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 selfpowered

ROS sensor is explored based on enzymatic biofuel cell (EBFC) to selectively detect oxygen (O 2 ) and hydrogen

peroxide (H 2 O 2 ). 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 O 2 and H 2 O 2 , respectively.

They show good sensitivity for each O 2 and H 2 O 2 fuel, while the sensitivity is quantifi ed 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/cm 2 at 0.4 V for O 2 and 440 μW/cm 2 at 0.5 V for H 2 O 2 , and this proves desirable step reaction occurs

within the given concentration range of fuels, which are 25–100 cc/min (O 2 ) and 1–3 mM (H 2 O 2 ). Furthermore, the fl exible

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.