EAGER: Exploiting Superior Electrochemical Characteristics of Scaled PEDOT:PSS Microelectrode Arrays for High Fidelity Electrocorticography

非技术：脑活动电生理临床制图具有高空间分辨率和高灵敏度，取代了其他非侵入性技术，如功能磁共振成像（fMRI）。这一临床程序对于大量对药物无反应或有不良副作用（如医学上难治性癫痫）的神经系统疾病患者非常重要。它在脑机接口方面也有很好的应用前景。大多数电生理装置利用贵金属作为与脑组织的接触界面，这些金属电极通过表面氧化还原反应或电容电荷筛选来检测离子电流和电位。另一方面，有机电极对离子具有渗透性，并允许脑活动的体积氧化还原反应和电容耦合。这种优异的电化学性能使有机电极能够解析来自大脑的微小电位，这对更好地理解和治疗神经系统疾病具有重要意义。但是，由于有机电极和底层金属衬垫之间的键合界面不稳定，它们的优越特性随着时间的推移而褪色，而金属衬垫将信号传递到外界。该项目旨在通过开发新的制造工艺来提高这些有机电极的稳定性，从而将其优越的性能延长数年。技术：该项目结合了电子材料加工，人体电生理记录和数据分析方面的专业知识，以开发聚（3,4-乙烯二氧噻吩）聚苯乙烯磺酸微电极的新几何形状。能够产生最低电化学阻抗和最高电化学稳定性的器件几何形状将被开发出来，并通过体外加速老化实验进行表征。当微电极在高温下浸泡在盐水溶液中时，阻抗和循环电流-电压特性将在几周的时间内被监测。表面和横截面扫描电子显微镜和原子力显微镜将被用来评估这些微电极的形态稳定性，并将为设备制造提供信息，以开发稳定的界面。该研究与学生的教育计划相结合，重点关注生物医学植入设备以及新兴的神经技术领域。该计划包括为本科生和研究生提供广泛的教育和培训项目，重点是少数民族、女性和其他代表性不足的群体。如果成功，这些设备将广泛地影响我们如何理解大脑，诊断大脑病变区域，并推动大脑植入物的发展，有可能使更广泛的社会人群获得这些信息。

Abstract Nontechnical: Electrophysiological clinical mapping of brain activity has high spatial resolution and high sensitivity that supersedes other noninvasive techniques such as functional magnetic resonance imaging (fMRI). This clinical procedure is important for a large population of patients with neurological disorders that either do not respond to drugs or have adverse side effects such as in medically intractable epilepsy. It also has promising applications in brain-machine interfaces. The majority of electrophysiological devices utilize noble metals as the contact interface with brain tissue, and these metal electrodes detect ionic currents and potentials by either surface redox reactions or capacitive charge screening. Organic electrodes on the other hand are permeable to ions and allow volumetric redox reactions and capacitive coupling of brain activity. This superior electrochemical performance allows organic electrodes to resolve minute potentials from the brain which has implications for better understanding and treatment of neurological diseases. But their superior characteristics fade with time due to instability of the bonding interface between the organic electrode and the underlying metal pads that carry the signals to the outside world. This project aims at improving the stability of these organic electrodes by developing novel fabrication procedures that can extend their superior performance for several years. Technical: This project combines expertise in electronic materials processing, electrophysiological recording from humans, and data analysis in order to develop new geometries of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate microelectrodes. Device geometries that can result in the lowest electrochemical impedances and highest electrochemical stability will be developed and characterized with accelerated aging experiments in-vitro. Impedance and cyclic current-voltage characterization will be monitored over the course of several weeks while the microelectrodes are immersed in saline solution at high temperatures. Surface and cross-section scanning electron microscopy and atomic force microscopy will be utilized to assess the morphological stability of these microelectrodes and will inform the device fabrication to develop stable interfaces. The research is integrated with an educational plan for students with a central focus on biomedical implant devices as well as on the burgeoning field of neuro-technology. The plan includes extensive education and training programs for undergraduate and graduate students, with an emphasis on minority, female, and other underrepresented groups. If successful, the devices will broadly impact how we understand the brain, diagnose diseased regions of the brain, and advance the development of brain implants potentially opening access to such information to broader societal populations.