A collaborative team of researchers from Penn State and Xiangtan University have devised a health monitor for the body using a person's sweat. The simple device is a patch applied to the skin, somewhat similar to a nicotine patch.
It collects sweat from the sweat glands and analyzes biomarkers such as ph and glucose. Sweat can either be induced by exercise or from the heat of the sun.
Huanyu "Larry" Cheng, the assistant professor of engineering science and mechanics at Penn State and an author of the study, explains that the patch consists of a small vial with multiple chambers.
In the chambers is a hydrophobic, water-repelling valve made of silicone rubber, located close to the opening. The channel is coated with a hydrophilic, water-attracting material for easy collection of sweat.
According to the researchers, unlike other sweat patches that use two openings, their patch only requires one. Their design uses a single opening that reduces the chance of evaporation, leading to a longer storage time for analysis later on. The findings of the study can be found in the journal Lab on a Chip.
Easy On-the-Spot Health Analysis
Using the colorimetric approach, the researchers have assigned color-coded analytes prepositioned in the various chambers. The chemicals from glucose or pH from the sweat can then be read by the naked eye or captured by a smartphone.
Additionally, the authors of the study can examine the sweat at different points in time using separate chambers using a method called chrono-sampling.
According to Cheng, the two-valve device is more complex as it requires a clean-room technique called photolithography. The process is usually used in microfabrication to selectively arrange a thin film substrate using light to shift a photomask's geometric pattern to a light-sensitive photoresist.
On the other hand, he says that their simpler one-valve device can be made without costly equipment making use of micromachining.
Health Indicators for the Healthcare Industry and Athletics
The researchers say that their sweat patch will be of interest to the healthcare industry. In particular, those under the field of athletics might find it can be used to monitor overheating. Furthermore, it could also adjust exercise levels for the athletes' maximum performance.
Moreover, the researchers are also teaming up with a researcher at Penn State Hershey Medical School on disease monitoring. They say that the device can have one chamber color-coded for pH, a second for glucose, and a third for sodium, all of which are disease markers.
In 2019, a group of researchers from the University of California, Berkeley, developed a similar sweat patch that could measure sodium in the sweat. Additionally, it could also determine a person's sweat rate directly from the skin. The study was then published in the journal Science Advances.
The patch designed by the Berkeley scientists collects sweat at the surface of the skin. Moreover, it analyzes it in real-time, using a custom printed circuit board. The board then transmits the collected data wirelessly to a mobile phone.
Sweat enters the patch through a valve that holds sensors that can measure glucose, sodium, and potassium. The valve then leads into two spiraling tubules that measure the person's sweat rate.
