Gianluca Maria Farinola, University of Bari Aldo Moro
Eric Daniel Glowacki, Johannes Kepler University Linz
Fiorenzo Omenetto, Tufts University
Clara Santato, Polythecnique Montreal
Symposium Support APL Photonics|AIP Publishing
Journal of Materials Chemistry B|Royal Society of Chemistry
Sony Deutschland GmbH
D2: Materials for Green and Edible Electronics
Monday PM, November 30, 2015
Hynes, Level 2, Room 209
2:30 AM - *D2.01
Edible Electronics: Bioinspired Materials and Structures for Next-Generation Ingestible Devices
Christopher J. Bettinger 1
1Carnegie Mellon Univ Pittsburgh United StatesShow Abstract
Ingestible electronic devices have the potential to obviate many of the challenges associated with chronic implants such as risk of infection, chronic inflammation, and costly surgical procedures. Examples of ingestible electronics include edible cameras, ingestible event monitors, and integrated smart drug delivery systems. Ingestible devices have made great advances in the early detection and improved treatment of disease by using commodity polymers and off-the-shelf electronic components. However, currently available materials fundamentally limit how these devices can be used. The potential clinical impact of ingestible electronics could be increased by expanding the application-specific materials toolbox for this class of medical devices. This talk will describe recent advances in bioinspired materials for potential use in edible devices. Examples include flexible biodegradable elastomers as structural polymers and melanin-based pigments as materials for on-board energy storage. Structure-property-processing relationships for these medical materials will be emphasized and prospective uses for these application-specific materials will be discussed.
3:00 AM - D2.02
Biodegradable Protein-Based Thin Film Transistors and Triboelectric Generators
Ting-Hao Chang 1 Jenn-Chang Hwang 1 Zong-Hong Lin 2 Jon-Yiew Gan 1
1National Tsing Hua University Hsinchu Taiwan2National Tsing Hua University Hsinchu TaiwanShow Abstract
Green electronics using biodegradable materials, such as protein-based polyelectrolytes, have attracted much interest in recently years because they are safe, nontoxic, and friendly to environment. In this article, we demonstrated two kind of green electronics devices, organic thin film transistor (OTFT) and triboelectric generator (TEG) fabricated with protein-based polyelectrolytes. In OTFT, protein was selected as gate dielectrics. The effective mobility of the device could be enhanced 30-40 times and the threshold voltage value reduced 10-20 times by varying the relative humidity from vacuum to air ambient. In TEG, protein also was chosen as the contact thin film. When the relative humidity was raised from 20% to 60%, the output open-circuit voltage increases to 40-50V and the output short-circuit current increases to 1-2 mu;A. These devices were demonstrated to be potential humidity sensors with good stability and durability
1.Lung-Kai Mao, Jenn-Chang Hwang, Ting-Hao Chang, Chao-Ying Hsieh, Li-Shiuan Tsai, Yu-Lun Chueh, Shawn S.H. Hsu, Ping-Chiang Lyu, Ta-Jo Liu, Pentacene organic thin-#64257;lm transistors with solution-based gelatin dielectric, Organic Electronics, 2013, 14, 1170.
2.Chun-Yi Lee, Jenn-Chang Hwang, Yu-Lun Chueh, Ting-Hao Chang, Yi-Yun Cheng, Ping-Chiang Lyu, Hydrated bovine serum albumin as the gate dielectric material for organic #64257;eld-effect transistors, Organic Electronics,2014, 14, 2645.
3.Ting-Hao Chang, Chen-Pan Liao, Jen-Ching Tsai, Chun-Yi Lee, Jenn-Chang Hwang, I-Min Tso, Yu-Lun Chueh, Ping-Chiang Lyu, Jon-Yiew Gan, Natural polyelectrolyte: Major ampullate spider silk for electrolyte organic #64257;eld-effect transistors, Organic Electronics, 2014, 15,954.
3:15 AM - D2.03
Edible Transistors for Ink-Jet Printed Bioelectronics on Pharmaceutical Capsules
Giorgio Ernesto Bonacchini 1 2 Guglielmo Lanzani 1 2 Mario Caironi 1
1Istituto Italiano di Tecnologia Milan Italy2Politecnico di Milano Milan ItalyShow Abstract
A recent trend in bioelectronics research focuses on the employment of biological and bioinspired materials to realize electronic devices that can operate non-invasively in contact with and within the human body. In particular, increasing efforts are being devoted to the design and production of edible electronic devices that target some relevant biomedical applications, such as gastrointestinal tissue stimulation, monitoring of patients adherence to medications and controlled drug delivery.
The aim of this study is to show that entirely edible organic transistors, both p-type and n-type, can be directly ink-jet printed on a commercial pharmaceutical capsule by using materials that are either biocompatible, nature derived or commonly used in the food industry. The transistor bottom-contacts and top-gate electrode consist of PEDOT:PSS, a very well known conducting polymer, also widely employed as a highly conformable neural electrode. Alternative conductive materials can be adopted, e.g. edible gold used for food decoration. Shellac, a biodegradable bug secreted resin, acts both as smoothing layer and dielectric. Hydrogen-bonded organic pigments such as quinacridone, indigoids and perylene derivatives offer very promising performances as organic semiconductors, reaching hole and electron mobilities exceeding 10-2 cm2V-1s-1 depending on the specific small molecule and deposition techniques. These organic pigments are practically insoluble in water and in many other organic solvents because of the strong intermolecular interactions ascribable to the H-bonds. For this reason the small molecules are deposited exploiting cleavable solubilizing tert-butoxycarbonyl (t-BOC) groups which are then removed by means of exposure to trifluoroacetic acid vapors. The t-BOC groups removal activates the latent H-bonds of the pigments which become completely insoluble and therefore exhibit an extremely low toxic potential, even lower than common food colourings. Moreover, these compounds can be functionalized with proteins without altering their electrical transport properties and the biological functionality of the proteins.
The present work thus demonstrates the all-printed realization of both p-type and n-type transistors on a commercially available pharmaceutical capsule. These devices hold considerable potential as basic multifunctional platforms for biosensors and bioactuators meant to operate within the gastrointestinal tract, as well as building blocks for an emerging class of biomedical devices dedicated to the monitoring of patients compliance to pharmacological treatments.
Rivnay, J., et al. (2013). Chem. Mater., 26(1), 679-685.
Kim, Y. J., et al. (2013). J. Mater. Chem. B, 1(31), 3781-3788.
Irimia-Vladu, et al. (2010). Adv. Funct. Mater., 20(23), 4017-4017.
Fattahi, P., et al. (2014). Adv. Mater., 26(12), 1846-1885.
G#322;owacki, E. D et al. (2013). Adv. Mater., 25(11), 1563-1569.
3:30 AM - *D2.04
Natural Materials for Environmentally Friendly Electronics
Mihai Irimia-Vladu 1
1Johannes Research Forschungsgesellschaft mbH Weiz AustriaShow Abstract
In a global e-waste totaling ~42 million tons for the year 2014 and expected to surge 33% by 2017, the humanity has already a difficult problem to address-according to the GLOBAL E-WASTE MONITOR 2014 of the United Nations University&’s Institute for the Advanced Study of Sustainability. One alternative to counteract the e-waste could be the fabrication of electronics either with earthly abundant-naturally occurring materials, or with materials derived from them. Our group investigated a large number of natural and nature-inspired materials as substrates, dielectrics, semiconductors and smoothening layers for the fabrication of organic field effect transistors and organic solar cells. The invited presentation will focus on the highlights of our recent research, especially with respect to natural dielectrics (cellulose and cellulose derivatives, waxes, gums, various grades of natural Shellac), flexible substrates resistant to high temperature processing exceeding 200 deg. C (plasticized Shellac) as well as natural and nature inspired semiconductors in the families of indigos, anthraquinones and acridones.
