Sweat-powered, skin-adhesive multimodal sensor for long-term and real-time sweat monitoring

The importance of continuous healthcare management has significantly accelerated the development of wearable devices for monitoring health-related physical and biochemical markers. Despite extensive research on wearable devices for physiological and biochemical monitoring, critical issues of power management and device/skin interfacial properties restrict the advancement of personalized healthcare and early disease detection. Here, we report a multimodal sweat monitoring device featuring a real-time display and long-term data analysis based on self-powered format of sweat-activated batteries (SABs). The polyvinyl alcohol-sucrose (PVA-Suc) hydrogel serves as the key component for the SAB, offering not only great long-term adhesive properties for conformable wearability but also significant power generation capabilities. A maximum current density of 44.06 mA cm⁻² and a maximum power density of 21.89 mW cm⁻² can be realized for the hydrogel based SAB. The resulting device integrates an advanced colorimetric and electrochemical sensor array to measure pH levels, glucose concentrations, and chloride ion levels in human sweat, with data wirelessly transmitted by Near Field Communication. The self-powering features and multiple mode sensing function offer sufficient power to support real-time monitoring of metabolic biomarkers in sweat, with the ability to visually observe changes in the colorimetric sensors for long-term data monitoring.