A SKIN-PATCH that communicates wirelessly with a smartphone to provide colorimetric analysis of sweat has now been developed, which could be used to monitor health during exercise.
In a new paper, Dr Ahyeon Koh, Micro and Nanotechnology Laboratory, University of Illinois, Urbana, USA, and colleagues report on their new adhesive microfluidic device which is applied directly to the skin. The device collects the sweat produced by its user and wirelessly transmits information that allows total sweat loss, pH, lactate, chloride, and glucose concentrations to be measured.
The design of the device includes a serpentine reservoir that routes the sweat to different channels filled with colour-responsive materials allowing volume and chemistry to be assessed. The colour changes then provide readouts which are analysed by taking a picture of the device with a smartphone. Near-field communication (NFC) electronics were built into the device so that information could be automatically communicated when an external device was detected nearby.
In their paper, the authors write: “The epidermal microfluidic devices introduced here represent versatile platforms for evaluating athletic performance and monitoring health and disease status.” For example, the authors explain, the concentration of lactate in sweat is an indicator of exercise intolerance and pH levels provide an index of hydration state. The team also tested the capabilities of the device to function during strenuous exercise with 12 healthy volunteers who wore them during a 104 km outdoor cycling race. They found no problems with the device in its ability to stay attached and collect sweat while causing no discomfort or irritation to its wearer.
In future applications, the authors felt that the devices could be used in athletic training to gain insight into critical electrolyte loss to guide earlier supplementation to prevent cramping or sudden fatigue. They concluded: “In this scenario, and in others of interest, data accumulated over time from individual users could serve as the basis for the development of analytic approaches for interpreting trends in marker concentrations, with the potential to provide warning signs associated with physical activities that lead to abnormal responses.”
Jack Redden, Reporter