Donglei (Emma) Fan, University of Texas at Austin
Jianping Fu, University of Michigan
Xingyu Jiang, National Center for Nanoscience and Technology
Matthias Lutolf, Ecole Polytechnique Federale de Lausanne
Symposium Support Air Force Office of Scientific Research
National Science Foundation
H3/B3: Joint Session: Biointerfaces
Monday PM, December 01, 2014
Sheraton, 2nd Floor, Grand Ballroom
3:00 AM - *H3.01/B3.01
Hydrogel Microbeads and Microfibers for Biomedical Applications
Shoji Takeuchi 1 2
1The University of Tokyo Tokyo Japan2Japan Science and Technology Agency Tokyo JapanShow Abstract
In this presentation, I am planning to talk about several MEMS/Microfluidic-based approaches for the rapid and reproducible construction of hydrogel microstructure. Hydrogels are attractive materials because of its excellent deformability, biocompatibility, and the ability to be chemically-modified. They are thus very useful for various biomedical applications including implantable monitoring and tissue engineering.
Fluorescent hydrogels hold great promise for in vivo continuous glucose monitoring with wireless transdermal transmission and long-lasting activity. We synthesized a highly-sensitive fluorescent monomer, and then fabricated injectable-sized fluorescent polyacrylamide hydrogel beads and fibers with high uniformity and high throughput. We find that the fluorescent beads provide sufficient intensity to transdermally monitor glucose concentrations in vivo.
Large-scale 3D tissue architectures that mimic microscopic tissue structures in vivo are very important for not only in tissue engineering but also drug development without animal experiments. We demonstrated a construction method of 3D tissue structures by using cell beads and cell fibers. To prepare the cellular beads, we used an axisymmetric flow focusing device (AFFD) that allows us to encapsulate HepG2 cells within monodisperse collagen beads. We then seeded 3T3 cells on the surface of the collagen beads. Finally HepG2 and 3T3 cells were successfully made contact with each other. Moreover, by putting these capsules in a 3D chamber and incubating them, we successfully established complicated and milli-sized 3D structures. We believe that altering the shape can be possible as simple as changing the mold, and will try to combine multiple types of cells to create more complex system that functions as a living organism. As the cell fibers, a cell-encapsulating core-shell hydrogel fiber was produced in a double coaxial laminar flow microfluidic device. When with myocytes, endothelial, and nerve cells, they showed the contractile motion of the myocyte cell fiber, the tube formation of the endothelial cell fibers and the synaptic connections of the nerve cell fiber, respectively. By reeling, weaving and folding the fibers using microfluidic handling, higher-order assembly of fiber-shaped 3D cellular constructs can be performed. Moreover, the fiber encapsulating beta-cells is used for the implantation of diabetic mice, and succeeded in normalizing the blood glucose level.
Yun Jung Heo , Hideaki Shibata , Teru Okitsu , Tetsuro Kawanishi, and Shoji Takeuchi: Long-term in vivo glucose monitoring using fluorescent hydrogel fibers, Proc. Natl. Acad. Sci. USA, vol. 108(33), pp. 13399-13403, 2011
Hideaki Shibata, Yun Jung Heo, Teru Okitsu, Yukiko Matsunaga, Tetsuro Kawanishi, and Shoji Takeuchi: Injectable hydrogel microbeads for fluorescence-based continuous glucose monitoring, Proc. Natl. Acad. Sci. USA, vol. 107, no. 42, pp. 17894-17898, 2010
Hiroaki Onoe, Teru Okitsu, Akane Itou, Midori Kato-Negishi, Riho Gojo, Daisuke Kiriya, Koji Sato, Shigenori Mirua, Shintaroh Iwanaga, Kaori Kuribayashi-Shigetomi, Yukiko Matsunaga, Yuto Shimoyama, and Shoji Takeuchi: Metre-long Cellular Microfibres Exhibiting Tissue Morphologies and Functions, Nature Materials, vol.12, pp. 584-590, 2013
3:30 AM - H3.02/B3.02
Bioactive and Cell-Laden Nanofibrous Scaffolds Fabricated through a One-Step Process
Qilong Zhao 1 Min Wang 1
1The University of Hong Kong Hong Kong Hong KongShow Abstract
Electrospinning is a popular technique for making nanofibrous tissue engineering scaffolds. After cell incorporation, the cell-scaffold construct can be used to regenerate various human body tissues/organs. However, owing to the normally dense structures of electrospun scaffolds, cells can only be seeded in 2D on scaffold surface using the post-electrospinning cell seeding approach. For putting cells in 3D and directly inside electrospun scaffolds, we designed and investigated a facile method by combining cell seeding with scaffold fabrication. In this method, cell electrospraying was performed concurrently with electrospinning of the scaffold, placing cell-encapsulated microspheres into the matrix of nanofibrous scaffold, and the subsequent immersion treatment dissolved the shell of microspheres, releasing the cells for the cell-laden scaffold. In our experiments, a dual-source dual power setup was employed for conducting concurrent cell electrospraying and electrospinning. For cell electrospraying, a coaxial device was used. A cell suspension of human umbilical vein endothelial cells (HUVECs) and a gelatin/alginate blend solution were fed into the inner and outer concentric tubes, respectively. Crosslinked, core-shell structured microspheres containing HUVECs could be dissolved by immersing them in a cell culture medium, releasing the cells. The microsphere structure and cell viability of both encapsulated cells and released cells were studied using SEM, live/dead staining assessment assisted by fluorescent microscopy and laser scanning confocal microscopy. The optimal condition for cell electrospraying was investigated by modulating major processing parameters (composition of polymer blend, applied voltage, flow rate, etc.). For electrospinning, emulsions were made using PLGA solutions and vascular endothelial growth factor (VEGF)-containing PBS (or PBS alone). They were subsequently electrospun to make nanofibrous scaffolds with or without VEGF incorporation. Various experiments were conducted for studying the morphological and structural properties of nanofibrous scaffold, as well as the release behavior of VEGF. When concurrent cell electrospraying and emulsion electrospinning was performed, bioactive and cell-laden scaffolds were fabricated. The post-electrospinning immersion treatment could release encapsulated cells in the nanofibrous scaffolds. Furthermore, the space left by the dissolved microspheres provided the room for subsequent cell proliferation and infiltration. Cell culture experiments and comparative studies were then performed for evaluating cell functions in scaffolds with or without VEGF incorporation. Results indicated that cell proliferation and cell infiltration were enhanced in VEGF-loaded scaffolds. This new fabrication method can lead to breakthroughs in developing electrospun scaffolds for the regeneration of complex human body tissues.
3:45 AM - H3.03/B3.03
Design Complex Hydrogel Microparticles for High Throughput 3D Cell Culture, Co-Culture and Microtissue Production
Yen-Chun Lu 1 Wei Song 1 Duo An 1 Robert Schwartz 2 Minglin Ma 1
1Cornell University Ithaca USA2Weill Medical College of Cornell University NYC USAShow Abstract
Cell encapsulation in hydrogel microparticles have been investigated for decades in various bioengineering applications including tissue engineering, and cell therapy. However, most of the time, the cells are encapsulated randomly in whatever material that forms the microparticles, most commonly alginate. The lack of control over the spatial organizations of the cells and the extracellular environment within the microparticles significantly limits for advanced applications. Here we report a novel, multi-fluidic cell microencapsulation approach where 1 or more types of cells are encapsulated in pre-assigned compartments in the microparticles with controlled extracellular matrix. These microparticles can be produced with controllable and nearly monondispersed sizes at rates of over 10,000 microparticles per min and therefore provide a promising platform for high throughput applications. We demonstrated the utilization of these extracellular matrix-supported microparticles for 3D culturing of cells that typically require specific microenvironment to survive such as human umbilical vein endothelial cells (HUVECs) and small intestine stem cells. By taking advantage of the confinement effect, we also showed robust and scalable productions of size-controlled multicellular microtissues. Lastly, to demonstrate the broad applications of these microparticles, we performed proof-of-concept studies on three different co-culture systems including cell segregations under 3D confined space, the supporting role of stromal cells in hepatocyte functions and the paracrine cell signaling in aggregation of endothelial cells, all in a high throughput manner.
4:30 AM - *H3.04/B3.04
Strategies for Creating Functions in Polymer-Based Materials by Combining Different Components
Andreas Lendlein 2 1
1University of Potsdam Potsdam Germany2Helmholtz-Zentrum Geesthacht Teltow GermanyShow Abstract
A common strategy for the creation of functions in polymeric materials is the targeted combination of different polymers or polymers with inorganic components and the design of the interface between the phases . Hereby the different components can be physically mixed or joined. Alternatively they can be covalently linked.
