As the emerging field of wearable diagnostics continues to gain traction, a flexible sensor that analyses sweat has been developed in a collaborative effort between L’Oréal and researchers from universities across the globe. Just slightly larger than an American quarter, it functions like a tiny lab stuck to the skin. A study published this week found it worked best on sweaty bicyclists, sticking even during a long-distance race in Arizona.
"We've been interested in the development of skin-like technologies that can mount directly on the body, to capture important information that relates to physiological health," said John Rogers, a materials scientist and bioengineer at Northwestern University in Illinois, and one of a number of developers who have been working on the skin patch. "And what we've demonstrated here is a technology that allows for the precise collection, capture and chemical analysis of biomarkers in sweat and perspiration."
Because human sweat contains many of the same biomarkers as blood, it can be used as a substitute in certain instances. However, analysing sweat using a skin patch doesn't hurt like a needle, and the results can be obtained far quicker. For fitness purposes, the patch could give an early warning that it's time for the wearer to hydrate, and with additional research, Rogers envisions a more sophisticated purpose, such as real-time monitoring of how the body adjusts during military training, or even to screen people for diseases such as diabetes or cystic fibrosis.
The patch’s functionality is simple: stick the patch on your skin and start moving. Tiny channels collect the wearer’s perspiration and route it to different compartments where it interacts with chemicals that change colour to reflect sweat loss, the perspiration acidity level, and concentrations of chloride, glucose and lactate. Designed for one-time use, it can even send its findings to your smartphone – just hold it over the patch and an accompanying app will interpret the colours present.
Though the device is primarily aimed at athletes, other industries have expressed an interest in the sweat-based technology. "Cosmetics companies are interested in sweat using these devices in their research labs to evaluate their antiperspirants and deodorants and so on,” Rogers said. “So sweat loss and sweat chemistry is interesting in that domain, as well. And then we have contracts with the military that are interested sort of in continuous monitoring of health status of war fighters."