高性能多孔β-磷酸三钙骨组织工程支架的3D打印

摘要

背景：虽然采用溶液浇铸/离子洗出法、原位成型法、静电纺丝法、相分离/冻干法、气体成孔法等制备骨组织工程支架可以获得比较满意的效果，但在精确性、孔隙均匀性、空间结构复杂性、支架个性化等方面略显不足。　　目的：利用3D打印制备β-磷酸三钙骨组织工程支架。　　方法：利用3D打印制备载药β-磷酸三钙支架，观察其结构，测量其孔隙率和力学强度。将载药β-磷酸三钙支架置入模拟体液中15周，观察其质量变化。将载药β-磷酸三钙支架与大鼠骨髓间充质干细胞共培养7 d，观察细胞黏附与形态变化。分别采用载药β-磷酸三钙支架浸提液与含体积分数15%胎牛血清的低糖 DMEM培养基培养大鼠骨髓间充质干细胞，培养24，48，72 h检测细胞A值，并确定细胞毒性分级；同时成骨诱导培养1周，检测两组细胞碱性磷酸酶活性。　　结果与结论：实验制备的支架微观孔隙呈不规则形，孔隙率高，孔隙分布均匀，孔隙连通率高，抗压强度大。载药β-磷酸三钙支架在15周内基本降解完全，与松质骨缺损修复时间相当。大鼠骨髓间充质干细胞黏附于载药β-磷酸三钙支架表面，并深入支架内部，生长良好，增殖活跃，细胞碱性磷酸酶活性有提高，说明载药β-磷酸三钙支架具有良好的细胞相容性。%BACKGROUND:Although the preparation of bone tissue engineering scaffolds can achieve satisfactory results by solvent casting/particulate leaching, in situ molding method, electrospinning, phase seperation/freeze drying, gas foaming, there are stil some deficiencies in the accuracy, pore uniformity, spatial structure complexity, personalized stents. OBJECTIVE:To prepareβ-tricalcium phosphate bone tissue engineering scaffolds using 3D printing. METHODS:Drug-loadedβ-tricalcium phosphate scaffolds were prepared with 3D printing, and the structure was observed to measure its porosity and mechanical strength. The scaffold was immersed in simulated body fluid for 15 weeks to observe the quality change. The scaffold was co-cultured with rat bone marrow mesenchymal stem cells for 7 days to observe celladhesion and morphological changes. Rat bone marrow mesenchymal stem cells were cultured in extracts of drug-loadedβ-tricalcium phosphate scaffold and low-glucose Dulbecco's modified Eagle’s medium containing 15%fetal bovine serum for 24, 48, and 72 hours, to determine the absorbance values and cytotoxicity grading, respectively. Meanwhile, the cells were subjected to osteogenic culture for 1 week, and the alkaline phosphatase activities in two groups were detected. RESULTS AND CONCLUSION:The prepared scaffold showed irregular micropores, high porosity, uniform pore distribution, high pore connectivity rate, and large compressive strength. The drug-loadedβ-tricalcium phosphate scaffold degraded completely with 15 weeks, and cancellous bone defect repair was completed in the same period. Rat bone marrow mesenchymal stem cells adhered to the surface of drug-loadedβ-tricalcium phosphate scaffold and went deep into the scaffold, showing good growth and proliferation. The activity of alkaline phosphatase was also improved. These findings indicate that the drug-loadedβ-tricalcium phosphate scaffold has good biocompatibility.