Artificial Skin Could Give People with Prosthetics a Sense of Touch

Skin with sensors — A photograph of the skin with flexible artificial mechanoreceptor inserts.

(Image credit: Bao Research Group, Stanford University)

Artificial skin created in a lab can "feel" similar to the way a fingertip senses pressure, and could one day let people feel sensation in their prosthetic limbs, researchers say.

The researchers were able to send the touching sensation as an electric pulse to the relevant "touch" brain cells in mice, the researchers noted in their new study.

The stretchy, flexible skin is made of a synthetic rubber that has been designed, to have micron-scale pyramid like structures that make it especially sensitive to pressure, sort of like mini internal mattress springs. The scientists sprinkled the pressure-sensitive rubber with carbon nanotubes— microscopic cylinders of carbon that are highly conductive to electricity — so that, when the material was touched, a series of pulses is generated from the sensor.

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To test whether the skin could create electric pulses that brain cells could respond to, the scientists connected the synthetic skin to a circuit connected to a blue LED light. When the skin was touched, the sensor sent electric pulses to the LED which pulsed in response. The sensors translated that pressure pulse into an electric pulses. When the sensors in the skin sent the electrical pulse to the LED — akin to touch receptors in real-life skin sending touch-sensation signals to the brain — a blue light flashed. The higher the pressure, the faster the LED flashed.

Using light to stimulate brain cells is a fairly recent area of study called optogenetics, in which scientists add special proteins to brain cells that let them react to light and shows scientists how different parts of the brain work. The advantage of using optogenetics over other technologies that directly stimulate neurons, such as electrodes directly attached to brain tissue, is that higher frequencies can be used, Lee said. Having a technology that can stimulate the cells at higher frequencies is important because it more accurately recreates the way that receptor cells send signals to our brains.

Elizabeth is a staff writer for Live Science. Her interests include the mechanics of weather phenomena, quirky animal behavior, natural disasters and recent developments in the world of genetic research. She has a Master of Arts degree from New York University’s Science, Health, and Environmental Reporting Program and has a bachelor’s degree in geology from Bryn Mawr College. Elizabeth has traveled all over the Western Hemisphere, where she’s touched a stingray, traversed the rim of a volcano and watched coral polyps feeding at night. Follow her on Twitter.