3D printing isn't just for toys and models -- doctors at the Wake Forest Institute for Regenerative Medicine announced yesterday that they've managed to 3D print "living" tissue and organs that functioned properly when implanted in animals. The team, led by Anthony Atala, is already renowned for printing the building blocks for human bladders. But now they've reached another level entirely: They say it's possible to print structures large and strong enough for humans. They've printed muscle structures, bone and ear tissue so far, according to Nature. With a little more work, the technology could revolutionize the way we approach surgical replacements (and finally make plenty of sci-fi biotechnology scenarios a reality).