Download or read book Nanoporous Gold as a Neural Interface Coating written by and published by . This book was released on 2015 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report that designing neural interfaces that maintain close physical coupling of neurons to an electrode surface remains a major challenge for both implantable and in vitro neural recording electrode arrays. Typically, low-impedance nanostructured electrode coatings rely on chemical cues from pharmaceuticals or surface-immobilized peptides to suppress glial scar tissue formation over the electrode surface (astrogliosis), which is an obstacle to reliable neuron-electrode coupling. Nanoporous gold (np-Au), produced by an alloy corrosion process, is a promising candidate to reduce astrogliosis solely through topography by taking advantage of its tunable length scale. In the present in vitro study on np-Au's interaction with cortical neuron-glia co-cultures, we demonstrate that the nanostructure of np-Au achieves close physical coupling of neurons by maintaining a high neuron-to-astrocyte surface coverage ratio. Atomic layer deposition-based surface modification was employed to decouple the effect of morphology from surface chemistry. Additionally, length scale effects were systematically studied by controlling the characteristic feature size of np-Au through variations in the dealloying conditions. In conclusion, our results show that np-Au nanotopography, not surface chemistry, reduces astrocyte surface coverage while maintaining high neuronal coverage and may enhance neuron-electrode coupling through nanostructure-mediated suppression of scar tissue formation.

Download or read book A Novel Material Screening Platform for Nanoporous Gold based Neural Electrodes written by Christopher Abbott Reece Chapman and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Neural-electrical interfaces have emerged in the past decades as a promising modality to facilitate the understanding of the electropathophysiology of neurological disorders as well as the normal functioning of the central nervous system, and enable the treatment of neurological defects through electrical stimulation or electrically-controlled drug delivery. However, chronically implanted electrodes face a myriad of design challenges, including their coupling to neural tissue (biocompatibility), small form factor requirement, and their electrical properties (maintaining a low electrical impedance). Planar electrode materials such as planar platinum and gold experience a large increase in electrical impedance when electrode dimensions are reduced to increase spatial resolution of neural recordings. A decrease in electrode surface area reduces the total capacitance of the electrode double layer resulting in an increase in electrode impedance. This high impedance can reduce the signal amplitude and increase the thermal noise, resulting in degradation of signal-to-noise ratio. Conventionally, this increase in electrical impedance at small electrode dimensions has been mitigated by coatings with rough morphologies such as platinum black, conducting polymers, and titanium nitride. Porous surfaces have high effective surface area enabling low impedance at small electrode dimensions. However, achieving long-term stability of cellular coupling to the electrode surface has remained difficult. Designing electrodes that can physically couple with neurons successfully and maintain low impedance at small electrode dimensions necessitates consideration of novel electrode coatings, such as carbon nanotubes and gold nanopillars. Another promising material, and focus of this proposal, is thin film nanoporous gold (np-Au). Nanoporous gold is a promising material for addressing these limitations because of its inherently large effective surface area allows for lower impedances at small form factors, and its modifiable surface morphology can be used to control cell-electrode coupling. Additionally, thin film nanoporous gold is fabricated by traditional microfabrication methods, and thus can be directly adopted by the current state-of-the-art neural electrode fabrication processes. All these properties make thin film nanoporous gold a promising candidate for use in neural electrode surfaces. This dissertation seeks to characterize both the morphological and the electrical response of neural cells to thin film nanoporous gold morphologies using an in vitro electrode morphology screening platform. The specific aims for this proposal are to: (i) develop a electrode morphology library that displays varying topographies to study structure-property relationships of thin film nanoporous gold and cellular response, (ii) characterize neural cell response to identified nanoporous gold topographies that reduce adverse tissue response in vitro, and (iii) develop an electrophysiology platform to characterize neural coupling to each identified nanoporous gold topography.

