Flexible Device Enables Sweat Gland Stimulation and Simultaneous Biosensing

Human sweat is rich in biomarkers that can be used to monitor a range of health conditions, from diabetes to genetic disorders. Many users prefer sweat sampling over blood collection because it is painless. However, one must engage in intense physical activity to produce enough sweat to extract sufficient nutrients or hormones from sweat for testing. This requirement is particularly challenging for those with limited mobility. Researchers have now developed a new type of sweat monitoring device that stimulates sweat production through drug delivery to the skin, eliminating the need for physical exertion.

The device was created through a collaboration between researchers at the Korea Institute of Science and Technology (KIST, Seoul, South Korea) and Northwestern University (Evanston, IL, USA). This innovative device applies a current to a drug-containing hydrogel, which then delivers the drugs directly to the sweat glands. The device is flexible, small, and soft, making it easy to attach to the skin. Sweat stimulated by the drug is channeled into microfluidic channels within the device and analyzed for biomarkers using integrated biosensors. This system facilitates the analysis of sweat biomarkers without the cumbersome need for hospital visits, reduces the risk of biomarker contamination during testing, and enhances the accuracy of the results. The device was tested on infants diagnosed with cystic fibrosis, measuring the chloride concentration in their sweat. The findings matched the accuracy of traditional sweat analysis methods used in hospitals, achieving over 98% accuracy.

Image: The device stimulates sweat production through drug delivery to the skin (Photo courtesy of KIST)

Moreover, the stability of the device on the skin was verified by monitoring skin temperature and pH levels. Given that cystic fibrosis primarily manifests during infancy, continuous monitoring of disease progression and the infant's physical condition is crucial. This device enables easy monitoring at home, significantly reducing the psychological and physical burden on young patients and their caregivers. Beyond its immediate application, this device represents a significant advance in the field of non-invasive disease monitoring technology using sweat, applicable not only to infants but also to healthy adults. Additionally, the technology used for drug delivery through the skin could potentially enhance the effectiveness of localized drug treatments for skin conditions or wounds, thus speeding up the healing process.

"Through two years of collaborative research with Northwestern University, we have not only addressed the limitations of existing methods for inducing sweat but also achieved success in clinical research, bringing us one step closer to commercialization," said Dr. Kim Joohee from KIST.

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