For many people, getting a tattoo is a way of expressing culture, membership or rebellion. In the near future, tattoos may be used to communicate, entertain and help us heal.
Scientists at the University of Illinois, Urbana-Champaign, along with colleagues at other institutions in the U.S., Singapore and China, have developed technology that integrates the skin with electronics for devices that can literally be worn on the body. Epidermal electronics, as they are called, match skin’s mechanical properties and can be applied the same way you would apply a temporary tattoo. Users place the device on the skin and rub it on with water; it can stay attached for more than 24 hours on most parts of the body. You can even sport the device incognito by hiding it under an actual temporary tattoo.
“The skin represents one of the most natural places to integrate electronics,” said one of the developers, materials scientist John Rogers of the University of Illinois, Urbana-Champaign. “As the largest organ in our body, and our primary sensory mode of interaction with the world, it plays a special role,” he said.
Researchers have been working on electronics that can bend and stretch for years. Circuits can either be written onto materials that are already flexible, or they can be constructed to be flexible themselves. In 2008, University of Tokyo engineers created a material of carbon nanotubes and rubber that could stretch by more than a third of its natural length to increase agility in robots. However, no one has been able to produce circuits that are as pliable as human skin.
The reasons for wanting such flexible circuitry range from enhancing entertainment devices to producing life-saving technologies. Imagine being able to wear your iPod or cell phone on your arm. Or, imagine doctors applying a device the size of a postage stamp to a person’s chest in lieu of bulky, uncomfortable electrocardiogram equipment.
One of the coolest potential applications is using the device to help people with disabilities control computers. In an experiment conducted by Rogers’s group, a device containing a microphone was applied to a person’s throat and fed the signal to a computer. The computer understood the words, “up,” “down,” “left,” and “right.” Rogers also believes epidermal electronics could provide an electronic link to subtle bodily processes, like the movement of enzymes and antibodies, to track the path of disease.
Rogers and his group leveraged several technological advances to create the skin-like circuitry. The group flattened the active circuit components, including the transistors, diodes, and other semiconductors, and shrunk them to the size of tiny imperfections on the skin. They also took advantage of the rubbery properties of elastomer, which are similar to those of the skin. The technical components are arranged on this elastomer, which sticks to the skin naturally by using the weak, short-range attractive forces existing between adjacent molecules. Finally, Rogers’s group used a computer program to predict movements of the skin to arrange the circuits in a pattern that is least likely to tear.
What kind of gadgets would you like to have tattooed to your skin? Metro cards, GPS devices? Leave us a comment with your futuristic ideas!