聚乳酸/羟基磷灰石复合材料的机械性能及其细胞毒性

Mechanical properties and cytotoxicity of polylactic acid/hydroxyapatite composites

目的：制备不同质量配比聚乳酸／羟基磷灰石（PLLA／HA）复合材料，对其机械性能和细胞毒性进行研究，得出两者的最佳质量配比，并探讨其作为乳前牙根管桩材料的可行性。方法：以NH4H2PO4、Ca（CH3COO）2·H2O和CH3COONH4为原料制备微球型HA。采用溶液共混法和热压成型法制备PLLA／HA复合材料，按复合材料中HA质量分数不同分为PI上A、PLLA-3％HA、PLLA-5％HA、PLLA-7％HA和PLLA9％HA组。采用扫描电子显微镜（SEM）观察HA形貌和尺寸；X射线晶体衍射（XRD）法进行物相分析；傅立叶变换红外光谱（FT—IR）法分析产物成分；万能材料试验机测试复合材料的弯曲强度和弹性模量；MTT法检测PLLA／HA复合物对L929细胞相对增殖率（RGR）的影响。结果：扫描电镜，所制备的HA为片层状晶体所构成的微球形，直径约1μm，大小均匀，形态一致。XRD图谱，观测到HA的特征峰，无明显杂峰。FTIR谱图中可见PO4^3-基团在565、606和1042cm。处的强吸收峰。与PLLA组比较，含有HA的各组PLLA—HA复合材料的弯曲强度和弹性模量明显增高（P〈0．01），PLLA-5％HA组材料的弯曲强度和弹性模量最大（138MPa、4．6GPa）。MTT法，PLLA、PLLA-3％HA、PLLA-5％HA、PLLA-7％HA和PLLA-9％HA各组复合材料RGR均在93％以上，细胞毒性级别均为0～1级。结论：PLLA／HA复合材料具有一定的力学性能，无细胞毒性，有望成为理想的乳前牙根管桩材料。

Objective To prepare polylactit acid / hydroxyapatite （PLLA/HA） composites by different mass ratios of PLLA and HA, and to investigate its mechanical properties and cytotoxicity to draw the best mass ratio of PLLA and HA, and to explore its feasibility as the root canal of the maxillary primary anterior teeth. Methods HA microspheres were prepared with NH4H2PO4, Ca （CH3COO）2 ~ H20, and CH3COONH4. PLLA/HA composites were prepared with solution blending and compression molding method. PLLA/HA composites were divided into PLLA, PLLA-3% HA, PLLA-5% HA, PLLA-7% HA, and PLLA-9% HA groups according to different HA mass percentages. The morphology and size of HA were observed by scanning electron microscope （SEM） ; the phase analysis was characterized by X-ray diffraction （XRD） ; the product ingredients were analyzed by fourier transform infrared spectroscope （FT-IR） ; the flexural strength and elasticity modulus of the composites were tested by universal material tester; MTT method was used to detect the influence of PLLA / HA composites in the relative growth rate（RGR） of L929 cells. Results The SEM results showed that the diameter of HA microspheroidals was 1 μm and HA was composed by lamellar crystals, possessing uniform size. HA characteristic peak was observed in the XRD pattern which showed no significant artifact peaks; the strong absorption peaks of PO4^3- groups were observed at 565, 606, and 1 042 cm 1 by FT-IR spectra. Compared with PLLA group, the flexural strength and elastic modulus in different PLLA/HA groups were increased significantly （P〈0.01）, and the meterial in PLLA-5% HA group reached the maximum flexural strength and elastic modulus （138 MPa, 4.6 GPa）. The MTT results showed the RGR of cells in PLLA, PLLA-3% HA, PLLA-5% HA, PLLA-7% HA, and PLLA-9% HA groups were all above 93%, and the cytotoxicity levels were 0 - 1. Conclusion PLLA/ HA composite material is expected to become the ideal root canal material of the maxillary primary anterior teeth due to the certain mechanical properties and non-cytotoxicity.