Sweat Health Monitor Measures Levels of Disease Markers

Sweat contains critical metabolites indicative of various health conditions, and unlike blood, collecting sweat is non-invasive. Levels of uric acid in sweat can indicate risks for gout, kidney disease, or heart disease, while glucose and lactate levels are key indicators for monitoring diabetes and exercise intensity, respectively. However, these chemicals are present in minute amounts in sweat, making them difficult to measure. Despite numerous developments, existing sweat sensors are complex, requiring specialized fabrication equipment and expertise. These sensors must also maintain flexibility and stretchability. Now, a 3D-printed wearable health monitor can effectively measure important biochemicals in sweat during physical activity, promising a simple, non-invasive method for tracking health and diagnosing prevalent conditions.

Developed by a team at Washington State University (Pullman, WA, USA), this proof-of-concept health monitor was manufactured using a novel one-step 3D printing process. It utilizes a single-atom catalyst and enzymatic reactions to amplify signals and accurately measure low biomarker levels. The device includes three biosensors that change color to reflect concentrations of specific chemicals. Built with extremely fine channels, the monitor assesses both the rate of sweating and the concentrations of biomarkers without needing any supporting structures, which avoids potential contamination issues during removal.

Image: The health monitor is flexible and designed to be comfortable to wear (Photo courtesy of Washington State University)

Tests on volunteers have shown that this monitor consistently and accurately tracks glucose, lactate, and uric acid levels, as well as sweat rate during exercise, with the results matching lab performance. Originally designed to measure three biomarkers, the system's flexibility allows for the addition and customization of more biomarkers based on specific health monitoring needs. Volunteers also found the monitor comfortable to wear. The research team is currently focused on refining the design and validation of the device and is exploring opportunities to commercialize the technology.

“Sweat rate is also an important parameter and physiological indicator for people’s health,” said Kaiyan Qiu, Berry Assistant Professor in WSU’s School of Mechanical and Materials Engineering. “We need to measure the tiny concentrations of biomarkers, so we don’t want these supporting materials to be present or to have to remove them. That’s why we’re using a unique method to print the self-supporting microfluidic channels.”

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Washington State University