Wearable sweat analysis using microfluidics offers a non-invasive approach for real-time health monitoring, with applications in chronic disease management, athletic performance optimization, and early-stage condition detection. However, most existing wearable sweat microfluidic devices are limited to single-mode operation either real-time or on-demand sampling and often lack precise control over sample volume, which compromises analytical accuracy and utility. To address these limitations, we present a novel wearable microfluidic device featuring a manual rotating fluid control mechanism and a finger-actuated pump for dual-mode sweat sampling. The rotational control mechanism directs sweat either into detection chambers for volume-independent sensor reactions or through the finger-actuated pump for precise volume control. The pump incorporates a dedicated collection chamber, enabling sweat accumulation and controlled delivery in a single actuation, ensuring reproducible sample volumes and facilitating on-demand analysis when required. Additionally, the device integrates two reaction chambers for simultaneous dual biomarker detection. Performance validation during a 40 minute exercise session, using a colorimetric glucose assay, demonstrated reliable sweat sampling and on-demand biochemical analysis. These results highlight the device's potential as a practical tool for personalized health monitoring and field applications.