4:30 AM - D2.05
Electron Transport through Bacterial Nanowires: An Ab Initio Study
Peter Yucheng Lu 1 Grigory Kolesov 1 Oscar Granas 1 Efthimios Kaxiras 1
1Harvard University Cambridge United StatesShow Abstract
The diverse set of biological electron transport mechanisms continues to be a key source of inspiration for the development of new technologies such as biofuel cells and dye-sensitized solar cells. We focus on an interesting recent example, which involves external electron transport through biological nanowires by the bacterium Shewanella oneidensis . In particular, this form of electron transport allows the bacterium to reduce heavy metals, which has the potential for environmental applications. The nanowires are constructed from cytochrome proteins that arrange stacks of heme molecules through which the transport process takes place. However, the details of this electron transport are difficult to study directly, so we take a computational approach to examine the microscopic mechanism. Using density functional theory (DFT), we set up a system of stacked heme molecules taken from the protein structure of the bacterial nanowire. Then, using time-dependent density functional theory (TDDFT), we simulate electronic excitations as well as charge injections, non-adiabatically propagating the electronic system using TDDFT with the ions following Ehrenfest dynamics. Our simulations reveal the complex nature of electron transfer through bacterial nanowires, and we hope that such a microscopic understanding of this unique electron transport mechanism will aid in the development of new bio-inspired applications.
 Breuer, M., Rosso, K. M., & Blumberger, J. (2014). Electron flow in multiheme bacterial cytochromes is a balancing act between heme electronic interaction and redox potentials. Proceedings of the National Academy of Sciences, 111(2), 611-616.
4:45 AM - D2.06
Bio-Inspired Stretchable Electrodes
Zijian Zheng 1
1Hong Kong Polytechnic Univ Hong Kong Hong KongShow Abstract
Stretchable conductive metallic structures are essential elements in the development of stretchable electronics. Current progress in this field has been mostly focused on man-made materials and structures for achieving high conductivity and high tensile strains. On the other hand, there are many natural structures that show inherently good stretchability, but they are not electronically conductive. This talk will discuss our latest development of stretchable metal electrodes (either opaque or transparent) on the basis of biologic al templates. Two particular examples will be discussed in detail. The first one is the fabrication of highly stretchable opaque metal electrodes and interconnects, namely “Electronic Petals (E-petals)”, which make use of the topographical micro/nano structures of rose petals to enable superb stretchability to metal thin films. The second example is the fabrication of stretchable transparent electrodes, namely “Vein-based Transparent Electrodes (VTEs)”, by chemical deposition of metal on natural veins of leaves. We demonstrate that these bio-inspired electrodes possess remarkable electro-mechano-opto properties that outweigh most best-performing man-made ones.
1. Y. Yu, C. Yan, Z. J. Zheng*, Adv. Mater.2014, 26, 5508-5516.
2. R. Guo, Y. Yu, J. Zeng, X. Liu, X. Zhou, L. Niu, T. Gao, K. Li, Y. Yang, F. Zhou,* Z. J. Zheng*, Adv. Sci.2015, 2, 1400021.
3. Y. Yu, Y. Zhang, K. Li, C. Yan, Z. J. Zheng*, Small2015, DOI: 10.1002/smll.201500529.
5:00 AM - D2.07
Conducting Polymer Composited with Nanofibrillated Cellulose for Large-Scale Power Electronics Applications
Magnus Berggren 1 Xavier Crispin 1 Abdellah Malti 1 Jesper Edberg 1 Lars Wagberg 2 Hjalmar Granberg 3
1ITN Norrkoping Sweden2KTH Stockholm Sweden3Innventia Stockholm SwedenShow Abstract
In PEDOT:PSS, the PSS polyanion serves as the primary dopant making the p-type PEDOT phase to become electronically conductive. DMSO is commonly added to PEDOT:PSS emulsions to impact the nano-morphology of resulting deposited thin films. By adding this secondary dopant the conductivity of PEDOT:PSS thin films is increased and can reach beyond 1000 S/cm. In the hydrated state, PSS can exhibit high cationic conductivity, in fact reaching 1 mS/cm. The high combined electronic and ionic conductivity of hydrated PEDOT:PSS thin films makes the material system excellent as the electrode and channel in electrochemical transistors, sensors, super-capacitors, fuel cells, bioelectronic delivery devices and more. Further development of these devices, and their crucial device parameters, would benefit from achieving high combined ionic-electronic conductivity in bulky electrode and channel geometries in 3D. However, it has been proven utterly difficult to reach large-scale, easily processable and stable bulky 3D-electrode configurations based on organic materials in general and on PEDOT:PSS in particular.
Nanofibrulated cellulose (NFC) is a 3D-scaffold nano-fiber system that is derived from cellulose biomass. NFC is a truly green material and has a low density, high mechanical properties, is stable in aqueous media, possesses several economic values and is also renewable. It turns out that PEDOT:PSS form conformal coatings along individual NFC fibers and the resulting morphology appears also open for the migration and transport of ions. Large-scale 3D-electrodes, reaching centimeters in size, based on PEDOT:PSS-NFC exhibit 1000 S/cm electronic conductivity in the PEDOT phase and a high ionic conductivity beyond 10 mS/cm. The resulting PEDOT:PSS-NFC electrode has been explored in super-capacitors, electrochemical transistors and conductors resulting in outstanding and record-high device parameters, such as an associated charge storage capacity, transconductance and current levels of 1 F, 1 S and 1 A, respectively.
5:15 AM - D2.08
Hydrogen-Bonded Organic Pigments for OFETs Operational in Aqueous Electrolytes of pH 1-10
Halime Coskun 1 Yasin Kanbur 2 Cigdem Yumusak 1 Eric Daniel Glowacki 1 Niyazi Serdar Sariciftci 1
1Johannes Kepler University Linz Austria2Karabuk University Karabuk TurkeyShow Abstract
Thin film transistors employing inorganic or organic semiconductors have proven useful for sensing applications in aqueous environments. Materials stability in aqueous media is a critical parameter for device design and a boundary condition of eventual practical applications. The operational stability of organic semiconductors has improved, but has remained limited. Herein we report on the hydrogen-bonded organic pigments epindolidione and quinacridone as water-stable semiconductors. Low-voltage field-effect transistors show remarkable operational stability in aqueous environments in a pH range of 1-10 without any passivation . We evaluate the effect of the ionic solutions on the transistor characteristics and the impact of insulating the source-drain contacts. Liquid environments do not appreciably effect the saturation current in transistors, however the off current is found to depend on the dielectric constant of the liquid with σprop; eε. This is interpreted in terms of an intercrystallite hopping model. The range of stability is unprecedented for organic semiconductors and most inorganic semiconductors as well and suggests these materials are highly suitable for applications in aqueous sensing devices.
