Scientists 3D-print a functional piece of a heart

Researchers have 3D-printed hearts using silicone and even a patient's own cells, but they haven't matched the full functionality of the real thing and aren't much good for repairing hearts. There's some progress on that front, however, as a team at Harvard's Wyss Institute has developed a technique for 3D-printing long cardiac macrofilaments that develop into muscle-like filaments which contract. The new method mimics the complex alignment of a heart's contracting elements (a difficult feat so ...