Bioprinting Complex Cartilaginous Structures with Clinically Compliant Biomaterials

Bioprinting is an emerging technology for the fabrication of patient-specific, anatomically complex tissues and organs. A novel bioink for printing cartilage grafts is developed based on two unmodified FDA-compliant polysaccharides, gellan and alginate, combined with the clinical product BioCartilage (cartilage extracellular matrix particles). Cell-friendly physical gelation of the bioink occurs in the presence of cations, which are delivered by co-extrusion of a cation-loaded transient support polymer to stabilize overhanging structures. Rheological properties of the bioink reveal optimal shear thinning and shear recovery properties for high-fidelity bioprinting. Tensile testing of the bioprinted grafts reveals a strong, ductile material. As proof of concept, 3D auricular, nasal, meniscal, and vertebral disk grafts are printed based on computer tomography data or generic 3D models. Grafts after 8 weeks in vitro are scanned using magnetic resonance imaging and histological evaluation is performed. The bioink containing BioCartilage supports proliferation of chondrocytes and, in the presence of transforming growth factor beta-3, supports strong deposition of cartilage matrix proteins. A clinically compliant bioprinting method is presented which yields patient-specific cartilage grafts with good mechanical and biological properties. The versatile method can be used with any type of tissue particles to create tissue-specific and bioactive scaffolds.