Solid-State Organic Electrochemical Transistors (OECT) Based on Gel Electrolytes for Biosensors and Bioelectronics

Organic electrochemical transistors (OECTs) have emerged as promising platforms for biosensors and bioelectronic devices due to their biocompatibility, low power consumption, and sensitivity in amplifying chemical signals. This review delves into the recent advancements in the field of biosensors and bioelectronics utilizing solid-state OECTs with flexible gel electrolytes. Gel electrolytes, including hydrogels and ionic liquid gels, offer improved mechanical compatibility and stability compared to traditional liquid electrolytes, making them suitable for wearable and implantable biosensing applications. We explore the properties and classifications of gel electrolytes for OECTs, highlighting their self-healing, responsive, temperature-resistant, adhesive, and stretchable characteristics. Moreover, we discuss the application of solid-state OECTs based on gel electrolytes in ion sensing, metabolite detection, and electrophysiological sensing. Despite significant progress, challenges such as manufacturing scalability and the development of responsive OECTs persist. Future directions involve leveraging the multi-responsiveness of hydrogel electrolytes for intelligent sensor designs, integrating solid-state OECTs with energy storage devices for self-powered applications, and advancing wireless communication functionalities for real-time health monitoring. This comprehensive overview provides insights into the potential of solid-state OECTs based on gel electrolytes and outlines future research directions in biosensing and bioelectronics.