掺锶聚磷酸钙的微观结构、体外降解性能和血管内皮细胞相容性研究

以聚磷酸钙（CPP）为对照，研究掺锶聚磷酸钙（SCPP）微观结构、体外降解产物和速率以及血管内皮细胞相容性，探讨了掺锶对CPP结构性能的影响。结果表明，掺锶改变材料的微观结构与降解性能。与CPP相比，SCPP材料晶粒变大，晶粒间连接更紧密形成平整表面；14 d SCPP降解释放的Ca2+和Pi浓度显著下降，即降解速率变慢，降解产物中出现Sr2＋，且浓度随时间增加。体外细胞培养结果显示，掺锶能提高材料与血管内皮细胞的相容性。SCPP表面内皮细胞更易粘附、铺展，融合生长形成单层内皮覆盖材料表面。SCPP降解液能显著促进内皮细胞的增殖(p<0.05)，经多元逐步回归分析知，降解液中的Sr2＋为影响增殖的主要因素(R2=0.670, p<0.01)。SCPP较CPP具有更好的血管内皮细胞相容性，可能促进血管的形成，是更理想的骨组织工程支架材料。

Study on the Microstructure, Degradation in vitro and the Cytocomptibility to Vascular Endothelial Cells of Strontium doped Calcium Polyphosphate

With the calcium polyphosphate(CPP) as a control, the microstructure, degradation in vitro and the cytocomptibility to vascular endothelial cells(VECs) of strontium-doped calcium polyphosphate(SCPP) were investigated, and the effects of strontium on the structure and properties of CPP scaffold were discussed. The crystalline grain of SCPP were enlarged, which linked together more tightly and developed a smoother surface. Moreover, the degradation rate of SCPP was slower. In the degradation fluid of SCPP, strontium was detected, the concentration of which increased with time. The cytocompatibility of SCPP was promoted apparently. The VECs on the SCPP scaffold attached more quickly and fully spreaded, developing a monolayer endothelium and wrapping the surface of scaffold. After cultured with the degradation fluid of SCPP, cell proliferation ability was up-regulated significantly(p<0.05). As the multiple stepwise regression results demonstrated, the main reason for proliferation increase is the strontium ions in the degradation fluid(R2=0.670, p<0.01).The results showed that, SCPP is more compatible with VECs, which is essential in angiogenesis, and may serve as a more promising scaffold for bone tissue engineering.