A universal oxygen scavenger for oxidase-based biosensors.

Oxidase-based electrochemical biosensors are widely deployed for point-of-use applications, yet oxygen interference remains a major challenge, substantially reducing sensing accuracy. Here, we developed a universal enzymatic O scavenger composed of alcohol oxidase, catalase, and paraformaldehyde to eliminate O within the sensor by converting it to water. Unlike other oxidases, alcohol oxidase exclusively uses O as an electron acceptor, preventing interference with the electron transfer chain involving the sensing oxidase. We demonstrated the compatibility of this O scavenger for calibration-free sensing of glucose, lactate, and creatinine in the concentration range relevant to human health. Without the O scavenger, sensor readings were less than 50% of those under inert gas conditions. With the O scavenger, the accuracy improved to 99%, even at low substrate concentrations. The general compatibility and performances of this alcohol oxidase-based O scavenger unlock the full potential of oxidase-based biosensors for reliable point-of-use sensing.