A bioinspired microfluidic wearable sensor for multiday sweat sampling, transport, and metabolic analysis.

Wearable sweat sensors enable noninvasive real-time biochemical monitoring, holding immense potential for personalized health care applications. However, achieving prolonged and reliable sweat sampling, along with stable biochemical analysis, remains challenging due to inconsistent secretion, rapid evaporation, and the reliance on external stimulation. Here, we present BMS3, a bioinspired microfluidic wearable sweat sensor system designed for multiday continuous metabolic monitoring. BMS3 integrates hierarchically graded microchannels and superhydrophobic-superhydrophilic Janus membranes, inspired by pitcher plant trichomes and lotus leaves to enable efficient low volume sweat collection, transport, and renewal. A miniaturized carbachol gel-based iontophoresis module autonomously induces localized sweat secretion. Furthermore, the microfluidic design sustains sweat sampling for over 2 days from a single iontophoresis session, eliminating the need for physical exertion. In vitro and in vivo studies in healthy participants and patients with gout demonstrate BMS3's capability for continuous metabolic monitoring. By simultaneously tracking uric acid, xanthine, and alcohol levels, it effectively differentiates normal and pathological states while delivering timely therapeutic feedback.