Northwestern researchers create color-changing skin patch to detect health issues

Alice Yin, Assistant Campus Editor

Researchers from Northwestern and the University of Illinois at Urbana-Champaign have developed a wearable skin patch that changes color when cardiovascular and skin issues arise.

The small wireless device is mechanically invisible, wearable 24 hours a day, and stretches and shrinks with the wearer’s skin. It uses up to 3,600 liquid crystals that detect body heat and monitor potential health problems and dry skin.

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

Researchers tested the device on the wrists of subjects. They’ve concluded that it will be useful in medicine, although it needs additional testing before a usable model is made.

The liquid crystals can detect blood flow rate and skin hydration. An algorithm interprets these findings and displays a color demonstrating the temperature distribution on that patch of skin within 30 seconds.

With thousands of temperature points covered by the patch to detect, the device rivals infrared technology used in hospitals, while being more practical and low-cost. Infrared technology usually can only be used in clinical and laboratory settings due to constraints and cost. This new device is wireless and photonic, which means it is a semiconductor powered through light manipulation.

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

The device can also utilize electromagnetic waves present in the air to power a heating system, detecting properties such as the skin’s thermal condition.

The paper is titled “Epidermal Photonic Devices for Quantitative Imaging of Temperature and Thermal Transport Characteristics of the Skin,” and was published Sept. 19.
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