 Eric Daniel Glowacki, Giuseppe Romanazzi, Cigdem Yumusak, Halime Coskun, Uwe Monkowius, Gundula Voss, Max Burian, Rainer T. Lechner, Nicola Demitri, Günther J. Redhammer, Nevsal Sünger, Gian Paolo Suranna, Serdar Sariciftci, Epindolidiones—Versatile and Stable Hydrogen-Bonded Pigments for Organic Field-Effect Transistors and Light-Emitting Diodes, Adv. Func. Mat., 25, 5, 2015
5:30 AM - D2.09
Bioconjugation of Hydrogen-Bonded Organic Semiconductors with Functional Proteins
Eric Daniel Glowacki 1 Rocco Roberto Tangorra 2 Halime Coskun 1 Dominik Farka 1 Alessandra Operamolla 2 3 Yasin Kanbur 1 Francesco Milano 4 Gianluca Maria Farinola 2 Niyazi Serdar Sariciftci 1
1Johannes Kepler Universitauml;t Linz Austria2Universita Degli Studi di Bari Aldo Moro Bari Italy3Consiglio Nazionale delle Ricerche - Istituto di Chimica dei Composti Organometallici Bari Bari Italy4Istituto per i Processi Chimico Fisici Bari ItalyShow Abstract
We demonstrate the direct bioconjugation of hydrogen-bonded organic semiconductors with two different complex functional proteins in an aqueous environment. The representative semiconductors are vacuum evaporated epindolidione and quinacridone
These molecules in thin films react spontaneously with N-hydroxysuccinimide functionalized linkers. Using covalent attachment for Rhodobacter sphaeroides reaction centre (RC) and the biotin-streptavidin lock-and-key system, the proteins were bound to the semiconductors, conserving their biofunctionality.
Surface-functionalization by linkers was investigated by Attenuated Total Reflection, Fourier Transform Infrared Spectroscopy ATR-FTIR, water contact angle measurements, and atomic force microscopy. Presence and integrity of the RC was investigated by charge recombination assay, in the case of biotinylation a quantum-dot labelled streptavidin was used. Preliminary results of investigations with biofunctionalized AFM will be presented, also.
As key results, our work shows that upon bioconjugation, the semiconductors preserve their favourable electrical properties even under water making hydrogen-bonded semiconductors promising platforms for bioelectronics devices.
5:45 AM - D2.10
Characterization of Indoles Self-Assembled Molecular Networks on Metals
Fabrizio De Marchi 1 Maryam Ebrahimi 1 Josh Lipton-Duffin 3 1 Jennifer MacLeod 2 1 Federico Rosei 1 4
1Institut National de la Recherche Scientifique - Centre Eacute;nergie Mateacute;riaux Teacute;leacute;communications Montreal Canada2Queensland University of Technology Brisbane Australia3Queensland University of Technology Brisbane Australia4McGill University Montreal CanadaShow Abstract
A wide variety of biological small molecules in nature are able to self-assemble into complex supramolecular structures. The products of these self-assembly processes are held to exacting standards, since their features and size are fundamental to the correct functioning of organisms. The ability to mimic the self-assembly behavior of these molecules to fabricate soft matter materials with interesting optoelectronic characteristics has focused the attention of many researchers. Among the studied materials, eumelanins are a particularly interesting candidate due to an ensemble of different characteristics. However, its structure/function interrelationships within the polymer are still under debate. With the aim to provide insights on the matter, we have been investigating the non-covalent interactions between eumelanin monomers.
In this work, we describe the behavior of one of the eumelanin monomers, 5,6-dihydroxyindole-2-carboxylic acid (DHICA) and its close relative indole-2-carboxylic acid (I2CA) on various metal substrates in Ultra High Vacuum condition. Once on the substrate, the molecules of I2CA form wide 2D structures, with a chevron-like morphology that is relatively independent from the substrate or preparation condition. The increased functionalization of DHICA leads instead to the formation of different structures that are strongly dependent to the substrate reactivity and periodicity that we have investigated by Scanning Tunneling Microscopy (STM). The low symmetry of the molecules, given by the presence of the pyrrole ring, leads to several conformations for each bonding disposition: only with the aid of density functional theory (DFT) calculations, we were able to gain insights of the molecular network structures. From these results, we investigate how the initial monolayer structure can affect the growth of device-ready thin films. By using Kelvin probe force microscopy (KPFM) and impedance spectroscopy, we are able to investigate how different monolayer structure would affect the charge injection in the film.
D1: Biomimetic and Biological Polymeric Materials
Gianluca Maria Farinola
Monday AM, November 30, 2015
Hynes, Level 2, Room 209
9:30 AM - *D1.01
Creating Functional Biomimetic Materials
Rajesh Naik 1
1AFRL Wpafb United StatesShow Abstract
The unique and diverse functions of biomaterials provide many opportunities in developing concepts, as well as new classes of materials and devices. The knowledge gained in understanding how biological materials are constructed and function has enabled the design of bioinspired/derived functional materials with tailored properties for optics, sensing, catalysis and electronics. We have employed experimental and computational approaches to understand structure-function relationships for the development of biomimetic materials, tailoring interfacial properties features and fabricating functional materials for the development of photonic ad electronic devices based on these biomimetic materials will be discussed. In this talk, I will highlight our efforts on using our fundamental understanding of biomolecular interactions, factors that influence bio-nanomaterials interactions and demonstrate the fabrication of biomimetic materials for sensing, catalysis and decontamination applications.
10:00 AM - *D1.02
Eumelanin-Based Organic Bioelectronics: Myth or Reality?
Alessandro Pezzella 1 4 Paola Manini 1 Lucia Panzella 1 Alessandra Napolitano 1 Orlando Crescenzi 1 Mario Barra 2 Antonio Cassinese 2 Maria Grazia Maglione 3 Paolo Tassini 3 Anna Musto 5 Angelica Navarra 5 Silvia Parisi 5 Cosimo Carfagna 4 Irene Bonadies 4 Francesca Cimino 4 Marco d'Ischia 1
1University of Naples "Federico II" Naples Italy2CNR Naples Italy3ENEA Naples Italy4CNR Naples Italy5Ceinge Naples ItalyShow Abstract
Eumelanins, the black insoluble pigments of human skin, eyes and substantia nigra (neuromelanin), stand today as a unique source of inspiration for the design and implementation of soft biocompatible multifunctional materials for bio-optoelectronic devices.1 Interest in eumelanins stems from bioavailability, biocompatibility and a peculiar set of physicochemical properties, i.e. broadband absorption in the UV-visible range, intrinsic free radical character, water-dependent hybrid ionic-electronic conductor behaviour, supporting optimistic feelings about a possible rise of eumelanin-mimics as innovative bioinspired solutions for organic bioelectronics.2
However, a number of conceptual and technological gaps still hinder a rapid progress of melanin-based organic electronics and bioelectronics, including in particular the limited contribution of electronic conductivity and current decay with time under biasing. Herein, we provide a concise overview of the structural and optoelectronic properties of melanins with a view to bringing to focus main issues and challenges en route to bioelectronic applications. Basic structure-property function relationships, fundamental tailoring strategies, processing and the balance of ionic-electronic processes will be addressed along with representative examples of eumelanin-based hybrids to orient ongoing efforts toward efficient and competitive eumelanin-based technology.
(1) d'Ischia, M.; Napolitano, A.; Pezzella, A.; Meredith, P.; Sarna, T. Angew Chem Int Edit2009, 48, 3914-3921.
