Visible light-based 3D bioprinted composite scaffolds of κ-carrageenan for bone tissue engineering applications

Three-dimensional (3D) printing of bone scaffolds using digital light processing (DLP) bioprinting technology empowers the treatment of patients suffering from bone disorders and defects through the fabrication of cell-laden patient-specific scaffolds. Here, we demonstrate the visible-light-induced photo-crosslinking of methacrylate-kappa-carrageenan (MA-kappa-CA) mixed with bioactive silica nanoparticles (BSNPs) to fabricate 3D composite hydrogels using digital light processing (DLP) printing. The 3D printing of complex bone structures, such as the gyroid, was demonstrated with high precision and resolution. DLP-printed 3D composite hydrogels of MA-kappa-CA-BSNP were prepared and systematically assessed for their macroporous structure, swelling, and degradation characteristics. The viscosity, rheological, and mechanical properties were also investigated for the influence of nanoparticle incorporation in the MA-kappa-CA hydrogels. The in vitro study performed with MC3T3-E1 pre-osteoblast-laden scaffolds of MA-kappa-CA-BSNP revealed high cell viability, no cytotoxicity, and proliferation over 21 days with markedly enhanced osteogenic differentiation compared to neat polymeric scaffolds. Furthermore, no inflammation was observed in the 21-day study involving the in vivo examination of DLP-printed 3D composite scaffolds in a Wistar rat model. Overall, the observed results for the DLP-printed 3D composite scaffolds of MA-kappa-CA and BSNP demonstrate their biocompatibility and suitability for bone tissue engineering. Through DLP printing, composite hydrogels of methacrylate-kappa-carrageenan (MA-kappa-CA-BSNP) encapsulated with bioactive silica nanoparticles have been fabricated into complex bone structures, such as the gyroid, with high precision and resolution.