Several examples for the design of functions are presented, each illustrating a different concept to gain a function. The multivalent binding of polyglycerols on micro porous polyetherimide membranes combines a separation capability with hemocompatibility . The covalent integration of nanoparticles as netpoints in a polymer network matrix enables a magneto sensitive reversible movement of the resulting hybrid material . The pore morphology of polymeric foams strongly influences their shape-memory capability . The internal geometry of a magnetic, active phase in a polymer matrix results in a triple shape effect, whereby the series of the shape changes can be determined by the applied stimulus .
The fundamental principles demonstrated in these material systems might stimulate further research in the field of multifunctional materials.
 M. Behl, M. Razzaq, A. Lendlein, Adv. Mater. 2010, 22, 3388-3410.
 A.T. Neffe, M. von Ruesten-Lange, S. Braune, K. Lützow, T. Roch, K. Richau, A. Krüger, T. Becherer, A.F. Thünemann, F. Jung, R.
Haag, A. Lendlein, J. Mater Chem B, 2014, 2, 3626-3635.
 M.Y. Razzaq, M. Behl, K. Kratz, A. Lendlein, Adv. Mater. 2013, 25, 5730-5733.
 T. Sauter, K. Kratz, A. Lendlein, Macromol. Chem. Phys. 2013, 214 (11), 1184-1188.
 M.Y. Razzaq, M. Behl, K. Kratz, A. Lendlein, Adv. Mater. 2013, 25, 5514-5518.
5:00 AM - H3.05/B3.05
Multifunctional Nerve Guidance Channels for Improved Neural Regeneration and Prosthetic Interfaces
Ryan Koppes 1 2 Xiaoting Jia 1 2 Seongjun Park 3 Christina Tringedes 1 Polina Anikeeva 1 2
1Massachusetts Institute of Technology Charlestown USA2Massachusetts Institute of Technology Cambridge USA3Massachusetts Institute of Technology Cambridge USAShow Abstract
There is currently no effective treatment strategy following traumatic injury to the peripheral nervous system (PNS) in either partial or full loss of extremity function. Recent work has demonstrated neural recording and electrical stimulation devices that allow for neural-motor control of prosthetic limbs. However, much improvement is required to reach the resolution of neural interfacing needed for physiological functionality. In addition to neural interfacing, tissue engineering strategies are potential means to restore functionality after traumatic injury to the PNS. However, current interventions are years from being effective in the clinic. Therefore, our goal is to engineer material platforms that both promote nerve regeneration and provide an electrical interface for prosthetic integration that is clinically relevant now.
To date, the influence of nerve channel geometry and dimensions of sub-200 mu;m scale on neural regeneration has been poorly investigated due to material processing. For interfacing with either the motor or sensory axons of the PNS, geometric constraints may provide a means for selectively regenerating axons to intimately interface electrodes with sensory or motor nerve fibers, respectively. Furthermore, topography robustly influences the orientation and length of neural growth. However, no technique currently exists to fabricate mu;m topography features on the interior surface of nerve guidance channels without the inclusion of films or rolling.
Herein, we present a new method for engineering polymeric nerve guidance channels with intrinsic topography or recording electrodes. Utilizing a thermal drawing process (TDP), macro-scale preforms of biocompatible polyetherimide were made with rectangular and cylindrical channels. Topographical features or electrodes composed of conductive polyethylene were machined and added to the preforms. TDP reduced the cross-sectional dimensions by up to 200 times while maintaining the original geometries. Rectangular, rectangular with microgrooves, and cyclindrical neural growth channels with dimensions 30-200 mu;m were evaluated in vitro for their influence on neurite outgrowth from primary dorsal root ganglia (DRGs). Total distance of neurite outgrowth into the channel as well as the orientation of neurite extension and cell nuclei within the channel were measured with respect to the geometry and dimensions of the growth channel. Preliminary data suggests that narrower channels (40-60 mu;m) enhance the orientation of DRG outgrowth compared to larger channels (>100 mu;m), but very limited growth is observed in small channels (<40 mu;m). However, inclusion of microgrooves within the large channel increases neurite orientation. These results demonstrate our ability to utilize the TDP to design new polymeric nerve guidance channels as a strategy for PNS regeneration and neural interfacing.
5:30 AM - H3.07/B3.07
How Architecturally and Functionally Complex Polymers Can Optimize Therapeutic Proteins In Vivo
Mi Liu 1 Gregor Fuhrmann 1 Pamp;#229;l Johansen 3 Jean-Christophe Leroux 1 Marc A Gauthier 2
1Swiss Federal Institute of Technology Zurich Zurich Switzerland2INRS Varennes Canada3University Hospital of Zamp;#252;rich Zurich SwitzerlandShow Abstract
In comparison to neutral linear polymers, functional and architecturally complex (i.e., non-linear) polymers offer distinct opportunities for enhancing the properties and performance of therapeutic proteins. However, understanding how to harness these parameters is challenging, and studies that capitalize on them in vivo are scarce. This presentation will cover this important topic with emphasis on two types of therapeutic proteins: ones for which long circulation in the bloodstream is desired, and ones for which retention and/or stabilization in the gastrointestinal tract is desired.
We will first present how the modification of an enzyme with a polymer of appropriate architecture can impart exceptionally low immunogenicity (e.g., generation/recognition of antibodies in vivo), with a commensurably low loss of therapeutic activity.[1,2] Secondly, we will also discuss how the modification of an enzyme with a polymer bearing appropriate functional groups can promote its stability (and thus therapeutic activity) at different locations in the gastrointestinal tract. Furthermore, functional polymers that interact with mucin will be shown to promote retention in the upper part of the gastrointestinal tract, and thus enhance the therapeutic activity of enzymes at this location. Overall, the importance of the findings will be framed with context to selected relevant diseases that stand to benefit most from the presented concepts. This work was supported by the Swiss National Science Foundation (310030_135732) and the Sassella Stiftung.
 Liu, Tirino, Radivojevic, Phillips, Gibson, Leroux, Gauthier. Advanced Functional Materials. 2013, 23, 2007
 Liu, Johansen, Zabel, Leroux, Gauthier. Submitted
 Fuhrmann, Grotzky, Lukicacute;, Matoori, Yu, Luciani, Walde, Schlüter, Gauthier, Leroux. Nature Chemistry, 2013, 5, 582
5:45 AM - H3.08/B3.08
Cellular and Biomolecule Isolation on Biodegradable Nanostructured Coatings
Eduardo Reategui 1 2 Nicola Aceto 3 James Sullivan 3 Anne Jensen 1 Eugene Lim 4 Mahnaz Zeinali 1 A. J. Aranyosi 1 Wei Li 5 Steven Castleberry 5 Aditya Bardia 3 Lecia Sequist 3 Daniel Haber 3 Paula Hammond 5 Mehmet Toner 1 Shannon Stott 3
1Massachusetts General Hospital Charlestown USA2Harvard Medical School Charlestown USA3Massachusetts General Hospital Cancer Center Charlestown USA4Massachusetts Institute of Technology Cambridge USA5Massachusetts Institute of Technology Cambridge USAShow Abstract
Nanostructured materials have been used as substrates for sensitive cellular or biomolecule recognition due to their high surface-area to volume ratio and biocompatibility. Whereas the deposition of these nanomaterials on surfaces is often irreversible, the analysis of the isolated biological samples is often limited to on-device microscopic imaging and spectroscopy applications. Therefore, biodegradable nanostructure substrates will facilitate the recovery of cells or biomolecules for downstream analysis (e.g., DNA, RNA, or proteomic analysis) and cell culture. Here, we describe a biodegradable nanostructured coating that allows for either temperature-responsive or mechano-sensitive degradation. The ultrathin coating (135.2 nm ± 8.6 nm) was formed by a layer-by-layer (LBL) deposition of biotinylated gelatin and neutravidin. Nanoroughness on the coating (30.7 nm ± 6.1 nm) was achieved by the incorporation of 70 nm streptavidin nanoparticles that were physisorbed directly on the gelatin coating. Temperature degradation of the applied coating to a glass or PDMS surface was achieved by raising the temperature to 370C; allowing their complete removal after 10 min. For local degradation of the coating, a normal force was applied through a frequency-controlled 80 µm microtip to dislodge partial regions of the coating, mimicking thixotropic hydrogel behaviors.
To demonstrate the biocompatibility and extremely sensitivity of the nanocoating, we used it for circulating tumor cells (CTCs) isolation and recovery. CTCs are extremely rare cells present in the blood stream of metastatic cancer patients (1 CTC per 109 blood cells) and their isolation and processing constitutes a technological challenge. We incorporated the nanocoating on our microfluidic HBCTC-Chip1 with tumor-cell specific antibodies at its surface (anti-EpCAM, anti-EGFR, anti-HER2). The clinical value of the nanocoating-microfluidic system was established when CTCs were detected in 87.5 % of patients with metastatic breast and lung cancer. The temperature degradation mechanisms of the nanocoating allowed recovery of 98.3 % ± 3.5 % of target cells with viabilities up to 92.03 % ± 4.5 %. Additionally, the frequency-controlled microtip allowed the recovery of individual CTCs from cancer patients that were analyzed for the presence of driver mutations in the PIK3CA (H1047R) and EGFR (exon 19 deletion and L858R) oncogenes.
