纳米羟基磷灰石表面接枝聚合左旋丙交酯

为了改善HA纳米粒子与有机PLGA的相容性,分别采用六亚甲基二异氰酸酯加乙二醇、左旋乳酸改性纳米粒子表面后或直接原位接枝聚合左旋丙交酯等3种不同方法,制备了表面修饰聚乳酸的纳米羟基磷灰石(PLLA-g-HA).FTIR、XPS、TEM、TGA测试表明PLLA成功接枝到HA的表面.其中六亚甲基二异氰酸酯加乙二醇改性HA纳米粒子所获得的PLLA接枝率远高于其它两种方法达25%,调整有机相和无机相的比例对PLLA接枝率的影响较小,其在氯仿中可以稳定分散2天以上.共混电纺丝后的拉伸测试表明PLLA-g-HA/PLAG复合纤维膜的力学性能高于HA/PLGA膜,当两者之间的比例为5%拉伸性能达到最大值.

GRAFTING POLYMERIZATION OF L-LACTIDE ON HYDROXYAPATITE NANOPARTICLES

Poly(lactid-glycolide acid)/hydroxyapatite(PLGA/HA) materials,as a class of composites,which have good bioactivity,absorbability and biodegradability,show promising applications in biomedical and tissue engineering fields.To improve the compatibility of HA and PLGA,the ring-opening polymerizations of L-lactic acid on three types of HA surfaces with different surface hydroxyl functionality:unmodified HA,HA modified with L-lactic acid,and HA modified with hexamethylene diisocyanate tethered ethylene glycol were carried out to produce poly(L-lactide acid) grafted hydroxyapatite(PLLA-g-HA).The results of FTIR,XPS,TEM and TGA show that PLLA was successfully grafted onto surface of HA by the above three methods.And the grafting rate of PLLA was dependent on the nature and steric environment of the hydroxyl groups on the HA surfaces,among which HA modified with(HMDI+EG) presented the best grafting percentage of 25%.The proportional change between inorganic and organic phase brought about little influence on PLLA grafting rate.The PLLA-g-HA can stably disperse in chloroform over 2 days without deposition.To investigate practicability of the composites used as bone guided regeneration membranes,tensile test after co-electrospinning shows that PLLA-g-HA/ PLAG nanofibrous membrane has better mechanical performance compared to HA/PLGA membrane,and its tensile force reaches maximum at 5% filling content.