Experimental Study on Novel Tissue Engineered Bone Constructed by HA/ZrO2 Scaffold Based on 3D Printing Technology Composite iPSCs-MSCs
Objective:To observe dogs'bone repairing ability in femoral shaft defect by using novel tissue engineered bone which was constructed by HA/ZrO2 scaffold based on 3D printing technology and induced pluripotent stem cell(iPSC)source mesenchymal stem cells(MSCs).Methods:CT scan data and 3D printing technology were used to construct dog femoral shaft defect HA/ZrO2 scaffold.The biomechanical property of scaffold was analyzed by electron microscope and mechanical test.The iPSCs were induced and differentiated into MSCs morphological cells,and in vitro co-culture system of scaffold and iPSCs-MSCs were constructed.Its cytotoxici-ty grade was determined.The cell adhesion and growth on the scaffold were observed by electron microscope.12 dogs were divided into 3 groups according to the difference of implant material,with 4 dogs in each group.Group A:dogs'25 mm mid femur were vacant after osteotomy.Group B:HA/ZrO2 scaffolds were implanted after osteotomy.Group C:HA/ZrO2 scaffolds composite iPSCs-MSCs were implanted after osteotomy.New born bone ingrowth,osseointegration ability and mechanical property were observed by X-ray,CT and mechanical test respectively.Results:HA/ZrO2 composite scaffolds were individually prepared by CT scanning precision data into 3D printed data.Scaffold compressive strength was reached to(48.94±0.65)MPa.Immunofluorescences showed that iPSCs-MSCs expressed Vimentin,while did not express OCT4 and Nestin.The cytotoxicity grade in vitro co-culture of scaffold material with iPSCs-MSCs was 0.Scanning electron mi-croscope(SEM)showed that spindle-shape iPSCs-MSCs adhered and grew on the surface of the HA/ZrO2 scaffold.X-ray examination showed:in group A,the broken end of the fracture was absorbed,and bone nonunion was formed;in group B and C,the scaffold was bonded strongly to the host bone,and the new bone was filled in the stent,with a continuous callus passing through.3D reconstruction of CT after surgery was showed new born bone mass per unit volume was reached to(219.45±3.15)mm3/cm3 in group B,while(222.99±5.97)mm3/cm3 in group C,and there was no significant difference between two groups(P＞0.05).Ultimate compressive test in week 12 showed that compressive strength reached to(52.21±2.41)MPa in group B,while(52.51±1.35)MPa in group C,and there was no significant difference between two groups(P＞0.05).Conclusion:The HA/ZrO2 scaffolds prepared by 3D printing were in accordance with the principle of clinical individualized treatment,which are with strong biomechanical properties and good biocompatibility.Novel tissue engineered bone constructed by HA/ZrO2 scaffold and iPSCs-MSCs could successfully repair femoral bone defect in dogs,and is an ideal replacement material for bone tissue.
3D printingHA/ZrO2induced pluripotent stem cells(iPSCs)bone defectbone tissue engineering
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