The role of sampling in wearable sweat sensors

Wearable sweat sensors demonstrate outstanding performance in non-invasive, real-time monitoring of vital biomarkers in sweat, which offer an opportunity for individuals to achieve dynamic monitoring their own physiology in molecular-level. As a key step in sweat analysis that impact the accuracy of results, frequently-used sweat sampling methods are introduced in this review, and the emphasis is sweat sampling in wearable sensors including absorbent materials, superhydrophobic/superhydrophilic surface, sweat guidance and epidermal microfluidic systems. In the end, we also propose the remaining challenges in the practical, large-scale application of wearable sweat sensors and provide personal prospects on the future development.