a linear relationship (R² =0.99832 for G-PANI modified Kapton sensor) between the anodic peak current (I_PA) and dopamine concentrations. The sensor has been mildly oxidized by ozonolysis for about 30 sec to introduce -COO- groups for the immobilization. The equivalent circuit obtained from the EIS spectra has a higher Rct (1.87 kΩ) after ozonolysis, due to the inhibition of the electron transfer between the modified electrode and the negatively charged redox species. After IL-6 antibody immobilization, R_ct increased (12.5 kΩ) because IL-6 antibody film acts as a kinetic barrier for the electron transfer of the redox marker. Under optimal analysis settings, the analytical performance of the G-PANI modified Kapton sensor is tested in the presence of varying amounts of IL- 6 antigens utilizing EIS methods (frequency range 10 kHz to 10⁶ kHz). The limit of detection for IL-6 antigen detection was 62.1283 pg/ml. In the future, we will be working on developing flexible paper-based electrochemical sensors for environmental estrogen detection.

We describe the synthesis, characterisation and therapeutic applications of bioconjugate based on cyclic peptides covalently attached to well-controlled polymeric chains. The conjugates assemble into short nanotubes (20 to 200nm) through the stacking of the cyclic peptide motives, with functionality imparted by the polymeric chains. The resulting constructs show remarkable properties in terms of cell penetration, and in vivo biodistribution.

A variety of different metal oxide nanoparticles have been used for biological applications. We have worked predominantly on TiO2 nanoparticles because the surface is easy to modify so that biomolecules can be attached with dopamine linkers and because the properties of the nanoparticles allow for it to produce ROS when exposed to agents like ionizing radiation. As such, the TiO2 nanoparticle can be localized to particular cells and also within cells by attaching particular biomolecules (EGFR, nuclear localization signals, etc). Upon localization near DNA, exposure of TiO2 to ionizing radiation (typical of that used in radiation therapy) can allow for radiosensitization. This can result in increased killing of cells with the TiO2 nanoparticles in the nucleus but not in other cells. Biological and clinical applications of this are broad. In addition, attachment of an imaging agent to the surface can also permit visualization under different conditions depending upon the agent. We have been able to detect TiO2 nanoparticles in cells and tissues using X-ray Fluorescence Microscopy (XFM).

Proteins mediate the critical processes of life and beautifully solve the challenges faced during evolution. Our goal is to design a new generation of proteins that address current-day problems not faced during evolution. In contrast to traditional protein engineering efforts, which have focused on modifying naturally occurring proteins, we design new proteins from scratch to optimally solve the problem at hand. We now use two approaches. First, guided by Anfinsen’s principle that proteins fold to their global free energy minimum, we use the physically based Rosetta method to compute sequences for which the desired target structure has the lowest energy. Second, we use deep learning methods to design sequences predicted to fold to the desired structures. In both cases, we produce synthetic genes encoding these novel protein sequences and characterize them experimentally. In this talk, I will describe recent achievements in de novo protein design, including the development of novel self-assembling protein nanomaterials. I will also highlight RFdiffusion, a powerful new guided diffusion model that generates proteins in a manner similar to the popular image-generating tool DALL-E.

Bioinspired de novo self-assembling peptides have been widely used for the development of soft biomaterials for a wide variety of biomedical and pharmaceutical applications, such as cell scaffolding for tissue engineering¹, controlled and localised drug delivery², biosensing³, and many others. The meticulous control of peptide-based nanomaterial properties over the length scale, by molecular design, remains the main challenge for tailoring biomaterials properties to meet the application needs. In our group, we have recently adopted a minimalistic molecular engineering approach for the development of Ultrashort Ionic-complementary Constrained Peptides (UICPs), which were rationally designed to self-assemble into amphiphilic β-sheet nanofibers with unique hydrogelation properties and surface activity.⁴ We have previously demonstrated the crucial role played by aromatic stacking for the formation and thermodynamic stabilisation of UICP β-sheet structures. Herein, we will show how charge interactions can be manipulated for fine tuning molecular self-assembly, morphology and size of nanofibrous structures formation and viscoelasticity of UICP hydrogels.

