Description
Brain computer interface (BCI) is a rapidly advancing technology which holds the potential to revolutionize the treatment and diagnosis of a wide range of neural disorders by providing a better understanding of functioning of the nervous system. For the treatment of spinal cord injuries as well as various other neurological diseases, one of the most widely used approaches involves electrically stimulating the nerve tissues via microelectrode arrays (MEA). This requires the interface material to be biocompatible, promote consistent integration with neurons and remain operational for a long period of time. Platinum is a widely used standard in commercially available MEAs due to its high conductivity. A new range of carbon-based neural probes comprising of Glassy Carbon (GC) as electrode material has been actively researched in the neural interface research community. GC is a promising material for neural interface applications due to its chemically inert nature, electrochemical stability and its unique tunable mechanical and electrical properties. In this study, we investigate the kinetics for different design configurations of glassy carbon and thin-film Platinum MEAs with an aim of developing a fundamental understanding of charge transfer mechanisms. Our approach includes study of the cyclic voltammetry (CV) behavior for both GC as well as thin film platinum MEAs which highlights upon the dominating behavior of the surface reaction i.e. either diffusion controlled, or adsorption controlled. Additionally, Electrochemical Impedance Spectroscopy (EIS) will present insight on charge transfer resistance as well as ionic mobility. To further understand the charging and discharging kinetics, we conduct voltage transient study of GC and Pt microelectrodes of the same geometry and dimension. Data presented in this thesis demonstrates that glassy carbon-based devices (Peska GC and hybrid) to be a better choice for neural stimulation and recording purposes as compared to platinum electrodes due to much faster electrochemical kinetics. This was further validated by the galvanostatic charge-discharge testing. Additionally, this thesis work also diverges into first time ever fabrication and electrochemical characterization of a glassy carbon based supercapacitor with an aim to serve as a stand-alone powering device utilizing brain’s physiological environment.
