Print your individual blood vessels, no use for red toner

Press Release 13.09.2011

Researchers was working at growing tissue and organs inside the laboratory for a very long time. Nowadays, tissue engineering enables us to accumulate artificial tissue, although science still hasn’t been successful with larger organs. Now, researchers at Fraunhofer are applying new techniques and materials to return up with artificial blood vessels of their BioRap project to be able to have the ability to supply artificial tissue and even perhaps complex organs in future. They’re exhibiting their findings on the Biotechnica Fair on the way to be happening in Hannover, Germany on October

There have been greater than 11,000 persons at the waiting list for organ transplantation in Germany alone at the start of this year, although at the average hardly half as many transplantations are performed. The purpose of tissue engineering is to create organs within the laboratory for opening up new opportunities on this field. Unfortunately, researchers have still not been capable of supply artificial tissue with nutrients because they don’t have the required vascular system. Five Fraunhofer-institutes joined forces in 2009 to return up with biocompatible artificial blood vessels. It seemed impossible to construct structures together with capillary vessels which might be so small and complicated and it was especially the branches and spaces that made life difficult for the researchers. But production engineering came to the rescue because rapid prototyping makes it possible to construct workpieces specifically consistent with any complex 3-D model. Now, scientists at Fraunhofer are engaged on transferring this technology to the generation of tiny biomaterial structures by combining two different techniques: the three-D printing technology established in rapid prototyping and multiphoton polymerization developed in polymer science.

Successful Combination
a three-D inkjet printer can generate 3-dimensional solids from a wide selection of fabrics in no time. It applies the fabric in layers of defined shape and these layers are chemically bonded by UV radiation. This already creates microstructures, but 3-D printing technology continues to be too imprecise for the fine structures of capillary vessels. It is because these researchers combine this technology with two-photon polymerization. Brief but intensive laser impulses impact the fabric and stimulate the molecules in a really small focus point in order that crosslinking of the molecules occurs. The fabric becomes an elastic solid, as a result of properties of the precursor molecules which were adjusted by the chemists within the project team. On this way highly precise, elastic structures are built in keeping with a three-dimensional building plan. Dr. Günter Tovar is the project manager on the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB based in Stuttgart. Once we caught up with him, he described the most recent work: »The person techniques are already functioning and they’re presently working within the test phase; the prototype for the combined system is being built.«

When ink becomes a man-made vessel system
You must have the proper material to fabricate 3-dimensional elastic solids. That is why why the researchers came up with special inks because printing technology itself requires very specific properties. The later blood vessels should be flexible and elastic and have interaction with the natural tissue. Therefore, the artificial tubes are biofunctionalized in order that living body cells can dock onto them. The scientists integrate modified biomolecules – comparable to heparin and anchor peptides – into the interior walls. In addition they develop inks made from hybrid materials that contain a mix of synthetic polymers and biomolecules right from the start. The second one step is where endothelial cells that form the innermost wall layer of every vessel within the body can attach themselves within the tube systems. Günter Tovar points out that »the liner is essential to ensure that the components of the blood don’t stick, but are transported onwards.« The vessel can only work inside the same fashion as its natural model to direct nutrients to their destination if we will establish a whole layer of living cells.

Opportunities for Medicine
The virtual simulation of the completed workpieces is simply as significant for project success because the new materials and production techniques. Researchers need to precisely calculate the design of those structures and the process the vascular systems to make certain optimum flow speeds while preventing back-ups. The scientists at Fraunhofer are still on the dawn of this entirely new technology for designing elastic 3-dimensionally shaped biomaterials, although this technology offers an entire series of opportunities for further development. Günter Tovar acknowledges »we’re establishing a basis for applying rapid prototyping to elastic and organic biomaterials. The vascular systems illustrate very dramatically what opportunities this technology has to provide, but that’s definitely not the sole thing possible.« One example could be increase completely artificial organs in keeping with a circulation system with blood vessels created on this fashion to produce them with nutrients. They’re still not fitted to transplantations, however the complex of organs can be utilized as a test system to interchange animal experiments. It might even be conceivable to regard bypass patients with artificial vessels. In any event, this can take a while until we will be able to actually be capable of implant organs from the laboratory with their very own blood vessels.

It is a project that the Fraunhofer Institute for Applied Polymer Research IAP in Potsdam, Germany, the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB in Stuttgart, Germany, the Fraunhofer Institute for Laser Technology ILT in Aachen, Germany, the Fraunhofer Institute for Manufacturing Engineering and Automation IPA in Stuttgart, Germany and the Fraunhofer Institute for cloth Mechanics IWM in Freiburg, Germany are all participating in. They’re exhibiting an oversized model of a man-made blood vessel printed with conventional with rapid prototyping technologies and samples in their current developments in Hall 9, Stand D10 on the Biotechnica Fair.