Temporary tattoos don't just look cool: A special one could end up saving your life by monitoring your vital signs.

An international team of researchers has designed an ultra-thin electronic device that attaches to the skin like a temporary tattoo and measures heart rate and other vital signs. This device, which has the thickness of a human hair, works without the bulky electrodes used in current hospital monitoring, according to a new study in the Aug. 11 issue of the journal Science.

The electronic skin is designed by John Rogers at the University of Illinois at Urbana-Champaign and colleagues. It sits on a layer of rubbery polyester built to have mechanical properties matching those of natural skin.

"Our goal was to develop an electronic technology that could integrate with the skin in a way that is mechanically and physiologically invisible to the user," Rogers said in a statement. "It's a technology that blurs the distinction between electronics and biology."

But there are other benefits to this new device.

Researchers said that that same device could potentially be used as an electronic bandage to speed up healing in wounds, burns, and other skin conditions. It could even provide touch sense to prosthetic devices such as artificial legs or arms, a press release noted, adding that it will eliminate the complicated wiring used in current hospital monitoring that can be an inconvenience for both patients and doctors.

Presently, the electrodes on heart monitors, for example, are gel-coated adhesive pads, which can cause people with sensitive skins to develop a rash from the adhesive.

According to the Advancing Science, Serving Society, or AAAS, Web site, the electronic skin is applied like a temporary tattoo. The device sticks to the skin by sheer attraction and weak forces called van der Waals forces, which exist between molecules of the same substance, hold the device in place but don't interfere with normal skin motion.

Therefore, the device can bend, wrinkle, and stretch without being damaged.

As for its middle layer, there is a metal, semiconductor, and insulator components needed for sensors, electronics, power supply, and light-emitting components.

The researchers tested the electronic skin on participants and showed that it works for up to 24 hours or more on the arm, neck, forehead, cheek, and chin. And best of all, it doesn't irritate the skin.

The team also used the device to take measurements of the electrical activities of the leg muscles and heart of participants. They found that the device's signals matched signals taken simultaneously with the conventional setup of bulk electrodes, conductive gel, and tape, the press release said.

With results like these, the suggestion is that electronic skins could one day replace the conventional hospital monitoring techniques. Researchers are now exploring commercial partnerships to develop the technology.

"Our ultimate goal is to generate commercial products that can be a broad benefit to society," Rogers said. "We will judge success by the extent to which this technology makes it into the wider world."

Watch this video of an epidermal electronic system, mounted on a commercial temporary transfer tattoo. Submitted to the AAAS by Rogers, it shows extreme flexibility and deformation after being attached to the skin.