UC Irvine's Sweat Patch Tracks Health

UC Irvine researchers said on May 13 that they had built a flexible skin patch that reads chemical signals in sweat without a battery. The device, described in a study published the same day in *Nature Biomedical Engineering*, is designed to track health markers continuously outside a lab or clinic. The patch works with a standard Android smartphone or a custom watch-like reader, according to the university and the journal. Researchers said it can monitor cortisol, glucose, lactate and urea in sweat for long periods in everyday settings. ### How does the patch work without a battery? The UC Irvine team said the sensor is wireless and battery-free because it draws power from a smartphone or nearby electronic reader. That setup removes the need to recharge the patch like a smartwatch or other wearable, according to a university report on the project. (news.uci.edu) The study in *Nature Biomedical Engineering* described the device as a “wireless, battery-free” multimodal sweat sensor that regenerates in place and supports real-time monitoring. UC Irvine named the system the In-Situ Regeneratable, Environmentally Stable, Multimodal, Wireless, Wearable Molecular Sweat Sensing System, or IREM-W2MS3. (news.uci.edu) ### What exactly is it measuring in sweat? UC Irvine said the patch simultaneously tracks cortisol, glucose, lactate and urea. The university linked those biomarkers to stress response, metabolic activity, physical exertion and kidney function. Rahim Esfandyarpour, the study’s senior author and a UC Irvine assistant professor of electrical engineering and computer science, said the device was built for “stable, ongoing sweat monitoring and health profiling.” In the university’s account, he said chronic illnesses and stress-related conditions affect hundreds of millions of people worldwide and require early diagnosis and consistent monitoring. (news.uci.edu) ### Why did the researchers focus on regeneration? Rahim Esfandyarpour said one of the main technical problems in long-term wearable biosensing is that sensing surfaces lose performance after repeated measurements because molecules stay bound to the sensing layer. He said the patch addresses that by restoring its sensing surface, allowing repeated use over longer periods. (news.uci.edu) The *Nature Biomedical Engineering* paper said the sensor “regenerates in situ” and can be used for continuous biomarker monitoring in everyday settings. That regeneration feature is central to the claim that the patch can move beyond short, one-time measurements. ### How long can it be worn? The journal summary said the sensor enables monitoring in naturalistic settings for up to seven days. (news.uci.edu) A separate report based on the UC Irvine release said the device monitored multiple biomarkers continuously for 21 days, but the primary paper summary available in search results specifies up to seven days. UC Irvine said the patch is intended to be worn continuously outside laboratory or clinical settings. (nature.com) The university also said the device can induce perspiration when needed, a feature meant to support use when natural sweating is limited. ### What do the researchers say it could be used for? UC Irvine said the platform could support future work in chronic disease management, stress and mental health monitoring, sports performance, preventive medicine, early disease-detection research and remote community health monitoring. (nature.com) Those are research-stated applications, not clinical approvals. (news.uci.edu) The Samueli School of Engineering funded the project, according to UC Irvine. The next public reference point for the work is the *Nature Biomedical Engineering* article published on May 13, 2026, which identifies the device and the biomarkers it tracks. (news.uci.edu)