Transparent artifact-free graphene electrodes for compact closed-loop optogenetics systems

Graphene offers unique advantages for implantable neural systems by combining properties like optical transparency, flexibility, high conductivity and biocompatibility in a single material. Here we report the first demonstration of a graphene-based compact closed-loop optogenetics system with the capability of recording and processing of neural activity in real time to control the light stimulation. We develop a process flow for high-yield large-area fabrication of transparent graphene microelectrode arrays on clear flexible substrates. Transparent graphene electrodes completely eliminate light-induced artifacts, which hinder the development of compact closed-loop optogenetics systems with conventional metal microelectrodes. We successfully demonstrate closed-loop operation with transparent graphene electrodes for simultaneous optical stimulation and electrical recordings without light artifacts.