3D打印磷酸钙涂层多孔镁金属支架的力学性能和生物相容性评估

Mechanical properties and biocompatibility assessment of 3D printed calcium phosphate coated porous magnesium metal scaffolds

背景负重部位骨松质的大面积缺损修复是临床中一个待解决的难题,多孔镁金属结合磷酸钙(Ca-P)生物活性涂层有望克服这一难题,但缺乏相应力学和生物相容性评价。目的评价Ca-P涂层多孔镁金属支架的力学性能和生物相容性。方法采用选择性激光熔化3D打印工艺制备多孔镁金属支架,通过化学转化法在多孔纯镁金属支架表面制备Ca-P生物活性涂层,与无涂层镁金属支架做对比。采用扫描电子显微镜和能量色散X射线能谱对材料涂层的形貌、成分进行表征;通过压缩力学实验绘制应力-应变曲线,并计算支架屈服强度和弹性模量。采用CCK-8法、活死染色和细胞黏附等手段检测多孔镁金属支架的生物相容性。结果制备Ca-P涂层多孔镁金属支架;扫描电子显微镜和能量色散X线能谱结果显示多孔镁金属支架内部镁颗粒呈现出融合体状;Ca-P涂层由花瓣状晶粒以一定的取向相互堆叠而成,与基体无缝隙紧密结合。力学性能测试显示,Ca-P涂层多孔镁金属支架抗压强度高于无涂层支架[(35.3±0.7)Mpa vs(31.0±1.0)Mpa,P=0.003,n=3],杨氏模量高于无涂层支架[(656.0±8.7)Mpa vs(623.0±7.0)Mpa,P=0.007,n=3];生物相容性结果显示,相比空白组,Ca-P涂层支架有显著促增殖作用,无涂层支架有显著抑制作用。结论相比无涂层多孔镁金属支架,Ca-P涂层多孔镁金属支架力学性能优,生物相容性好,可用于负重部位骨松质缺损的修复。

Background The restoration of large cancellous bone defects in weight-bearing sites is a major problem to be solved in clinical practice.Currently,calcium phosphate(Ca-P)bioactive coatings combined with porous magnesium is expected to solve this problem,but the evaluation of mechanical properties and biocompatibility is lacking.Objective To evaluate the mechanical properties and biocompatibility of the porous magnesium scaffolds with Ca-P coating.Methods The porous magnesium scaffold was manufactured by selective laser melting 3D printing and Ca-P bioactive component was successfully coated on the surface of scaffolds by chemical transformation while the scaffold without coating was the control group.The morphology and composition of the coating were characterized by scanning electron microscopy(Scanning electron microscope,SEM)and energy dispersive spectroscopy(Energy-dispersive X-ray spectrometry,EDS).The compression mechanics experiment was conducted and the stressstrain curve was drawn to calculate the yield strength and elastic modulus of the scaffold.The biocompatibility of porous magnesium scaffolds was tested by CCK-8 assay,live and dead staining and cell adhesion experiment.Results Porous magnesium scaffolds with Ca-P coating had been successfully manufactured.The results of SEM and EDS showed that the magnesium particles in porous magnesium scaffolds presented a fused sheet and the Ca-P coating was composed of petal-like grains stacked with each other in a certain orientation,integrated with magnesium matrix closely.Mechanical tests showed that the compressive strength of porous magnesium scaffolds coated with Ca-P was higher than that of non-coated scaffolds(35.3±0.7 Mpa vs 31±1.0 Mpa,P=0.0029,n=3),so as Young's modulus(656±8.7 Mpa vs 623±7.0 Mpa,P=0.0076,n=3).The biocompatibility experiments showed that compared with the control group,Ca-P coated scaffolds significantly promoted cell proliferation(P<0.05),while uncoated scaffolds had significant inhibitory effect(P<0.05).Conclusion The Ca-P coated porous magnesium scaffolds are featured with strong mechanical properties and good biocompatibility,which can be applied for the treatment of cancellous bone defects in weightbearing sites.