Ion‐Selective Organic Electrochemical Transistors: Recent Progress and Challenges

The charged species inside biofluids (blood, interstitial fluid, sweat, saliva, urine, etc.) can reflect the human body's physiological conditions and thus be adopted to diagnose various diseases early. Among all personalized health management applications, ion-selective organic electrochemical transistors (IS-OECTs) have shown tremendous potential in point-of-care testing of biofluids due to low cost, ease of fabrication, high signal amplification, and low detection limit. Moreover, IS-OECTs exhibit excellent flexibility and biocompatibility that enable their application in wearable bioelectronics for continuous health monitoring. In this review, the working principle of IS-OECTs and the recent studies of IS-OECTs for performance improvement are reviewed. Specifically, contemporary studies on material design and device optimization to enhance the sensitivity of IS-OECTs are discussed. In addition, the progress toward the commercialization of IS-OECTs is highlighted, and the recently proposed solutions or alternatives are summarized. The main challenges and perspectives for fully exploiting IS-OECTs toward future preventive and personal medical devices are addressed.