Download or read book Nanoporous Metals for Advanced Energy Technologies written by Yi Ding and published by Springer. This book was released on 2016-03-19 with total page 229 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers the state-of-the-art research in nanoporous metals for potential applications in advanced energy fields, including proton exchange membrane fuel cells, Li batteries (Li ion, Li-S, and Li-O2), and supercapacitors. The related structural design and performance of nanoporous metals as well as possible mechanisms and challenges are fully addressed. The formation mechanisms of nanoporous metals during dealloying, the microstructures of nanoporous metals and characterization methods, as well as miscrostructural regulation of nanoporous metals through alloy design of precursors and surface diffusion control are also covered in detail. This is an ideal book for researchers, engineers, graduate students, and government/industry officers who are in charge of R&D investments and strategy related to energy technologies.

Download or read book Nanoporous Gold written by Arne Wittstock and published by Royal Society of Chemistry. This book was released on 2012-03-28 with total page 265 pages. Available in PDF, EPUB and Kindle. Book excerpt: High-surface-area materials have recently attracted significant interest due to potential applications in various fields such as electrochemistry and catalysis, gas-phase catalysis, optics, sensors and actuators, energy harvesting and storage. In contrast to classical materials the properties of high-surface-area materials are no longer determined by their bulk, but by their nanoscale architecture. Nanoporous gold (np-Au) represents the fascinating class of mesoporous metals that have been intensively investigated in recent years. The current interest and the increasing number of scientific publications show that np-Au by itself is an outstanding nano-material that justifies a book devoted to all aspects of its properties and applications. The resulting publication is a discussion of this unique nano-material and is an accessible and comprehensive introduction to the field. The book provides a broad, multi-disciplinary platform to learn more about the properties of nanoporous gold from an inter-disciplinary perspective. It starts with an introduction and overview of state-of-the-art applications and techniques characterizing this material and its applications. It then covers the progress in research within the last years. The chapters are in-depth overviews written by the world's leading scientists in the particular field. Each chapter covers one technique or application so that the reader can easily target their favoured topic and will get the latest and state-of-the-art information in the field.

Download or read book Implantable Microdevices written by Wen Li and published by MDPI. This book was released on 2019-10-23 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: Implantable microdevices, providing accurate measurement of target analytes in animals and humans, have always been important in biological science, medical diagnostics, clinical therapy, and personal healthcare. Recently, there have been increasing unmet needs for developing high-performance implants that are small, minimally-invasive, biocompatible, long-term stable, and cost-effective. Therefore, the aim of this Special Issue is to bring together state-of-the-art research and development contributions that address key challenges and topics related to implantable microdevices. Applications of primary interest include, but are not limited to, miniaturized optical sensing and imaging tools, implantable sensors for detecting biochemical species and/or metabolites, transducers for measuring biophysical quantities (e.g., pressure and/or strain), and neural prosthetic devices.

Download or read book Neuromodulation written by Elliot Krames and published by Academic Press. This book was released on 2018-01-05 with total page 1828 pages. Available in PDF, EPUB and Kindle. Book excerpt: Neuromodulation: Comprehensive Textbook of Principles, Technologies, and Therapies, Second Edition, serves as a comprehensive and in-depth reference textbook covering all aspects of the rapidly growing field of neuromodulation. Since the publication of the first edition seven years ago, there has been an explosion of knowledge in neuromodulation, optogenetics, bioelectronics medicine and brain computer interfacing. Users will find unique discussions of the fundamental principles of neuromodulation and therapies, and how they are applied to the brain, spinal cord, peripheral nerves, autonomic nerves and various organs. The book focuses on comprehensive coverage of spinal cord stimulation, non-interventional and interventional brain stimulation, peripheral nerve stimulation, and the emerging fields of neuromodulation, including optogenetics and bioelectronics medicine. Provides a comprehensive reference that covers all aspects of the growing field of neuromodulation Written by international, leading authorities in their respective fields of neuromodulation, pain management, functional neurosurgery and biomedical engineering Includes new chapters on optogenetics, bioelectronics medicine and brain computer interfacing

