PEDOT: Tosylate-polyamine-based enzymatic organic electrochemical transistors for high-performance glucose biosensing in human urine samples

Abstract

We present the development of enzymatic PEDOT-PAH-based (polyethylenedioxythiophene-polyallylamine hydrochloride) organic electrochemical transistors (OECTs) for glucose detection in human urine samples via direct immobilization of glucose oxidase (GOx) onto PEDOT-PAH via electrostatic interactions. An alternative method for recording OECT responses was introduced, involving continuous switching of gate potential and subsequent data processing, which becomes effective for monitoring protein adsorption and reconstructing temporal response curves to analyte injections. Investigation into the sensing mechanism revealed the pivotal role of pH changes induced by enzymatic catalysis in the transistor response. Evaluation of OECT performance in media with higher ionic strength and buffering capacity demonstrated glucose sensing even in complex biological matrices, including promising results in human urine samples with sensitive response up to 2 mM spiked glucose concentration. These findings not only underscore the functionality of the proposed glucose sensor but also highlight the potential of enzymatic OECT-based sensors for biosensing applications in real biological media.