In summary, our nanoscale, reversible biomaterial would enable and/or improve downstream assays through the release of any surface (e.g. beads, glass surfaces) that was initially employed to selectively isolate cells, proteins or DNA from a biological specimen.
1 Stott, S. L. et al. Isolation of circulating tumor cells using a microvortex-generating herringbone-chip. Proceedings of the National Academy of Sciences107, 18392-18397, doi:10.1073/pnas.1012539107 (2010).
H4: Poster Session I: Inorganic Biodevices
Monday PM, December 01, 2014
Hynes, Level 1, Hall B
9:00 AM - H4.01
Purification of Microvesicles by Standing Surface Acoustic Wave (SSAW)
Kyungheon Lee 1 Huilin Shao 1 Ralph Weissleder 1 Hakho Lee 1
1Massachusetts General Hospital Boston USAShow Abstract
Circulating microvesicles (MVs) have emerged as a promising surrogate for tissue-based markers, enabling non-invasive, real-time disease monitoring. Purifying MVs for downstream analyses, however, still remains a challenging task, which often involves time-consuming and extensive procedures (e.g., ultracentrifugation, multiple filtration). We herein present a new microfluidic platform for MV isolation and enrichment from clinical samples. The system utilizes acoustophoresis to size-selectively separate MVs. Interdigitated electrodes, patterned on LiNbO3 substrate, were used to generate standing surface acoustic wave (SSAW) inside a microfluidic channel, and the resulting acoustic radiation force separated MVs according to their size and density. The design and operation of the device was optimized through numerical simulation. When applied to sort nanobeads, the system achieved > 90% sorting yields. We further used the system to collect MVs from pRBC (packed red blood cell) samples as well as from cell culture media. The microfluidic-SSAW device successfully isolated and enriched pure MV population, which was confirmed by downstream molecular analyses (Western blotting). Based on label-free and continuous in-flow separation, the developed platform could be an ideal tool for fast preparation of intact MVs.
9:00 AM - H4.02
Importance of Diode Circuit Element in Electrolyte-Oxide Interface for Nanopore Ion-Transistors
Sung-Wook Nam 1 Binquan Luan 1 Eduard A Cartier 1 Marinus Hopstaken 1 Ajay K Royyuru 1 Gustavo A Stolovitzky 1
1IBM T.J. Watson Research Center Yorktown Heights USAShow Abstract
Nanopore ion transistors are electrofluidic elements conceived to manipulate the transport of molecular species through nanopores using electric fields. In this work, we report on a newly discovered diode circuit element existing in the electrolyte-oxide interface, and its importance for electrofluidic gating in ion transistors. We built sub-20 nm nanopore ion transistor devices and characterized ionic transport of KCl electrolytes. Simultaneous monitoring of electric currents of source (Is), drain (Id) and gate probes (Ig), allowed us to characterize both ionic and interfacial transports, as a function of gate voltage (Vg). Ionic transport through the nanopore was modulated such that negative (-) gate voltage bias induced an increase of ionic current, representing p-type transport, suggesting that the majority carrier contributing to ionic transport is positively charged potassium ion (K+) which screens the surface charges of pore wall. Interestingly, a characterization of Ig showed the presence of a diode circuit element in the electrolyte-oxide interface: The electric field created by negative (-) gate voltage bias reaches the electrolyte more effectively than that created by a positive (+) gate voltage bias, thus leading more efficient electrical-control over ionic transport. This diode functionality in electrolyte-oxide interface results in the unipolar transport of ion transistor. Based on the analysis of secondary ion mass spectrometry (SIMS) of the gate oxide layer, we suggest that the diode functionality is attributed to the diffusion of permeable potassium ions into the gate oxide, driven by negative (-) gate voltage biases. Our interpretation of the electrolyte-oxide interfacial effect clarifies electrofluidic gating behavior in ion transistors.
9:00 AM - H4.03
Electrochemical Etching of Silicon: High-Aspect-Ratio Nanopore Arrays on Membranes
Torsten Schmidt 1 Miao Zhang 1 Fatemeh Sangghaleh 1 Jan Linnros 1
1KTH Royal Institute of Technology Kista SwedenShow Abstract
Electrochemical etching (EE) of silicon in hydrofluoric acid has been shown to be an outstanding tool to realize a large variety of structures addressing a broad range of applications. Examples are the well-known luminescent porous silicon1 and well-defined homogenous pore arrays in the micrometer as well as sub-µm range.2-5
Nowadays, for demanding applications, such as molecular filtering and possibly sequencing of binary encoded DNA strands, solid-state membranes featuring an array of well-separated nanopores with diameters of about 2 nm are desirable. To meet these extraordinary requirements, light-assisted EE on structured silicon can be applied. The formation of nanopores, either in bulk silicon or on silicon membranes, is based on the local dissolution of surface atoms in pre-defined etching pits. Pore growth and pore diameter are, respectively, driven and controlled by the supply of positive charge carriers.
Performing EE on moderately-doped n-type bulk silicon, arrays with sub-100 nm wide pores were fabricated. In particular, straight nanopores with aspect ratios above 1000 (~19 µm deep and ~15 nm pore tip diameter) were achieved. However, inherent to the formation of such narrow pores is a radius of curvature of a few nanometers at the pore tip, which favors electrical breakdown resulting in rough pore wall morphologies.6
The Si membranes, used in our study, were fabricated on silicon-on-insulator (SOI) wafers using the Bosch process of inductively-coupled plasma etching. Array patterns in the sub-micro scale were defined on the membrane front side by optical or e-beam lithography. Electrochemical etching was then carried out individually on free-standing Si membranes, which are 100 µm in diameter and between 300 nm and 5 µm thick. So far, nanopores with diameters from 7 nm to 15 nm have been obtained on 300 nm thick membranes. To verify that pores have been etched through the whole membrane, the nanopore arrays were subjected to simple translocation experiments with fluorophore-tagged oligonucleotides. Based on optical detection, well-distinguishable single translocation events could be observed simultaneously for several nanopores (pore pitch distance 2 µm).
L. T. Canham, Appl. Phys. Lett. 57 (10), 1046-1048 (1990)
V. Lehmann et al., Materials Science and Engineering B69-70, 11-22 (2000)
P. Kleimann et al., Mater. Sci. Eng. B 69-70, 29-33 (2000)
J. Linnros et al., Physica Scripta 126, 72 (2006)
G. Laffite et al., Journal of the Electrochemical Society 158, 1 D10-D14 (2011)
T. Schmidt et al., submitted (2014)
9:00 AM - H4.04
Hybrid Fabrication of Controlled TiO2 Nanowire Arrays for Cellular Analysis
Young-Shik Yun 1 2 Jong-Souk Yeo 1 2
1Yonsei University Incheon Korea (the Republic of)2Yonsei University Incheon Korea (the Republic of)Show Abstract
According to advanced nanotechnologies in the field of biomedical engineering, an understanding of cellular responses with nanostructures becomes increasingly important. It requires a fabrication of nanostructures with a precise control of their size and positions in order to investigate the interactions between nanostructures and cellular responses. Electron beam lithography (EBL) as a top-down approach has been considered as one of the most powerful processes to fabricate and control nano-scale patterns. In this work, we fabricate Ti-based nanowires based on both top-down and bottom-up approaches using EBL and vapor-liquid-solid (VLS) method for the nanoscale resolution control of the nanowires. The size and the position of TiO2 nanowire arrays are controlled by EBL. Au-nanodot arrays are patterned on a substrate by the EBL as a seed pattern of TiO2 nanowire arrays. The nanodot arrays play an important role for catalysts using VLS method as bottom-up approach. In order to control the spacing between nanodots, we optimize the EBL process with Poly(methyl methacrylate) (PMMA) as an electron beam resist. Metal lift-off is used to transfer the spacing-controlled nanodots. The sample is then placed in a tube furnace and heated at a synthesis temperature of 850 °C. After the heat-treatment, TiO2 nanowire arrays grow from the nanodots through the VLS method. The controlled growth of TiO2 will be used to the study of interactions between nanostructures and cellular responses. We will examine the cellular response of osteoblasts as a function of the size and spacing of nanowires.
