A functioning centimeter-scale human heart pump has been 3D printed in the laboratory by researchers from the University of Minnesota and the University of Alabama. The 1.5 cm structure effectively pumps fluids and could serve as a heart muscle model to study diseases and test new therapies.

Previous attempts to print cardiomyocytes derived from pluripotent human stem cells failed to achieve desired cell densities in the extracellular matrix. The researchers overcame this limitation by optimizing an ink made A functioning centimeter-scale human heart pump has been 3D printed. Source: Molly E. Kupfer et al.from extracellular matrix proteins, combining the ink with human stem cells and applying this formulation to 3D print the chambered structure.

An appropriate cell density was realized by culturing the stem cells within the structure and by fostering differentiation in situ, the cells developed into cardiomyocytes in an environment that closely simulates that of a real heart. After one month of development, the cells began to beat together in a structure designed to fit into the abdominal cavity of a mouse for further study. The closed sac structure includes a fluid inlet and fluid outlet, enabling the researchers to measure how a heart moves blood within the body.

The 3D-printed living pump maintains function for at least six weeks, compared with a longevity of two weeks demonstrated by previous models. The technology described in Circulation Research could lead to the development of spatially designated pacemaker cells and other increasingly complex structures.