Stimulation And Recording Electrodes For Neural Prostheses

This book provides readers with basic principles of the electrochemistry of the electrodes used in modern, implantable neural prostheses. The authors discuss the boundaries and conditions in which the electrodes continue to function properly for long time spans, which are required when designing neural stimulator devices for long-term in vivo applications. Two kinds of electrode materials, titanium nitride and iridium are discussed extensively, both qualitatively and quantitatively. The influence of the counter electrode on the safety margins and electrode lifetime in a two electrode system is explained. Electrode modeling is handled in a final chapter.

Technological advances have greatly increased the potential for, and practicability of, using medical neurotechnologies to revolutionize how a wide array of neurological and nervous system diseases and dysfunctions are treated. These technologies have the potential to help reduce the impact of symptoms in neurological disorders such as Parkinson’s Disease and depression as well as help regain lost function caused by spinal cord damage or nerve damage. Medical Neurobionics is a concise overview of the biological underpinnings of neurotechnologies, the development process for these technologies, and the practical application of these advances in clinical settings. Medical Neurobionics is divided into three sections. The first section focuses specifically on providing a sound foundational understanding of the biological mechanisms that support the development of neurotechnologies. The second section looks at the efforts being carried out to develop new and exciting bioengineering advances. The book then closes with chapters that discuss practical clinical application and explore the ethical questions that surround neurobionics. A timely work that provides readers with a useful introduction to the field, Medical Neurobionics will be an essential book for neuroscientists, neuroengineers, biomedical researchers, and industry personnel.

Signi?cant progress has been made in the development of neural prostheses for restoration of human functions and improvement of the quality of life. Biomedical engineers and neuroscientists around the world are working to improve the design and performance of existing devices and to develop novel devices for arti?cial vision, arti?cial limbs, and brain-machine interfaces. This book, Implantable Neural Prostheses 2: Techniques and Engineering Approaches, is part two of a two-volume sequence that describes state-of-the-art advances in techniques associated with implantable neural prosthetic devices. The techniques covered include biocompatibility and biostability, hermetic packaging, electrochemical techniques for neural stimulation applications, novel electrode materials and testing, thin-?lm ?exible microelectrode arrays, in situ char- terization of microelectrode arrays, chip-size thin-?lm device encapsulation, microchip-embedded capacitors and microelectronics for recording, stimulation, and wireless telemetry. The design process in the development of medical devices is also discussed. Advances in biomedical engineering, microfabrication technology, and neu- science have led to improved medical-device designs and novel functions. However, many challenges remain. This book focuses on the engineering approaches, R&D advances, and technical challenges of medical implants from an engineering p- spective. We are grateful to leading researchers from academic institutes, national laboratories, as well as design engineers and professionals from the medical device industry who have contributed to the book. Part one of this series covers designs of implantable neural prosthetic devices and their clinical applications.

Despite enormous advances made in the development of external effector prosthetics over the last quarter century, significant questions remain, especially those concerning signal degradation that occurs with chronically implanted neuroelectrodes. Offering contributions from pioneering researchers in neuroprosthetics and tissue repair, Indwel

A study of neuroprosthetics. It is broadly divided into three sections which address: neuroanatomy and neurophysiology, biomaterials and biocompatibility, stimulation and recording techniques; clinical applications of neuroprosthetics; and future developments.

The prospect of interfacing the nervous system with electronic devices to stimulate or record from neural tissue suggests numerous possibilities in the field of neuroprosthetics. While the creation of a "six million dollar man" may still be far into the future, neural prostheses are rapidly becoming viable theories for a broad range of patients wit

