Wearable Self‐Powered Biosensor for Continuous Lactate Monitoring in Sweat

The continuous monitoring of sweat lactate is a critical task in sports and medical applications. This paper introduces a self‐powered biosensor for the continuous monitoring of sweat lactate. A biofuel cell (BFC)is prepared using thionine as a bioanode mediator, with poly(ethylene glycol) diglycidyl ether and a chitosan–genipin membrane incorporated in the bioanode. This system achieves an open‐circuit voltage of 0.75 V and output power density of 0.163 mW cm –2 in the presence of 100 mM lactate. The self‐powered biosensor is constructed by integrating the BFC with a voltage booster and Bluetooth transmitter. An on‐body test is conducted on an exercising individual. The output signal of the self‐powered biosensor is converted into lactate concentrations through manual pH adjustment. A correlation between the lactate concentrations in sweat and blood is observed. Overall, the proposed self‐powered lactate biosensor can continuously monitor sweat lactate, with potential applications in the sports and medical domains.