A library of 18 peptide sequences (4-5 residues long) was developed to study the effect of the sequence net charge, charge density distribution, reversal of charge order and ionic self-complementarity on their propensity towards self-assembly and gelation. Interestingly, 12 of these peptides self-assembled into β-sheet nanofibrous structures forming hydrogels at pH 4.5-5, as confirmed by ATR-FTIR, SEM, TEM, SAXS and oscillatory rheology. Full control over β-sheet content (ranging from ~30-80%), fibre morphology (thin fibrils, thick straight fibre bundles, twisted helical nanofibres, flat nanoribbons and nanotubes) and sizes (~4-67 nm in diameter), as well as gelation (critical gelation concentrations ranging from <7.5 to >100 mM) and viscoelastic properties (storage moduli G’ ~0.1-100 KPa) was achieved by the careful positioning of both Glu and Lys residues at both C- and N-termini, in the sequence core and on both the hydrophilic and hydrophobic faces of the peptide chain. In essence, this design approach enabled/disabled lateral growth along the β-sheet ladder via electrostatic attraction (counter charge, anion-pi and cation-pi)/repulsion, hence controlling fibre thickness, morphology, entanglement, and the resulting viscoelasticity of the system. Our UICPs platform thus provides the flexibility in peptide molecular design for the manufacturing of soft biomaterials with versatile properties that can be in future tailored to the relevant biomedical application.
Acknowledgements
The authors would like to thank Rachel Armitage at De Montfort University for her assistance with SEM experiments and Natalie Allcock at University of Leicester for helping with TEM imaging. This work was funded by the Newton-Mosharafa fund awarded to A.K. and M.E. and the Egyptian Government missions’ sector scholarship awarded to M.S. The authors are also grateful to Diamond Light Source for awarding beamtimes (SM28806 and SM28287) to this project.
References
[1] Castillo-Diaz L., Elsawy M., et al. Journal of Tissue Engineering 2016; 7: 1-15.
[2] Elsawy M., Wychowaniec J., et al. Biomacromolecules 2022; 23: 2624-2634.
[3] Yousaf S., King P., et al. Analytical Chemistry 2019; 91: 10016-10025.
[4] Wychowaniec J., Patel R., et al. Biomacromolecules 2020; 21: 2670-2680.

