A Small-Sized Graphene Fiber Electrode for MRI-Compatible Single-Neuron Recording

Graphene fibers, due to their biocompatibility, have attracted increasing attention in the field of bioelectronics. However, the trade-off between interface impedance and fiber size presents a significant challenge for their application in neural recording. In this work, we developed a flexible graphene fiber electrode for action potential recording by modifying 20–40 μm graphene fibers with poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS). The electrode exhibits low impedance at 1 kHz (55.94 ± 11.8 kΩ) and enables in vivo action potential recording in mice, with a peak-to-peak amplitude of 191.2 μV and a signal-to-noise ratio (SNR) of 11 dB. Furthermore, in 9.4 T T2-weighted MRI, the artifact size produced by the proposed graphene electrode is only 32.8% of that caused by 20 μm platinum-iridium (Pt-Ir) electrode. These results demonstrate the potential of the proposed graphene electrodes for multimodal neuroscience research.