This research was supported by the MSIP(Ministry of Science, ICT and Future Planning), Korea, under the “IT Consilience Creative Program” (NIPA-2014-H0201-14-1002) supervised by the NIPA(National IT Industry Promotion Agency)
9:00 AM - H4.05
Generating and Trapping Device for Size-Controlled Microbubbles Using Patterned Carbon Nanotubes
Hiroshi Nishimura 1 Kaori Hirahara 3 2
1Osaka University Suita Japan2Osaka University Suita Japan3Osaka University Suita JapanShow Abstract
The extraordinary electrochemical properties of micrometer and nanometer sized fine bubbles, which are so-called microbubbles and nanobubbles, respectively, make them attractive for application in medical science and agriculture fields. Recently many application studies, such as bioactivation, clinical tests for bactericidal activities and wound cleaning, cleansing of seawater pipes, and so on., are already well underway, showing its potential. In addition, a method for trapping individual protein molecules using the gas-liquid interfaces on bubbles is also being developed. For promoting further applications utilizing such fine bubbles, detailed fundamental understanding is essential, especially regarding the correlation between size-dependent characteristics and resulting effects. Here we propose a novel electrochemical device using carbon nanotubes (CNTs), which can generate microbubbles with a uniform size and trap them individually to the specific addresses of the device. This device has a potential to enable us to single bubble level investigations with well-controlled sizes. It will also applicable to the manipulation or trapping of protein molecules and cells for their fundamental studies at single molecular or single cell level.
The devices proposed in this study employ patterned CNTs as the electrode for bubble generation by water electrolysis. Hole-patterned Fe catalyst was firstly fabricated at a pitch of 30#65374;200mu;m on a conductive Si substrate by photolithography process. Surface of the substrate at individual holes were insulated by 20nm thickness layer. Patterned CNTs were then fabricated on this substrate by chemical vapor deposition. After wiring the substrate to facilitate electricity from a power source, the electrode configuration was finally obtained in which only patterned CNTs exposed by insulating around the Si substrate and conductive wire.
Water electrolysis was conducted in a 10% NaOH aqueous solution using the fabricated electrode as a cathode. We found that hydrogen microbubbles generated on individual holes with a uniform size, at an applied voltage of 5 V. The experimental results showed that the bubble size can be controlled precisely by the reaction time and variation in the applied voltage. Furthermore, the bubbles still persist even after cutting off voltage. It demonstrates that the device can also function as a reservoir for bubbles with fixed diameter. Minimum diameter of the bubbles depended on the size of CNT hole pattern. It is expected to be possible to operate smaller bubbles less than 30mu;m in further study, by developing the CNT electrode with finer patterning.
This work was supported by JSPS KAKENHI Grant No. 26286024. Photolithography process was supported by the Nanofabrication Platform in Nanotechnology Open Facilities, Osaka University.
9:00 AM - H4.06
Use of Selenium Nanoparticles to Treat Head and Neck Squamous Cell Carcinoma (HNSCC)
Christopher Edward Hassan 1
1Northeastern University Boston USAShow Abstract
Selenium nanoparticles have been found to protect cells with normal p53 genes from cancer medications such as cisplatin and paclitaxel, while simultaneously leaving cells with mutant p53 proteins vulnerable to such drugs. This has allowed for higher doses than would otherwise be safe to administer. These observations will be applied to head and neck squamous cell carcinoma (HNSCC) cells. The protective selectivity of elemental selenium nanoparticles on these cells, as well as the ambient mucus which can also carry the mutated p53 protein, will be analyzed. Selenium functionalized with PEG will also be explored as a possible option. Additionally, the mechanism for converting glutathione and selenite to glutathione disulfide and elemental selenium will be analyzed.
9:00 AM - H4.07
Dextran Coated Cerium Oxide Nanoparticles as Antioxidants
Ece Alpaslan 1 Amit K. Roy 1 Thomas J. Webster 2
1Northestern University Boston USA2Northestern University Boston USAShow Abstract
The presence of Reactive Oxygen Species (ROS) and Reactive Nitrogen Species (RNS) contribute to the progression of several human diseases. In clinical applications, antioxidants as Vitamin C and E and other free radical scavengers have only achieved limited success due to a lack of targeted delivery. However, recent advancements in nanotechnology have enabled targeted delivery, as well as the elimination and control of oxidation reactions, as smaller sizes induce greater oxidative stress. Some of the most studied nanomaterials, which may act as potential antioxidants, are rare earth oxide nanoparticles, fullerenes and carbon nanotubes. With recent reports on cerium oxide nanoparticles (CNP) being neuroprotective, radioprotective, and anti-inflammatory, CNP may be a novel potential free radical scavenger. Considering these facts, CNP may promote cell survival under oxidative stress to limit ROS and RNS damage.
The objective of this study was to determine whether human dermal fibroblast (HDF) cells are able to recover from cytotoxic reagents as hydrogen peroxide (H2O2) or hydroquinone (HQY) in the presence of CNP.
Sub 5 nm dextran coated CNPs were synthesized from 5 mL aqueous solutions of 1 M cerium nitrate (Sigma Aldrich, St Louis, MO) and 10 mL of 0.1 M dextran T-10 (Pharmacosmos, Holback, Denmark) and these solutions were added drop wise to 30 mL of a 30% ammonium hydroxide (Sigma Aldrich, St. Louis, MO) solution while stirring for 24 hours at 25 omicron;C.
TEM results revealed that the particles were around 3 nm and Dynamic Light Scattering results confirmed that there was no significant change in the size of the particles after storing them for a month.
Cell proliferation was assessed using MTS kit per the manufacturer&’s instructions. HDF (ATCC® PCS-201-010trade;) cells were cultured using DMEM (ATCC® 30-2003trade;), 10% FBS (ATCC® SCRR-30-2020trade;) and a 1% penicillin-streptomycin solution (ATCC® 30-2300trade;). The cells were seeded at 5,000 cells /well, allowed to adhere for 24 hours and the following day, the culture was treated with cytotoxic agents like H2O2 or HQY with the concentration range from 100 to 800µM. After 24hrs of incubation, the MTS reagent was added and was determined. A dose of 400µM for both cytotoxic agents was found effective in killing 50% of the cells. In order to determine the cyto-protective function of CNP, some of these cells were preincubated with ceria at 500 µg/mL concentration for 24hrs followed by the addition of cytotoxic agents. The culture was incubated for 24hrs before MTS assays. Results were compared with only 400 µM of H2O2 and HQY, but not CNP treated cells.
Sub 5 nm dextran coated CNP were synthesized and cultured with HDF cells, which were then treated by cytotoxic reagents. The results showed that CNP treated cells were able to recover from the oxidative damage /cytotoxicity exerted by the drugs, suggesting that CNP may act as antioxidants within the body.
9:00 AM - H4.08
A Mucus- and Biofilm-Resistant Modification on Endotracheal Tubes
Jun Li 1 Daniel Donahue 1 Gregory Brotske 1 Phu Nguyen 1 Michael Bouchard 1 Zheng Zhang 1
1Teleflex Medical Cambridge USAShow Abstract
Mucus accumulation on medical devices such as the endotracheal tubes (ETTs) can cause serious occlusion and infection issues. Our research focused on understanding the interaction between mucin and different types of surfaces, and led to the development of a betaine-modified PVC substrate that can resist both mucus/sputum accumulation and bacterial attachment. A full-sized ETT tube was modified and exhibited a significant mucus reduction in an animal model.
Both hydrophobic and hydrophilic polymeric substrates were prepared, with their contact angles ranging from nearly zero to 130o. PVC surfaces were applied with positive, negative ,zwitterionic, and uncharged modifications. It was found that some highly hydrophobic and highly hydrophilic surfaces can resist mucus adsorption. The surfaces of betaine-modified, full size, PVC ETT exhibited a 48-65% reduction in mucus attachment in vitro, as measured by radiolabeled porcine mucin. The betaine-modified PVC ETT surfaces also reduced the attachment of S. aureus (MRSA) and C. albicans by nearly 99% and reduced P.aeruginosa by 76%. A process was developed to modify a full-sized ETT on both outside and inside surfaces. In a 5-hour sheep study betaine-modified ETTs showed a significant reduction in mucus/sputum attachment.
9:00 AM - H4.09
Microtopographic Control of Nanostructure Self-Assembly
Laith Kadem 1 Julia Purtov 1 Constanze Lamprecht 1 Christine Selhuber-Unkel 1
1Christian-Albrechts-University of Kiel Kiel GermanyShow Abstract
Here we report the use of diblock-copolymer micelle nanolithography (BCML) to create gold nanoparticle arrays on microtopographic substrates. BCML is a widely used technique to generate quasi-hexagonally arranged patterns of metal nanoparticles on surfaces. Lateral spacing between nanoparticles is controlled by the molecular weight of the diblock copolymers, polymer concentration and surface coating parameters. Application to microtopographic substrates results in a superposition of nano- and microstructures, where particle nanospacings are additionally controlled by the microtopography. Our simple self-assembly method yields neighboring microdomains that display different interparticle nanospacings on a single substrate by a single BMCL step. It therefore provides a novel and high-throughput strategy to generate micro-nanostructured surfaces. Furthermore, these micro-nanostructured surfaces are of high interest in cell biology, as both nanostructures and microstructures are known to control cell behavior. In particular we will use this new platform to study cellular adhesion processes that are influenced by parameters such as ligand spacing and density.
