August, 22nd, 2024 Sports activities can lead to injuries, often to the cartilage in the joints, if the strain is incorrect. Untreated cartilage defects can lead to osteoarthritis in old age, for which there is currently no effective treatment. Personalised cartilage cell implants from the 3D printer should provide a remedy in future. Special printing inks containing the body’s own cartilage cells are being developed for this purpose. The four-year project by the Fraunhofer Institute for Applied Polymer Research IAP and the Brandenburg University of Technology Cottbus-Senftenberg (BTU) started in January 2024 and is being funded by the Federal Ministry of Education and Research (BMBF) with around 2 million euros.

Cartilage damage in the knee or other joints shows little ability to heal itself, as cartilage has no blood vessels. A proven method for treating such defects is the transplantation of the body’s own cartilage cells. This involves taking healthy cartilage cells from a less stressed area of the affected joint, multiplying them in the laboratory and then transplanting them into the damaged area of cartilage. Although this technique helps to alleviate pain, improve joint function and slow down the progression of cartilage damage, it cannot be used in all cases. Alternatives are being sought for larger cartilage defects in particular.

3D bioprinting, also known as bioprinting, opens up enormous potential here. This manufacturing technology makes it possible to produce biological tissue in a three-dimensional format. As with conventional additive manufacturing processes, 3D bioprinting involves building up layers of materials to form a specific structure. However, biomaterials are used as printing inks, in which living cells can even be embedded.

Bioinks for 3D bioprinting

‘In the BioPol-3D project, we are developing inks for 3D bioprinting that already contain the patient’s cartilage cells. The cells are embedded in a hydrogel. These bioinks can be cross-linked or stabilised during or after printing to create the desired shape and structure,’ explains Professor Ruben R. Rosencrantz, Head of the “Life Science and Bioprocesses” research department at the Fraunhofer IAP and holder of the “Biofunctional Polymer Materials” chair at BTU.

One of the hydrogel matrices used by the researchers is glycopolymers. These are specially synthesised and are ideal for recreating the natural environment of cartilage cells in the body. So far, however, glycopolymers have not been used as a construction material. As part of the project, the team is investigating how suitable the glycopolymers are for 3D bioprinting in terms of their material and processing properties and optimising them for this purpose. ‘In developing these glycopolymers, we are combining our chemical and biotechnological expertise at the Fraunhofer IAP in a unique way. This combination plays a decisive role for BioPol-3D, as the material optimisation must be very precisely matched to the biological processes. ’, says Rosencrantz.

‘Our approach of printing the cartilage cells goes beyond conventional methods, because we bring the biological component – the cartilage cells – directly into shape. In other words, we don’t first print a scaffold on which cells are later deposited,’ adds BTU colleague Professor Ursula Anderer, who heads the “Cell Biology and Tissue Engineering” working group.

‘There are a number of parameters that we have to take into account in order to develop printable inks: the sensitive cartilage cells must remain vital, the inks must be biocompatible and biodegradable in a controlled manner and, finally, the desired cartilage mould must have a high degree of stability and strength. Our aim is to establish an advanced 3D cell culture for the treatment of cartilage damage and at the same time revolutionise the production of such moulded bodies through additive manufacturing,’ says Anderer.

3D bioprinting strengthens Lusatia’s innovative power

3D bioprinting is an up-and-coming market that is attracting numerous small and medium-sized enterprises and start-ups – a development that will also benefit Lusatia. ‘The intensive collaboration between the BTU and the ‘Biologisation/Biofunctionalisation of Polymers BioPol’ project group at the Fraunhofer IAP offers great potential for developing even more innovative materials for 3D bioprinting in the future. If these materials and processes prove successful, we will also be able to open up applications in the fields of sensor technology or cosmetics in the future. This strengthens the region’s innovative power in the field of 3D printing and promotes structural change activities in Lusatia,’ says Rosencrantz.

The text was translated with the support of DeepL Translator, a translation with artificial intelligence