骨修复材料聚磷酸钙晶型对其降解性能和细胞相容性的影响

Effect of crystal type on degradation and cell compatibility of calcium polyphosphate for bone repair

背景:聚磷酸钙是具有生物活性、可生物降解性和适当力学性能的新型骨修复材料,但是晶型对它的降解性能和细胞相容性的影响罕见报道。目的:探索骨修复材料聚磷酸钙的晶型对其降解性能和细胞相容性的影响规律。设计、时间及地点:对比观察实验,于2005-12/2007-02在四川大学组织工程支架材料研究室完成。材料:通过控制保温温度,制备不同晶型的聚磷酸钙。方法:进行体外降解实验,用扫描电镜观察其形貌;进行细胞相容性实验,观察成骨细胞在浸提液和降解液中的生长情况。主要观察指标:不同晶型聚磷酸钙失重率,磷酸根浓度,骨细胞生长曲线,细胞增殖率,细胞毒性。结果:不同晶型聚磷酸钙的降解速率与磷酸根浓度增长速率一致,都是γ-聚磷酸钙>β-聚磷酸钙>α-聚磷酸钙。不同晶型聚磷酸钙的浸提液和降解液中细胞生长速率不同,在第6天时β-聚磷酸钙增殖率最高;浸提液和降解液中β-聚磷酸钙、α-聚磷酸钙细胞毒性均为0;γ-聚磷酸钙在前期细胞毒性为0,后期为1。结论:通过改变聚磷酸钙的晶型可以调节其降解速率;各种晶型聚磷酸钙具有良好的细胞相容性,其中β型聚磷酸钙促成骨细胞增殖最明显,可作为新型骨修复材料。

BACKGROUND： Calcium polyphosphate （CPP）, which has the nature of bioactivity, biodegradation and proper mechanical property, is a novel material for bone repair. But until now, the effect of crystal type on its degradation and cell compatibility is still a question. OBJECTIVE： To explore the effect of crystal type on the degradation and cell compatibility of CPP for bone repair. DESIGN, TIME AND SETTING： Control observations were performed at the Laboratory of Tissue Engineering Scaffold Materials in Sichuan University from December 2005 to February 2007. MATERIALS： CPP with different crystal types was prepared by sintering at different temperature. METHODS： The degradation experiment was done in vitro. The sample was characterized by scanning electron microscope. The cell compatibility was studied by observing the growth of osteoblasts in the leaching liquor and degradation liquor. MAIN OUTCOME MEASURES： The weight loss of CPP with different crystal type was calculated in the degradation experiment in vitro： the concentration of PO4^3- from CPP during the degradation was determined by molybdenum blue photometric method： in leaching and degradation liquor, the growth curve of osteoblasts, RGR and toxicity grade was obtained respectively. RESULTS： The speed of degradation was γ-CPP〉β-CPP〉 α -CPP, which was consistent with the speed of the PO4^3- concentration increase. The growth rate of osteoblasts in the leaching liquor and degradation liquor of CPP with different crystal types was distinct, the highest value was observed in β-CPP at 6 days. The toxicity grade of α -CPP and β -CPP was 0, and the cell compatibility of γ-CPP was 0 at first and then turned to be 1. CONCLUSION： The degradation rate of CPP can be controllable by changing its crystal structure, and its favorable compatibility will enable CPP, especially β-CPP is the most effective to promote the proliferation of osteoblasts, thus it can be used as a novel bone repair material.