Bionic Scaffold Mimicking The Skeletal Structure For Large Segmental Bone Defect Regeneration

Objective:GelMA-MBGNs hydrogel and GeIMA/VEGF-Lip hydrogel cross-link in a 3D-printing mold successively to form a scaffold mimicking the structure of skeletal system.And investigate its ability to promote large segmental bone defect regeneration.Methods:Mesoporous bioactive-glass nanoparticles(MBGNs)synthesized by modified template method treated with 3-Aminopropyltriethoxysilane(APTEs)to prepare aminated bioactive glass(MBGNs-NH2).Bioactive glass modified with GelMA(G-MBGNs)was obtained by grafting GelMA monomer molecules on the surface of microspheres by carbodiimide method.Finally,G-MBGNs were dispersed into GelMA solution and crosslinked to obtain gels(GelMA-MBGNs).Liposomes loading vascular endothelial growth factor(VEGF-Lip)were prepared by reverse-phase evaporation and uniformly dispersed into a gel solution in GelMA solution to obtain a gel(GelMA/VEGF-Lip).Material characterization and related cell experiments were performed on the above two gel systems.The above two gel systems were successively cross-linked in a 3D printed mold to form a scaffold having similar structure of skeletal system.The rabbit tibia defect model was used to evaluate the scaffold’s ability to promote the regeneration process of skeletal system in vivo.Micro-CT and H&E staining were adopted to evaluate osteogenic activity.Conclusion:GelMA-MBGNs has certain mechanical properties.Vitro cell experiments show that it has good biocompatibility and can promote the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells.GelMA/VEGF-Lip has the function of sustained release of VEGF.And its ability to promote the angiogenic process of human umbilical vein endothelial cells was observed in vitro cell experiments.The bionic scaffold consisted of GelMA-MBGNs and GelMA/VEGF-Lip can induce the reestablishment of periosteum,bone and blood vessels,which was observed in the rabbit tibia defect model in vivo.