Engineering news
It’s hoped that monitoring perspiration could eventually reduce the need for invasive procedures such as taking blood, and provide real-time information about issues such as dehydration or fatigue.
In a paper published in the journal Science Advances, a team from the University of California, Berkeley, described a new sensor design that can be rapidly manufactured using a ‘roll-to-roll’ processing technique that prints the sensors onto a sheet of plastic, like ink being printed on to a newspaper.
They used the sensors to monitor electrolytes and metabolites in sweat in volunteers as they exercised, and in others who were experiencing chemically induced perspiration.
"The goal of the project is not just to make the sensors but start to do many subject studies and see what sweat tells us – I always say 'decoding' sweat composition," says Ali Javey, a professor of electrical engineering and computer science at UC Berkeley and senior author on the paper. "For that we need sensors that are reliable, reproducible, and that we can fabricate to scale so that we can put multiple sensors in different spots of the body and put them on many subjects.”
The new sensors contain a microscopic, spiralling tube called a microfluidic, which wicks sweat from the skin. By tracking how quickly the sweat moves through the tube, sensors can tell how much a person is sweating. The tubes are also fitted with chemical sensors to detect concentrations of potassium, sodium and glucose.
The Berkeley team worked with researchers at the VTT Technical Research Centre in Finland to develop a quick means of manufacturing the sensors. "Roll-to-roll processing enables high-volume production of disposable patches at low cost," says Jussi Hiltunen of VTT. "Academic groups gain significant benefit from roll-to-roll technology when the number of test devices is not limiting the research. Additionally, up-scaled fabrication demonstrates the potential to apply the sweat-sensing concept in practical applications."