New electronic tattoos, as soft and pliable as real skin, could monitor heart, brain and muscle activity for any changes, and automatically detect any problems.
"We're trying to bridge that gap, from silicon-wafer based electronics to biological, 'tissue-like' electronics, to really blur the distinction between electronics and the body," study researcher John Rogers, of the University of Illinois Urbana-Champaign, said in a statement.
Because the tattoos could monitor and deliver electrical impulses in living tissue, they will hopefully open a door to a whole range of what Rogers calls "bio-integrated" medical devices.
For instance, the electronic tattoos could be use to prevent epileptic seizures, or to monitor heart functions in real-time. These are areas where traditional electronic devices are a tough squeeze. By implanting the flexible device onto or around the skin layer, doctors can make movable, thin devices instead of bulky and brittle implants. [Video: How Electronic Tattoo Works]
The temporary digital tattoos resemble small computer chips and are made of tiny, wavy silicon structures containing circuits that are thinner than a human hair; they attach directly to the skin and can bend and stretch with the body. The embedded electrodes can simplify medical diagnostics, act as a computer input device and control computers through speech if implanted on the throat.
Prototypes of the circuits are being tested that can detect muscle movement, heart activity and brain waves just by being placed on the surface of the skin like temporary, stick-on tattoos. The prototypes can detect the body's electrical activity nearly as well as conventional, rigid electrode devices in use currently.
According to study researcher Yonggang Huang, of Northwestern University, the main challenge they faced was to make electronics as soft as skin. "The mechanics behind the design for serpentine-shaped electronics makes the device as soft as the human skin. The design enables brittle, inorganic semiconductors to achieve extremely vast stretchability and flexibility. Plus, the serpentine design is very useful for self adhesion to any surface without using glues," Huang said in a statement.
To monitor the heart, these elastic electronics could be woven into a mesh that gets wrapped around the heart like a stocking. "It's designed to accommodate the motion of the heart but at the same time keep active electronics into contact with the tissue," explains Rogers. "As the skin moves and deforms, the circuit can follow those deformations in a completely noninvasive way."
Roger's experimental model connects to the heart's electronic circuitry and can detect when its beating goes awry. The model then sends an electronic current in to correct the heartbeat. He hopes to work on a similar implant that could monitor and control current in the brain, which could help treat epileptic seizures.
The devices could also be useful in the special case of babies, who don't do well with larger, rigid sensors, Rogers said: "They are such tiny humans that this epidermal form of electronics could really be valuable in the monitoring of these babies in a manner that is completely noninvasive and mechanically 'invisible.'"