中文摘要：

采用滴注法将海藻酸钠与钙离子交联,制成负载血管内皮生长因子（VEGF）的藻酸钙核心球,利用层层自组装技术在核心球的表面依次包覆壳聚糖、海藻酸和壳聚糖,壳聚糖中负载万古霉素（VAN）,形成多药载药缓控体系.采用正交实验考察海藻酸钠浓度、钙离子浓度及壳聚糖浓度对VEGF和VAN的药物包封率和载药量的影响,优化了制备工艺.采用扫描电子显微镜观察多层微球的表面、截面形貌及粒径,采用傅里叶变换红外光谱检测海藻酸盐与壳聚糖的自组装情况,分别采用酶联免疫吸附（ELISA）双抗体夹心法和紫外分光光度法检测VEGF和VAN的包封率、载药量及体外释放情况.结果表明,海藻酸钠最优浓度为0.04g/mL,氯化钙最优浓度为0.15g/mL,壳聚糖最优浓度为0.01g/mL.微球光滑圆整,均质实心,直径900~1100μm,VEGF的包封率达61.31%,VAN的包封率为3.48%.体外释放实验结果表明,VEGF缓释时间为15.5d,并出现2个释放高峰;VAN缓释时间为4.5d,释药情况平稳持续,无明显突释.双重载药多层包覆微球兼具控制感染和促进血管生成两种潜能,有望应用于组织工程骨的基础研究和临床实践.

英文摘要：

The core ball carrying vascular epithelial growth factor（VEGF） was first prepared by crosslinking of alginate and calcium.Then,chitosan,alginate,and chitosan again were coated on the surface of the core ball layer by layer using self-assembly technology,which constituted a multi-drug loaded release-controlled system at last,and vancomycin was loaded in the chitosan layer.The effect of the concentration of alginate,calcium and chitosan on microspheres＇ morphology,size,drug loading and in vitro release was studied by an orthogonal experiment to find the best formula design.Morphologies of the surface and cross section and diameter were observed by scanning electron microscopy（SEM）.Infrared absorption spectrum of the multilayer microspheres was also detected by Fourier transformed infrared spectrometer（FTIR）.The result showed that the best concentrations of alginate,calcium and chitosan were 0.04,0.15 and 0.01 g / m L,respectively.And in this case,the multilayer microspheres were typical spherical with smooth surface and the internal solid structure with a diameter ranging from 900 to 1100 μm.The entrapment efficiency of VEGF and vancomycin was 61.31% and 3.48%,respectively.In vitro,the release of VEGF could be sustained stably for up to15.5 d with two releasing peak,which is surprising and exciting.As well,the release of vancomycin lasted for 4.5 d,which also meets the clinical needs.The research indicates that VEGF and vancomycin loaded multilayer microspheres possess good controlled release characteristics and have the potentials of controlling infection and promoting vascularization at the same time,which is hopeful for basic research and clinical application of tissue engineering bone（TEB）.