Download or read book Advanced Functional Porous Materials written by Arya Uthaman and published by Springer Nature. This book was released on 2021-11-13 with total page 690 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents synthesis, characterization, and applications of macroporous, mesoporous, nanoporous, hierarchical porous, porous metals, and porous ceramics. Special emphasis is given to the preparation of porous activated carbon materials and porous ionic liquid-derived materials for CO2 emissions mitigation. Additionally, a chapter includes the physical and mathematical modeling in porous media. Many analytical techniques for characterization are discussed in this book. Also, the biomedical and industrial applications of porous materials in adsorption, catalysis, biosensors, drug delivery, nanotechnology are described. The content helps solving fundamental and applied problems in porous materials with length scales varying from macro- to nano-level.

Download or read book Handbook of Neuroengineering written by Nitish V. Thakor and published by Springer Nature. This book was released on 2023-02-02 with total page 3686 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Handbook serves as an authoritative reference book in the field of Neuroengineering. Neuroengineering is a very exciting field that is rapidly getting established as core subject matter for research and education. The Neuroengineering field has also produced an impressive array of industry products and clinical applications. It also serves as a reference book for graduate students, research scholars and teachers. Selected sections or a compendium of chapters may be used as “reference book” for a one or two semester graduate course in Biomedical Engineering. Some academicians will construct a “textbook” out of selected sections or chapters. The Handbook is also meant as a state-of-the-art volume for researchers. Due to its comprehensive coverage, researchers in one field covered by a certain section of the Handbook would find other sections valuable sources of cross-reference for information and fertilization of interdisciplinary ideas. Industry researchers as well as clinicians using neurotechnologies will find the Handbook a single source for foundation and state-of-the-art applications in the field of Neuroengineering. Regulatory agencies, entrepreneurs, investors and legal experts can use the Handbook as a reference for their professional work as well.​

Download or read book Short Term Versus Long Term Challenges in Functional Biomaterials Interfacing Living Systems Two Sides of the Coin written by Davide Ricci and published by Frontiers Media SA. This book was released on 2022-03-11 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nanoporous Gold As a Fuel Cell Material written by SHRUTI BAHARANI and published by LAP Lambert Academic Publishing. This book was released on 2011-03 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: Electrochemical dealloying has proven to be an efficient way of fabricating nanoporous gold, the morphology of which can be tailored by controlling factors such as the etching time, temperature of electrolyte, composition of the alloy, pre and /or post heat treatment and voltage to suit applications such as fuel cell electrodes and sensors. This work aims at studying the effect of such factors as the electrolyte concentration on the morphology of the emerging material. A model relating the processing parameters and pore size is established by statistical approaches using the Design Expert 7.1 software. An equation that captures the individual as well as interaction effects on nanoporous gold is proposed. The validity of the equation is verified by existing research results. Simulation of this material under applied external load was done to achieve static properties in comparison with bulk gold. The applications where this might be helpful have been mentioned.

