Integrated Wearable Sensors Based on Sweat-Driven Hydrovoltaic Chips for Metabolite and Electrolyte Monitoring.

Wearable integrated sensors enable the continuous measurement of useful biomarkers without any additional equipment or accessories. However, the limited variety of ion-selective electrodes restricts their range of applications. Furthermore, sensors based on electrochemical techniques require energy consumption and additional electrodes, which limits their applicability in a long-term test. Here, we report an integrated wearable sensor based on sweat-driven hydrovoltaic chips (HSIWS) for the first time. Compared with conventional electrochemical sensors, the hydrovoltaic devices need neither additional reference electrode nor the energy input. The multiple parameters can be directly read out through the output voltage by interacting with the sweat to be measured. Particularly, three sensing modules are integrated with one microfluidic module, and these modules are assembled into a lab-on-skin patch to perform in situ sweat sampling and health analysis. With the help of electronic module, the fabricated HSIWS system achieves simultaneous, noninvasive, and wireless monitoring of the metabolite and electrolyte concentration as well as the body surface temperature. Furthermore, we evaluate its application potential for physical monitoring in healthy volunteers during physical exercise. Such HSIWS system may provide a design strategy for integrated wearable sensors and thus promote long-term self-health management.