If dry bacteria spores of the genus Bacillus were boxers, commentators would say they punch above their weight.
When they dehydrate, the rod-shaped spores— dormant cells that help the microorganism survive tough environmental conditions and are naturally found in soil and vegetation—shrivel or curl like a leaf. Add some moisture and they straighten out again. Studies have shown that they can absorb water and expand with remarkable force. Now scientists say this phenomenon can be harnessed to use the microbes as a potential source of renewable energy or as muscles to make superstrong robots.
In research recently reported in the journal Nature Nanotechnology, a team detailed how they smeared spores on a flat piece of rubber and created a bacteria-powered generator.
Artificial muscles that drive the powerful limbs or subtle facial expressions of robots can be made using nothing more than fishing line and sewing thread, researchers say. Such components work essentially the same way as toy airplanes powered by rubber bands.
"We can take a very inexpensive material that you can find at your local store and convert it to a powerful muscle that outperforms very complicated technologies," says Ray Baughman, a materials scientist and director of the University of Texas at Dallas NanoTech Institute.
The scientists imagine their new technology will find use in applications where superhuman strength is desired, such as in robots, exoskeletons and prosthetic limbs. For example, by twisting a bundle of polyethylene fishing lines, each about 10 times the width of a human hair, a coiled polymer muscle results that can lift 16 pounds, and 100 of these muscles operating in parallel much like natural muscles could lift about 1,600 pounds, Baughman says.
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