超临界流体技术制备脱矿骨基质/聚乳酸复合材料及相关性能

摘要

目的:以聚乳酸(PLA)为塑型剂,通过超临界二氧化碳(SC-CC2)合成法,将脱矿骨基质(DBM)构建成三维多孔组织工程骨材料,并选取最适复合分子量及最适复合比例,为骨库大量骨皮质不能被有效利用提供一种有效的解决办法.方法:取不同重均分子量的PLA,利用SC-CO2合成法制备多孔材料,通过孔隙率、生物力学性能评价,筛选出与DBM复合的最适分子量；将DBM与PLA按1/9、2/8、3/7、4/6、5/5、6/4、7/3质量比均匀混合,相同方法制备一系列复合多孔材料,通过孔隙率、生物力学性能、体外细胞毒性、扫描电镜观察,选择最适的DBM/PLA复合比例.结果:5万、10万、50万重均分子量PLA支架材料孔隙率分别为65.39％、76.46％、85.52％,10万重均分子量PLA支架材料抗压强度及弹性模量为264.03及49.71MPa,优于5万及50万重均分子量PLA; DBM与PLA不同比例复合,随着DBM含量的增加材料孔隙率逐渐变大,力学性能逐步下降,细胞毒性逐渐降低,当DBM含量为60％时,材料的孔隙率为79.71％,抗压强度及弹性模量为108.72及13.82MPa,细胞毒性为0级或1级,扫描电镜观察材料混合均匀,结合致密,材料孔隙分布均匀.结论:10万重均分子量的PLA更适合与DBM进行复合；6/4为DBM/PLA的最佳复合比例.%Objective: To prepare a composed biomaterial of demineralized bone matrix (DBM) with polylactic acid (PLA) through supercritical carbon dioxide (SC-CO2) synthesis, in order to widen utilization of cortical bone of tissue bank. Meth ods: Porous composite was made by PLA of different molecular weight, and sodium chloride served as moulding agent. In terval porosity and mechanical properties were tested to decide the most appropriate molecular weight of PLA. DBM and PLA were mixed according to different mass ratios (1/9, 2/8, 3/7, 4/6, 5/5, 6/4, 7/3 ) and series porous composited ma terials were prepared by the SC-CO2 synthesis. The interval porosity, mechanical properties and cytotoxicity in vitro were tested and electronic microscopic (SEM) scanning was performed to determine the mixture of DBM and PLA with biggest in tensity. Results: The interval porosity of the composed scaffold prepared with different molecular PLA was 65.39% (50 kD), 76. 46% (100 kD), and 85. 52% (500 kD). The compressive strength and elastic modulus of the polymer com posed with PLA (100 kD) were 264. 03 Mpa and 49. 71 Mpa respectively, which were better than those of the polymer com posited with PLA of 50 kD or 500 kD. The interval porosity of the composite was up-regulated with the increasing of DBM content, while the mechanical properties and cytotoxity dropped inversely. When DBM reached 60% of the DBM/PLA com posite, the interval porosity was 79. 71%, the compressive strength and elastic modules was 108. 72 Mpa and 13. 82 Mpa re spectively, and the cytotoxicity ranks scored 0 or 1. SEM observation also showed that DBM and PLA mixed equally and compactly with well distributed pores. Conclusion : PLA (100 kD) is more suitable to be composited with DBM and 6 ∶4 is the best ratio of DBM and PLA.