Figure 1.

Schematic illustrations and optical images of a miniaturized sweat microfluidic device designed to measure four key sweat nutrients via colorimetric analysis, and to serve as a mounting location for a transdermal nutrient patch. a) Schematic illustration in exploded view of the design of the microfluidic sensor and the nutrient patch. b) Diagram of the geometry of a microreservoir for colorimetric analysis. The red dashed box highlights the depth of the structure. c) Image of the device mounted on the fingertip. Scale bar: 1 cm. d) Optical image of a complete system placed next to a vitamin tablet. Scale bar: 1 cm. e) Image of the nutrient patch. Scale bar: 1 cm.