Printing Veins with a 3D Printer

Engineers at the University of Colorado Boulder have developed a way to mimic the complex geometry of blood vessels using 3D printing. The technique could help doctors come up with new ways to fight vascular disease such as hypertension, by creating artificial tissue with soft, pliable arteries and veins. It uses oxygen to set 3D-printed models with different degrees of hardness.
"Oxygen is usually a bad thing in that it causes incomplete curing," said Yonghui Ding, one of the authors of the study. "Here, we utilize a layer that allows a fixed rate of oxygen permeation." By tightly controlling how oxygen is spread during the printing process, the researchers were able to build objects with the same geometry, but with different levels of rigidity. The results were published in the journal Nature.

As part of their experiment, the engineers created a small Chinese warrior figure, printed so that the outer layers remained hard while the interior remained soft. They also printed three versions of a simple structure. a beam supported by two rods. Depending on how hard or soft the different parts were designed to be, the structure would either stand firm or slump.

The printer can currently work with biomaterials down to a size of 10 microns; about one-tenth the width of a human hair. Future iterations will aim to get this down even further.