What if a wearable sensor could show changes in your body instantly, without disposable test strips or separate readout devices?
The blue color on the display darkens as the intensity moves from Level 1 to Level 4.
Korea University researchers, led by Koo Ja-hyun, have developed a reusable wearable sweat sensor that combines biochemical detection with an integrated visual display for continuous health monitoring.
The system introduces a digital colorimetric approach that addresses a key limitation of conventional paper based diagnostic kits, which are typically single use and not suited for continuous tracking.
At the core of the device is an electrophoretic colour display built using titanium oxide particles placed between electrodes, including a transparent indium tin oxide electrode layer. When voltage is applied, the particles align to produce visible colour changes. This mechanism allows the sensor to visually indicate biomarker levels and then reset for repeated use.
The display is integrated with an electrochemical sweat sensor and Bluetooth Low Energy connectivity. When biomarker levels such as lactate exceed predefined thresholds, the patch changes color while simultaneously transmitting quantitative data to a connected mobile device.
In testing with seven adult users, the system demonstrated continuous monitoring of lactate levels in sweat, enabling estimation of muscle fatigue based on exercise intensity and duration. The display darkens progressively as levels increase, providing a direct visual cue without requiring constant app interaction.
Operating at low power, the reusable patch is designed for extended monitoring of multiple biomarkers. By combining skin sensing, visual feedback, and wireless data transmission, the system points toward wearable devices that can track physiological changes in real time without relying on disposable components.