β-偏磷酸钙晶须增强左旋聚乳酸材料的体外降解

对用于骨折内固定的β-偏磷酸钙晶须/左旋聚乳酸(β-CMP_W/PLLA)复合材料在体外降解过程中强度的变化、 分子量和微观形貌进行了初步研究。结果表明: 在人体模拟体液(SBF)中浸泡, 前8周材料的强度变化较小, 25wt%β-CMP_W/75wt%PLLA降解20周后的抗压强度值仍高达103MPa; 45wt%β-CMP_W/55wt%PLLA降解12周后抗压强度约为初始值的88%。扫描电镜图表明, 随降解时间的延长, 因聚乳酸溶解而在样品中形成孔洞。在降解周期内, SBF溶液的pH值随β-CMP_W/PLLA降解时间的延长基本保持稳定。凝胶渗透色谱检测结果表明, PLLA的数均相对分子质量和重均相对分子质量随降解时间的延长而降低, 降解20周后数均相对分子质量约为20万, 重均相对分子质量下降了32%。

In vitro degradation behavior of β-calcium metaphosphate whiskers/poly L-lactide composite

The strength, molecular weight and morphology of β-calcium metaphosphate whiskers/poly L-lactide composites (β-CMPW/PLLA) for internal fixation of bone fractures were measured after degradation in the simulated body fluid. The results indicate that the compress strength of the composites can maintain in 8 weeks. The strength of 25wt% β-CMPW/75wt% PLLA maintains at 103 MPa in 20 weeks, and the strength of 45wt% β-CMPW/55wt% PLLA drops to approximately 88% of the initial value in 12 weeks. The scanning electron microscope (SEM) images show that PLLA disappears increasingly and a few pores are formed on the rods surface of the samples. The pH value of the simulated body fluid can keep stabilization during degradation. Gel permeation chromatography(GPC) patterns show that the molecular weight of PLLA significantly decreases with the immersion time. The number-average molecular weight is about 200000 and the weight-average drops 32% after degradation for 20 weeks.