(2) Organic Electronics: Emerging Concepts and Technologies Fabio Cicoira (Editor), Clara Santato (Editor) ISBN: 978-3-527-41131-3 464 pages September 2013
10:30 AM - D1.03
Eumelanin Thin Films and Metal Electrodes: Nanostructures Formation under Electrical Bias for Memory Applications
Eduardo Di Mauro 1 Luiz Gustavo Simao Albano 2 1 Olivier Carpentier 1 Myriam Lalancette-Jean 1 Sergio Ivan Yanez Sanchez 1 Ndembi Ignoumba Ignoumba 1 Fabio Cicoira 3 Carlos Frederico Graeff 2 Clara Santato 1
1Polytechnique Montreal Montreal Canada2UNESP Bauru Brazil3Polytechnique Montreacute;al Montreacute;al CanadaShow Abstract
Eumelanin is a dark-brown pigment present in animals, fungi and microorganisms, featuring functions such as thermoregulation, photoprotection, free radical quenching and properties such as biodegradability, biocompatibility and mixed ionic-electronic conduction . Furthermore, the two types of indolic building blocks impart to eumelanin metal-chelation properties .
In hydrated eumelanin thin films deposited between Au electrodes, upon application of an electrical bias (1 V), dendritic nanostructures have been observed, leading to a steep current increase : the phenomenon was due to the combined action of the chlorides present in the pigment and of its chelating units and resembled the resistive switch taking place in memory devices, thus opening to the perspective of using eumelanin for such kind of applications.
Here we report on nanostructures forming in eumelanin films between metal electrodes (Au, Pd and Ag of relevance in microelectronics and Fe and Cu of relevance in biology). Sigma (synthetic, from tyrosine), Sepia (natural, from Sepia Officinalis) and DMSO melanin (synthesized in dimethylsulfoxide, thus featuring sulphonated groups) were used. Sigma and Sepia melanin differ in the ratio of the two indole building blocks and in the chloride content, whereas DMSO melanin lacks the phenolic hydroxyls groups, likely responsible for the chelation of multivalent cations. The formation of nanostructures was studied by Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). Preliminary results on both Sigma and Sepia melanin thin films processed in DMSO suggest that the time needed for the formation of nanostructures in the case of Au electrodes is strongly dependent on the amount of chlorides present, with a threshold-like behavior. Counter experiments with pure solvent DMSO showed partial dissolution of the electrode, but no dendrite formation, confirming the role of melanin as a chelating agent and nanostructure-growth favourable matrix. Results on Pd electrodes (Sigma melanin with Cl- 8% w/w) show terrace-shaped bridging structures. We are at present establishing an extended correlation between parameters such as biasing time, chemical eumelanin composition, shape and size of the eumelanin nanostructures to increase the current knowledge of the interactions between the pigment eumelanin and metals, and to give a further insight into the possibility of using eumelanin thin films in memory devices.
 M. d&’Ischia et al, Pigm Cell Melanoma R, 26, 5, 616-633, 2013.
 L. Hong and J. Simon, J Phys Chem B, 111, 28, 7938-7947, 2007.
 J. Wünsche et al, Adv Funct Mater, 23, 45, 5591-5598, 2013.
10:45 AM - D1.04
Eumelanin for Flexible, Bio-Micro-Supercapacitors
Prajwal Kumar 1 Eduardo Di Mauro 1 Fabio Cicoira 1 Francesca Soavi 2 Clara Santato 1
1Ecole Polytechnique Montreal Montreal Canada2Universitagrave; di Bologna Bologna ItalyShow Abstract
Biocompatibility and biodegradability make the pigment eumelanin (EuM), which is based on dihydroxyindole and dihydroxyindole carboxylic acid building blocks, an interesting candidate for applications in bioelectronics and sustainable electronics.
In addition, the efficient and reversible charge storage properties of EuM in aqueous electrolytes permits to exploit it as an electrode in electrochemical energy storage/conversion devices, such as batteries and supercapacitors.
Here we report on aqueous micro-supercapacitors making use of EuM-based electrodes.
A preliminary characterization of EuM drop casted on a current collector made of carbon paper (EuM/CP) was performed by cyclic voltammetry (CV) at different scan rates. Different aqueous electrolytes such as ammonium acetate buffer at pH 5.5, sodium sulfate at pH 5.5, phosphate buffered saline at pH 7.4, and ammonia buffer pH 10 were used to test the effect of the pH and of the nature of the electrolyte ions on the storage properties. At pH 5.5, EuM electrodes featured a specific capacitance values as high as 150 F g-1, which is of great interest for supercapacitor applications. The catechol-quinone moieties present in the EuM and the proton conducting properties of EuM are likely responsible for the reversible pseudocapacitive current observed. Other moieties, such as COOH and aromatic amines, also play a role in determining the pseudocapacitive behavior of eumelanin.
EuM/CP supercapacitors in ammonium acetate buffer at pH 5.5 where tested by repeated galvanostatic charge/discharge cycles between 0 V and 0.75 V at various current densities, namely 0.25, 0.50, 1.25, 2.50, 12.50 mA cm-2 with the highest current corresponding to ~90 A g-1 of EuM. The EuM/CP supercapacitors featuring 27 µg of EuM loading displayed a maximum energy density of ~0.1 mWh cm-2 and a maximum power of ~20 mW cm-2. The cycling stability of the EuM/CP supercapacitor was demonstrated over 100,000 charge-discharge galvanostatic cycles.
Based on such promising results, flexible bio-micro-supercapacitor were fabricated on polyethylene terephthalate (PET) substrates by conventional lithography technique using Ti/Au as current collector. The conductive carbon Super C-65 and polyvinylidene fluoride (PVDF) binder were blended with eumelanin. The flexible bio-micro-supercapacitor was able to operate at very fast CV scan rates (up to 10 V s-1). These results suggest that EuM based bio-micro-supercapacitor may serve as biodegradable power source for implantable medical devices.
11:30 AM - *D1.06
Functional Analysis of Synthetic Cell Adhesion Receptors (Integrins) in Polymeric Membrane Mimetics
Christoph Zaba 1 Oliver Bixner 1 Sonja Zayni 1 Darren Tan 1 Martina Mueller 2 Gianluca Bello 1 Ute Reuning 2 Eva Kathrin Sinner 1
1University of Natural Resources and Life Sciences, BOKU, Vienna Vienna Austria2Technische Universitaet Munich (TUM) Munich GermanyShow Abstract
Integrins, as transmembrane heterodimeric receptors, take over important functions in cell adhesion, migration, proliferation, survival (apoptosis), and signal transduction, in many physio- as well as pathophysiological settings. Characterization of integrins and their ligand/antagonist binding is notoriously difficult due to high integrin redundancy and ubiquity. Bypassing the intrinsic difficulties of cell-based integrin expression, purification, and reconstitution, we present for the functional analysis of such the synthesis of a heterodimeric integrin receptor assembled into a block-copolymeric membrane mimic. We present synthesis and function (interfering in cell adhesion) of functionally active integrin avszlig;3, generated by in vitro membrane-assisted protein synthesis (iMAPS) involving motility studies based on labeling with ligand - functionalized quantum dots as 'molecular lanterns'. This work presents a robust and adaptable polymer-based platform for characterization of time and space resolved integrin - ligand interactions.
