3D printer makes tiniest human liver ever

April 25, 2013

Cross-section of multi-cellular bioprinted human liver tissue, stained with hematoxylin & eosin (H&E) (credit: Organovo)

Lab-grown livers have come a step closer to reality thanks to a 3D printer loaded with cells, New Scientist reports.

Created by Organovo in San Diego, California, future versions of the system could produce chunks of liver for transplant.

The mini-livers that Organovo made are just half a millimeter deep and 4 millimeters across but can perform most functions of the real thing.

To create them, a printer builds up about 20 layers of hepatocytes and stellate cells — two major types of liver cell. Crucially, it also adds cells from the lining of blood vessels. These form a delicate mesh of channels that supply the liver cells with nutrients and oxygen, allowing the tissue to live for five days or longer. The cells come from spare tissue removed in operations and biopsies.

The realistic structure and functioning of the mini-livers make them good predictors of the toxicity of drugs and other substances.

Organovo’s ultimate goal is to create human-sized structures suitable for transplant; the big hurdle is being able to print larger branched networks of blood vessels to nourish such an organ.