fig4

Figure 4. Structural design for sweat sampling in flexible sweat electronics. (A) Wearable sweatband channel for sweat collection. Reproduced with permission^[55]. Copyright 2017, American Chemical Society; (B) Sweatainer system for sweat collection. Reproduced under the terms and conditions of the CC BY^[56]. Copyright 2023, Author(s), published by The American Association for the Advancement of Science; (C) The chamber with hydrophobic valves to reduce sweat evaporation and contamination. Reproduced with permission^[57]. Copyright 2020, Royal Society of Chemistry; (D) Cactus spines inspired patch with wettability patterned channels. Reproduced with permission^[58]. Copyright 2021, Wiley-VCH; (E) Hydrophilic fillers into the sensing channel to enhance the uptake of sweat. Reproduced under the terms and conditions of the CC BY^[16]. Copyright 2021, Author(s), published by Springer Nature.