Fig. 4: Future opportunities for wearable colorimetric sweat monitoring systems.
From: Skin-interfaced colorimetric microfluidic devices for on-demand sweat analysis
The use of digital light processing (a) to fabricate microfluidic devices95 and (b) its grayscale to fabricate mechanically gradient materials103. c Eco-friendly microfluidic devices consisting of biodegradable thermoplastic copolyester elastomer (TPC) for the microfluidic layer and a cellulose film with an acrylic pressure-sensitive adhesive (PSA) for the sealing layer60. d Common oil-control sheets to filter sebum in sweat105. e Microfluidic devices with ten micropillars in the inlet to filter microspheres and skin debris44. f The directional liquid transport system that exploits the interconnected sawtooth-shaped capillary channels with wedge-shaped micropillar array106. g Color change diagram of PTA/ethanol photo-redox cycle108. h The exploded view of the integrated microfluidic non-enzymatic glucose sensor with a replaceable porous encapsulating reaction cavity30. i The colorimetric analysis with precise time point to determine the temporal variations of biomarkers in sweat109.
