Scientists design muscles for shape-shifting, cell-sized robots

"If you want to build this electronics exoskeleton, you need it to be able to produce enough force to carry the electronics," said researcher Marc Miskin. "Ours does that."

By Brooks Hays

Jan. 4 (UPI) -- Physicists at Cornell University have designed and built a muscle to power tiny cell-sized robots capable of conducting electricity, changing shape and sensing their environs.

The muscle is a kind of spacesuit or exoskeleton, inside which cell-sized scientific payloads can be stored. The microscopic bots can be deployed inside the body and be used to study and interact with biological processes and components at micron-scale.


"You could put the computational power of the spaceship Voyager onto an object the size of a cell," Cornell physicist Itai Cohen said in a news release. "Then, where do you go explore?"

"Right now, you can make little computer chips that do a lot of information-processing," said Paul McEuen, director of the Kavli Institute at Cornell for Nanoscale Science. "But they don't know how to move or cause something to bend."

The new muscle, or exoskeleton, derives its impressive shape-shifting, reactive mobility from a motor composed of graphene and glass. The motor is called a biomorph and it bends in reaction to heat, electricity or a chemical reaction.

The biomorph bends because the two materials have different physical reactions to the same thermal stimuli. When one material stretches out and expands more than the other, the tension between the two layers forces the biomorph to bend to relieve strain.


Chemical stimuli trigger ion flows into the glass, causing the glass to expand and triggering a bend.

Combinations of bendable portions and hard ridges yield tiny folds in the exoskeleton, causing the biomorph to form specific shapes, including cubes and pyramids.

Scientists built the exoskeleton using a method called atomic layer deposition. They layered silicon dioxide onto aluminum over a micro cover slip, then added a single atomic layer of graphene using a technique known as wet-transferring.

When folded, the biomorph is "three times larger than a red blood cell and three times smaller than a large neuron."

Scientists have previously built scaffolding at similarly small scales, but not with the ability to carry electronic payloads.

"If you want to build this electronics exoskeleton, you need it to be able to produce enough force to carry the electronics," said postdoctoral researcher Marc Miskin. "Ours does that."

Scientists didn't design their robot with a specific purpose and there is no immediate application. But researchers expect other scientists to find novel ways to use their new technology.

The researchers described the robotics breakthrough in the journal PNAS.

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