12:00 PM - D1.07
Polymer-Controlled Nucleation and Growth of Magnetite Nanoparticles
Nico A.J.M. Sommerdijk 1 Jos J.M. Lenders 1 Cem Levent Altan 2 Vladimir Dmitrovic 1 H.R. Zope 3 Ayana Yamagishi 4 Paul H.H. Bomans 1 Atsushi Arakaki 4 Alexander Kros 3 Gijsbertus de With 1 Heiner Friedrich 1 S Bucak 2
1Eindhoven Univ of Technology Eindhoven Netherlands2Yeditepe University Istanbul Turkey3Leiden University Leiden Netherlands4Tokyo University of Agriculture and Technology Tokyo JapanShow Abstract
Magnetite (Fe3O4) is a widespread magnetic iron oxide encountered in geology as well as biomineralization, which also has many technological applications. Its magnetic properties depend largely on the size and shape of the crystals, and at room temperature only 20-80 nm particles display single-domain ferrimagnetic behavior. In nature, magnetotactic bacteria are encountered that indeed produce chains of aligned uniform and monodisperse magnetite crystals in this size range, thereby optimally utilizing their magnetic properties for navigation in the Earth&’s magnetic field.
Although biology achieves such control by applying proteins with defined amino acid sequences, often not these specific sequences/structures but the resulting overall physicochemical properties (such as charge and hydrophobicity) are the governing factors during mineralization. Indeed, in the case of the magnetite biomineralization proteins rich in acidic amino acids (negative charges) are found to dominate the impact on crystal morphology. Although many biomineralization systems can be mimicked synthetically using additives and templates, achieving control over the nucleation and growth of iron oxides is difficult as they are only sparingly soluble in water (-log(Ksp) = 34-44, typically), and biomimetic experiments generally result in polydisperse products that often do not exceed the superparamagnetic size range (<20 nm).
Here we show that control over the size and sipersibility, and thereby over the properties of magnetite can be achieved in aqueous media through polypeptide additives by controlling the supersaturation and thereby the crystallization kinetics. We have developed a synthesis protocol to controllably produce random co-polypeptides to rule out any structural effects, and created a library of these copolymers with varying monomer contents to study their compositional effects. We employ this library in s specifically designed co-precipitation methods, show that a pathway via a poorly ordered precursor material enables a more gradual evolution of the supersaturation, enabling crystals with sizes similar to those encountered in magnetotactic bacteria.
12:15 PM - D1.08
Reversible, Stimuli-Responsive Color Change in Protein Materials
Christopher Glover 1 Ryan Juneau 1 Eva Rose Murdock Balog 1
1University of New England Biddeford United StatesShow Abstract
As components of biomaterials, recombinant proteins provide structural and functional specificity, controlled composition, and intrinsic biocompatibility. However, recombinant proteins are often lacking in terms of scalability, durability, and utility outside the biological milieu. We are engineering proteins to address these limitations. For example, the protein crustacyanin is a component of crustacean carapace responsible for pigmentation. Crustacyanin and similar carotenoid-binding proteins have materials applications in food science, artificial coloration, antioxidant biosensing, thermochromics inks, and light- and energy-harvesting. We explore whether carotenoprotein production and isolation is improved upon fusion to an elastin-like polymer. Toward the development of tunable, protein-based, color-changing “smart” materials, we test the hypothesis that in the presence of stimuli-responsive elastin-like polymers, crustacyanin can experience environmental change sufficient to induce reversible changes in bound carotenoid absorption. Other recent optoelectronic/materials applications of elastin-like polymer materials will also be presented.
Gianluca Maria Farinola, University of Bari Aldo Moro
Eric Daniel Glowacki, Johannes Kepler University Linz
Fiorenzo Omenetto, Tufts University
Clara Santato, Polythecnique Montreal
Symposium Support APL Photonics|AIP Publishing
Journal of Materials Chemistry B|Royal Society of Chemistry
Sony Deutschland GmbH
D4: Bioinspired and Biological Structuresmdash;from Charge Transport to Bio-Mimetic Membranes and Tissues
Tuesday PM, December 01, 2015
Hynes, Level 2, Room 209
2:30 AM - *D4.01
Grotthuss Mechanisms: From Proton Transport in Ion-channels to Bioprotonic Devices
Marco Rolandi 2 1
1Univ of Washington Seattle United States2University of California, Santa Cruz Santa Cruz United StatesShow Abstract
In 1804, Theodore von Grotthuss proposed a mechanism for proton (H+) transport between hydrogen bonded water molecules that involves the exchange of a covalent bond between H and O with a hydrogen bond. This mechanism also supports the transport of OH- as a proton hole and describes proton transport in intramembrane proton channels. Inspired by the Grotthuss mechanism and its similarity to electron and hole transport in semiconductors, we have developed semiconductor type devices that are able to control and monitor a current of H+ as well as OH- in hydrated biopolymers derived from shrimp and squid. I will present the integration of these devices with enzymes and ion channels. I will also discuss recent data on biopolymers extracted from fish sensory organs.
3:00 AM - *D4.02
Cephalopod-Inspired Photonic and Protonic Devices
Alon Gorodetsky 1
1Univ of California-Irvine Irvine United StatesShow Abstract
Cephalopods (squid, octopuses, and cuttlefish) are known as the chameleons of the sea - they can alter their skin&’s coloration, patterning, and texture to blend into the surrounding environment. These remarkable capabilities are enabled by the unique morphology of cephalopod skin, as well as by its constituent proteins and nanoscale structures. I will discuss our work on new types of photonic and protonic devices fabricated from cephalopod-derived materials. Our findings may hold implications not only for the next generation of stealth and bioelectronics technologies, but also for gaining insight into the mechanisms that underpin cephalopods&’ camouflage abilities.
3:30 AM - D4.03
The Electronic Influence of Abasic Sites in DNA
Jason Slinker 1 Marc McWilliams 1 Rita Bhui 1
1Univ of Texas at Dallas Richardson United StatesShow Abstract
Abasic sites in DNA are of interest due to their prevalence as both naturally-forming defects and as synthetic inclusions for biosensing purposes. The electronic impact of these defects in DNA sensor and device configurations has yet to be clarified. Here we report the effect of an abasic site on the rate and yield of charge transport relative to undamaged and mismatch-containing duplexes through surface-bound DNA electrochemistry on multiplexed chips. This approach enables direct temperature-controlled comparison under biologically relevant conditions with redundancy and ensures identical assembly conditions of each sequence. Transport yield through the abasic site monolayer strongly increases with temperature, but the yield relative to an undamaged monolayer decreases with temperature. This is opposite to the increasing relative yield with temperature from a mismatched base pair, and these effects are accounted for by the unique structural impact of each defect. Notably, the effect of the abasic site is nearly doubled when heated from room temperature to 37 °C. The rate of transport is largely unaffected by the abasic site, showing Arrhenius-type behavior with an activation energy of ~300 meV. Detailed investigation of the electronic impact of an abasic site elucidates the electrical impact of these biologically spontaneous defects and aids in the continued development of electrical and electrochemical biological sensors for DNA damage and DNA damage repair.
