Participants rode on stationary bikes to produce enough sweat for the study’s sensor to analyze. (Credit: Getty Images)

A team of researchers has demonstrated a battery-free, wireless biochemical sensor that detected the blood sugar — or glucose — humans excrete from their skin when they exercise.

The team fabricated a smart necklace — complete with a functional clasp and pendant — which, once placed around their necks, was used to monitor the glucose level of study participants as they exercised.

Instead of a battery, it works using a resonance circuit, which reflects radiofrequency signals sent out by an external reader system. After engaging in indoor cycling for 30 minutes, participants took a 15-minute break, during which they drank sugar-sweetened beverages, before resuming cycling.

The results showed the sensor tracked the glucose levels successfully, which suggests it will work to monitor other important chemicals in sweat. Additionally, the smart necklace requires only a minimum amount of sweat for the interface to work due to the miniaturized structure of the sensing interface.

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