| Neural stimulation has shown success in alleviating symptoms of neurological disorders, however the long term performance of these devices are limited by electrode corrosion caused by electrical stimulation. This study presents the effects of continuous stimulation on glassy carbon (GC) micro-electrode arrays on a flexible polyimide substrate. We report on the in-vitro and in-vivo stability of GC electrodes, specifically exploring corrosion mechanisms, effects of increasing the voltage amplitude in stimulation, and the electrochemical stability window. Electrode corrosion was characterized by scanning electron microscopy (SEM), optical microscopy, energy dispersive x-ray spectroscopy (EDX), electrochemical impedance spectroscopy (EIS), Pourbaix diagram, cyclic voltammetry (CV), and Tafel analysis. The corrosion rate was estimated by performing extrapolating the corrosion current from the Tafel plot. Results show that corrosion rate of GC electrodes in a PeSKa device is 155um/ year. Overall, this research provides new information on the effects of GC corrosion and supports the use of GC as a viable material for neural electrodes, especially in chronic implantation. |
