Significance Sweat as a typical body fluid for analysis can provide rich biochemical information and is easy to collect. Electrochemical sensors with the advantages such as easy miniaturization, high sensitivity, and low cost stand out from other sensors, and the detection of various body fluids by wearable electrochemical sensors can achieve a non-invasive and non-invasive, simple operation, integrated diagnosis and treatment, and personalized medical process. By reviewing the research of flexible wearable electrochemical sensors in sweat composition analysis and its application status, the integration of wearable electronic devices with textile field is promoted and the future development of smart textile technology is driven. It also drives the huge demand and potential of sweat wearable electrochemical sensors in molecular chemistry, analytical chemistry, medical-military and aerospace fields. Progress This paper provides an overview of the advances in sweat extraction strategies, different analytes and electrochemical sensor substrate materials, respectively. Among them, sweat extraction strategies have evolved from conventional external stimulation or exercise sweating to microfluidic collection of sweat, even sitting still. For complex analytes in sweat, endogenous analytes are the initial targets for detection, especially glucose, a substance abundant in sweat, its sensors have been evolved from enzymatic to non-enzymatic, addressing the drawback that biological enzymes are easily inactivated. However, with the development of personalized medicine needs, monitoring the metabolic concentration of some oral or injectable clinical drugs in body fluids has become necessary. In addition to drug molecules, sweat detection of some prohibited drugs can also help police officers and other law enforcement. Finally, electrochemical sensor substrates were initially commonly used materials for rigid electrodes, and since the comfort of wearing them was greatly hindered, the construction of electrochemical elements on flexible substrates (polydimethylsiloxane, polyethylene terephthalate, etc.) was investigated, however, the most ideal was always textile-based materials that fit the human body perfectly, so the final development was to give textiles conductivity before constructing electrochemical sensors, which has led to significant progress in wearable e-textiles. Conclusions and Prospect Nowadays, wearable devices are gradually evolving from single-modal sensing to multimodal sensing capabilities. They can detect signals such as strain, bioelectricity and pressure in the skin along with numerous markers in sweat. The integration of electrochemical sensors for multiple target substances also relies on external power supplies, circuit boards, etc., which increases the rigidity of the sensors to some extent and also requires the development of flexible, long duration power supply devices. Sensors constructed on flexible stretchable substrates mostly rely only on screen printing technology, with relatively poor conductivity and stability. Research on paper-based and textile-based electrochemical sensors is still in its infancy, and the poor electrical conductivity of substrates leads to low sensitivity for the detection of substances with low concentration, and high-precision, high-sensitivity textile-based wearable electrochemical sensors are yet to be tapped for innovation. In addition, the challenges for e-textile sweat biosensors in the textile and electronic fields remain the synthesis and construction of textile-based biosensing materials, skin-sensor interface design, and embedded wireless data acquisition and transmission. With the demand for multimatter sensing, wearable e-textile devices need to focus more on breathability, portability, and performance stability, and also consider cost and simple and economical preparation strategies to make a long effort to realize wearable smart textiles. © 2023 China Textile Engineering Society. All rights reserved.
