Monitoring sweat through sweat-analyzing devices has a huge potential in the field of physical fitness and medical applications, states a study by a team of researchers from different universities in the Republic of Korea—Hanyang University, Korea Institute of Science and Technology, Seoul National University, and Yonsei University; published in Nature Communications.
Using sweat-analyzing devices can aid us in various ways: maintain hydration during workouts, recognize pre-symptoms of heart attacks and hypoglycemic shocks, provide information on blood composition, monitor health conditions in a non-invasive manner, and can be used for a long time since they are non-invasive, mentions the study.
In their study, the team focused on two improvements, which they felt were required at the time, in sweat-analyzing devices: increasing operating time (tackling the problem of less number of sweat sensors and mixing of old and new sweat) and constructing wireless epidermal (of the skin) patches that were energy efficient.
The researchers created a wireless patch (sweat VIA sensor) that generates ‘spike’ (signal) patterns on exposure to sweat, these spike patterns’ frequency is proportional to the rate of perspiration (sweating). These sweat-analyzing devices have open, truncated cone-shaped channels with electrodes; where sweat would enter from the base of the cone, travel away from the skin, through the cone, and would be absorbed by a hydrophilic (water-liking) layer at the cone’s open, truncated end.
The team aimed to create an event-based data transmission method, the event being sweat filling and emptying the cones in the epidermal patch. As the sweat would enter and leave the cones, a spike-like signal would be generated by the epidermal patch with the help of the electrodes embedded in the cone.
This approach utilizes only 0.63% of the energy consumed when compared to continuous data transmission with operation time being more than 24 hours, claim the researchers. The team believes that their sweat-analyzing device can be coupled with various on-skin sensors and computing technologies for sustainable, intelligent healthcare.
In a recent study by a team of researchers from University of Hawaiʻi at Mānoa, USA, published in Science Advances, the team developed a 3D-printed skin patch called the ‘sweatainer’. This patch is an epidermal microfluidic (using microchannels for fluids to pass through), or an ‘epifluidic’, device with valves that can control the sweat’s flow through the microchannels. This sweat-analyzing device is transparent and has components with sizes lesser than 100 micrometers.
The researchers were able to test the sweat-analyzing device’s functioning during stationary cycling, where they demonstrated multiple sweat sample collection and analysis of the sweat chloride concentration using colorimetric analysis (determining concentration of compounds as a factor of change in color of the liquid of interest).
Moreover, the team believes that their sweat-analyzing device is a big step forward in sweat-based analysis and can be used in diagnostics, biobanking (collecting body fluids for research), and with clinical chemistry experiments. The use of 3D printing can aid in developing customized designs of sweat-analyzing devices, integrating the device into clinical studies, and using very low concentrations of sweat.
