Self-powered wearable electrochemical sensor based on composite conductive hydrogel medium for detection of lactate in human sweat

Sweat, a vital metabolic product in the human body, contains valuable biomarkers that reflect human conditions. Among these, lactate concentration serves as a significant indicator of human physiological states. In this study, we present an innovative self-powered wearable electrochemical sensor designed for real-time lactate detection in human sweat. This sensor utilizes a composite conductive hydrogel medium, showcasing its potential in monitoring and assessing human health. The sensor incorporates two key components: the lactate oxidase/ reduced graphene oxide/carbon cloth electrode (LOx/rGO/CCE) as the anode and the bilirubin oxidase/reduced graphene oxide/carbon cloth electrode (BOx/rGO/CCE) as the cathode. These electrodes are integrated into a substrate comprising a conductive hydrogel composed of Poly (3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) and hydrophilic polyurethane (HPU). The sensor's performance was evaluated. The linear detection range spans from 10 nM to 50 mM, with an impressive detection limit of 4.38 nM, demonstrating its high sensitivity and selectivity towards lactate detection with long-term stability. Additionally, this sensor has been successfully applied to real-time monitor lactate concentration on athletes' skin by combining it with selfmade equipment and smartphones. The test results demonstrate minimal error compared to the results obtained from high-performance liquid chromatography. This technology opens up a valuable tool for monitoring and assessing human physiological conditions and new possibilities for advancements in health management, sports monitoring, and medical diagnostics.