High‐Performance MXene/PEDOT‐PSS Microscale Fiber Electrodes for Neural Recording and Stimulation

Abstract The pursuit of advanced neural interfaces hinges on developing electrode materials with enhanced cathodic charge storage capacity (CSCc), charge injection capacity (CIC), and low impedance. 2D nanomaterials, particularly MXenes, have emerged as leading candidates due to their outstanding electrical properties. However, current fabrication strategies have not fully leveraged the potential of MXene, limiting the performance gains in neural recording and stimulation applications. Here, a novel microscale fiber electrode (MPP) engineered from Ti₃C₂ MXene and PEDOT‐PSS using a two‐step solidification wet spinning process is presented. These 30 µm fibers exhibit a conductivity of (2.16 ± 1.46) × 10⁵ S m⁻¹, low interfacial impedance, and high CSCc and CIC, achieving substantial improvements in signal fidelity and stimulation efficiency. The MPP electrodes demonstrate robust electrochemical stability, biocompatibility, and magnetic resonance imaging (MRI) compatibility, excelling across various modalities, including electroencephalography (EEG), electromyography (EMG), electrocardiography (ECG), cortical recordings, and subthalamic nucleus deep brain stimulation (STN‐DBS). These results mark a significant step toward scalable, high‐performance neural interfaces that can transform neurotherapeutic applications.