AsianScientist (Aug. 8, 2016) – An international research team has developed a battery-free, wireless health monitoring patch that can be laminated onto the skin. Details of their device were published in Science Advances.
Commercially-available wearable devices currently used to monitor temperature, blood pressure, oxygenation, blood flow and other factors usually consist of hard components mounted on straps and worn on the wrist. As such, they are ultimately limited by the size and weight of the batteries used for their power supply.
More recent wearable devices have stretchable, ‘skin-like’ properties, but these also require batteries, hard-wired connections or both to enable operation.
Here, Mr. Kim Jeonghyun from Hanyang University in Seoul and colleagues have designed an ultra-thin, stretchable electronic circuit that adheres to the skin like a temporary tattoo. Instead of relying on batteries for power, the device works using wirelessly transmitted power from an external device.
Once wirelessly powered, optoelectric sensors in the device are activated, causing LEDs to illuminate the underlying skin. Some of this light penetrates into the skin but is ultimately reflected back to the device, where it is captured, measured, and transmitted to an external reader. Data from LEDs that emit in the red and the infrared region of the spectrum can be correlated to blood oxygenation, while the time variation of flashing LEDs yields information about heart rate.
Testing the patch in a small group of volunteers, the researchers demonstrated that the device is able to measure changes in skin color, heart rate, blood oxygen level and UV radiation exposure. The battery-free operation allows the thin circuit to be engineered in a much thinner, lighter and more wearable format than would otherwise be possible, opening up the possibility for use in a variety of healthcare applications.
This specific type of wireless scheme, known as near-field communication, is similar to that used for wireless payments such as Apple and Android Pay, making the device compatible with smartphones, tablets and other consumer electronics.
The article can be found at: Kim et al. (2016) Battery-free, Stretchable Optoelectronic Systems for Wireless Optical Characterization of the Skin.
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Source: Science Advances; Photo and Video: Kim Jeonghyun et al.
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