and Medicine for Seniors
New Skin-Like Device Warns of
Cardiovascular, Skin Health Problems
Ease of use, small size may appeal to many senior
citizens, frequent victims of cardiovascular problems; monitors blood
By Megan Fellman
Alerts wearer to any heart trouble or dry skin,
stretches, compresses and twists, just like skin, 24/7 health
Sept. 25, 2014 - A new wearable
medical device can quickly alert a person if they are having
cardiovascular trouble or if it’s simply time to put on some skin
moisturizer, reports a Northwestern University and University of
Illinois at Urbana-Champaign study supported by the National Science
The small device, approximately
five centimeters square (about two inches), can be placed directly on
the skin and worn 24/7 for around-the-clock health monitoring. The
wireless technology uses thousands of tiny liquid crystals on a flexible
substrate to sense heat. When the device turns color, the wearer knows
something is awry.
“Our device is mechanically
invisible -- it is ultrathin and comfortable -- much like skin itself,”
Yonggang Huang, one of the senior
researchers. The research team tested the device on people’s wrists.
“One can imagine cosmetics
companies being interested in the ability to measure skin’s dryness in a
portable and non-intrusive way,” Huang said. “This is the first device
of its kind.”
Huang led the portion of the
research focused on theory, design and modeling. He is the Joseph
Cummings Professor of Civil and Environmental Engineering and Mechanical
Engineering at Northwestern’s
McCormick School of Engineering and Applied
The technology and its relevance to
basic medicine have been demonstrated in this study, although additional
testing is needed before the device can be put to use. Details are
online in the journal Nature
“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-first author of the
study and research assistant professor of civil and environmental
engineering at Northwestern.
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. (When skin is dehydrated, the thermal conductivity
The device is an array of up to
3,600 liquid crystals, each half a millimeter square, laid out on a
thin, soft and stretchable substrate.
When a crystal senses temperature,
it changes color, 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.
“These results provide the first
examples of ‘epidermal’ photonic sensors,” said
John A. Rogers, the paper’s
corresponding author and a Swanlund Chair 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.”
Rogers, who also is director of the
Seitz Materials Research Laboratory, led the group that worked on the
experimental and fabrication work of the device. He is a longtime
collaborator of Huang’s.
With its 3,600 liquid crystals, the
photonic device has 3,600 temperature points, providing sub-millimeter
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 settings, 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.
The title of the paper is
“Epidermal Photonic Devices for Quantitative Imaging of Temperature and
Thermal Transport Characteristics of the Skin.” In addition to Zhang, Li
Gao and Viktor Malyarchuk of the University of Illinois at
Urbana-Champaign are co-first authors.