Download or read book Introduction to Nanoporous Gold written by and published by . This book was released on 2011 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fabrication of Nanoporous Gold and Biological Applications written by Badharinadh Uppalapati and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Fabrication of nanoporous gold electrodes by dealloying Au:Ag alloys has attracted much attention in sensing applications. In the first part of this work, the electrochemical response of the redox active molecule, potassium ferricyanide, in a solution of bovine serum albumin in buffer, serum or blood was studied using nanoporous gold and comparisons made to planar gold. Nanoporous gold electrodes with different surface areas and porosity were prepared by dealloying Au:Ag alloy in nitric acid for different dealloying times, specifically, 7.5, 10, 12.5, 20 minutes. Characterization was done using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDX), and cyclic voltammetry (CV). Using cyclic voltammetry, planar gold electrodes exposed to bovine serum albumin in buffer showed a decrease in Faradaic peak current and an increase in peak splitting for potassium ferricyanide. The time required for the peak Faradaic current to drop to one-half of its original value was 3 minutes. At nanoporous gold electrodes, however, no significant reduction in Faradaic peak current or increase in peak splitting was observed. Nanoporous gold electrodes having the smallest pore size and largest surface area showed ideal results to biofouling. These electrodes are believed to impede the mass transport of large biomolecules while allowing small redox molecules to exchange electrons effectively with the electrode. In the second part of this work, the open circuit potential (OCP) of biologic solutions (e.g., blood) was measured using nanoporous gold electrodes. Historically, the measurement of blood redox potential has been hindered due to significant fouling and surface passivation of the metal electrodes. As nanoporous gold electrodes retained electrochemical activity of redox probes like potassium ferricyanide in human serum and rabbit blood, they were used to measure the OCP of blood and plasma from various animals like pig, rabbit, rat, monkey and humans. Comparisons were made to planar gold electrodes. The OCP values at both the planar gold and nanoporous gold electrodes were different from each other and there was variability due to different constituents present in blood and plasma. The OCP of rabbit blood and crashed rabbit blood was measured and the values were found to be different from each other indicating that ORP helps in measuring the animal condition. Ascorbic acid was added to rabbit and sheep blood and OCP measured at the nanoporous electrodes. Addition of reducing agent to blood at different intervals and different concentrations showed a change in potential with concentration.

Download or read book Carbon Nanotubes written by M. Meyyappan and published by CRC Press. This book was released on 2004-07-28 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon nanotubes, with their extraordinary mechanical and unique electronic properties, have garnered much attention in the past five years. With a broad range of potential applications including nanoelectronics, composites, chemical sensors, biosensors, microscopy, nanoelectromechanical systems, and many more, the scientific community is more moti

Download or read book Modification of Patterned Nanoporous Gold Thin Film Electrodes Via Electro annealing and Electrochemical Etching written by Tatiana Dorofeeva and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanostructured materials have had a major impact on various fields, including medicine, catalysis, and energy storage, for the major part due to unique phenomena that arise at nanoscale. For this reason, there is a sustained need for new nanostructured materials, techniques to pattern them, and methods to precisely control their nanostructure. To that end, the primary focus of this dissertation is to demonstrate novel techniques to fabricate and tailor the morphology of a class of nanoporous metals, obtained by a process known as dealloying. In this process, while the less noble constituent of an alloy is chemically dissolved, surface-diffusion of the more noble constituent leads to self-assembly of a bicontinuous ligament network with characteristic porosity of ~70% and ligament diameter of 10s of nanometers. As a model material produced by dealloying, this work employ nanoporous gold (np-Au), which has attracted significant attention of desirable features, such as high effective surface area, electrical conductivity, well-defined thiol-based surface modification strategies, microfabrication-compatibility, and biocompatibility. The most commonly method used to modify the morphology of np-Au is thermal treatment, where the enhanced diffusivity of the surface atoms leads to ligament (and consequently pore) coarsening. This method, however, is not conducive to modifying the morphology of thin films at specific locations on the film, which is necessary for creating devices that may need to contain different morphologies on a single device. In addition, coarsening attained by thermal treatment also leads to an undesirable reduction in effective surface area. In response to these challenges, this work demonstrates two different techniques that enables in situ modification of np-Au thin film electrodes obtained by sputter-deposition of a precursors silver-rich gold-silver alloy. The first method, referred to as electro-annealing, is achieved by injecting electrical current to np-Au electrodes, which leads coarsening due to a combination of Joule heating and other mechanisms. This method offers the capability to anneal different electrodes to varying degrees of coarsening in one step, by employing electrodes patterns with different cross-sectional areas – easily attained since np-Au can be patterned into arbitrary shapes via photolithography – to control electrode resistivity, thus current density and the amount of electro-annealing of an electrode. A surprising finding was that electro-annealing lead to electrode coarsening at much lower temperatures than conventional thermal treatment, which was attributed to augmented electron-surface atom interactions at high current densities that may in turn enhance surface atom diffusivity. A major advantage of electro-annealing is the ability to monitor the resistance change of the electrode (surrogate for electrode morphology) in real-time and vary the electro-annealing current accordingly to establish a closed-loop electro-annealing configuration. In nanostructured materials, the electrical resistance is often a function of nanostructure, thus changes in resistance can be directly linked to morphological changes of the electrode. Examination of the underlying mechanisms of nanostructure-dependent resistance change revealed that both ligament diameter and grain size play a role in dictating the observed electrode resistance change. The second method relies on electrochemical etching of ligaments to modify electrode morphology in order to maintain both a high effective surface area and large pores for unhindered transport of molecules to/from the ligament surfaces – an important consideration for many physico-chemical processes, such fuel cells, electrochemical sensors, and drug delivery platforms. The advantage of this method over purely chemical approach is that while an entire sample in exposed to the chemical reagent, the etching process does not occur until the necessary electrochemical potential is applied. Similar to the electro-annealing methods, electrical addressability allows for differentially modifying the morphology individual electrodes on a single substrate. The results of this study also revealed that electrochemical etching is a combination of coarsening and etching processes, where the optimization of etching parameters makes it possible precisely control the etching by favoring one process over the other. In summary, the two techniques, taken together in combination with np-Au’s compatibility with microfabrication processes, can be extended to create multiple electrode arrays that display different morphologies for studying structure−property relationships and tuning catalysts/sensors for optimal performance.

