Biomaterials Meet Organic Electrochemical Transistors: Materials, Interfaces, and Biosensing Frontiers
Organic electrochemical transistors (OECTs) are emerging as powerful biosensing platforms, offering high transduction efficiency, low‐voltage operation, and intrinsic compatibility with aqueous and physiological environments. Central to their recent progress is the strategic integration of biomaterials, which govern interfacial charge transfer, doping dynamics, and recognition specificity. A complete understanding of biomaterial‐enabled OECTs requires not only insights into intrinsic material chemistry but also interface engineering and device design principles that dictate signal transduction and reproducibility. In this review, we critically examine the full spectrum of biomaterials integrated into OECT biosensors (from natural macromolecules, such as proteins, nucleic acids, and polysaccharides to biocompatible polymers and synthetic engineered interfaces). Particular emphasis is placed on interfacial chemistries, including silanization and click reactions, that control receptor orientation, density, and long‐term stability. Beyond materials design, we discuss operating physics, signal transduction mechanisms, and device engineering strategies, thereby linking molecular‐scale chemistry with device‐level performance. By consolidating these interdisciplinary advances, we provide a timely roadmap for reproducible, scalable, and clinically relevant OECT biosensors. With growing demand for high‐performance and sustainable sensing platforms in precision medicine and environmental monitoring, this review highlights both key achievements and outstanding challenges that will shape the next generation of bioelectronic technologies.