A wearable enzyme sensor enabled by the floating-gate OECT with poly(benzimidazobenzophenanthroline) as the catalytic layer.

Abstract

With the advantages of miniaturization, simple device structure, and fast response, the organic electrochemical transistor (OECT) has become an emerging platform for developing wearable enzyme sensors for real-time health monitoring. The floating gate (FG) OECT employs a distinct signal acquisition and amplification structure, mitigating the effects of non-specific physical adsorption during the sensing process and preventing contamination of the electrolyte solution by side reaction products. The current work reports a feasible wearable enzyme sensor using a poly(benzimidazobenzophenanthroline) (BBL)-Nafion-enzyme-Nafion stacking structure as the sensing layer of the FG OECT. Based on the experimental results, the BBL film with an area of 3.14 mm² and a thickness of 175 nm can generate an open circuit potential of 199.61 mV in 10^- 1 M hydrogen peroxide compared with the blank control. Then, the FG OECT is integrated with the flexible microfluidic systems for on-skin detection of glucose, lactate, and uric acid with sensitivities of 92.47, 152.15, and 74.27 µA·dec^- 1, respectively. This FG OECT-based wearable enzyme sensor will open new windows for multiplexed detection of sweat metabolites.