3:45 AM - D4.04
Synthesis and Electrochemical Characterization of Oligonucleotide-Inspired Organic Nanowires
Amir Mazaheripour 1 Nina Huesken 2 Jonah-Micah D Jocson 1 Anthony Burke 1 Alon A. Gorodetsky 1
1Univ of California-Irvine Irvine United States2University of Bochum Bochum GermanyShow Abstract
One-dimensional organic nanowires have emerged as idealized model systems for investigating charge transport mechanisms at molecular length scales. However, there are significant difficulties associated with the synthesis and electrical characterization of well-defined organic nanowires. By drawing inspiration from oligonucleotide synthesis, we have developed a facile strategy for the assembly of organic semiconductor building blocks in predetermined arrangements on a DNA-like backbone. Not only can the resulting constructs be purified/processed under partially aqueous conditions via known biochemical techniques, but also they feature many of the advantages of standard oligonucleotides, including a well-defined length, geometry, and sequence context. We have self-assembled monolayers of our nanowires on gold substrates and investigated their charge transport properties with electrochemical techniques. Our findings hold significance both for fundamentally understanding nanoscale charge transport phenomena and for the development of new types of biological and molecular electronic devices.
4:30 AM - *D4.05
Engineering Polymer-Based Regenerative Nerve Implants
Stephanie P. Lacour 1 Alba de Luca 1 Cedric Paulou 1
1EPFL Lausanne SwitzerlandShow Abstract
Peripheral nerves are tubular structures carrying parallel axons bundled in fascicules. Following nerve injury, the peripheral nervous system has the ability to regenerate because of a permissive environment and activation of the intrinsic growth capacity of neurons. Yet functional recovery is rarely achieved, especially over long gaps.
In this context, we are developing single and multi-lumen nerve implants based on soft elastomers, biodegradable gels and compliant electrodes to (1) support and promote robust regeneration of axons, (2) understand how peripheral neurons interact with their immediate physical environment, and (3) communicate reliably with the regenerating axons.
Conduits filled with fast-degradable fibrin-laminin gels that encapsulate adipose-derived stem cells support improved and robust outgrowth of neurites. Implant&’s surfaces decorated with dense arrays of soft PDMS micropillars promote alignment of growing neurites. Soft thin-metal film electrodes embedded in the PDMS microchannel implant provide an efficient recording interface with the regenerating neurons.
Combined into a unique implant, these bioinspired designs offer an exciting avenue for efficient regenerative nerve prosthesis.
5:00 AM - *D4.06
The Engineering of Bio-Leather
Gabor Forgacs 1 2 Karoly Jakab 2 Francoise Marga 2 Brendan Purcell 2
1University of Missouri Columbia United States2Modern Meadow, Inc. Brooklyn United StatesShow Abstract
Leather is a material with long history. Due to its unique properties it is widely used in numerous consumer applications such as apparel, shoe, furniture, automotive and many others. Leather is the byproduct of the meat industry. As such it requires the raising, transporting and slaughtering of animals, which carries a large and unsustainable environmental footprint. In addition to the environmental and resource challenges of the livestock industry, leather presents additional challenges to manufacturers. Due to variations in size and shape and imperfections from the rough lives of animals, only a fraction of available hide material can be used as premium leather. The material that is used in products varies widely in quality from hide to hide. Manufacturers must deal with variability in leather thickness, stretch, color, texture, strength, and other significant properties.
We describe the development of bio-leather, a novel biomaterial. The basic concept underlying bio-leather is that the complex anatomical skin of the animal is not required to produce a material with leather-like properties rather what is needed is the collagen matrix, the major component of skin and the cornerstone of leather. Another novelty of our approach is that it uses established principles of tissue engineering beyond regenerative medicine, its traditional domain of applicability. Specifically, our bio-leather is derived from carefully selected and engineered collagen secreting mammalian cell lines, sourced from live animals. We build a three dimensionally organized collagen matrix, the analogue of the hide of live animals. This tissue is subsequently tanned to prepare it for further processing. Tanning of our material requires the development a novel leather chemistry technologies as historical methods do not apply.
An engineered and sustainable leather would solve many of the problems manufacturers face when using animal-derived leather. The material could be grown to the desired size and shape, optimized for the efficient manufacture of final products. Bioengineered leather can be tuned to the exact physical properties desired by a manufacturer, and could be made in consistent quality. With engineered bio-leather, manufacturers would discard less material as waste, and would be able to produce better and more consistent products. Furthermore, it could be produced at a lower environmental cost and in a no-kill way, without the need to slaughter animals.
Finally, due to its unique method of fabrication, bio-leather could be combined with advances in industries such as electronics and photonics. This would allow, in particular, for built-in biological functionalities into a comfortable wearable material.
5:30 AM - *D4.07
Bioelectronics with Natural and Artificial Membrane Transporters
Aleksandr Noy 1 2
1Lawrence Livermore National Lab Livermore United States2Univ. of California Merced Merced United StatesShow Abstract
Membrane transport is critical to cellular functionality, which makes membrane proteins potentially important components of a bioelectronic toolkit. Integrating membrane proteins with nanoelectronics requires a versatile biocompatible matrix that can preserve and enhance the protein functionality. We accomplish this task by using hierarchical assembly of lipid molecules and membrane proteins onto silicon nanowire transistor to create 1-D bilayer devices—a bioelectronic platform that can convert proton and ion transport events into electrical signals. In this presentation I will discuss several examples of bioelectronic devices that use passive ion channels and active ATP-driven and light-driven pumps, as well as biological modifiers to drive and regulate electronic functionality. I will also talk about our ongoing efforts to create more robust and scalable bioelectronic platforms and membrane transporters.
D3: Bioelectronics and Biophotonics Interfacesmdash;From Sensing to Medicine
Tuesday AM, December 01, 2015
Hynes, Level 2, Room 209
9:00 AM - D3.01
Development of Lactate Sensor Using Field Effect Transistor Combined with Molecularly Imprinted Polymer Interface
Shoichi Nishitani 1 Taira Kajisa 2 Toshiya Sakata 1
1Univ. of Tokyo Tokyo Japan2PROVIGATE Inc. Tokyo JapanShow Abstract
Introduction: Lactate is a well-known biomolecule which is produced as a result of anaerobic respiration of various organisms. As it is now known that stem cells mainly use anaerobic respiration to produce energy source , it is meaningful to develop lactate sensor which can be applied to monitor cellular respiration of stem cells in real time manner. Phenylboronic acid (PBA) has an ability to bind to diol compounds, such as lactate and saccharides, which induce negative charge on the boron atom of PBA . Our group has been detected the charge changes derived from PBA-sugar equilibrium using field effect transistor (FET), whose extended gate was modified with PBA self-assembly monolayers . In this research, we have investigated the possibility of specific detection of lactate by use of FET combined with lactate template molecular imprinted polymer (MIP) gel containing PBA molecule.
Method: MIP gel coated-gate FET with lactate template was prepared by following procedure. First, Au/Ti was sputtered on the glass substrate, and the plastic ring was glued on the surface. After washing Au surface with piranha/ozone, 10 uL of monomer solution with initiator was dropped on it and spin coated. Polymerization was initiated by irradiation of UV light. Finally, polymer was washed with HCl/methanol solution to extract the template molecule, lactate. In the FET analysis, surface potential change was monitored by use of FET real-time monitoring system when the sample solutions (lactate and glucose) were added to the solution system of MIP gel coated-gate FET with lactate template, which was equilibrated with phosphate buffer solution (pH 7).
