PDGF/BMP-2-CMsHA/PLGA复合支架的制备及性能

摘要

将壳聚糖缓释微球与可降解多孔支架复合,构建可次第释放不同生长因子的骨组织工程支架,并进行表征和性能研究.首先,制备载骨形态发生蛋白-2的壳聚糖微球(BMP-2-CMs),然后将微球与纳米羟基磷灰石/羟基乙酸(nHA/PLGA)及血小板衍生生长因子(PDGF)按照一定的比例混合,通过粒子沥虑-冷冻干燥复合工艺制备PDGF /BMP-2-CMsHA/PLGA复合支架.BMP-2-CMs呈规则球形,粒径分布在4～10 μm之间,BMP-2包封率为65.9％,载药量为0.134％.PDGF/BMP-2-CMsHA/PLGA复合支架孔径为100～200 μm,孔隙率为51.2％,抗压强度为7.7 MPa,8周降解率为20.1％.7d时,PDGF和BMP-2累计释放率分别为75.0％和42.2％;14 d时,PDGF和BMP-2累计释放率分别为79.9％和53.5％.分析可知,复合支架中释放的PDGF和BMP-2能够持续有效地促进人脐静脉血管内皮细胞(HUVEC)和成骨细胞(MG63)的增殖和分化,具有良好的生物活性.由此可得,PDGF/BMP-2-CMsHA/PLGA复合支架能够次第释放PDGF和BMP-2,且能够显著促进HUVEC和MG63的增殖和分化.%In order to construct a bone regeneration scaffold that could sequentially releasedifferent growth factorsat proper stage,the composite of sustained-release microspheres and biodegradable porous scaffolds was prepared in this study.Firstly,BMP-2 loaded chitosan microspheres (CMs) were prepared and compounded to the nano hydroxyapatite/poly lactic-co-glycolic acid (nHA/PLGA) with PDGF to build a scaffold that can release growth factors sequentially.The results showed that the BMP-2-CMs were spherical shape with diameters of 4-10 μm.The encapsulation efficiency of the BMP-2 in CMs was 65.9％ and the loading capacity was 0.134％.The prepared PDGF/BMP-2-CMsHA/PLGA scaffold possessed 100-200μm pore diameter,51.2％ porosity,7.7 MPa compressive strength and 20.1％ degradation at 8 weeks.The cumulative releases of PDGF and BMP-2 from PDGF/BMP-2-CMsHA/PLGA scaffolds were respectively about 75.0％ and 42.2％ at 7 d and 79.9％ and 53.5％ at 14 d.PDGF and BMP-2 released from scaffold could promote cell proliferation and differentiation effectively.The biological activity of these growth factors was more durable and effective.The results demonstrated that PDGF/BMP-2-CMsHA/PLGA scaffolds had excellent drug sustained-release performance,which would controllably release PDGF and BMP-2 sequentially and maintain their biological activity effectively.