A few years ago, at University of Wisconsin-Madison, researchers developed transparent graphene-based neural electrode arrays that can be used for novel brain imaging applications. Apparently these became a hit so much so that requests from other scientists around the world overwhelmed the Wisconsin team. To respond to so much interest, we learned through the website Graphene-Info, that the Wisconsin team published a paper in Nature Protocols going through all the details required to build and use such devices.
To further expand the practical uses of these electrode arrays, the team partnered with researchers at University of Wisconsin-Milwaukee, Mahidol University in Bangkok, Thailand, and Medtronic PLC Neuromodulation, and delved into how to apply them for electrophysiology, fluorescent microscopy, optical coherence tomography, and optogenetics.
From the study abstract in Nature Protocols:
Transparent graphene-based neural electrode arrays provide unique opportunities for simultaneous investigation of electrophysiology, various neural imaging modalities, and optogenetics. Graphene electrodes have previously demonstrated greater broad-wavelength transmittance (~90%) than other transparent materials such as indium tin oxide (~80%) and ultrathin metals (~60%). This protocol describes how to fabricate and implant a graphene-based microelectrocorticography (μECoG) electrode array and subsequently use this alongside electrophysiology, fluorescence microscopy, optical coherence tomography (OCT), and optogenetics. Further applications, such as transparent penetrating electrode arrays, multi-electrode electroretinography, and electromyography, are also viable with this technology. The procedures described herein, from the material characterization methods to the optogenetic experiments, can be completed within 3–4 weeks by an experienced graduate student. These protocols should help to expand the boundaries of neurophysiological experimentation, enabling analytical methods that were previously unachievable using opaque metal–based electrode arrays.