9:00 AM - H4.10
The Development of Screw-Sense Responsive Fluorescent Probes
Francis Lister 1 Jonathan Clayden 1
1University of Manchester Manchester United KingdomShow Abstract
The controlled inversion between a left-handed (M) and right-handed (P) screw-sense preference of an achiral helix can create a binary switch with a signal relay achievable over the length of the helix.1
Peptides of achiral α-aminoisobutyric acid have proven to be effective at relaying stereochemical information from one terminus to the other via control of their screw sense preference.2 The helical fidelity of (Aib)n helices has proven to be exceptionally high,3 with a recent publication highlighting their use in the control of an achiral reaction site 60 bonds away from the nearest chiral centre.4 This equates to a chiral relay through an achiral helix over a distance of 4 nm, roughly the thickness of a cell membrane.
Other recent work, which has made use of diastereotopic NMR probes 5 has highlighted the potential use of these (Aib)n helices in the development of a synthetic analogue of a G-protein coupled receptor,6 which transmits a signal through a conformational change in its trans-membrane domain.
While successful, the developed NMR probes are incompatible with a membrane environment and novel probe types are required to develop these systems further. Fluorescence techniques are highly sensitive, non-invasive and compatible with the translucent membrane.
The central aim of this project is to develop a chiral fluorescent probe using two pyrene chromophores that responds to changes in helical environment with a change in the excimer/monomer (E/M) ratio observed in the pyrene fluorescence region.7
A variety of probe structures containing two pyrene units were synthesised. These were attached to the C-terminus of N-terminally Cbz-L-Phe or Cbz-D-Phe controlled (Aib)4 helices, which have opposing screw-sense preferences. Successful probes were identified as those exhibiting different E/M ratios for the L- and the D- controlled helices.
The earlier designs of the probe structures were found to overpower the control delivered by the Phe residue when attached to the (Aib)4 scaffolds. The most recent generation of probes however exhibit both reduced control and an observable difference in E/M ratio when comparing the L-Phe and D-Phe controlled species.
It would appear that the development of these probes, which need to be enantiomerically pure to respond to changes in helicity, centres around the fine balance of control from both termini. Work is on-going to investigate new probe designs, looking particularly at ways to reduce control and improve probe response.
1) Clayden, J. et al., Nature (London), 2004, 431, 966-971
2) Solagrave;, J. et al., J. Am. Chem. Soc., 2011, 133, 3712-3715.
3) Clayden, J. et al., Angew. Chemie Int. Ed. 2009, 48, 5962-5965.
4) Byrne, L. et al., Angew. Chemie Int. Ed. 2014 53, 151-155.
5) Brown, R. A. et al., Nat. Chem., 2013, 5, 853-860.
6) Rasmussen S. G. F. et al., Nature, 2011, 477, 549-555.
7) Bains G. et al., Molecules, 2011, 16, 7909-7935.
9:00 AM - H4.11
Reconfigurable Photonic Microcapsules for Building Blocks of Photonic Devices
Shin-Hyun Kim 1 Tae Min Choi 1 Jin-Gyu Park 2 Vinnothan Manoharan 2
1KAIST Daejeon Korea (the Republic of)2Harvard University Cambridge USAShow Abstract
Colloidal crystals possess photonic stop band and exhibit selective reflection of light at the band wavelength. This is promising properties for many photonic applications. For example, the colloidal crystals can be used for structural color pigments and ultraviolet- or infrared-screening materials depending on position of the stop band. However, most colloidal crystals have been prepared in a film form on solid substrate, which severely limits the ease of further processing and structural reconfigurability. Although emulsion drops have been used as templates to produce closely packed spherical crystals, the resultant structures are still not reconfigurable and the dynamic control is lost.
One way to overcome such limitations is to encapsulate crystalline colloidal arrays in flexible microcapsules. High mobility of colloids in the liquid core of microcapsule allows their rapid rearrangement and flexible membrane enables the deformation of photonic microcapsules into desired shape. To achieve this, we prepare double-emulsion drops with a capillary microfluidic device and use them as templates to produce microcapsules. An aqueous suspension of polystyrene particles is used to form an innermost phase of the double-emulsion drops, whereas monomer resin, containing small amount of photoinitiator, is used to form a middle phase. The polystyrene particles in the aqueous core are negatively charged, which provides electrostatic repulsion between particles, leading to the crystallization of the particles into face-centered cubic (fcc) lattice. During crystallization, (111) plane of fcc lattice, a hexagonal array of colloids, is formed along the spherical inner wall and this provides rotation-independent stop band. The monomer resin is solidified into a highly flexible membrane by in-situ photo-polymerization, making the photonic structure highly stable and reconfigurable. The resultant photonic microcapsules can be employed as building block to construct various photonic devices. For example, the microcapsules are compressed between two parallel glass slides and densely packed to form a 2D photonic sheet with negligible voids; each microcapsule is deformed to a hexagonal disk. Upon the compression, particles in the capsules rearrange by aligning their (111) plane along the inner surface of the deformed membrane. Therefore, the sheet, composed of arrays of #64258;attened microcapsules, exhibits uniform re#64258;ection along whole the surface. The photonic microcapsules can be further assembled to make photonic structures with 3D shape, which is otherwise difficult to achieve. High reconfigurability, ease of processing, and potential controllability of stop band position of photonic microcapsules will provide new opportunity as building blocks for practical photonic devices.
9:00 AM - H4.12
The Use of MRI Technology for Studying the Adhesion of Microparticles
Nina Sarvasova 1
1Institute of Chemical Technology, Prague Prague Czech RepublicShow Abstract
In every development of functional particles, there is an important part consisting of the study of their behaviour in conditions simulating their end use. For such measurements, there are several methods available, though only few of them can yield any results without damaging or irreversibly changing the studied material. Magnetic Resonance Imaging (MRI) is a method widely acknowledged as a suitable one for such purposes, as it is non-destructive, non-invasive and provides the opportunity to observe the experiment in “real-time” arrangement. In this work, MRI was used as a means to observe the behaviour, mainly adhesion, of selected microparticles in 3D differentiated media.
As a part of this work, porous media with different pore sizes were created from Polydimethylsiloxane (PDMS) using solid template method. Each of the porous layers was placed within the flow cell connected to the peristaltic pump enabling the flow through the system. Thus, such setting allowed for both, stationary and flow measurements in the MRI scanner. Resulting scans were evaluated and processed using graphic software ImageJ. Regarding the microparticles used in this work, two types of composite particles containing magnetic nanoparticles were used, one with the size around 1.5 mm and the other with the size of approximately 100 mm. Magnetic nanoparticles contained in composite microparticles belonged to the crucial requirements for these experiments, since it acted as a contrast agent thus allowing for particle observation in MRI scans. In addition, the loss of the particles after the experiment was estimated indirectly using UV/VIS spectroscopy as the loss of Fe3+ in the circulating solution.
In summary, 3D complex PDMS media were created with the porosity estimated using MRI. These were successfully used in the flow experiments to study the adhesion of SiO2/PNIPAM/Fe3O4 and Alginate/SiO2/Fe3O4 microparticles. In both cases, there was some adhesion observed and it was also backed up with the concentration loss of Fe3+ ions in inlet and outlet streams during the experiments.
9:00 AM - H4.13
Acoustic Levitation for Neural Tissue Engineering
Charlene Bouyer 1 2 3 Pu Chen 1 Utkan Demirci 1
1School of Medicine, Stanford University Palo Alto USA2Inserm Lyon France3Universitamp;#233; Lyon 1 Lyon FranceShow Abstract
Engineering of multilayered cell sheets is motivated by the needs to understand cell-cell communication and to reconstruct brain tissues in vivo. For example, engineering of cortex tissue is demanded for broad applications ranging from understanding of neuron mapping to brain drug discovery. Current technologies for generation of cortex tissue are based on fabrication and assembly of neuron-encapsulating hydrogels. However, these methods are limited by problems including large time budget, incapability for manipulating large amount of cells and low cell viability. Here, we demonstrate an acoustofluidic technology platform allowing fabrication of bulk hydrogels containing multilayers of neurons in a rapid and cost-effective manner. As an initial concept validation, we illustrated levitation of microbeads with densities from 1.025 g/cm3 to 1.13 g/cm3 and sizes from 8 µm to 500 µm, in fluid densities from 1 g/cm3 to 1.205 g/cm3. We then explored acoustic standing waves for trapping cells in either negative or positive pressure regions of acoustic standing waves according to their acoustic impedance. Multilayered cell sheets were created in the acoustic waves in less than 10 seconds. The engineered cortex included 6 layers of neurons surrounding by soma cells. The levitated cell structures is stabilized by rapid UV crosslinking of hydrogel within 30 seconds. Cells viability assays indicated cytocompatibility of this method. We expect that these in vitro engineered artificial cortex can be used as an alternative choice for brain slides for neuroscience and brain study.
