A hierarchical dual-lock mechanism empowered epifluidic patch for rapid glucose feedback in exercise-induced sweating

A wearable epifluidic patch featuring a hierarchical dual-lock mechanism is introduced. Tetrahedral DNA nanostructures co-localize enzymes at defined spacing to promote substrate channeling and accelerate kinetics, while a gelatin hydrogel stabilizes the enzymatic microenvironment during hydration cycles, ensuring uniform reaction conditions for homogeneous signal formation. This design produced a visible glucose-responsive signal within 30 s, with a linear range of 50–400 µM and a detection limit of 9.98 µM. Integrated with passive microfluidics and smartphone imaging, the patch enables sequential sampling in human trials conducted during physical exercise. The hierarchical immobilization method, device design, and system integration outlined demonstrate a platform for intuitive, electronics-free colorimetric sensing in dynamic environments.