Structure–Property Modulation in Pyrolytic Photoresist Films Enabled Size-Dependent Electrochemical Performance of Neural Interfaces

Neural probes are critical devices used to monitor and record brain activity, usually connected to neurons to measure neural activity. However, traditional metal electrodes face numerous challenges, including high Young's modulus, susceptibility to electromagnetic interference, insufficient biocompatibility, and the risk of corrosion and delamination. In this study, we explore a highly biocompatible carbon material, a pyrolytic photoresist film (PPF), developed through a photoresist pyrolysis process. The effects of the pyrolysis temperature and hold time on material properties were systematically studied. The optimal pyrolysis condition was identified as 1000 °C for 2 h. Furthermore, a quantitative model was established to link the electrode's geometric area with electrochemical performance and optimize the performance of PPF neural probes. Ultimately, we successfully fabricated a multichannel flexible neural probe with superior electrochemical performance.