An ultra-thin skin-like patch that mounts directly onto the skin like a temporary tattoo combines electronic components for sensing, medical diagnostics, communications, and human-machine interfaces. The skin-mounted electronic innovation was developed by a team of researchers led by John A. Rogers, professor of engineering at the University of Illinois in collaboration with Northwestern University engineering professor Yonggang Huang.

The 'smart skin'(http://bit.ly/rSgVwj) circuit bends, wrinkles, and stretches with the mechanical properties of skin. The researchers demonstrated their concept through a diverse array of electronic components mounted on a thin and rubbery substrate, including sensors, LEDs, transistors, radio frequency capacitors, wireless antennae, and conductive coils and solar cells for power.

Electronics mounted directly to the skin, with no need for wires, conductive gel or pins. They bend, stretch and deform with the same mechanical propertis of skin, granting the wearer comfort and freedom of movement. Photo: John Rogers

The skin-mounted electronics have many biomedical applications, including EEG and EMG sensors to monitor nerve and muscle activity. In addition to gathering data, skin-mounted electronics could provide the wearers with added capabilities. For example, patients with muscular or neurological disorders, such as ALS, could use them to communicate or to interface with computers. The researchers found that, when applied to the skin of the throat, the sensors could distinguish muscle movement for simple speech. The researchers have even used the electronic patches to control a video game, demonstrating the potential for human-computer interfacing.

The collaboration resulted in a device geometry the researchers call filamentary serpentine, in which the circuits for the various devices are fabricated as tiny, squiggled wires. When mounted on thin, soft rubber sheets, the wavy, snakelike shape allows them to bend, twist, scrunch and stretch while maintaining functionality.

The researchers are working to integrate the various devices mounted on the platform so that they work together as a system, rather than as individually functioning devices, and to add Wi-Fi capability.

"The vision is to exploit these concepts in systems that have self-contained, integrated functionality, perhaps ultimately working in a therapeutic fashion with closed feedback control based on integrated sensors, in a coordinated manner with the body itself," Rogers said.

The National Science Foundation and the Air Force Research Laboratory supported the work.