This handbook volume aims to provide a comprehensive, self-contained, and authoritative reference in MEMS. It covers the theoretical and practical aspects including but not limited to sensors, actuators, RF MEMS, micro fluids and bio MEMS systems. It is particularly recommended to undergraduates, postgraduates, researchers, scientists, and field experts. This comprehensive summary will provide a solid knowledge background and inspire innovations in this highly interdisciplinary field. The handbook series consists of 5 volumes: Micro/nano fabrication technology, MEMS, Nanomaterial, Nanomedicine and Applications of micro-/nanotechnologies in IT. Experienced researchers and experts are invited to contribute in each of these areas.The series is published under Springer Major Reference works, which allows continuous online update and publication. These features allow newcomers and other readers to keep in touch with the most up-to-date information in micro-/nanotechnologies.It presents an overview of the knowledge base, as well as selected topics and provides comprehensive and authoritative information on the field for researchers, engineers, scientists and graduate students who are involved in different aspects of micro-/nanotechnologies.This publication will provide inspiration for innovative research and application ideas for continued growth of the field.

Electrode coatings form an integral part of implantable microelectrode arrays (MEAs) which are the basis for chronic neural interfaces capable of providing feedback though neural recording and eliciting functional response through electrical stimulation in patients with lost or impaired neurological functionality. The aim of this dissertation was to develop and assess chronically stable electrode materials with low-impedance and high charge-injection capacity for neural recording and stimulation respectively. To this end, we have investigated three types of transition metal oxide thin-films, iridium oxide, ruthenium oxide and a mixed ruthenium/titanium oxide formed by a DC magnetron reactive sputtering process. We have characterized these films in terms of their microstructure, composition and electrochemistry in order to establish the relationship between film properties and electrochemical charge-injection capacities. Sputtered iridium oxide films (SIROF) and ruthenium oxide films (RuOx) were deposited by reactive sputtering in a DC magnetron sputtering system using water-vapor as a reactive plasma constituent. The films deposited using a combination of oxygen and water-vapor showed lower impedance and higher charge-injection capacity than the films deposited using oxygen alone. The films deposited using only water-vapor as the reactive gas showed the presence of nano-sized metallic iridium and ruthenium on the SIROF and RuOx films respectively. Systematic investigation by plasma optical spectroscopy, surface characterization and electrochemical measurements revealed that the incorporation of water-vapor as a reactive gas constituent, along with oxygen, alters the reduction-oxidation (redox) state of the plasma as well as the microstructure and the electrochemical characteristics for the SIROF and RuOx films. A 3:1 water-vapor to oxygen plasma condition formed a hydrous, low-crystallinity and nodular film microstructure that enabled both electronic and ionic conduction producing an apparent optimal electrode coating with low impedance for recording and high charge-injection capacity for stimulation. Electrochemical measurements on SIROF and RuOx electrodes, deposited using a ratio of watervapor to oxygen 3:1, demonstrated that these have minimal contribution towards oxygen reduction, an unwanted side reaction and also showed rapid reversibility of their respective Faradaic processes during stimulation current pulsing. These films were found to be electrochemically stable for ~1 billion pulses at biphasic 8 nC/phase (0.4 mC/cm2 ) constant current stimulation in an inorganic model of interstitial fluid at 37o C and also showed no indication of cytotoxicity towards primary cortical neurons in a cell viability assay. Additionally, we investigated the deposition and characterization of sputtered mixed oxide films consisting of ruthenium/titanium oxide (RuTiOx) as a neural stimulation and recording electrode. This study was motivated by the observation that RuOx films deposited at optimal watervapor:oxygen gas flow ratios were more friable and thus less physically stable than SIROF deposited under the same conditions. Incorporation of titanium resulted in an increased the hardness of the film, by a factor of two with respect to RuOx films, while still maintaining an adequately low enough impedance for recording and a charge-injection capacity suitable for clinical neural stimulation.

Despite their demonstrated effectiveness, the long term use of microscale neuroprosthetic devices is compromised by the post-implantation tissue reaction that often forms around the device. This book studies ways to improve the tissue reaction to implanted neuroprosthesis by use of a controlled drug release mechanism, quantified by novel measurement techniques. The author describes solutions to the problem of tissue reaction around microscale neuroprostheses and an also examines an improvement in neural stimulation and recording capability. The author, Andre Mercanzini is Review Editor for Frontiers in Neuroengineering. He holds two U.S. patents on microassembly.