With the ability to connect wirelessly with any smartphone a new soft wearable microfluidic skin patch, that senses sweat may soon be used to monitor health during exercise and sport, with the ability to alert the wearer when they are becoming dehydrated. A new study carried out with the assistance of 21 volunteers who were all in good physical shape, was very successful in using the stretchy patch to collect samples of sweat and capturing some key markers. These markers ranged from sweat rate to glucose and even pH.
A new approach
When it comes to examining the health and fitness levels of individual’s wearable technologies offer a whole new approach. Containing electrolytes, small molecules and even proteins, sweat is an abundant source of biomarkers that is yet untapped.
These biomarkers have the potential to be utilised in the further diagnosis of diseases such as cystic fibrosis. The thin and very soft microfluidic device, which owes its design to Ahyeon Koh and colleagues, adheres to the skin allowing it to collect and then analyse sweat. The patch has several different channels and reservoirs on the surface and through these the sweat is channelled to measure several things; sweat volume, pH, lactate, glucose concentrations and chloride. This is done using colorimetric readouts. Wireless data transmission and image processing software are then employed to allow researchers to carry out an analysis of the readouts using smartphones to capture an image of the sweat patch.
The patch test
In order to put the devices through their paces they were tested on nine healthy subjects in a controlled lab setting whilst they took part in an indoor cycling session. To be able to compare these results to those that imitated real-life the patch also tested on 12 volunteers as part of a long distance outdoor cycling event. The readouts from the patch were the compared to sweat analysis results from a conventional lab and it was found that the biomarkers consistently matched. Not only that but for the duration of the test the patch remained where it had been placed and the volunteers experienced no tenderness or irritation to the skin.
The team of researchers behind the technology believe that it has the potential to be used for the analysis of other bodily fluids, like saliva and tears. They also suggested that at some point in the future it might be possible to modify the patch to assist in identifying cases of illegal drug use.