Wearable Patch That Powers Itself and Reads Sweat for 21 Days

A new skin‑attached device can keep working for three weeks without a battery, thanks to wireless power from a phone or wrist reader. The patch draws electricity from the nearby device’s magnetic field and uses it to refresh its sensor surface, so it stays accurate over time. The technology was created by researchers at the University of California, Irvine and is called IREM‑W2MS3. It looks like a flexible band that sticks to the skin and analyzes sweat in real time. Instead of needing exercise or special equipment, the patch can make a person sweat on demand. It does this by activating a hydrogel inside the patch when it receives power from the reader. The sensor can detect four important molecules in sweat: cortisol, glucose, lactate and urea. These chemicals give clues about stress levels, blood sugar, exercise intensity and kidney health.Because the patch works under different temperatures, humidity levels and pH values, it can be used in everyday life. The research team tested it for 21 days and found no loss of signal quality. The key feature is the self‑cleaning surface. A low voltage pulse removes molecules that would otherwise stick to the sensor and reduce its performance. This regeneration lets the device keep measuring accurately for long periods. Researchers believe that combining wireless power, surface regeneration and multi‑marker detection could make continuous health monitoring more practical for conditions such as diabetes or kidney disease. The team has filed a patent and is exploring ways to bring the product to market.