Our sweat, despite a portrayal of hard work, which emits a sometimes-potent smell, offers a plethora of information of what’s happening inside our body. However, collecting this sweat in a clean fashion is time-consuming and nonetheless messy. Now, researchers have created a bandage-like biosensor that collects sweat and analyzes it via a smartphone, according to a report in ACS’ journal Analytical Chemistry. The researchers hope this device can someday help diagnose diseases.
Unlike blood, sweat can be captured with less invasive techniques. Currently, researchers have developed tools such as temporary tattoos or microfluidic devices that can collect and analyze sweat. However, these practices often require wires or electronics.
In response, Tailin Xu, Li-Ping Xu, Xueji Zhang, and colleagues set their sights on creating a wearable biosensor—similar to a bandage—that samples sweat. Additionally, they wanted to implement a color-changing feature to quantify different components in the sweat.
In order to create their device, the researchers coated a flexible polyester film with a super-hydrophobic silica suspension. Then, they etched microwells into the silica layer to act as a “bucket” to collect the sweat. The bottom of the wells contain dyes that change color according to pH levels or different concentrations of chloride, glucose, or calcium. Lastly, the researchers added an adhesive back to the device so it could appropriately attach to a person’s skin.
The researchers then attached their device to an individual exercising, where the perspiration changed colors when collected in the microwells. By imaging and analyzing the colors with a smartphone, the researchers were able to determine that the individual’s sweat pH was 6.5 to 7.0, with a chloride concentration of 100 mM, and trace amounts of calcium and glucose.
In order to make the device more effective in analyzing sweat, the researchers are planning on increasing the sensitivity.
