Bioprinting: Where do your bones come from?

Maybe it comes printed from the Fraunhofer-IGB in Stuttgart/Germany. Bio inks remain flowable during printing, after which they are irradiated with UV light and cross-linked to hydrogels, i.e. water-containing polymer networks. Since the molecules can be chemically modified, the researchers can produce gels with different strengths and different swelling behaviour – and thus cartilage or fatty tissue. In cooperation with the University of Stuttgart, the researchers have recently succeeded in creating two different hydrogel environments: on the one hand, firmer gels with mineral components in order to provide bone cells with the best possible supply, and on the other hand, softer gels without mineral components in order to enable blood vessel cells to arrange themselves in capillary-like structures.

Now the team could produce bone ink. The cells processed in the ink will be able to regenerate the original tissue, i.e. form bone tissue themselves. The secret of the ink is a special mixture of the powdery bone mineral hydroxylapatite and biomolecules. “The best artificial environment for the cells is one that comes as close as possible to the natural conditions in the body,” explains Dr. Kirsten Borchers, who is responsible for the bioprinting projects. “The function of the tissue matrix in our printed tissues is therefore performed by biomaterials that we produce from components of the natural tissue matrix.
The vascularisation ink forms soft gels in which capillary structures have been able to establish themselves. Cells that form blood vessels are introduced into the ink. The cells move, migrate towards each other and form systems of capillary networks from small tubular structures. If this bone substitute were implanted, the connection of the biological implant to the blood vessel system of the recipient would function much faster than with implants without capillary-like structures.