Result and Future Plan: When lactate was introduced onto the MIP gel coated-gate FET with lactate template, the surface potential shifted clearly in the negative direction based on the increase of negatively charged PBA derived from binding to lactate. Moreover, the decrease of the surface potential in the FET could be observed depending on the concentration of lactate addition, and we have confirmed even at lower concentration of 10 uM, which would be appropriate for sensing in human blood. Thus, we succeeded to develop sensor specific to lactate to some extent. On the other hand, the signal from glucose was controlled by MIP gel interface, even though surface potential decreased for addition of glucose. In the future, we hope to improve further the specificity of the sensor and apply it for sensing living cells.
 T. Suda, K. Takubo, G. L. Semenza, Cell Stem Cell 9, 298-310 (2011).
 F. K. Sartain, X. Yang, C. R. Lowe, Chem. Eur. J.14, 4060 - 4067 (2008).
 T. Kajisa, T. Sakata, ChemElectroChem1, 1647 - 1655 (2014).
D5: Poster Session: Biological and Bioinspired Materials for Photonics and Electronics
Eric Daniel Glowacki
Tuesday PM, December 01, 2015
Hynes, Level 1, Hall B
9:00 AM - D5.01
Bioinspired Systems Formed by Mixed Algal Polysaccharides-Enzyme Systems Immobilized in Lipid Langmuir Blodgett Films: Enhancement of the Enzyme Activity and Possible Use as a Urea Biosensor
Audrey Kalinouski de Brito 1 Cristina Souza Freire Nordi 1 Luciano Caseli 1
1Federal University of Sao Paulo Diadema BrazilShow Abstract
Films organized at the molecular level are useful systems for a variety of applications since their properties can be easily controlled and manipulated. The Langmuir-Blodgett (LB) technique is a well-established way to produce ultrathin films with the possibility to stack layers transferred from monomolecular films organized at the air-water interface. In this sense, it is growing the interest for the fabrication of LB films produced with biological molecules, such as enzymes, lipids and polysaccharides, originating a type of systems classified as a bioinspired system. In this present work, we used algal exopolysaccharides (EPS) from Cryptomonas sp to serve as an intermediate matrix for the adsorption of enzymes on lipid monolayers at the air-water interface. Firstly, the lipid dioctadecyldimethylammonium bromide (DODAB) was spread on the top of EPS aqueous solutions. After that, the enzyme urease was inserted below the DODAB monolayer, allowing for its incorporation to the interface. The urease was then co-adsorbed with EPS on the lipid monolayer, and the three-component film was compressed by mobile barriers until the collapse of the monolayer. Surface pressure-area isotherms and Polarization modulation reflection-absorption spectroscopy (PM-IRRAS) showed that the presence of EPS enhanced urease adsorption. By keeping the surface pressure of 30 mN/m constant, the film was then transferred to the air-water interface to solid supports. PM-IRRAS spectroscopy showed that the secondary structure of the enzyme kept intact, and atomic force microscopy showed that the morphology of the lipid films was significantly affected with the presence of EPS and urease, with the formation of some aggregates. The enzyme activity of urease was then essayed with UV-vis spectroscopy with several molecular architectures for the LB films, trying all possible combinations involving urease, EPS and DODAB. The results showed that the presence of EPS enhanced the enzyme activity of urease, which was higher than in solution. Enzyme activity was also essayed for urease aggregated with EPS in the aqueous subphase for DODAB monolayer, and the results showed a lower value than for urease without EPS in the aqueous subphase for the same lipid monolayer. These results then indicated that the best molecular accommodation for urease is when it is present in a polysaccharide-lipid surface rather than interacting with EPS in solution. The results also showed a good stability and conservation of the enzyme activity for at least two months. The results of this work, as a proof-of-concept experiment, seem therefore important for the fabrication of urease sensors with easy control of the molecular architecture.
Acknowledgements: FAPESP and CNPq
9:00 AM - D5.02
Conductance Oscillations in Single DNA Duplexes: Evidence of Intermediate Tunneling-Hopping Transport Regime in DNA Charge Transport
Limin Xiang 1 3 Julio L Palma 1 3 Chris Bruot 3 Vladimiro Mujica 1 Mark A. Ratner 2 Nongjian Tao 3
1Arizona State University Tempe United States2Northwestern University Evanston United States3Biodesign Institute Tempe United StatesShow Abstract
Charge transport in double-stranded DNA, is involved in many basic chemical and biological processes, and its understanding is critical if they are to be used in electronic devices. This important phenomenon is often described as either coherent tunnelling over a short distance or incoherent hopping over a long distance. Here, we show evidence of an intermediate regime where coherent and incoherent processes coexist in double-stranded DNA. We measure charge transport in single DNA molecules bridged to two electrodes as a function of DNA sequence and length. Generally the resistance of DNA increases linearly with length, as expected for incoherent hopping. However, a periodic oscillation is superimposed on the linear length dependence for DNA sequences with stacked GC base pairs, indicating a partial coherent transport. Our calculations of the molecular orbital distribution also indicates a strong delocalization among the stacked Guanies bases. Finally, by fittting the data with Buttiker's partially coherent in hopping model, we obtained a coherent length of ~0.56 nm, about two base pairs long.
9:00 AM - D5.03
Non-Fluorescent DNA Sensing by Enzymatic Polymerization on Grating Structures
Isao Aritome 1 3 Renpeng Gu 1 Ravi Kapoor Kumar 2 Michael Hirtz 2 Stefan Zauscher 1
1Duke University Durham United States2Karlsruhe Institute of Technology Karlsruhe Germany3JSR Corporation Yokkaichi JapanShow Abstract
DNA microarrays are a powerful and universal analytical tool in biological/medical research and diagnostics. However, the read-out approach is still relying on fluorescence markers and infrastructures in the form of fluorescence microscopes and/or fluorescence scanners. Here we propose a novel approach to facilitate a purely optical read-out DNA detection by combining enzymatic DNA polymerization1, 2 with the diffracting grating principle3. The basic idea is to exploit the strong dependence of the diffraction intensity on the grating height. By patterning oligonucleotide probe strands which get amplified by DNA polymerization only after a target strand hybridizes with the latent grating structure, the grating height increases which will boost the diffraction intensity.
The scheme of our approach is described as follows:(I) a grating of probe oligonucleotide, immobilized at their 3&’ termini, is patterned. The resulting grating is so thin that it shows only minor diffraction intensity. (II) When a matching target DNA strand hybridizes onto the probe oligonucleotide grating, it intercalates, but position the 3&’ terminus of the target strand away from the substrate surface, where it is accessible to serve as an initiator for the subsequent enzymatic DNA polymerization. This hybridized strand is still latent in its diffraction activity, since the hybridization does not significantly alter the grating&’s height. (III) When the grating is incubated with TdT (terminal deoxynucleotidyl transferase) enzyme in the presence of mononucleotides, TdT attaches selectively only to the hybridized gratings with accessible 3&’ termini, and extends the oligonucleotide strands. (IV) This conditional DNA polymerization increase the grating height which in turn amplifies the optical diffraction capability of the grating.
To elucidate the efficacy of our concept, DNA polymerization from a simple oligonucleotide grating was performed. A 600nm period of patterned 5&’ thiol-modified (dA)20 on gold film was fabricated by means of E-beam lithography and incubated with TdT enzyme in the presence of dATP. As a result of enzymatic extension of the oligonucleotide from 3&’ termini, thickness of the oligonucleotide layer increased in the order of 10nm, and incident angle dependent color change, which stem from the light diffraction by the grown grating structure, was confirmed even by visual observation.
