Oriented Nanochannel Aerogels for High-Transconductance Organic Transistors and Ultrasensitive Biosensors

Organic electrochemical transistors (OECTs) are promising for various sensors, but their transconductance and sensitivity are restricted by limited ion penetration/transport of dense active layers. Here, inspired by oriented biological ion channels, differently oriented nanochannel semiconductor aerogels and the aerogel-based OECTs are developed via a liquid crystal templating strategy. Compared with dense and random (or horizontal) porous structures, the vertical nanochannel structure shows significantly enhanced ion penetration/transport, enabling an ultrahigh transconductance of 118.5 mS, significantly higher than those of state-of-the-art OECTs with a similar channel size. The vertical nanochannel OECT-based multi-channel microfluidic biosensor system exhibits ultralow detection limits of 1 pM, 0.01 fg mL^-1, and 0.1 pM in response to uric acid, immunoglobulin G, and deoxyribonucleic acid, respectively, approximately one to three orders of magnitude lower than those of dense devices. It can detect trace amounts of different biomolecules in body fluids like urine and serum for accurate disease diagnosis/prevention. This work presents a versatile strategy for creating oriented nanochannel materials and electronics for various advanced applications.