Thin and soft adhesive patches that move and stretch with a person's skin can use inexpensive, readily available electronics to create complex wireless health monitors, U.S. researchers say.
Applied to the skin, a unique construction method of origami-like folded wires will allow such devices to flex and bend without being hampered by rigid electronic parts.
By monitoring health parameters and sending update wirelessly to a computer or cellphone, they could revolutionize medical monitoring processes such as EEG or EKG testing, engineers at Northwestern University and the University of Illinois reported in the journal Science.
"We designed this device to monitor human health 24/7, but without interfering with a person's daily activity," Northwestern University Professor Yonggang Huang says.
"It is as soft as human skin and can move with your body, but at the same time it has many different monitoring functions," Huang added. "What is very important about this device is it is wirelessly powered and can send high-quality data about the human body to a computer, in real time."
Comparing the flexible sensors with traditional EEG and EKG monitors, the researchers discovered the wireless devices performed as well as conventional type sensors, while patients found them much more comfortable.
The researchers had previously developed skin sensors utilizing custom ultrathin and specially designed components, but have turned to commercially available electronic chips to achieve the same results at lower costs.
The researchers turned to microfluidic design to overcome the challenge of combining relatively large and stiff commercial electronic chips with the elastic material of the skin patches.
The patches are made of fluid-filled thin plastic envelopes, with the chip parts sitting on small, elevated support points.
That allows them to be bonded to the patch beneath will still giving the patch the ability to move and stretch with a person's body movements, they said.
The chips are connected with tiny wires configured like origami figures, which can unfold to allow movement in all directions while maintaining contact with the chips.
Since chips can't stretch, that task is given instead to the connecting wiring, the researchers say.
"The application of stretchable electronics to medicine has a lot of potential," Huang says. "If we can continuously monitor our health with a comfortable, small device that attaches to our skin, it could be possible to catch health conditions before experiencing pain, discomfort and illness."