9:00 AM - H4.14
Barcoding Cells Using Magnetic Nanowires for Multiplexed Detection
Anirudh Sharma 1 Gregory M Orlowski 2 Seung Yeon Kim 3 Allison Hubel 4 Bethanie J.H. Stadler 1
1University of Minnesota Minneapolis USA2UMass Medical School Worcester USA3Georgia Institute of Technology Atlanta USA4University of Minnesota Minneapolis USAShow Abstract
Magnetic multi-layered barcode nanowires composed of gold/nickel multilayers with various surface coatings were used as agents for multiplexed detection in a heterogeneous cell population. Cell sorting and identification using magnetic beads, quantum dots and fluorescent probes is limited by single antibody-labeled magnetic beads or by the number of spectrally resolvable fluorophores (wavelengths). The ability of barcode nanowires to label populations of cells with unique magnetic signatures would enable identification and separation of multiple cell populations. Here, selective targeting of A549 human lung carcinoma and human THP-1 cells (monocytic leukemia) was followed by magnetic detection and demultiplexing using first order reversal curve diagrams (FORC diagrams) and coercivity values obtained from magnetic hysteresis curves through Vibrating Sample Magnetometer (VSM).Various imaging techniques will be shown to illustrate the barcoding concept when applied to a heterogeneous cell population - including differential interference contrast (DIC), reflectance and fluorescence. A combination of these techniques and SEM/TEM imaging was used to study dependence of cellular uptake on nanowire concentrations, lengths and surface coatings. Toxicity analysis included exposing peritoneal macrophages from C57 Bl/6 mice to the barcodes nanowires and then monitoring IL-1b and TNF-α levels, and metabolic activity (MTS assay). Almost no cell death was induced and minimal quantities of IL-1b and TNF-α were induced over a six hour incubation period. In short, barcode nanowires hold much promise for multiplexed diagnosis and therapy.
9:00 AM - H4.15
Decarboxylation and the Following Adduct to Alkenes Using TiO2 Photocatalyst
Kento Shimaoka 1 Yuki Taleda 1 Makoto Yamashita 1 Shota Kuwahara 1 Kenji Katayama 1
1Chuo university Tokyo JapanShow Abstract
Carboxylic acids are abundant in nature and are also produced industrially on a large scale, and organic reactions employing them have received much attention. Recently, several decarboxylation reactions using carboxylic acids have been reported using photosensitizers, which utilize a photoinduced single electron transfer . Although this reaction is proceeded under a mild condition, it is difficult to remove the photosensitizers from the solution after the reaction. On the one hand, semiconductor photocatalyst has attracted attention because it is nontoxic and it can be easily separated from the solution. We have developed various photocatalytic reactions using microreactors inside which titanium oxide was coated as a photocatalyst. By using this reactor, we could proceeds photocatalytic reactions without any electric power sources by using the capillary force and diffusion of chemicals driven by the concentration gradient.  In this study, we applied decarboxylation reactions by using the photocatalytic microreactor instead of the molecular photosensitizers. Capillaries coated with a photocatalytic material were put into a test tube, where 1 mL of a reactant solution was added and UV-LED (365 nm) were iiradiated for photoreaction. As a result, we could successfully observe the decarboxylation reactions of carboxylic acids, which was confirmed from the dimer molecules generated from the radicals. Furthermore, the adduct reactions of the radicals generated from the carboxylic acids to various electron-deficient alkene were confirmed. Y. Yoshimi, T. Itou, M, Hatanaka, Chem. Commun. 2007, 5244-5246  K. Katayama, Y. Takeda, K. Kuwabara, Chem. Commun, 48, 7368-7370 (2012)
9:00 AM - H4.16
Mechanically Stimulated Release from Layered Drug Delivery Systems with Electrosprayed Micro-/ Nano- Superhydrophobic Coatings
Julia Wang 1 Jonah A Kaplan 1 Yolonda L Colson 2 Mark W Grinstaff 1
1Boston University Boston USA2Brigham and Women's Hospital Boston USAShow Abstract
Tissue expanders are medical devices commonly used to grow autologous soft tissue for transplantation to eliminate tissue rejection and minimize scarring. For the over 2.9 million women in the US living with breast cancer, the primary course of treatment is removal of the tumor by surgery and subsequent breast reconstruction with tissue expanders, during which saline is injected every week in order to provide space for a permanent breast implant. However, the success of tissue expansion is compromised by increased fibrosis from necessary radiation therapy for reduced cancer recurrence. In order to provide better breast reconstruction after radiation therapy, we have incorporated the strain mechanics of the tissue expander to develop a biocompatible, multi-layered system that delivers cytokines and drugs based on applied strain. In the absence of tensile strain, the electrosprayed superhydrophobic barrier coating (contact angle >167°) consisting of interconnected micro- and nano-sized particles of biocompatible polymers, poly(ε-caprolactone) [PCL] and poly(glycerol stearate-co-ε-caprolactone), maintains a stable air layer to prevent drug release from the core. The absorbent core (polyester/cellulose) is tolerant of a variety of solvents, allowing versatile drug loading. When tension is applied, the mechanical mismatch between the coating and core material leads to strain-dependent crack propagation of these coatings, allowing water to infiltrate and subsequently release adsorbed agents. We demonstrate strain-dependent release (ε = 0%, 30%, or 100%) of Yellow 5/ Blue 1 and FITC-BSA in phosphate buffered saline and serum, and apply this system to the strain-dependent release of cisplatin (cytotoxic) and SN-38 (cytostatic). This delivery system is further evaluated with 3T3 fibroblasts, where strain-dependent amounts of TNF-α is delivered to decrease collagen production. Incorporating the mechanics of the tissue expander to trigger drug and cytokine release from this strain-dependent drug delivery system may improve breast reconstruction after radiation therapy while providing a continued reduction in cancer recurrence. The ease in fabricating these coatings and versatility in core loading affords a simple, tunable mechanoresponsive drug delivery system to apply to medical devices, such as tissue expanders.
9:00 AM - H4.17
Microwave Synthesis and Application of N Doped Nano TiO2 for Aromatic Wastewater Treatment
Mahdi Fathizadeh 1
1Ilam University Ilam Iran (the Islamic Republic of)Show Abstract
TiO2, as a photocatalyst, has been extensively used for wastewater treatment and air purification. Recently, many researches have been done aiming to improve the efficiency of photocatalysts under visible light by modification of TiO2. The N-doped TiO2 especially shows a significant photocatalytic activity under visible light irradiation. Two different methods are used to dope nitrogen in TiO2; the first one is sol-gel synthesis and the second one is physical method (ion implantation, magnetron sputtering). In this work, the microwave heating methods was used for fabrication of the N-doped TiO2. Then, the wastewater was treated by N-doped TiO2 under the visible light.
First, the microemulsion phase was prepared by adding aqueous phase (5 mol/L of tetrabutyltitanate in nitric acid) into oil phase (the mixture of Triton X-100, 1-hexanol, cyclohexane) with Urea as nitrogen source. Then, the mixture was transferred to a 250 mL polyethylene autoclave. Heat treatments were done at temperatures between 60 to 120°C and duration of 45 to 75 min. After the microwave heat treatment, the mixture was cooled down to room temperature and washed with deionized water several times to remove the oil from N-doped nano TiO2 powder. The photcatalytic property of N-doped nano TiO2 was tested by its efficiency in elimination of aromatic compounds in wastewater. A 1000 W halogen lamp with glass optical filter as sun light was used in the 250 mL batch reactor which was cooled by water circulation though jacket side.
The XRD patterns of synthesized N-doped nano TiO2 showed that 60 °C is not suitable for the synthesis. The anatase phase has been appeared without any phase change after nitrogen doping using microwave heating at 60 0C and 75 min. Increasing the microwave heating temperature caused peak broadening for N-TiO2 samples compared to the undoped ones. The distribution (PDI) and particle size of N-doped nano TiO2 were measured by DLS which showed increasing the temperature from 60 to 120 °C raise both the particles size and PDI. Increasing the exposure time amplified the particle size with PDI remaining unchanged at a constant temperature. As can be seen from the SEM images at 90 0C and 75 min, the N-doped TiO2 sample has uniform nanoparticles with average diameter of 25-30 nm.
XPS analysis was done to examine the states of the doped nitrogen samples. There are Ti, O, and N elements on the surface of the samples with different peak intensities. The optical absorption range of the doped samples was shifted to the lower energy region, from 380 to 500 nm.
The results of aromatic decomposition showed that the optimal heat treatment condition is at 90 0C and 75 min. At the highest temperature and time, the potocatalytic activity of N-doped nano TiO2decreased as a result of an increase in the ratio of Ti to N suggesting that when the mole ratio of Ti to N is higher than the optimal value, the photocatalytic activities will decrease rapidly under visible light.
