A Soft, Wearable Microfluidic Device for the Capture, Storage, and Colorimetric Sensing of Sweat

By Ahyeon Koh, Daeshik Kang, Yeguang Xue, Seungmin Lee, R. Pielak, Jeonghyun Kim, Taehwan Hwang, Seunghwan Min, Anthony R. Banks, P. Bastien and 12 more. Science Translational Medicine, 2016

1,135 citations recorded by the source corpus.

A soft, skin-mounted microfluidic device captures microliter volumes of sweat and quantitatively measures biochemical markers by colorimetric analysis. Better health? Prepare to sweat Wearable technology is a popular way many people monitor their general health and fitness, tracking heart rate, calories, and steps. Koh et al. now take wearable technology one step further. They have developed and tested a flexible microfluidic device that adheres to human skin. This device collects and analyzes sweat during exercise. Using colorimetric biochemical assays and integrating smartphone image capture analysis, the device detected lactate, glucose, and chloride ion concentrations in sweat as well as sweat pH while stuck to the skin of individuals during a controlled cycling test. Colorimetric readouts showed comparable results to conventional analyses, and the sweat patches remained intact and functional even when used during an outdoor endurance bicycle race. The authors suggest that microfluidic devices could be used during athletic or military training and could be adapted to test other bodily fluids such as tears or saliva. Capabilities in health monitoring enabled by capture and quantitative chemical analysis of sweat could complement, or potentially obviate the need for, approaches based on sporadic assessment of blood samples. Established sweat monitoring technologies use simple fabric swatches and are limited to basic analysis in controlled laboratory or hospital settings. We present a collection of materials and device designs for soft, flexible, and stretchable microfluidic systems, including embodiments that integrate wireless communication electronics, which can intimately and robustly bond to the surface of the skin without chemical and mechanical irritation. This integration defines access points for a small set of sweat glands such that perspiration spontaneously initiates routing of sweat through a microfluidic network and set of reservoirs. Embedded chemical analyses respond in colorimetric fashion to markers such as chloride and hydronium ions, glucose, and lactate. Wireless interfaces to digital image capture hardware serve as a means for quantitation. Human studies demonstrated the functionality of this microfluidic device during fitness cycling in a controlled environment and during long-distance bicycle racing in arid, outdoor conditions. The results include quantitative values for sweat rate, total sweat loss, pH, and concentration of chloride and lactate.

Subfields: Biomedical Engineering, Organic Chemistry

View Paper: https://www.semanticscholar.org/paper/84a9944cb082f216174ed23bb7d69071b54fd62b

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In Biomedical Engineering

Citations in the corpus

Battery-free, wireless sensors for full-body pressure and temperature mapping (2018, background): “The overall soft, deformable construction affords skin-compatiblemechanics, as described in the context of related devices with simple authentication functionality (28).”
Skin-interfaced systems for sweat collection and analytics (2018, background): “Although, to date, such colorimetricmeasurements of chloride, glucose, lactate, andpH levels have limitations in accuracy compared to conventional laboratory techniques, they are promising for use in ambulatory exercise settings at a low cost and without requiring capital equipment (53), and future ”
Wearable Health Devices—Vital Sign Monitoring, Systems and Technologies (2018, positive): “[57] have developed a epidermal sweat patch with microfluidic channels able to monitor sweat rate and uses biomarkers to monitor lactate, chloride, pH and glucose levels.”
A Critical Review of Consumer Wearables, Mobile Applications, and Equipment for Providing Biofeedback, Monitoring Stress, and Sleep in Physically Active Populations (2018, background): “Sweat pads/patches have been developed at academic institutions for measuring skin temperature, pH, electrolytes, glucose, and cortisol (Gao et al., 2016; Koh et al., 2016; Kinnamon et al., 2017).”