Recyclable Semiconductor Aerogel Electrochemical Transistors for Ultrasensitive Biosensors.

Recyclable organic electronics such as organic electrochemical transistors (OECTs) show great potential for sustainable bioelectronics and sensors. However, it is challenging to achieve recyclability of the OECTs, and the reported active layers of the OECTs typically feature dense semiconductor films with limited ion permeation/transport. Here, recyclable and flexible OECTs based on nanoporous aramid nanofibers/semiconducting polymer aerogels are developed. The resulting OECTs exhibit significantly enhanced ion permeation and transport and record-high transconductance of 136.5 mS among the OECTs with similar channel sizes. The aerogel OECT-based microfluidic dual-channel biosensor shows record-low detection limits of 10 and 1 pM in response to lactate and lysozyme, respectively, making it capable of identifying trace amounts of biomarkers in real body fluids such as saliva and tear. In addition, the semiconducting aerogels are recyclable, offering the possibility of reuse of the transistors. This work presents a powerful approach to recyclable semiconductor aerogels and ultrasensitive OECT biosensors for wearable/sustainable applications.