A flexible and biocompatible trilayer coaxial heterogeneous structure microfiber electrode for long-term electrophysiological recordings in freely moving mice

Neuroscience and neural engineering face the critical challenge of accurately capturing and interpreting electrophysiological signals for understanding brain function and developing neural prosthetics. Here, we develop a trilayer coaxial heterogeneous structure flexible neuronal electrode, rSF-Au-PC, which addresses these challenges through its innovative design and superior performance. Developed <i>via</i> a multi-step, large-scale fabrication process, the rSF-Au-PC electrode features an adjustable diameter and low specific impedance (7.67 MΩ at 1 kHz), ensuring precise signal capture. It also boasts high charge storage capacity (51.16 mC cm^-2), high charge injection capacity (19.11 mC cm^-2), and high signal-to-noise ratio (14.48 dB after three weeks), which are essential for reliable electrophysiological signal recording. The electrode's remarkable biocompatibility and robust electrochemical and mechanical stability make it suitable for long-term use, outperforming conventional tungsten wire electrodes in chronic <i>in vivo</i> applications. This advancement holds significant implications for neuroscience applications, particularly those requiring extended electrophysiological surveillance, and may pave the way for future innovations in neural prosthetics and diagnostic technologies.