By tightly coiling high-strength polymer fishing line and basic sewing thread, an international team of researchers have created artificial muscles of superhuman strength that can be made on the cheap.
“In terms of comparison, if you had a muscle made from our material that was the same length and weight as a natural muscle, in general it could lift about a hundred times more force than a natural muscle can,” said Carter Haines, a PhD student at the University of Texas Nanotech Institute in Dallas, which led the international research team.
For heavy lifting, researchers say a single artificial muscle of bundled, twisted fishing line can lift 7.25 kilograms. Writing in the journal Science, Haines, the report's lead author, says the synthetic muscles could be used to power human-like robots, prosthetic limbs and exoskeletons for people whose muscles have atrophied.
“One of the simpler things to do, as opposed to, let's say, replace a missing limb, is to see [if we can] create something like a glove that would fit over" a hand or limb that has lost function, he said.
According to the report, the scientists say twisted sewing thread of a diameter less than human hair works just as well and could be used for applications requiring less force. For example, a synthetic muscle used to power mechanical robots that perform minimally invasive microsurgery, Haines says.
When heated, the muscles twist along their length, contracting to produce the force, and, when cooled, the muscles relax. They can be powered by temperature changes or a simple battery.
When threaded through fabric, Haines says the invention could open pores in clothing when it is hot to let in cool air and tighten fabric when it is cold.
The muscles are easy to make, says Haines, because they require materials that can be purchased at any store. Students learning about the technology are making the synthetic muscles for school science projects.