Electronic skin: How prosthetic limbs could one day learn to feel

Gold nano-particles could change the way people with prostheses experience the world

Touch Bionics i-limb
(Image credit: Jeff J Mitchell/Getty Images)

Today's most advanced prosthetic hands can mimic the actions of the real thing, letting people tie their shoes, play cards, or type without much trouble. What they can't do very well is feel.

That could all change thanks to scientists at the Technion-Israel Institute of Technology, who are developing electronic skin that might one day give people with prostheses the power to sense touch, temperature, and humidity.

The e-skin is made out of gold nano-particles surrounded by molecules called ligands. Scientists found that when covering a surface, the e-skin conducted electricity differently depending on how it was bent, as particles moved closer together or farther apart. That enabled it to detect as little as tens of milligrams of pressure.

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What it ultimately means, says research leader Dr. Hossam Haick, is that the material "is at least 10 times more sensitive in touch than the currently existing touch-based e-skin systems."

That's right, e-skin isn't new. In 2010, researchers at the University of California, Berkeley, created a version made out of nanowires. Last year, Stanford scientists made progress on e-skin that actually healed itself when ruptured, just like real skin.

Today's prosthetic limbs, like Touch Bionics' i-limb, are incredibly dexterous, and are even capable of sensing someone's muscle signals to change positions. Still, they are mostly one-way streets, taking input from the user but not giving much feedback. E-skin could change all of that.

The material could also have big implications for robotics. Robots are great at gripping hard metal parts in factories. They are not, however, very good at doing things like handling produce or interacting physically with human beings.

If we ever want household robots to cook our meals or take care of grandma, they are going to need a strong sense of touch — dire warnings about SkyNet and Cylons be damned.

The Technion team's material could also be put on things like bridges or engines to detect stresses or tiny cracks that would otherwise go unnoticed.

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Keith Wagstaff is a staff writer at TheWeek.com covering politics and current events. He has previously written for such publications as TIME, Details, VICE, and the Village Voice.