"Scientists have created a synthetic stingray that's propelled by living muscle cells and controlled by light, a team reports Thursday in the journal Science."

"And it should be possible to build an artificial heart using some of the same techniques, the researchers say."

"'I want to build an artificial heart, but you're not going to go from zero to a whole heart overnight,' says Kit Parker, a bioengineer and physicist at Harvard University's Wyss Institute. 'This is a training exercise.'"

Previous artificial hearts have been versions of mechanical pumps. An artificial heart made from living muscle cells would behave more like a natural heart, Parker says, and would be able to grow and change over time.

"The heart's built the way it is for a reason," he says. "And we're trying to replicate as much of that function as we possibly can."