Key points from article :
Scientists 3D printed a functioning centimetre-scale human heart pump in the lab.
Used a combination of extracellular matrix protein ink and stem cells to 3D print the heart.
Expanded stem cells in to high density structures and then differentiated into heart muscle cells.
Cells organized to make a 1.5 cm long closed sac with a fluid inlet and fluid outlet.
Worked together contracting spontaneously and synchronously.
Plans to subject it to disease and damage in order to study heart diseases.
Research by University of Minnesota published in the journal Circulation Research.