Dependence of hybridization/sensing efficiency and optical diffraction activity on probe oligonucleotide density will also be demonstrated.
1. Chow, D. C.; Lee, W.-K.; Zauscher, S.; Chilkoti, A. J. Am. Chem. Soc.2005, 127, 14122.
2. Tjong, V.; Yu, H.; Hucknall, A.; Rangarajan, S.; Chilkoti, A. Anal. Chem.2011, 83, 5153.
3. Lenhert, S.; Brinkmann, F.; Laue, T.; Walheim, S.; Vannahme, C.; Klinkhammer, S.; Xu, M.; Sekula, S.; Mappes, T.; Schimmel, T.; Fuchs, H. Nat. Nanotechnol.2010, 5, 275.
9:00 AM - D5.04
Nanostructured Hybrid Materials by Self-Assembly of Nanoparticles Induced for Biomolecules
Luiz Fernando Gorup 1 Andressa Mayumi Kubo 1 Luciana Silva Amaral 1 Edson Rodrigues-Filho 1 Edson R. Leite 1 Elson Longo 2 Emerson R. Camargo 1
1Federal Univ-Sao Carlos Sao Carlos Brazil2UNESP Satilde;o Carlos BrazilShow Abstract
The use of bio-design concepts is a promising strategy to fabricate materials with properties of great scientific and technological interest. There are numerous examples of materials obtained by employing concepts of biomimetics, engineering and bio-inspired and biotemplates that has gained prominence position in the chemistry of the materials, especially when these structured systems are employed in DNA, bacteria or fungi. A variety available of biological structures enables several innovative alternatives to overcome the limitations of conventional synthesis methods. In this context, the fusion of biotechnology with materials chemistry has benefited several areas of strategic technologies such as catalysis, health and sensor development. Thus, this work propose the use of design concept of biomimetic to establish a protocol to fabricate self-organized systems of metal nanoparticles on surfaces with the composition, structure and morphology controlled in the shape of plates, wires, tubes using among other metals, ceramics and polymers. Biomolecules were produced by fungi Penicillium brasilianum, which were added in systems containing surfaces to be coated with metal nanoparticles. Biomolecules act as an agent to induce self-assembly of metal nanoparticles on the surfaces of silicon wafers. The first tests consisted of silicon wafers suspended by a thread in a system containing gold nanoparticles and hyphae of the fungus for a period of 5 days. The experiment indicated that the metabolites produced by the fungi and released in the middle act directly on the stability of the nanoparticles in the colloidal suspension, causing deposition on the available surfaces, are organic or inorganic. The deposition of the nanoparticles of the nanoparticle layer resulting in a self-assembly effect induced by micellar biomolecules produced by fungi. The presence of metabolites produced by the fungi colloidal medium directly affects the stability of the nanoparticles, favoring the formation of successive layers of nanoparticles. The silicon wafers have a surface coated with gold nanoparticles in the form of spheroidal and the surfaces coating variable thickness between 25 nm to 200 nm.
9:00 AM - D5.05
Nanostructured Materials in the Form Meshed Network Tridimensional Microtubes Made by Fungal Biotemplates
Luiz Fernando Gorup 1 Andressa Mayumi Kubo 1 Luciana Silva Amaral 1 Edson Rodrigues-Filho 1 Edson R. Leite 1 Elson Longo 1 Emerson R. Camargo 1
1Federal Univ-Sao Carlos Sao Carlos BrazilShow Abstract
The use of biotemplates concepts is a promising strategy for obtainment materials with properties of great scientific and technological interest. Biotechnology and supramolecular systems usually vary from a few nanometers up to no more than any micrometer, which facilitates their combination for the manufacture of large heterostructures morphological and functional complexity. Inorganic nanoparticles are particularly useful to be used as building blocks of hybrid self-organized systems can be synthesized in large quantities. In this work is proposed use design concept of biotemplate with mycelial fungi Penicillium brasilianum by the fabrication of nanostructured materials in the form meshed network tridimensional microtubes. In first step were prepared microtube by self-organized of metal nanoparticles with 20 nm synthetized by Citrate Methold on surfaces of hyphae fungal. The 2 g of mycelial mass were auditioned in 100 mL of colloidal gold 1,0 mmolL-1 for 20 days. The second step was lyophilization of microtubes of gold a consolidated wire after heated under oxygen flow at 400 oC for 2h and analyzed by SEM and Electrical characterization. Initial examination of images SEM showed substantial changes in the morphology of the surface when compared to original hybrid material before annealing. Instead of a uniform layer of well-characterized gold nanoparticles, it is possible to observe a rough surface of consolidated wires in substitution of the original microtubes. The coalesced nanoparticles, forming a rough surface wires consolidated instead of original microtubes. The resulting material has preserved the original memory biotemplate morphology, forming a surface having high surface area and similar to a sponge with a high mechanical strength and potential catalytic activity The nanostructured materials in the form meshed network have microtube with mean diameter calculated (0,58 mu;m) is almost half of the value calculated for gold microtube (1,24 mu;m) but with approximately the same distribution. Probable, one or more microtubes fused to form a thicker wire, which can be observed by the twisted shape of the gold microwires. Electrical characterization of nanostructured materials, showed a typical metal behavior was observed in the electrical resistance, increasing the resistance with the temperature increasing and the ohmic response indicates continuous, metallic connections across the sample. The low resistance is that expected for grain-boundary-dominated transport in a polycrystalline metal.
9:00 AM - D5.06
Deprotonation of Polyaniline (PANI) Films: XPS and ToF-SIMS Studies
Mohd Muzamir Mahat 1 3 4 Damia Mawad 1 3 4 Geoffrey Nelson 1 Sarah Fearn 1 Robert G Palgrave 2 David Payne 1 Molly Stevens 1 3 4
1Imperial College London London United Kingdom2University College London London United Kingdom3Imperial College London London United Kingdom4Imperial College London London United KingdomShow Abstract
Polyaniline (PANI) films in the emeraldine salt form deprotonate in physiological media and thus their conductivity is reduced thereby limiting their potential use in the area of regenerative medicine [1, 2]. Therefore a thorough understanding of deprotonation of PANI thin films is vital. In this study, we demonstrate the utilisation of X-ray photoelectron spectroscopy (XPS) to elucidate and quantify the deprotonation of PANI films upon incubation in physiological conditions. Time of flight secondary ion mass spectroscopy (ToF-SIMS) served as complimentary technique to surface map the presence of anion dopant both before and post incubation. PANI was doped chemically by a small acid molecules; p-toluene sulfonic acid (pTSA) and camphor sulfonic acid (CSA) and thin films fabricated using the spin coating technique. This was followed by incubation in phosphate buffered saline (PBS), at pH 7.4 for 24 hours. Changes in the protonation level of these films were assessed by careful analysis of the N 1s core line spectra, revealing the doping level at the surface if the PANI films. The level of doping was determined by the area ratio of positively charged nitrogen at higher binding energy (401 eV and 402 eV) to the total N 1s spectra. PANI films were found to de-dope as this ratio decreased from 22.5% to 13.3% for pTSA and 29.2% to 18.4% for CSA after 24 hours. This suggests that the dopant bo