A Core–Sheath Sensing Yarn‐Based Electrochemical Fabric System for Powerful Sweat Capture and Stable Sensing

Abstract Wearable sweat sensing technologies have received wide attention for personalized health monitoring with continuous and molecular‐level insight in a noninvasive manner. However, it remains significantly challenging to simultaneously capture a sufficient volume of sweat and achieve stable contact between electrodes and sweat, especially in a relatively mild sweating condition. Herein, a wearable electrochemical fabric sensor is developed by embroidering diversified sensing yarns with a multi‐ply cotton sheath and carbon nanotube‐based sensing fiber core into a super‐hydrophobic fabric substrate. The device allows for sweat enrichment among the core–sheath sensing yarn and reduce ineffective diffusion, thus remarkably increasing the sweat capture efficiency. As a result, only 0.5 µ L of sweat is needed to achieve stable circuit connectivity, 1/20 of the lowest volume reported to date. The device also maintains a highly durable sensing performance, obtained even during dynamic deformation processes such as bending, twisting, and shaking. It can be further designed into an integrated sports shirt system, which can perform real‐time monitoring of multiple chemical information (e.g., glucose, Na + , K + , and pH) of sweat for users at the states of both intense exercise conditions such as badminton and relatively mild conditions like walking and eating.