Washington (ISJ) - Researchers at Northwestern University and University of Illinois in the USA have developed a small wearable device, which can quickly alert a person if he has any cardiac trouble.
The small device approximately five centimetre square can be placed directly on the skin and worn 24x7 for round-the-clock health monitoring, says a news release by the University.
The device uses wireless technology with thousands of tiny liquid crystals on a flexible substrate to sense heat. When the device turns colour, the wearer is alerted something is wrong.
"Our device is mechanically invisible, it is ultrathin and comfortable, much like skin itself," said Yonggang Huang, one of the senior researchers at Northwestern University. The research team tested the device on the wrists of volunteers.
"One can imagine cosmetics companies being interested in the ability to measure skin's dryness in a portable and non-intrusive way," Huang, who led the portion of the research focused on theory, design and modelling, said. "This is the first device of its kind."
The technology uses the transient temperature change at the skin's surface to determine blood flow rate, which is of direct relevance to cardiovascular health and skin hydration levels. The technology and its relevance to basic medicine have been demonstrated in the study, although additional testing is needed before it can be put to use.
"The device is very practical ? when your skin is stretched, compressed or twisted, the device stretches, compresses or twists right along with it," said Yihui Zhang, co-author of the study and research assistant professor of civil and environmental engineering at Northwestern University.
The device is an array of up to 3,600 liquid crystals, each half a millimetre square, laid out on a thin, soft and stretchable substrate. When the crystal senses temperature, it changes colour, Huang said and the dense array provides a snapshot of how the temperature is distributed across the area of the device. An algorithm translates the temperature data into an accurate health report ? all in less than 30 seconds.
With its 3,600 liquid crystals, the photonic device has 3,600 temperature points, providing sub-millimetre spatial resolution that is comparable to the infrared technology currently used in hospitals.
The infrared technology, however, is expensive and limited to clinical and laboratory setting, while the new device offers low cost and portability. The device also has a wireless heating system that can be powered by electromagnetic waves present in the air. The heating system is used to determine the thermal properties of the skin.
Source: Northwestern University
Image credit: John A. Rogers/University of Illinois