New Publication: High-Resolution Graphene Microelectrodes

A paper by first-year doctoral student Arata Okoshi, second-year doctoral student Tatsuya Murakami and alumnus Toshiya Aoki has been published!

Low-cost fabrication of graphene-based microelectrodes via SU-8 latent-pattern lift-off for organic microdevices, Arata Okoshi, Tatsuya Murakami, Toshiya Aoki, Shotaro Yoshida, Journal of Micromechanics and Microengineering, 36, 045013, (2026). [Link]

Microfabricating graphene, an organic material suitable for recording biological electrical signals, has required complex and expensive processes. In this study, we developed a new microfabrication technique called “latent-pattern lift-off” and demonstrated a very simple method for producing graphene microelectrodes with features as small as approximately 2 μm.

First, micropatterns are exposed through a photomask in SU-8 photoresist, but the usual immediate development step is omitted, leaving exposed latent-pattern SU-8. An “ink” of graphene nanoplatelets dispersed in ethanol is then spin-coated onto it. Development proceeds through the graphene nanoplatelet film, lifting off the SU-8 and graphene outside the latent pattern. This improves the resolution of simple lift-off fabrication of graphene electrodes beyond the approximately 20 μm minimum feature size of conventional methods.

We also demonstrated biosensors with low impedance suitable for neuronal electrical recording and high capacitance suitable for electrical stimulation, as well as microheater electrodes for microactuators. Using the graphene as gate, drain and source electrodes enabled organic electrochemical transistors, which hold promise for highly sensitive biosensing.

We consider this simple graphene-electrode fabrication method useful for a variety of organic microelectronics and bio-MEMS technologies, and will pursue further application studies.