A Harvard research team led by Kevin Kit Parker, PhD, has aligned muscle cells with each other across several centimeters to make new muscular thin films that may one day repair damage to living organs and to treat new drugs. The sheets of polymer coated with living muscle may even create life-like bio-machines, researchers say.
By zapping the muscle-bound sheets with electricity, the muscle cells were coaxed to contract, bending and flexing the polymer sheets. Sometimes the movement continued spontaneously; other times it proceeded only in tandem with the electrical inputs. The movements of the “robots” mimicked swimming, clawing, and crawling.
"I think the greatest accomplishment is not that we made these walking devices," team leader Parker said. Rather, the achievement was that the team was able to get the muscle cells—and the molecular motors inside them—to line up properly to become working muscle fibers. "In order to have rhythmic contraction, you need to have proper alignment" of the muscle cells, Parker said. "To date, that is what has vexed tissue engineers."
To arrange the cells so that they are mechanically and electrically connected, the researchers created micropatterns of proteins. These proteins created "cues" for rat muscle cells deposited on the plastic, guiding their alignment. Once the cells were deposited on a surface patterned with the proteins, they oriented themselves to form a working tissue, Parker says.
"The first application of these [rat muscle films] might be in drug assays" that look at the benefits and side effects of particular drugs on heart cells, Parker said.
"We need to try to get human cells to grow" on the films, because this would open up another possibility—making replacement tissues and organs—he added. With sheets of muscle tissue, doctors could repair holes in the heart or diseased bowels. They could also be used in artificial arms or legs.
Illustration: Heart-muscle cell thin layer. – Science.
NewScientist (09/06/07) with video
National Geographic News (09/06/07) with video
Technology Review (09/07/07)
Medical News/UK (09/08/07)