Non-invasive, 3D-printed sweat monitor for tracking health

Published in the journal ACS Sensors, the study showcases a 3D-printed health monitor capable of tracking glucose, lactate, uric acid levels, and sweat rates in volunteers. Chuchu Chen, a WSU PhD. student and first author, highlights the importance of this advancement, noting particularly that diabetes is a global problem.

"I think 3D printing can make a difference to the healthcare fields, and I wanted to see if we can combine 3D printing with disease detection methods to create a device like this."

The monitor employs a unique one-step 3D printing process, using a single-atom catalyst and enzymatic reactions to enhance signal strength and detect low levels of biomarkers. It features three biosensors that change colour to indicate specific biochemical levels.

The method of sweat analysis is a non-invasive alternative to blood sampling to enable  health monitoring. Sweat's uric acid levels can signal risks of gout, kidney disease, and heart disease, while glucose levels help manage diabetes. Lactate levels indicate exercise intensity, as Kaiyan Qiu, Berry Assistant Professor in WSU’s School of Mechanical and Materials Engineering, explained:

"Sweat rate is also an important parameter and physiological indicator for people’s health."

Measuring tiny amounts of these chemicals in sweat is challenging. Other sweat sensors exist but are often complex and require specialised equipment. This new monitor’s design, incorporating self-supporting microfluidic channels, avoids contamination issues common with traditional support structures.

Qiu elaborates: "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."

The device proved accurate and reliable in trials, comparing well with lab results. It is also comfortable for wearers and can be customised to measure additional biomarkers. The team aims to further refine the design and validation, with commercialisation as the ultimate goal. The WSU Office of Commercialisation has filed a provisional patent to protect this technology, with funding from the National Science Foundation and the Centres for Disease Control and Prevention.