9:00 AM - H4.18
Inorganic-Derived Iron Oxide/Silica Nanoparticles for Magnetic Isolation of Nucleic Acid
Valentin Natarov 1 Dzmitry Kotsikau 1 Vladimir Survilo 2 Vladimir Pankov 1
1Belarusian State University Minsk Belarus2Ltd. "Vega", Group of Companies "Alcor Bio" St. Petersburg Russian FederationShow Abstract
In recent 10 years, there has been an intense interest in the preparation of modified magnetic nanoparticles for biomedical applications. Magnetic separation is a well-proven method for isolation of nucleic acids from biological samples. Facile synthesis of iron oxide/silica nanoparticles via non-expensive inorganic precursors is presented in this paper.
The synthesis is based on a three-step process, involving i) synthesis of magnetite nanoparticles by combined hydrolysis of Fe2+ and Fe3+ salts with aqueous ammonia at room temperature; ii) silica sol formation by the addition of necessary quantity of hydrochloric acid into sodium silicate solution containing the magnetite nanoparticles; iii) oxidation of the obtained Fe3O4#8210;SiO2 mixed sol with water solution of hydrogen peroxide. Size, shape and colloidal stability of the nanoparticles were found to be strongly dependent on various processes. In order to optimize the synthesis conditions, the effect of pH, nature of precursors, concentrations of solutions, steering intensity and temperature has been studied. All operations were carried out in water solutions under constant stirring without the addition of any stabilizers. In order to adjust the size of the agglomerates and to prevent their further aggregation, the particles were redispersed in physiologic saline.
Structural studies have been performed by XRD, TEM and IR-spectroscopy. Colloidal stability, magnetic properties, chemical composition, specific surface area and extraction efficiency of DNA molecules have been also studied.
The content of silica component in the prepared Fe3O4#8210;SiO2 composite was estimated by chemical analysis to be about 35-40 wt. %. According to XRD characterization of powdered samples, the composite consists of well-crystalline Fe3O4 nanoparticles mixed with X-ray amorphous silica. The occurrence of silica phase was proved by IR spectroscopy. The diameter of the obtained spherical nanoparticles varies from 40 to 80 nm for the Fe3O4#8210;SiO2 composite, and from 8 to 10 nm for the initial Fe3O4 grains.
Specific saturation magnetization of the powdered Fe3O4#8210;SiO2 sample was measured to be about 30-35 A#8729;m2kg-1. This value provides a complete and fast magnetic separation of the oxide particles from a solution using a standard magnetic holder.
The DNA isolation has been tested by a standard protocol in the presence of a chaotropic agent using salmon sperm DNA as a test sample. Extraction was measured by real-time PCR and found to be comparatively higher than efficiency of other commercially available nanoparticles. Thus, the synthesized magnetic nanoparticles meet the basic requirements as a component of DNA isolation kit.
9:00 AM - H4.19
Development of Multifunctional Silica Nanoparticles as Carrier for Cellular Delivery
Bhavana Deore 1 Michael L Barnes 1 Arnold Kell 1 Pankaj Bhowmik 2 Patricia Polowick 2
1National Research Council Ottawa Canada2National Research Council Saskatoon CanadaShow Abstract
The delivery of biomolecules into cells is crucial in modern biological systems. Most naked biomolecules are poorly delivered to cells owing to poor stability, potential toxicity and incompatible charges. Therefore, various natural and synthetic vectors are being investigated as cellular delivery vehicles. Silica nanocarriers are promising candidates for such cellular delivery due to their multifunctionality, stability, tunable size and charge and biocompatibility. Here, we present the synthesis and characterization of multifunctional luminescent silica nanoparticles and discuss their subsequent use as cell delivery vehicles and biomolecule sensors.
9:00 AM - H4.20
Conservative and Dissipative Interactions in Multimodal Force Microscopy Driving Multiple Higher Eigenmodes
Sangmin An 1 2 Christian J. Long 1 2 Vladimir Aksyuk 1 Santiago D. Solares 2 3
1National Institute of Standards and Technology Germantown USA2University of Maryland College Park USA3University of Maryland College Park USAShow Abstract
In multifrequency atomic force microscopy (AFM) the cantilever probe is often excited at two or more resonance frequencies simultaneously and the respective dynamic responses are detected and analyzed, enabling simultaneous measurement of multiple surface properties. While the large-amplitude oscillation of the first eigenmode is used for topographical measurement, the smaller-amplitude oscillation of the higher eigenmodes is used for mapping surface stiffness, average dissipative behavior or other surface properties during the scan . Recently, a trimodal AFM technique has been developed, which uses two higher eigenmodes (for example, the second and third) for compositional mapping and subsurface visualization of soft matter, respectively . More recently a 4-eigenmode multimodal technique has been introduced [S.D. Solares, S. An and C.J. Long, “Multifrequency Tapping-Mode Atomic Force Microscopy Beyond Three Eigenmodes in Ambient Air,” submitted]. In this presentation we describe the dynamics of multimodal AFM based on experimental and computational results, focusing on the variation of the conservative and dissipative interactions during imaging and spectroscopy as the free oscillation amplitude of individual eigenmodes changes with respect to the rest of the active eigenmodes. We quantify the conservative and dissipative interactions for each eigenmode in terms of its respective virial and average dissipative power per oscillation cycle, in order to extract compositional information at different measurement frequencies. This type of multimodal characterization opens new avenues for more comprehensive material property measurement than what is currently possible.
< References >
 R. Garcia and E.T. Herruzo, Nat. Nanotech.7, 217 (2012)
 D. Ebeling, B. Eslami and S.D. Solares, ACS Nano7, 10387 (2013)
9:00 AM - H4.21
Microfabrication of Controllable Submicron Period Structures Employing Direct Femtosecond Laser Holographic Lithography System
Tomas Tamulevicius 1 Tadas Kudrius 2 Vytautas Stockus 2 Gintas Slekys 2 Dainius Virganavicius 1 Linas Simatonis 1 Asta Tamuleviciene 1 Ausrine Jurkeviciute 1 Nerijus Armakavicius 1 Sigitas Tamulevicius 1
1Kaunas University of Technology Kaunas Lithuania2Altechna Ramp;D Vilnius LithuaniaShow Abstract
Ultrafast pulsed laser holographic lithography (HL) setup for controllable period direct patterning employing a custom made diffraction optical element (DOE) has been assembled, tested and applied for production of different submicron period microstructures. Controllable period direct patterning HL system was designed in such a way that the laser beam was divided into two equal intensity beams that were collimated and then focused employing two lens 4f imaging system on the sample placed on a computer controlled XYZ translation stage. Second harmonic beam from the 1030 nm wavelength Yb:KGW femtosecond laser (Light Conversion) and XYZ translation stage (Aerotech) were employed. The DOE based beam splitter was designed from the set of 15 different period diffraction gratings arranged in one circle. In this DOE each grating diffracted the laser beam at different angles. Two beams imaged by the lens system were merged on the sample surface at different angles producing different period interference fringes. The setup was applied for machining of different type of microstructures including photomasks in chromium and iron oxide films on a glass substrate, point by point direct diffractive metallic surface inscription, direct laser ablation of diamond like carbon as well as silver - diamond like carbon (Ag:DLC) based nanocomposite thin films and submicron biosensor chips on fused silica. 1-D periodic structures with variable period were produced employing interference of the second harmonic (515 nm) of femtosecond laser. The morphology of periodic structures was analyzed by scanning electron microscopy and atomic force microscopy, mapping of the surface composition was done by energy dispersive x-ray spectroscopy, optical properties were studied by registering far field distribution of the diffracted light by the structures. Typical applications of such structures as templates in capillary assisted self assembly of nanoparticles as well leaky wave biosensor are provided. Reflection spectra as well as spectral composition of the resonant guided mode were registered in case of produced DLC and Ag:DLC nanocomposite gratings on fused silica. It is shown that high throughput submicron patterning technique is efficient tool in production of periodic structures in different material including biocompatible and chemically inert material such as diamond like carbon. Moreover it is demonstrated that direct HL laser ablation technique enables production of periodic structures in nanocomposite materials avoiding surface segregation processes that is typical for plasma based technologies. This kind of submicron structures in nanocomposites, combining resonant plasmonic properties of the nanoparticles as well as resonant response of the periodic structure, presents a novel type of biosensors operating in different liquid analytes without any functionalization of the surface.
