| The elucidation of learning and memory and of the pathophysiology of Parkinson's Disease (PD), Muscular Dystrophy (MD), and severe episodic depression are important goals driving contemporary neuroscience. However, this research and the development of long-term neuroprostheses for treating disorders of the human nervous system have been hindered by the unavailability of low-impedance, high resolution, solid-state electrodes In this research, we created the Polypyrrole-coated Vertically Aligned Carbon Nanofiber Microbrush Array (Ppy-coated VACNF MBA) and electrodes constructed from single 30 nm diameter multi-walled carbon nanotubes (sMWNT Electrode). These novel devices achieve the important goals of preventing washout of cellular constituents, eliciting electrical activity without electrolyzing water, concentrating the electric field, and localization of endogenic signal sources. Furthermore, these probes can potentially be used for high spatial resolution electrophysiology.;We show for the first time the application of Ppy-coated VACNF MBA and sMWNT Electrodes to electrophysiological stimulation, recording, and whole cell voltage clamp of electrically active cells. Compared to Tungsten Wire Electrodes, a platinum metal electrode array (MEA), and an As-grown VACNF MBA, the Ppy-coated VACNF MBA effects the highest stimulation efficiency. Importantly, the Ppy-coated VACNF MBA is the first reported neuroelectrical device that is able to elicit bioelectrical activity with excitation voltages that eliminate electrolysis which is potentially toxic to cells. The sMWNT electrode is the first reported nanoscale solid-state electrode capable of intracellular and extracellular electrophysiological probing. With respect to a glass micropipette electrode, the sMWNT electrode provides higher spatial resolution, effects higher stimulation efficiency in extracellular and intracellular excitation applications, detects field potentials with higher SNR, and displays lower error voltages in whole cell voltage clamp improving accuracy. We discovered that, in addition to electrode impedance, electrode geometry, and placement are design parameters that influence the performance of electrophysiological probes. Multi-sMWNT electrode architectures achieve enhanced extracellular stimulation efficiency and SNR, signal source localization, electric field concentration, and whole tissue bioimpedance monitoring.;These novel findings underscore the feasibility of incorporating sMWNT electrodes and Ppy-coated VACNF electrodes into future neuroprosthetic devices for therapy of diseases such as PD, AD, and depression. |
