Wearable Microfluidic Colorimetric Sweat Sensors for Real-Time Personalized Hydration Monitoring

1 page.Continuous, real-time sweat analysis is an underdeveloped field with promising applications ranging from clinical health care to athletic performance. Noninvasive, biochemical measures indicative of physical exertion, hydration, and injury risk are highly sought-after. This is demonstrated by the recent commercial release of Gatorade’s Gx Sweat Patch. Currently, microfluidic devices allow for noninvasive collection and storage of sweat through precisely engineered microchannels but lack a method to record continuous sweat rates. Sweat rate and biomarker composition are highly variant between individuals, requiring a personalized hydration feedback approach. The biomarker variance is significantly attributed to sweat rate, making rate normalized biomarker concentrations from recorded continuous sweat rates indicative of performance metrics. A low-cost and passive method to record the continuous sweat rate would enable real-time sweat loss measurement and hydration feedback. This proposed project will develop methods to accomplish this through wearable microfluidic colorimetric sweat sensors. First screening colorimetric reagent candidates will identify a timing dye that will become the basis for the colorimetric system. The identified candidate will provide color gradients for physiologically sweat rates ranging from 3 to 34 μL/hour for a collection area of r = 3 mm. Then benchtop studies will create the colorimetric system that is capable of visually quantifying the collected sweat rate in microfluidic devices. This will provide a future opportunity to develop a smartphone app for immediate analysis. Attaining continuous sweat rates will normalize biomarker concentrations which correlate to health and performance metrics and are highly coveted in the biomedical and sports science communities