A Self-Powered Dual ROS Sensor Adopting Biofuel Cell Platform for Real-Time and Selective Monitoring of Oxygen and Hydrogen Peroxide

Abstract

Reactive oxygen species (ROS) play a crucial role in various biological processes, and their accurate detection is essential for biomedical applications. Although various types of ROS sensors are explored, there are demands for sensors that can be applied to wearable and implantable devices to measure the concentration of ROS in the human body. In this study, a self-powered ROS sensor is explored based on enzymatic biofuel cell (EBFC) to selectively detect oxygen (O₂) and hydrogen peroxide (H₂O₂). Furthermore, this ROS sensor utilizes buckypaper and polydimethylsiloxane (BP@PDMS)-based electrode. For anode, glucose dehydrogenase is immobilized on BP@PDMS, while as cathode, both bilirubin oxidase (BOD) and horseradish peroxidase (HRP) are immobilized on BP@PDMS, and the two cathodes detect O₂ and H₂O₂, respectively. They show good sensitivity for each O₂ and H₂O₂ fuel, while the sensitivity is quantified by measuring their reduction current density. Furthermore, polarization curves of full cell prepared with one anode and two cathodes show maximum power density of 129 µW/cm² at 0.4 V for O₂ and 440 µW/cm² at 0.5 V for H₂O₂, and this proves desirable step reaction occurs within the given concentration range of fuels, which are 25–100 cc/min (O₂) and 1–3 mM (H₂O₂). Furthermore, the flexible design of self-powered ROS sensor explored in this study highlights its possibility for integration into wearable and implantable devices, while this study proves that ROS sensor adopting EBFC platform can show high sensitivity and selectivity, and excellent adaptability for associated applications.