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New Electronic Sensors Stick To Skin As Temporary Tattoos

A new type of sensor uses flat, flexible electronics printed on a thin rubbery sheet, which can stick to human skin for at least 24 hours.
John A. Rogers
A new type of sensor uses flat, flexible electronics printed on a thin rubbery sheet, which can stick to human skin for at least 24 hours.

Researchers have created a new thin flexible sensor that can be applied with water, like a temporary tattoo. Measuring activity in the brain, heart and muscles, the innovation could cut down on the number of wires and cables medical personnel use to monitor patients, among other applications.

The electronics can bend, stretch and squeeze along with human skin, and maintain contact by relying on "van der Waals interactions" — the natural stickiness credited for geckoes' ability to cling to surfaces.

In addition to being designed with a hardy serpentine pattern that resists tearing, the sensors are thinner than a human hair.

"These devices were made through 'transfer printing' fabrication processes that create flexible versions of high-performance semiconductors," according to Science.

The sensors could even be integrated into actual temporary tattoos, making patients feel a bit less Borg-like — and even offering a chance for style points.

In one test, a device that included a microphone was applied to a person's throat. The computer hooked up to the sensor could make out the words "up," "down," "left," and "right" — opening up the possibility that the sensors might help people with disabilities.

In an abstract of a Sciencearticle publishing their research, titled "Epidermal Electronics" (the full article is available only to subscribers), the study's authors say the "tattoos" could run on solar cells — and may eventually be used to create a new class of game controller:

Solar cells and wireless coils provide options for power supply. We used this type of technology to measure electrical activity produced by the heart, brain, and skeletal muscles and show that the resulting data contain sufficient information for an unusual type of computer game controller.

"The skin represents one of the most natural places to integrate electronics," materials scientist John A. Rogers of the University of Illinois, Urbana-Champaign, told Science. "As the largest organ in our body, and our primary sensory mode of interaction with the world, it plays a special role."

The new sensors were developed by Rogers and his colleagues in Singapore, China and the United States. According to Technology Review, the researchers see many uses for the technology:

Ultimately, Rogers says, "we want to have a much more intimate integration" with the body, beyond simply mounting something very closely to the skin. He hopes that his devices will eventually be able to use chemical information from the skin in addition to electrical information.

The new electronic tattoos should not be confused with the Digital Tattoo Interface, a 2x4-inch touch-screen implanted subcutaneously and powered by blood. And that, in turn, should not be confused with the more common "plasma display" used in many TVs.

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Bill Chappell is a writer and editor on the News Desk in the heart of NPR's newsroom in Washington, D.C.