INTRODUCTION
Assembling peptides represent a versatile chemical toolbox for the development of soft shear thinning nanomaterials exploited for a variety of biomedical applications. Herein, we developed two de novo ultra-short ionic co-complementary peptide sequences (5 amino acids long, each) capable of co-assembly into β-sheet nanofibers, immediately forming hydrogels upon mixing the countercharge peptide solutions. These peptides were designed based on the tetrapeptide Phg4.¹ These are the cationic peptide KPhg4 and the anionic counterpart E(Phg4)^Rev, in which the charged residues are alternating with phenylglycine (Phg) and distributed in a pattern conferring a charge co-complementarity between both sequences. Both peptides were characterized for molecular assembly and hydrogelation at the physiological pH 7.4, both individually and in combination where co-assembly into nanofibres is induced through counter charge interaction. Also, these biomaterials were used for emulsifying pharmaceutical oils, forming O/W emulsion hydrogels (emulgels). These dual-phase systems were used for loading both hydrophilic and hydrophobic anticancer drugs for sustained localised drug delivery against human malignant glioblastoma U87 MG cells.
EXPERIMENTAL METHODS
1. Emulgel formation: Peptide solutions were mixed at different molar ratios, pH and total peptide concentrations and at different O:W ratios. 2. ATR-FTIR spectroscopy: Characterisation of peptides’ secondary structures. 3. Thioflavin T assay: Quantification of β-sheet secondary structures and for co-assembly kinetics. 4. Oscillatory rheology: Characterisation of gels viscoelastic properties. 5. Scanning electron microscopy (SEM): Characterisation of the emulgel's network and vesicular structures. 6. Transmission electron microscopy (TEM): Characterisation of nanostructures morphology. 7. In vitro drug release. 8. Cell culture and cell viability assay: Cytotoxicity assay of emulgels and drug-loaded emulgels against U87 cells.
RESULTS & DISCUSSION
Individual peptides neither self-assembled into β-sheet structures nor formed hydrogels at the physiological pH over a wide range of peptide concentrations. Mixing counter charge peptide solutions at pH 7.4 spontaneously formed self-supported hydrogels over a wide range of peptides molar ratios (1:9-9:1) of total peptide concentrations 10-50 mg/mL. The highest abundance of β-sheets was observed for mixtures prepared at and around the equimolar ratio with fast rate of co-assembly (equilibrium within 1 hour after mixing). Also, these peptide mixtures showed a unique surface activity, forming O/W emulsions when mixed with oily phase at 5-50 mg/mL peptide concentration and different O:W ratios (2:8-8:2). Oscillatory rheology showed that gel stiffness is controllable by fine-tuning molar ratios of peptide components. SEM showed the formation of microspheres (15-60 µm diameter) within the gel nanofibrous network for all formulations, with fibres diameter estimated using TEM. Plain gels with a net positive charge (high cationic to anionic peptide molar ratio) showed significant cytotoxicity against U87 cells. In addition, the hydrophilic anticancer drug; vincristine sulfate, loaded into the emulgel aqueous phase showed sustained drug release profiles over 96 hours with improved cytotoxicity against U87 cells. These results suggest that the physico-mechanical properties, drug loading capacity and cytotoxicity of these systems are dependent on pH, peptides molar ratio, total peptide concentration and O:W ratio, which in turn will have a direct effect on emulgel’s anticancer activity.
CONCLUSIONS
In conclusion, these emulgels showed that the mesoscopic and bulk mechanical properties and cytotoxicity can be tuned by molecular design, pH, peptide concentration, and molar ratio and O:W ratio control, to develop biomaterials that can satisfy the needs of combination anticancer therapy.
REFERENCES
[1] Wychowaniec, J et al., Biomacromolecules, 21(7):2670-2680, 2020.

The leading causes of corneal damage are keratoconus, Fuchs endothelial dystrophy, keratoconus, and corneal ulceration. Once corneal damage causes visual impairment or blindness, cornea transplantation is the best treatment option to restore vision. Corneal tissue engineering provides an alternative to corneal transplantation to overcome limited donor tissue availability and drawbacks of transplantation. However, the complex mechanical, structural, and optical properties of the cornea make tissue engineering a challenging application. The expected properties of a corneal tissue-engineered scaffold include water permeability, optical transparency, and mechanical strength along with biodegradability, biocompatibility, and porosity. Some of these properties such as superior optical transparency and biocompatibility can be provided by peptide-based hydrogels. In this study, two different self-assembled peptide hydrogels are investigated for corneal stromal tissue engineering. Both MAX8 and RADA16-I peptides convert into β-sheet-forming hydrogels at high ionic strength and physiological pH. <div>Additionally, MAX8 peptides are modified with three different peptide ligands to enhance cell adhesion and inhibit neovascularization in the scaffold during stromal regeneration. The peptide hydrogels demonstrated proper optical transparency between %90 and %100 and refractivity of 1,337 mimicking natural corneas while maintaining 3D structure for corneal stromal cell proliferation. Hydrogels made up of MAX8 exhibited 40 ±1 Pa, 35,68 Pa, and 78,20 Pa average crossover modulus with different biomarker ligands and RADA8 showed similar results. The gel recovery was also observed after 10 μN constant shear stresses were applied to both hydrogels. On the other hand, human stromal keratocytes continued expressing cell-specific markers, collagen-I and keratocan, in both hydrogel formulations indicating their potential applicability.
This work is funded by 2232 International Fellowship for Outstanding Researchers Program of TÜBITAK (Grant number 118C371). The funder had no role in study design, data collection or analysis, the decision to publish, or the preparation of this abstract.

