Photopolymerizable and non-gelling gelatin for the preparation of tissue substitutes by additive manufacturing techniques

Introduction: Gelatin, derived from native collagen, is a very promising matrix material for tissue engineering applications, e.g. due to its native RGD content. Because future medical technology needs flexible and effective technologies for regenerative medicine, e.g. bioprinting, the formulation of processable bioinks consisting of cells and biomolecules from the native extracellular matrix (ECM) becomes increasingly interesting. The objective of the present study is the preparation of gelatin based biomaterials that constitute both, processable precursor solutions and hydrogels with tunable physico-chemical properties for engineering of bioartificial tissue substitutes. Materials and methods: For additive assembly of bioartificial tissue photocrosslinkable gelatin was prepared by derivatization with methacrylic anhydride [1]. In view of constituting bioartificial cartilage chondroitin sulfate (CS) was also modified. Hydrogels were gained by photo-induced radical crosslinking in the presence of water-soluble photoinitiator IG2959. The viscoelastic properties and long-term stability of the gels have been analyzed by swelling experiments and rheological measurements. Gels were investigated as encapsulation matrices for porcine articular chondrocytes to evaluate their applicability in respect to the generation of artificial cartilage. Processability by piezoelectric printing of the precursor solution was analyzed and printing of viable chondrocytes was performed (Nanoplotter NP2.1, GeSiM mbH, Germany)[2]. Results: We provide ECM-based hydrogels with tunable physico-chemical properties for use as biomimetic extracellular matrix for three-dimensional tissue substitutes. The developed precursor solutions hold low viscosities and no gelling effects. Hence, the hydrogel system is suitable for processing in additive manufacturing e.g. piezoelectric inkjet bioprinting. We proved that the addition of CS to the bioartificial ECM substitute could promote the re-constitution of the chondrocyte- specific phenotyp after expansion in 2D cultivation. Discussion and conclusions: The developed biobased hydrogel system is suitable for processing by printing techniques and constitutes a biofunctional ECM substitute. Thus it will contribute to the development of biological implants in the near future.” Acknowledgments: The authors thank the Fraunhofer-Gesellschaft, the European Commission (Artivasc3D,GA 263416), and the Peter-und-Traudl-Engelhorn Stiftung for financial support. Disclosure: The authors have nothing to disclose