Sticker-Like Thin Wearable Sensor Monitor Biomarkers without Needing External Power Source

Sensor measures biomarkers
Image credit: John Rogers Lab, Northwestern University

Soft wearable sensors that intimately adhere to the human body can be successfully used continuously collect vital health data. Scientists have been creating wearable skin-like electronics for several years now. However, powering them in a user-friendly manner is still challenging. Wearable devices that are used for collecting health data require bulky batteries or tethered to an external power source.

Researchers from Northwestern University have tackled this problem by developing self-powered sensing elements and a set of compact electronics to transmit data and receive power.

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The sticker-like sensor, described in the journal Science Advances, can measure pH, glucose, chloride, and other biomarkers in sweat in real time, and most importantly, it doesn’t require any battery. Researchers believe their new sensor can potentially be used in sports medicine or as a glucose monitor for people with diabetes.

This is how it works. The disposable sticker absorbs sweat on the wearer’s skin and sends it to a chamber. Some of the chambers measure the volume of sweat; others contain dyes that change color in response to pH or chloride levels, reports C&N.

Sticker sensor
Image credit: John Rogers Lab, Northwestern University

“It fits into a broader trend that you’re seeing in medicine, which is personalized, tailored approaches to treatment and delivery of care,” said John Rogers, a biomedical engineer at Northwestern University in Illinois and the key designer of the device.

Some chambers in the device contain electrochemical reagents that respond to glucose or lactate, producting a tiny local voltage that can be read out by electronics on the sticker. When the wearer stands near an antenna or swipes a phone over the sensor, flexible circuits within the sensor pick up a small amount of power from emitted radio waves and use the resulting electrical pulses to read out the electrochemical sensors and transmit the data.

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When working out, an individual’s sweat could tell if that person is dehydrated or their cells have stopped burning calories aerobically. Rogers’s start-up Epicore Biosystems has partnered with L’Oréal and Gatorade to develop consumer versions of the pH and electrolyte sensors.