Bacterial resistance is currently compromising the antibiotics activity that saved millions of people in the last 8 decades¹. Recently, peptide-based hydrogels were introduced as soft, versatile, shear-thinning and thixotropic materials that can be sprayed for topical applications. Thanks to their biocompatibility, biodegradability and physicochemical tunability, peptide hydrogels have a great potential to be used as sprayable antimicrobial biomaterials for treatment of infected wounds. They might also overcome the antibiotic resistance through multi-mechanisms of bacterial killing. So, this work aimed to utilise ultra-short de novo ionic-complementary peptide sequences (4 – 5 amino acids) for the development of antimicrobial bionanomaterials based on the peptide self-assembly into β-sheet nanofibers and building networks of hydrogel in response to pH change.
Based on this, Phg4 peptide, previously reported by our group² was compared to 2 other Phg4 derivatives (EPhg4 and KPhg4) to investigate the role of charge type and distribution on the self-assembly into β-sheet fibers and hydrogel and whether such modifications could impart antimicrobial activity for the hydrogel. Interestingly, the three peptides self-assembled into β-sheet fibrillar assemblies and entangled to form hydrogels in response to pH change, as revealed from molecular (FTIR) and mesoscopic (SEM and TEM) characterisation. Critical gelation concentration (CGC) was significantly affected by peptide modifications, where it decreased from 37 mM for Phg4 to 15 mM for EPhg4, while KPhg4 showed to have the highest CGC at 75 mM concentration. Oscillatory rheology revealed viscoelasticity of hydrogels formed by the three peptides and ability to recover from shear stress i.e. thixotropic materials implying their sprayability. Hydrogel stiffness varied for the three peptides, with a storage moduli G’ of 10 and 93 KPa for Phg4 and EPhg4 at 75 mM, respectively, however KPhg4 appeared as viscous weak gel that did not show linear viscoelasticity.
To investigate the inherent antibacterial activity of the three developed hydrogels, time killing point assays were carried out against the 2 bacterial species commonly responsible for causing wound infections (Methicillin-resistant S. aureus, gram positive and P. aeruginosa, gram negative). Strikingly, all hydrogels exhibited in vitro bactericidal behaviour against planktonic P. aeruginosa MPAO1 (10⁵ CFU/mL) within 2 hours (hrs) besides their ability to prevent P. aeruginosa biofilm formation in a concentration dependent killing manner where the higher the peptide concentration, the shorter the time needed for eradication that ranged from 2--8hrs. On the other hand, hydrogels of the three peptides did not show any antimicrobial activity against MRSA NCTC 10442, which was also confirmed by observation of bacterial cell morphology using SEM and confocal laser scanning microscopy (CLSM). Phg4-based hydrogel (92 mM) was then selected for further investigations and showed antibacterial activity towards both planktonic and surface population of four different clinical P. aeruginosa strains obtained from University Hospital Southampton NHS Foundation Trust in addition to other ESKAPE pathogens (A. baumannii 18X50606 and E. coli NCTC 8003, K. Pneumoniae ATCC 700831).
In conclusion, these ultrashort constrained ionic complementary peptides based on their stable self-assembly could be considered as a promising approach for treating wound infections as well as tackling the bacterial resistance and might be used as biomimetic ECM scaffolds for tissue regeneration at the wound site.
REFERENCES
[1] Ventola, C. Lee. "The antibiotic resistance crisis: part 1: causes and threats." Pharmacy and therapeutics 40.4 (2015).
[2] Wychowaniec, Jacek K., et al. "Aromatic stacking facilitated self-assembly of ultrashort ionic complementary peptide sequence: β-sheet nanofibers with remarkable gelation and interfacial properties." Biomacromolecules 21.7 (2020).