Conjugated Radical Polymer-Based Organic Electrochemical Transistors for Biosensing Devices

Abstract

Despite containing attractive redox-functional groups in their structure, research on radical polymers (RPs) and their integration into biosensing applications remains limited. Herein, we propose a study on integrating newly synthesized conjugated RP (BTMP-EDOT) with conventional conjugated polymer (P3MEET) systems, employing them as the active channel material in organic electrochemical transistor (OECT)-based biosensors designed for detecting dopamine (DA). Through precise blend composition adjustment, the optimized OECT exhibits a volumetric capacitance value (C*) of 243 F cm–3 and a maximum transconductance (g m) of ∼400 mS. Moreover, we achieved an exceptional clinical-level detection limit for DA at 1 pM and remarkable ultraspecificity, even in the presence of a large excess of interferents. The highly sensitive and selective DA biosensing performance is achieved through meticulous design, which involves harnessing the redox activity of TEMPO active sites to enhance ion penetration into the bulk channel film and engineering a synergistic inter- and intramolecular π-orbital overlap between the primary constituents to facilitate efficient electronic transport along and between the polymer chains. Furthermore, our proposed design concept, coupled with CRP structure modification, could enable the development of OECTs with exceptional performance tailored for low-cost and disposable DA biosensing applications.