| Objectives Barium titanate/polylactic acid(BT/PLA)composite membrane was prepared by solution casting method and was given piezoelectric property after corona polarization treatment.And its effects on the adhesion,proliferation and osteogenic differentiation of MC3T3-E1 and the ability of promoting bone regeneration in vivo were investigated.Methods In experiment 1,barium titanate/polylactic acid composite films with different proportions were prepared by solution casting with polylactic acid as raw material and dichloromethane as organic solvent.According to the mass ratio(W/W)of the film BT and PLA,they were divided into 6 groups,which were marked as 0% group(BT/PLA=0/100);5% group(BT/PLA=5/95);10% group(BT/PLA=10/90);20% group(BT/PLA=20/80);30%group(BT/PLA=30/70);40% group(BT/PLA=40/60).The piezoelectric properties of the films were given by high-voltage corona treatment with corona polarization treatment device.The surface microstructure of the films was observed by scanning electron microscope.The phase composition of the materials before and after polarization was analyzed by X-ray diffractometer,the hydrophilicity of the materials was tested by contact angle measuring instrument,and the piezoelectric constants d33 of the materials after polarization were tested by quasi-static d33 tester.In Experiment 2,the optimal barium titanate content was determined to be 20% according to the physical and chemical properties test results from Experiment 1.The 0% and 20%BT/PLA composite film materials before and after polarization treatment were separately co-cultured with MC3T3-E1 cells to test the ability of cell adhesion,proliferation,and osteogenic differentiation.And one side of the material was polarized as the cell inoculation surface.In Experiment 3,a full-thickness bone defect model with a diameter of 5mm was constructed on both sides of the sagittal suture of the skull of SD rats.And the defect spacing should be at least 2mm.The above four groups of materials were implanted in the defect,and the left and right sides were randomly controlled.The defect group without material cover was blank control.Weeks 4 and 12 after surgery,imaging and histological methods were used to evaluate the bone repair of skull defects covered by materials in rats.Results 1 BT/PLA composite films with different BT contents were successfully prepared by solution casting method.The scanning electron microscope,X-ray diffraction,water contact angle experiment,and pressure point constant test results showed that when the mass ratio of barium titanate to composite film was 20%,the polarized composite film material had good physical and chemical properties.After polarization,the piezoelectric constant of d33 reached(7.03±0.26)p C/N,and the difference was statistically significant compared with other groups(P<0.05).2 CCK-8 assay results showed that on the 4th day of culture,the proliferation activity of the cells in the polarized 20% group was higher than that in the unpolarized 20% group(P<0.05).On the 7th day of culture,the proliferation activity of the cells in the polarized20% group was higher than that of the blank control group,the unpolarized 0% group,and the unpolarized 20% group(P<0.05);the fluorescence microscope and scanning electron microscope exhibited that the cells in the polarized 20% group were polygonal and had obvious pseudopodia;compared with the unpolarized 20% group,polarized 0% group and unpolarized 0% group showed better cell adhesion ability;the alkaline phosphatase activity detection results showed that on the 4th day of culture,the alkaline phosphatase activity of the polarized 20% group was higher than that in the unpolarized 0% group and the unpolarized 20% group(P<0.05);on the 7th day of culture,the alkaline phosphatase activity of the polarized 20% group was higher than that of the unpolarized 0% group,the unpolarized 20% group,and polarized 0% group(P<0.05).3 X-ray and CBCT scanning results showed that in the polarized 20% group,obvious new bone was formed from the defect edge to the center within 4 weeks,and the defect area was significantly reduced.At 12 weeks after surgery,the defect was almost completely closed,and the new bone was smooth and continuous,and the bone density was similar to normal bone tissue.New bone was formed in the polarized 0% group at 4weeks,but the defect closure was not as good as that in the polarized 20% group.The defect was not closed at 12 weeks,and the new bone was thin.The results of HE and Masson staining showed that in the polarized 20% group,bone regeneration was active and new bone formation was obvious at 4 weeks,while in the 12 weeks,new bone completely occupied the defect area and mineralization was obvious.In the polarized 0% group,less new bone was observed at the defect edge at 4 weeks,and the original bone was not completely healed at 12 weeks after surgery.Only a small amount of new bone was formed at the defect edge in the unpolarized 20% group and the unpolarized 0% group.The defect group was filled with thin,loose connective tissue.The quantitative histological results showed that the bone repair in the polarized 20% group was the best at 4 weeks and 12 weeks after surgery,which was significantly better than that in the polarized 0% group,the unpolarized 20% group and the unpolarized 0% group;polarization 0% group followed;the defect group had the worst bone repair(P<0.05).Conclusions 1 BT/PLA composite piezoelectric film material has good piezoelectric property and cytocompatibility.2 The excellent osteogenic property of BT/PLA composite piezoelectric film has been confirmed in vitro and vivo experiments,which provides a new idea for the selection of guiding bone tissue regeneration membrane materials.Figure 27;Table 6;Reference 85... |
PDF Full Text Request