Surface modification of a neural sensor using graphene

Electrodes are known to degrade after implantation. This research used a novel approach to improve the performance of electrodes. Graphene obtained using the method of graphite exfoliation was applied to a neural implant. Electrochemical experiments were carried out to evaluate the properties of graphene as a coating material in two aspects. The first was to study the effects of a graphene coating on metal and its oxidation. The second was to investigate effects of the same on tissue encapsulation. Results of AFM analysis showed that the graphene not only provides good electrical conductivity for signal transport, but also serves as a coating material in order to prevent the substrate from being oxidized. The variation of phase shift in the electrochemical impedance spectroscopy (EIS) measurement was reduced due to the graphene coating. In addition, the Nyquist loci showed less pronounced RC effect of the electrodes coated with graphene. A circuit model of an electrode interface was established in order to represent the interfacial impedance. Results in this study suggest that the graphene has great advantages in the application of neural implant.