9:00 AM - H4.22
Wireless Neural Excitation via Transcranial Magnetothermal Stimulation
Ritchie Chen 1 Gabriela Romero 1 Michael Christiansen 1 Polina Anikeeva 1
1MIT Cambridge USAShow Abstract
Current technologies to stimulate intact brain circuits suffer from several limitations. For example, pharmacological agents lack specificity and lead to unwanted side effects, while electrical stimulation is highly invasive. Herein, we demonstrate that wireless neural excitation can be evoked by remotely controlled heat dissipation via magnetic nanoparticle (MNP) transducers. By sensitizing cells to heat through the expression of the thermosensitive cation channel TRPV1, robust neural excitation is demonstrated in close proximity to ferrofluids in vitro and in vivo . We find that trains of action potentials can be controlled with repeated thermal cycles, and that subpopulations of neurons can be stimulated in deep brain structures. Our MNPs, optimized to dissipate heat efficiently and to elicit low immunoreactive response, may potentially serve as a new paradigm to achieve deep brain stimulation.
9:00 AM - H4.23
Alignment of Collagen Fiber in Pneumatic Soft Micromold (PSMM) Device
Po-Jung Huang 1 Jun Kameoka 2 1 Alvin Yeh 3
1Texas Aamp;M University College Station USA2Texas Aamp;M University College Station USA3Texas Aamp;M University College Station USAShow Abstract
We have demonstrated the fabrication of fiber oriented collagen microparitlces by pneumatically actuated soft micro-mold (SMM) device. Collagen fiber alignment has been considerably important recently in tissue engineering because fiber scaforld in real tissue, including tendon, bone, blood vessels, and skin are aligned to constract the specific shapes and structures. Collagen orientation also plays a crucial role in cell proliferation, migration, and tumor metastasis and they are highly demanded by may fields. Currently, strain-induction, magnetical, electrochemical and microfluidic approach are reported to orient collagen fibers for generating artificial tissue. However, the collagen orientation established by these approaches are highly limited, complicated and far from the practical level to generate specific shape of tissue. Therefore, we present the SMM device approach to orient collagen fibers in microparticles that pneumatically deform the template and create force inside micropatterns at which collagen fibers are orientated along the direction of the expansion of mold. Second Harmonic Generation (SHG) is the useful tool to investigate the alignment index (AI) of collagen fiber in microparticles. Alignment index (AI) is the range from 1.0 for random alignment to 4.55 for strong alignment. The alignment index of fibers in microparticles made by the SMM device increases 40%.
9:00 AM - H4.24
Energetics of Formation and Hydration of Functionalized Silica Nanoparticles: An Atomistic Computational Study
Vagner Alexandre Rigo 1 Lucas Stori de Lara 2 Caetano Rodrigues Miranda 3
1Universidade Tecnolamp;#243;gica Federal do Paranamp;#225; (UTFPR) Cornamp;#233;lio Procamp;#243;pio Brazil2Universidade Estadual de Ponta Grossa Ponta Grossa Brazil3Universidade Federal do ABC Santo Andramp;#233; BrazilShow Abstract
Silica based nanomaterials have received great attention for nanomedicine and biological applications  due to their biocompatible properties . SiO2 nanoparticles can be used for drug delivery and for applications in imaging diagnostic . In many of these applications, nanoparticles are suspended in a fluid and a common way to maintain the suspension consists to functionalize the nanoparticle with either hydrophobic  and hydrophilic  groups. The functional form, chain length , graft density and distribution of groups at surface can be tuned to kept the suspension and improve the nanoparticle functionality. Using a combination of First-Principles calculations based on Density Functional Theory with van der Waals dispersion correction and Molecular Dynamics, the energetics of formation and hydration of functionalized silica nanoparticles were studied. The energetics and effects of group density were evaluated in both; hydrophilic (ethylene-glycol) and hydrophobic (sulfonic) organosilane functional groups, and the optimum group density were obtained in vacuum and aqueous environment . In vacuum, an optimum graft density of 4.2 and 4.5 groups/nm2 was obtained for hydrophobic and hydrophilic coverage, based on Molecular Dynamics calculations. Interestingly, a double well energy profile is obtained when functionalized nanoparticles are placed within aqueous media, and those minima for hydrophilic groups appear at lower coverage compared to hydrophobic one. The double energy minima is explained by the H2O molecules arrangement as function of the group density on nanoparticles surface.
 I.I. Slowing, J.L. Vivero-Escoto, C.-W. Wu, V.S.-Y. Lin, Mesoporous silica nanoparticles as controlled release drug delivery and gene transfection carriers, Adv.Drug.Deliv.Rev. 60, 1278-1288 (2008)
 V. Chin, B.E. Collins, M.J. Sailor, S.N. Bhatia, Compatibility of Primary Hepatocytes with Oxidized Nanoporous Silicon, Adv.Mater. 13, 1877-1880 (2001)
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 Y-L. Lee, Z.-C. Du, W.-X. Lin, Y.-M. Yang, Monolayer behavior of silica particles at air/water interface: A comparison between chemical and physical modifications of surface, J. of Colloid and Interface Sci. 296, 233-241 (2006)
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 V. A. Rigo, C.R. Miranda, L.S. de Lara, Energetics of formation and hydration of functionalized silica nanoparticles: an atomistic computational study, Appl. Surf. Sci. 292, 742-749 (2014)
9:00 AM - H4.25
Decreased Macrophage Responses on Nanoscale Hydroxyapatite: Experimental Results
Garima Bhardwaj 1 Thomas Jay Webster 1
1Northeastern University Boston USAShow Abstract
Introduction: To assess the immunological response on implants, the host response to materials must be determined prior to implantation. This response is highly dominated by macrophages.Macrophages not only fuse to become multinucleated foreign body giant cells, but they also activate T lymphocytes by expressing co-stimulatory molecules (e.g., CD86 and CD80) and surface antigens (e.g., MHC II).This current study modified the surface of titanium by coating it with nanoscale hydroxyapatite, in a range of sizes, using electrophoretic deposition (EPD) with both AC and DC current. Macrophages were then seeded onto this surface and their behavior observed.
Materials and Methods: Nanoscale hydroxyapatite (HA) was synthesized using a wet chemical synthesis process to possess an array of different sizes in the nanometer scale.HA was then coated onto a titanium mesh purchased from Alpha Aesar (Catalog no.7440-32-6) by electrophoretic deposition with AC and DC current.Surface characterization was done using SEM,contact angle analysis and AFM. Macrophages purchased from ATCC (RAW 264.7 (ATCC® TIB-71trade;)) were cultured using EMEM (ATCC® 30-2003trade;), 10% FBS (ATCC® SCRR-30-2020trade;) and a 1% penicillin-streptomycin solution (ATCC® 30-2300trade;). Cell adhesion and proliferation was observed using MTS assays after 1, 3, 5 and 7 days. Levels of TNF-α, IL-1, IL-6 and nitrite released by the macrophages were studied. Bacterial assays also were conducted using Staphylococcus aureus (ATCC® 29740trade;) and Pseudomonas aeruginosa (ATCC® 39324trade;) strains of bacteria. 0.03% tryptic soy broth (TSB) and agar plates (Sigma-Aldrich) were used as the media.A dilution of 108 bacteria/mL was then prepared using 0.03% TSB and the samples were treated with 2 mL of the 108 bacteria/mL solution and incubated for 24 hours. The bacteria solution was removed and the samples were rinsed twice with PBS.The number of bacterial colonies formed on each sample was counted and using these values, the number of bacteria/mL was found.
Results and Discussion: Results of the present study demonstrated that the change in the HA surface topography affected the adhesion and proliferation of macrophages leading to a reduced activation of macrophages with increased nanometer HA roughness. The level of TNF-α, IL-1, IL-6 and nitrite released by macrophages decreased with increasing HA nanometer surface roughness. Bacterial activity also decreased with increased HA nanometer surface roughness.
Conclusions: Results of the present study demonstrated that the present coating procedure and its parameters, when used to synthesize nanometer HA roughness, reduced macrophage attachment and activation (TNF-α, IL-1, IL-6 and nitrite release). Bacterial activity also reduced on nanometer rough HA coatings.
Acknowledgements: The authors would like to thank Northeastern University for funding.
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WITHDRAWN 11/29/2014 In Vitro and In Vivo Performance of an Antioxidant Coating for Chronic Neural Electrodes
Noah Robert Snyder 1 2 Jenna Hanner 1 Xinyan Tracy Cui 1 2 3
1University of Pittsburgh Pittsburgh USA2Carnegie Mellon Pittsburgh USA3University of Pittsburgh Pittsburgh USAShow Abstract
Understanding the direct mechanism behind neuronal loss near chronically implanted electrodes is essential for the development of treatment paradigms that can improve the abiotic/biotic interface. Recent research has demonstrated neuronal degeneration and inflammatory gliosis at the vicinity of neural electrodes. Gliosis, is characterized by the activation of glial cell types, both microglia and astrocytes, and results in the formation of glial scar tissue and the production of a variety of neurotoxic factors. Activated microglia secrete pro-inflammatory cytokines, initiate the recruitment of additional macrophages/microglia, and produce various cytotoxic factors including reactive oxygen/nitrogen speci