Artificial blood vessels made through 3D printing

Posted by Emma Woollacott

German scientists say they're building a 3D printer that can print out artificial blood vessels.

Through their BioRap project, says the Fraunhofer team, they expect to be able to supply artificial tissue and possibly even complex organs.

Up to now, researchers have been unable to supply artificial tissue with nutrients because they don't have the necessary vascular system. And it seemed impossible to build structures such as capillary vessels because of their complexity and small size.

Now, though, the researchers say they've been able to combine the 3-D printing technology established in rapid prototyping with multiphoton polymerization.

A 3-D inkjet printer can generate three-dimensional solids from a wide variety of materials very quickly - but is still too imprecise for the fine structures of capillary vessels. But combining this technology with two-photon polymerization, says the team, allows highly precise, elastic structures to be built according to a three-dimensional building plan.

Brief but intensive laser impulses impact the material and stimulate the molecules in a very small focus point so that crosslinking of the molecules occurs. The material becomes an elastic solid, due to the properties of the precursor molecules that have been adjusted by the chemists in the project team.

"The individual techniques are already functioning and they are presently working in the test phase; the prototype for the combined system is being built," says project manager Dr Günter Tovar.

So that living body cells can dock onto the artificial blood vessels, the scientists integrate modified biomolecules – such as heparin and anchor peptides – into the inside walls. They've also developed inks made of hybrid materials that contain a mixture of synthetic polymers and biomolecules right from the beginning.

There are enormous possibilities for the technique, says Tovar.

"We are establishing a basis for applying rapid prototyping to elastic and organic biomaterials," he says.

"The vascular systems illustrate very dramatically what opportunities this technology has to offer, but that’s definitely not the only thing possible."

One possibility would be building up completely artificial organs based on a circulation system using artificial blood vessels created in this fashion to supply them with nutrients. They wouldn't be suited for transplantations, says Tovar, but could be used instead of animal experiments.