Photo-crosslinked gelatin methacryloyl strengthened with nanoparticles for regeneration of rabbit calvarial defects

Abstract Background Gelatin methacryloyl (GelMa) hydrogel has been regarded as a promising biomaterial in the field of bioprinting and biofabrication. The aim of this study was to investigate the efficacy of photo-crosslinked GelMa hydrogel and calcium phosphate nanoparticles (CNp) when applying different fabrication methods for bone regeneration. Methods Four circular defects were created in the calvaria of 10 rabbits. Each defect was randomly allocated to the following study groups: 1) the sham control group; 2) the GelMa group (defect filled with crosslinked GelMa hydrogel); 3) the CNp-GelMa group (GelMa hydrogel crosslinked with nanoparticles); 4) CNp + GelMa group (crosslinked GelMa loaded with nanoparticles). At two, four and eight weeks, samples were harvested, and histological and micro-computed tomography analyses were performed. Results Histomorphometric analysis showed that CNp-GelMa and CNp + GelMa groups at 2 weeks were significantly greater in total augmented area compared to the control group (P  0.05). Crosslinked GelMa hydrogel with nanoparticles exhibited good biocompatibility with minimal inflammatory reaction. Conclusion Crosslinked GelMa hydrogel with calcium phosphate nanoparticles might enhance new bone formation. Further improvement in mechanical stability and resistance to enzymatic degradation is needed prior to application in bone regenerative procedures.