A high-strength mineralized collagen bone scaffold for large-sized cranial bone defect repair in sheep

Large-sized cranial bone defect repair presents a great challenge in the clinic.The ideal cranioplasty materials to realize the functional and cosmetic recovery of the defect must have sufficient mechanical support,excellent biocompatibility,good osseointegration and biodegradability as well.In this study,a high-strength mineralized collagen(MC)bone scaffold was developed with biomimetic composition,microstructure and mechanical properties for the repair of sheep largesized cranial bone defects in comparison with two traditional cranioplasty materials,polymethyl methacrylate and titanium mesh.The compact MC scaffold showed no distinct pore structure and therefore possessed good mechanical properties.The strength and elastic modulus of the scaffold were much higher than those of natural cancellous bone and slightly lower than those of natural compact bone.In vitro cytocompatibility evaluation revealed that the human bone marrow mesenchymal stem cells(hBMSC)had good viability,attachment and proliferation on the compact MC scaffold indicating its excellent biocompatibility.An adult sheep cranial bone defect model was constructed to evaluate the performances of these cranioplasty materials in repairing the cranial bone defects.The results were investigated by gross observation,computed tomography scanning as well as histological assessments.The in vivo evaluations indicated that compact MC scaffold showed notable osteoconductivity and osseointegration with surrounding cranial bone tissues by promoting bone regeneration.Our results suggested that the compact MC scaffold has a promising potential for large-sized cranial bone defect repair.

Osteogenesis effects of magnetic nanoparticles modified-porous scaffolds for the reconstruction of bone defect after bone tumor resection

The treatment of bone defect after bone tumor resection is a great challenge for orthopedic surgeons.It should consider that not only to inhibit tumor growth and recurrence,but also to repair the defect and preserve the limb function.Hence,it is necessary to find an ideal functional biomaterial that can repair bone defects and inactivate tumor.Magnetic nanoparticles(MNPs)have its unique advantages to achieve targeted hyperthermia to avoid damage to surrounding normal tissues and promote osteoblastic activity and bone formation.Based on the previous stage,we successfully prepared hydroxyapatite(HAP)composite poly(lactic-co-glycolic acid)(PLGA)scaffolds and verified its good osteogenic properties,in this study,we produced an HAP composite PLGA scaffolds modified with MNPs.The composite scaffold showed appropriate porosity and mechanical characteristics,while MNPs possessed excellent magnetic and thermal properties.The cytological assay indicated that the MNPs have antitumor ability and the composite scaffold possessed good biocompatibility.In vivo bone defect repair experiment revealed that the composite scaffold had good osteogenic capacity.Hence,we could demonstrate that the composite scaffolds have a good effect in bone repair,which could provide a potential approach for repairing bone defect after bone tumor excision.