Researchers from Northwestern University and the University of Illinois at Urbana-Champaign have developed a health monitor capable of tracking heart and skin condition while worn discretely on the skin. Measuring around 5 cm squared (0.8 in sq), the patch is designed to be inconspicuous and alert the user to conditions ranging from dry skin to cardiovascular problems.

The skin-like patch is intended to be worn around the clock, making its comfort a major design focus. It comprises 3,600 liquid crystals, each measuring around 0.5 mm squared that lay atop a stretchable substrate. When worn, these crystals serve as temperature points, monitoring temperature changes on the skin's surface.

By tracking these changes in temperature, the device can identify the wearer's blood flow rate, which is indicative of cardiovascular health, while also monitoring skin hydration. When temperature change is detected, the patch changes color to alert the user that something is amiss. An algorithm then turns the temperature data into decipherable health information, a process the researchers say takes around 30 seconds.

"One can imagine cosmetics companies being interested in the ability to measure skin’s dryness in a portable and non-intrusive way,” said Yonggang Huang, one of the senior researchers. "This is the first device of its kind.”

Electromagnetic waves in the air power the device's wireless heating system, which is used to gauge the thermal properties of the skin. The researchers claim with its 3,600 temperature points, the spatial resolution of the device is comparable to that of infrared technology, though with a much lower price tag and better portability.

“These results provide the first examples of ‘epidermal’ photonic sensors,” said John A. Rogers, the paper’s corresponding author and professor of materials science and engineering at the University of Illinois. “This technology significantly expands the range of functionality in skin-mounted devices beyond that possible with electronics alone.”

The research was published in the journal Nature Communications.

View gallery - 3 images