I’ll say it again: Scientists have created a synthetic stingray that’s propelled by living muscle cells and controlled by light.

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But the ultimate goal isn’t a cyborg sea monster - it’s a human heart.

“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.”

Full, fascinating story here.