Low-Impedance Low-Artifact PEDOT: PSS-Coated Graphene Electrodes Towards High Density Optogenetic Electrophysiology

Graphene electrode arrays hold promise for in vivo optogenetic electrophysiology. In such studies, it would be ideal to enable spatial oversampling with a high-density array, which is challenging to maintain both low electrode impedance and low light-induced artifact. To this end, we present a 28-μm pitched, poly(3, 4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS)-coated graphene electrode array, which was found to feature both low electrode impedance and low artifact in optogenetic electrophysiology. The resulting array was able to record the optogenetically stimulated signals, whose amplitudes increased with the stimulus intensity and maximized next to the responsive cell. Such PEDOT:PSScoated graphene electrodes are suitable to ultimatelyform a flexible array for high density optogeneticelectrophysiology in vivo.