Onion cells turned into artificial muscles

You can use an onion to flavor your stir fry or keep an avocado from turning brown. Now, according to a new study, you can also use it to make an artificial muscle.

To be clear, no one is talking about a fist-sized onion pumping away like a heart. The first onion muscle prototypes are very small – just a few onion cells long. They were created from the thin, translucent layer of epidermal cells that lies just below the dry outer skin of the onion.

But it turns out that if you freeze-dry these cells, coat them in gold, and then hook them up to an electric current, they will contract or elongate depending on how much voltage you use. As the cells contract or elongate, they cause the entire length of cells to bend.

“Overall, the cells contract and bend like human muscle,” said lead researcher Wen-Pin Shih of National Taiwan University. According to the study, this is an engineering first.

The authors define an artificial muscle as one that bends in response to an external stimulation. Prior to this study, researchers had tried to make artificial muscles with various types of polymers that could contract or expand, but none that could also bend at the same time.

So far, the researchers have demonstrated how two small artificial muscles made of onion could be used almost like a pair of tweezers to pick up a small piece of a cotton ball. But Shih said more intriguing applications may be on their way.

“Gold electrode and onion muscles are both biocompatible, so this work could be applied for biomedical manipulations,” he said.