Bioinspired Microfluidic Wearable Sensors for Continuous Sweat Sampling and Metabolic Monitoring

Wearable sweat sensors have shown strong potential for noninvasive health monitoring by providing access to dynamic biochemical information. However, continuous monitoring of sweat metabolites remains challenging due to low and variable sweat rates, inefficient sampling, and signal distortion arising from evaporation, contamination, and accumulation. These limitations restrict the accuracy and practical deployment of current wearable systems. In this thesis, we present bioinspired microfluidic strategies to enable continuous sweat sampling, transport, and metabolic analysis under physiologically relevant conditions. We demonstrate how a Janus interface with asymmetric wettability and geometry enables directional vertical transport at the inlet and outlet, while hierarchical microchannel guides flow across the microfluidic and sensing regions. These design elements enable transport even at low sweat rates while preventing stagnation and backflow, resulting in continuous sweat transport without the need for active pumping. This extends the effective sampling window and reduces the number of sweat induction sessions required. The platform is integrated with electrochemical sensing modules for real-time detection of metabolites and is further extended toward multiplexed sensing of biomarkers relevant to metabolic health. The system is validated through on-body human studies under stimulated conditions, with initial evaluation during exercise-induced sweating. Overall, the works presented here establish design principles for coupling sweat induction, sampling, and sensing, advancing wearable biofluid technologies for continuous and noninvasive metabolic monitoring.