An Epidermal Sweat Patch for Tracking Metabolite Levels and Correlation Analysis in Biofluids

Continuous, in situ monitoring of sweat biomarkers offers a promising approach for non-invasive metabolic assessment, but its practical implementation remains limited by sensing stability and the insufficiently defined physiological relationship between sweat and systemic biofluids. Here, we develop an epidermal sweat patch that integrates a non-enzymatic electrochemical interface based on Au-Ni(OH)₂ dual aerogels for glucose monitoring. The complementary roles of Ni(OH)₂-mediated glucose adsorption and Au-assisted electrooxidation enable sensitive and stable sensing, with a calculated detection limit of 0.1 µM and >95% signal retention after 5 weeks. Combined with microfluidic sweat sampling, signal processing and wireless communication, the patch enables real-time on-body tracking of sweat glucose during daily activities. In human studies, sweat glucose shows positive associations with interstitial fluid and blood glucose, with Pearson correlation coefficients of up to 0.828, while subgroup analyses further reveal interindividual variability. These results support the physiological relevance of sweat glucose as a complementary signal for metabolic monitoring. Overall, this work integrates non-enzymatic sensing, wearable system design and cross-biofluid analysis within a single platform, providing a practical framework for physiologically interpretable sweat-based glucose monitoring.