Skin-Conformal Multifunctional Microfluidic Colorimetric Detection Device for Multiplexed Sweat Analysis

Real-time and in situ sweat analysis provides a straightforward, economical, convenient, and noninvasive method for monitoring human health and diagnosing diseases at an early stage. In this study, a flexible, skin-interfaced, multifunctional microfluidic colorimetric detection device is developed for the in situ collection and multi-index analysis of sweat. This innovative device integrates an optimized microfluidic design, effective colorimetric chemical techniques, and a sophisticated multilayer layout, collectively enabling precise measurements of various sweat parameters. The incorporation of capillary bursting valves (CBVs) within the microfluidic device facilitates directional sweat transportation, effectively mitigating cross-contamination. This device simultaneously measures the content of urea, chloride ions, and magnesium ions, pH levels, and skin temperature, as well as the volume and rate of sweat loss. The detection results can be simply read by the naked eye or through a smartphone application, enhancing user convenience. The successful application of the microfluidic colorimetric device in healthy volunteers demonstrates its practical application potential. This work introduces a simple, low-cost, flexible, and convenient sweat analysis device, paving the way for in situ, noninvasive, and intelligent wearable measurements of multiple components and indicators in sweat.