Download or read book Silicon Carbide Technology for Advanced Human Healthcare Applications written by Stephen E. Saddow and published by Elsevier. This book was released on 2022-07-13 with total page 370 pages. Available in PDF, EPUB and Kindle. Book excerpt: After over two decades of focused research and development, silicon carbide (SiC) is now ready for use in the healthcare sector and Silicon Carbide Technology for Advanced Human Healthcare Applications provides an up-to-date assessment of SiC devices for long-term human use. It explores a plethora of applications that SiC is uniquely positioned for in human healthcare, beginning with the three primary areas of technology which are closest to human trials and thus adoption in the healthcare industry: neural implants and spinal cord repair, graphene and biosensors, and finally deep tissue cancer therapy using SiC nanotechnology. Biomedical-inspired engineers, scientists, and healthcare professionals will find this book to be very useful in two ways: (I) as a guide to new ways to design and develop advanced medical devices and (II) as a reference for new developments in the field. The book's intent is to stimulate ideas for further technological enhancements and breakthroughs, which will provide alternative solutions for human healthcare applications. - Discusses the utilization of SiC materials for biomedical applications - Provides a logical pathway to understand why SiC is ideal for several critical applications, in particular for long-term implantable devices, and will serve as a guide to new ways to design and develop advanced medical devices - Serves as a reference for new developments in the field and as a technology resource for medical doctors and practitioners looking to identify and implement advanced engineering solutions to everyday medical challenges that currently lack long-term, cost-effective solutions

Download or read book Electrodes and the Measurement of Bioelectric Events written by Leslie Alexander Geddes and published by John Wiley & Sons. This book was released on 1972 with total page 394 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Electrophoretic Deposition of Nanomaterials written by James H. Dickerson and published by Springer Science & Business Media. This book was released on 2011-09-18 with total page 381 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive overview of contemporary basic research, emerging technology, and commercial and industrial applications associated with the electrophoretic deposition of nanomaterials. This presentation of the subject includes an historical survey, the underlying theory of electrophoresis, dielectrophoresis, and the colloidal deposition of materials. This is followed by an assessment of the experimental equipment and procedures for electrophoretic and dielectrophoretic aggregation, manipulation, and deposition of nanoparticles, nanotubes, and other nanomaterials. Additional chapters explore the specific science and technology of electrophoretic film formation, using widely studied and application-driven nanomaterials, such as carbon nanotubes, luminescent nanocrystals, and nano-ceramics. The concluding chapters explore industrial applications and procedures associated with electrophoretic deposition of nanomaterials.