Don't Sweat the Small Stuff

More than just a fashion choice, a new wearable sensor, developed by researchers at the Tokyo University of Science, Japan, can monitor sweat electrolytes using a heat-transfer-based textile (1).

“The proposed sensor can be transferred to fiber substrates, and thus can be incorporated into textiles such as T-shirts, wristbands, and insoles,” said corresponding author and Associate Professor Isao Shitanda in a press release (2).

Screen-printed ion sensors were fabricated using heat-transfer printing and polyester films. The innermost layers of the design comprise chloride selective and reference electrode membranes to minimize the risk of allergic reactions and irritations. The textile-based sensor also contains a cloth compartment making it lightweight, soft, and non-irritating when attached to the skin. This textile technology enables even and quick distribution of sweat between the electrodes, establishing and maintaining electrical contact.
 

The researchers reported a lower detection limit of 1 × 10^-4.3 and noted good ion selectivity/stable responses independent of acidity and alkalinity alterations, especially in the pH of sweat.

On-body testing revealed that the sensor signals – transmitted in real time – can be indicative of dehydration. “Since chloride is the most abundant electrolyte in human sweat, measuring its concentration provides an excellent indicator of the body’s electrolyte balance and a useful tool for the diagnosis and prevention of heat stroke,” explained Shitanda (2).