Maskless production of neural-recording graphene microelectrode arrays

This paper describes the production of a new version of high-performance microelectrode arrays (MEAs) that can be custom produced and used to explore in vitro neural networks. The MEAs were manufactured using direct write technology and comprised graphene microelectrodes and SU-8 insulation on a glass substrate, where graphene was grown by chemical vapor deposition on copper foil and then transferred to the substrate. The graphene MEAs experimentally exhibited adequate electrical specifications, with the electrode characterized using noise testing, cyclic voltammetry, and impedance spectroscopy. The MEAs herein exhibited improved properties over those previously reported in the literature. The average impedance at 1 kHz for the electrodes herein was 5.2 kΩ, which is compatible with commercial MEAs which present values between 30 and 400 kΩ. Further, the MEA device herein did not show biotoxicity and is thus adequate for cellular potential measurements.