The future vision of implants comprises the generation of artificial tissue generated from the patient’s own cells. With respect to the automated generation of artificial tissues by bioprinting technology we develop printable and photo-crosslinkable material systems, based on bio-polymers derived from the native extracellular matrix (ECM). Such bioinks can be used for 3D encapsulation of cells and cell printing, thereby constituting biomimetic matrices with adjustable properties to mimic the native matrix of different tissue.
In this study we present biopolymer-based biomaterials which were used for the biofabrication of artificial articular cartilage with biomimetic hierarchical structure.
Photo-crosslinkable ECM derived biopolymers gelatin, chondroitin sulfate, and hyaluronan were prepared by their derivatization with methacrylic anhydride. These biopolymer derivatives can be converted into thermostable hydrogels by UV-induced radical crosslinking in the presence of a water-soluble photoinitiator. The viscous behavior of gelatin precursor solutions is adapted to the requirements of the printing technologies by additional functionalization with acetyl groups.
The developed bioinks were then used for bioprinting of zonal cartilage models with appropriate biopolymer composition for replication of the three cartilage zones . Criteria for evaluation of the hydrogel compositions were the visco-elastic properties of the resulting hydrogels, such as mechanical strength, swellability, and degradability, as well as their potential to preserve cell viability and functionality in terms of collagen 2 productions and glycosaminoglycane production of the encapsulated primary porcine chondrocytes. Finally, three-dimensional, zonal cartilage models were fabricated and evaluated for their quality.