fig2
Figure 2. Representative flexible substrates and their material characteristics for wearable optical sweat sensors. The illustrated substrates include PDMS, hydrogels, textiles, paper, and TPU. Created in BioRender. Chu Wang. (2026) https://BioRender.com/w58hd9a, Adobe Illustrator, and Maxon Cinema 4D R21. PDMS: Polydimethylsiloxane; TPU: thermoplastic polyurethane.
