Patch for sweat analysis

Like other biological fluids, sweat contains a huge amount of information about what is happening in the body. However, collecting this fluid for analysis, usually by draining or absorption from the surface of the skin, can be a lengthy and unpleasant procedure. To facilitate this task, a group of researchers from the United States and China has developed a biosensor in the form of a patch that not only collects, but also, using a smartphone, analyzes the composition of sweat.

The patch is a biosensor before (left) and after (right) sweating.

Compared to many other biological fluids, such as blood, sweat provides opportunities for non-invasive diagnosis of health conditions. Previously, researchers have already offered various tools for collecting and analyzing sweat, such as tattoos and microfluidic devices, but their functioning usually requires wires, as well as electronic or other complex devices. The authors wanted to make the device as easy to use as possible.

To do this, they coated an elastic polyester film with an extremely hydrophobic suspension of silicon oxide. After that, microlunks were etched into the silicon oxide layer to collect sweat. Dyes were applied to the bottom of the wells, changing color depending on the level of acidity (pH), the concentration of glucose and chlorine and calcium ions. An adhesive base was applied to the film, after which the resulting patch was glued to the volunteer's skin. During training, sweat accumulated in microlunks and the corresponding holes on the upper surface of the patch changed color. Processing the patch image using a smartphone allowed the researchers to determine that the pH of sweat was 6.5-7, the concentration of chlorine ions was about 100mmol, and glucose and calcium were contained in sweat in residual amounts. Currently, researchers are working on increasing the sensitivity of the device.

Article by Xuecheng He et al. Flexible and Superwettable Bands as a Platform towards Sweat Sampling and Sensing is published in the journal Analytical Chemistry.

Evgenia Ryabtseva, portal "Eternal Youth" http://vechnayamolodost.ru based on the materials of the American Chemical Society: Biosensor 'bandage' collects and analyzes sweat.