Fibers/Textiles-Based Flexible Sweat Sensors: A Review

With the rise of smart textiles, fibers/textiles-based sensors are being applied in various situations, such as healthcare, green energy, and environmental monitoring. The field of health monitoring mainly involves the detection of human secretions (such as sweat, saliva, urine, and excrement). Among them, sweat is extensive and closely related to human health, so it is receiving more and more attention. Various sensors are used for sweat detection, but fiber/textile-based flexible sensors have unique advantages and thus have emerged as an important branch. So, this Review aims to 1) explain the physiological mechanism of sweating and metabolites; 2) introduce the advantages of fibers/textiles as the substrate of sweat sensors; 3) outline different kinds of fibers/textiles-based flexible sweat sensors (enzymatic biosensors, non-enzymatic biosensors, ion-selective sensors, and others) and explain their working principle; 4) summarize the applications of such sensors in different fields (physical condition monitoring, power supply, drug monitoring, mental state monitoring, etc.). Moreover, the opportunities and challenges of flexible fiber/textilebased sweat sensors will also be discussed. This Review will help promote the diversified development of sweat sensors, which is significant for manufacturing advanced sweat detection and diagnostic systems.