Scientists have published a breakthrough development in the journal Applied Physics Letters – a new type of artificial muscle that (unlike previous iterations) is able to expand and contract in different directions, at the same time.
Researchers from National Taiwan University led by Wen-Pin Shih, Ph.D., were experimenting with onion cells to improve the form and function of artificial muscles. The epidermal (skin) cells of onions are naturally arranged in a tight, blocky lattice – which the researchers theorized could be used to create a more versatile artificial muscle. Previous developments have only yielded artificial muscles that either expand or contract to manipulate a structure, but not at the same time.
Unfortunately, the onion cells alone were not sufficient to create an artificial muscle with more robust movement options. To modify their designs, the researchers treated the cells with an acid to dissolve select proteins – which made the cells more pliable while allowing them to maintain their lattice. Next, they added a micro-layer of gold over the structure.
Gold is a unique element because it is both highly malleable and electrically conductive. By driving controlled voltages into the gold, the scientists were able to get the artificial muscle to bend and stretch similarly to natural muscles. To demonstrate their findings, the researchers combined two artificial muscles to create a pair of tweezers – which was used to pick up a cotton ball.
Shih and his team are still tweaking the thickness of the gold layer and the voltage requirements, but this groundbreaking advancement could go a long way to improving technologies such as prosthetic limbs, robots, and implanted medical devices. And it’s possible thanks to gold’s unique properties.