A 3D printer can generate tissues using cells and polymers that are larger and more robust than previously printed biological structures.

Credit: Nature Biotech.

Bioprinted 3D organs could one day help people who need transplants, but existing methods tend to produce only small, simple structures. Larger ones lose their shape, or die because nutrients cannot reach their centres. To build larger, stronger tissues, Anthony Atala and his colleagues at Wake Forest Institute for Regenerative Medicine in Winston-Salem, North Carolina, devised a 3D-printing system that adds biodegradable polymers for structural support. By combining polymer-based frames with hydrogels containing cells, the researchers printed a human-sized ear (pictured), a human jawbone fragment, a segment of mouse muscle and a piece of rat skull. Microchannels printed in the structures helped nutrients to flow into the tissues.

The team implanted some of the structures into rodents and found that the tissues survived over weeks and months.

Nature Biotech. http://dx.doi.org/10.1038/nbt.3413 (2016)