Very Thin Tattoo-Like Wearable Patch Monitors and Diagnoses Health Problems from Sweat

Image credit: John Rogers Lab, Northwestern University

In the near future, you’ll be able to learn about your health condition by simply sticking a patch on your skin.

Researchers at Northwestern University developed a wearable device that can monitor and diagnose health problems by analyzing the sweat on your skin.

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The device is a wearable patch that measures the chemical contents of sweat on the skin. It could be used to screen for cystic fibrosis, and give athletes real-time performance data.

While fitness trackers like Apple Watch and Fitbit can track your health data, these devices are rigid and bulky. The new device, developed at John Rogers’ lab, is so thin and flexible that it looks like a temporary tattoo. It adheres to the skin to analyze the chemistry of your sweat. It detects key biomarkers in sweat and sends the data wirelessly to a smartphone app. The device can collect data on wearer’s pH, sweat rate, chloride levels, glucose and lactate – high levels of which could signal cystic fibrosis, diabetes or a lack of oxygen.

“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 architect of the device.

sweat sensor
Image credit: John Rogers Lab, Northwestern University

Some similar devices in development use electric sensors to read chemicals. Others rely on calorie count, in which the intensity of the color in the readout matches the concentration of the chemical being monitored. The new device delivers all of that in a battery-free and wireless form, reports the New York Times.

“This looks like the first version in which they integrated all of it in one device,” said Martin Kaltenbrunner, an engineering professor at Joannes Kepler University Linz, in Austria, who was not involved in the research. “The level of technology that is in this paper is very, very advanced.”

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Sweat naturally flows into the device’s very tiny holes located at the base. The sweat then travels through a network of valves and microchannels, each roughly the width of a human hair, and accumulates into a tiny reservoir. Each reservoir has a sensor that reacts with chemicals like lactate or glucose found in the sweat.

“That’s basically it,” Dr. Rogers said. “There’s nothing that penetrates the skin, and there’s no power supply that’s driving flow.”

The device was described in the journal Science Advances.