With gold and rat heart cells, scientists make a robot stingray

Here's a critter that would be a showstopper in your aquarium: By layering rat heart cells over a gold skeleton, scientists have built tiny swimming artificial stingrays that can be driven and guided by light. These little ray-bots, described in the journal Science, may offer insight into building soft robotics, studying the human heart -- and perhaps even building an artificial one from scratch. Senior author Kit Parker, a Harvard bioengineer, first got the idea for these tiny ray-bots when his young daughter tried to pet a stingray at an aquarium and it quickly and gracefully evaded her hand. Parker watched the rippling body, which reminded him of the stringy cord-like trabeculated muscle on the endocardial surface of the heart, and a thought struck him: He could probably build something that moved like that. "It kinda hit me like a thunderbolt," he said.