可注射聚富马酸丙二醇酯/β-磷酸三钙骨水泥的体外生物活性及其降解性

In vitro bioactivity and degradability of injectable poly(propylene fumarate)/beta-tricalcium phosphate bone cement

背景:聚富马酸丙二醇酯具有室温固化特性,β-磷酸三钙具有良好的生物相容性,但是目前缺乏聚富马酸丙二醇酯/β-磷酸三钙复合骨水泥的系统研究。目的:制备聚富马酸丙二醇酯/β-磷酸三钙复合骨水泥,考察其体外生物活性和降解性。方法:采用液相沉淀法制备β-磷酸三钙,两步法合成聚富马酸丙二醇酯高分子,制备可注射聚富马酸丙二醇酯/β-磷酸三钙复合骨水泥。(1)体外矿化:将聚富马酸丙二醇酯/β-磷酸三钙复合骨水泥、聚甲基丙烯酸甲酯骨水泥分别浸泡于模拟体液中7 d,检测材料表面羟基磷灰石沉积。(2)体外降解:将聚富马酸丙二醇酯/β-磷酸三钙复合骨水泥浸泡于PBS中,在相应的时间点检测吸水率、失重率、体系pH值、压缩强度及表面和断面形貌变化。结果与结论:(1)体外矿化:可注射聚富马酸丙二醇酯/β-磷酸三钙复合骨水泥表面能够沉积羟基磷灰石,聚甲基丙烯酸甲酯骨水泥表面未沉积羟基磷灰石;(2)体外降解:聚富马酸丙二醇酯/β-磷酸三钙在PBS中63 d内体系pH值稳定,材料降解温和;84 d材料失重率为13.5%;扫描电镜显示聚富马酸丙二醇酯/β-磷酸三钙表面为溶蚀降解,压缩强度随着降解时间延长逐渐降低,有利于降解过程中力学性能的完整性和持续性;(3)结果表明:聚富马酸丙二醇酯/β-磷酸三钙复合骨水泥是一种具备体外矿化和降解能力的材料。

BACKGROUND：Poly（propylene fumarate） （PPF） can crosslink at room temperature, andβ-tricalcium phosphate （β-TCP） has good biocompatibility, but PPF/β-TCP composite bone cement has not yet been systematical y studied. OBJECTIVE：To prepare PPF/β-TCP composite bone cement and to explore its in vitro bioactivity and degradability. METHODS：β-TCP and PPF were respectively synthesized by liquid-phase precipitation and a two-step method, and PPF/β-TCP composite bone cement was prepared through mixing PPF withβ-TCP. The in vitro bioactivity of PPF/β-TCP was compared with the commercial poly（methyl methacrylate） （PMMA） through the ability of forming hydroxyapatite after immersed in simulated body fluid for 7 days. The in vitro degradability of PPF/β-TCP was studied via investigating the transformation of pH values, water uptake and mass loss, compressive strength and morphology at each time point. RESULTS AND CONCLUSION：There were hydroxyapatites formed on the PPF/β-TCP material, but none on the commercial PMMA material. The pH values of the PPF/β-TCP were stable in PBS for 63 days, indicating its degradation is moderate;the mass loss was up to 13.5%after 84 days. Scanning electron microscope displayed the degraded PPF/β-TCP surface, and its compressive strength was decreased gradual y, which good for the integrity and sustainability of mechanical properties during degradation. These results suggest that PPF/β-TCP bone cement holds mineralization and degradability in vitro.