Organic Electrochemical Transistors for Neural Sensing: Materials, Devices, and Integration Strategies

Organic electrochemical transistors (OECTs) are emerging as powerful platforms for neural sensing, bridging the gap between ionic signaling in biological tissue and electronic readout. Their volumetric ionic-electronic coupling, high transconductance, low-voltage operation, and mechanical compliance enable faithful amplification of weak neural signals while minimizing tissue mismatch. OECTs achieve multifunctional interfacing by amplifying weak signals and simultaneously monitoring electrophysiological and neurochemical activity through their soft, ion-mediated operation, extending beyond conventional electrode approaches. Recent advances in materials, including conducting polymers, organic semiconductors, and hybrid systems, expand the performance and versatility of OECT channels and gates. Device innovations such as horizontal, vertical, and fiber-based architectures further tailor OECTs to cortical, deep-brain, and peripheral applications. Integration strategies emphasize flexible and stretchable platforms, chronic and bioresorbable implants, multiplexed arrays for large-scale mapping, and closed-loop systems that unify sensing, processing, and stimulation. Despite significant progress, challenges remain in achieving long-term stability, scalable fabrication, and clinical translation. Continued innovation in materials, device architectures, and system-level integration is expected to transform OECTs into versatile platforms for next-generation neural interfaces and bioelectronic medicine.