【作者】 汪学军；

【导师】 宋国君；

【作者基本信息】 青岛大学 ， 材料学， 2009， 博士

【摘要】 组织工程研究中,支架的构建是一个非常重要的内容。为了模仿天然细胞外基质的纳米纤维结构,本文研究采用热致相分离法制备了聚乳酸纳米纤维多孔支架,其纤维直径约为80～750 nm,支架的孔隙为微米级,孔径约为1～20μm,且相互贯穿连通,孔隙率高达94.6%,支架具有纳米和微米共存的亚微观结构形态。但是纳米纤维支架的力学性能较低,本文制备了羟基磷灰石或壳聚糖纤维增强型聚乳酸纳米纤维复合支架,并研究了它们的微观结构、孔隙率、力学性能、体外降解和蛋白质吸附等特性。引入纳米羟基磷灰石大幅度增强了聚乳酸纳米支架网络,并有效减缓了聚乳酸在体外降解过程中的pH下降和提高了单位质量支架的蛋白质吸附能力。硅烷改性的纳米羟基磷灰石提高了羟基磷灰石与聚乳酸的界面结合力,使羟基磷灰石分散情况更好,在增强效果以及蛋白质吸附能力上又有进一步的提高。同样,引入壳聚糖纤维大幅度增强了聚乳酸纳米支架网络,并有效减缓了聚乳酸在体外降解过程中的pH下降和提高了单位质量支架的蛋白质吸附能力。利用DCC对壳聚糖纤维进行表面改性,在壳聚糖纤维表面缩合聚乳酸,有效提高了壳聚糖纤维与聚乳酸的界面结合力,改性壳聚糖纤维在支架中的分散情况更好。综合研究结果表明,采用羟基磷灰石或壳聚糖纤维与聚乳酸复合制得的多孔纳米纤维支架具有良好的微观结构、孔隙率、压缩模量、体外降解特性和蛋白质吸附能力,可作为一种新型的综合性能良好的组织工程支架使用。更多还原

【Abstract】 Scaffold fabrication is one of key processes in tissue engineering.To mimic the nano-fibrous architecture of natural extracellular matrix,porous nano-fibrous poly-L-lactic acid(PLLA) scaffold was fabricated by thermally induced phase separation method.The scaffold combined nano-and micro-architecture,in which it had nanometer fiber(diameter around 80～750 nm),interconnective pores(D=1～20μm) and high porosity(94.6%).However,nano-scale scaffolds are weaker than the microscale scaffolds. In this study,nano-fibrous PLLA scaffolds reinforced by nano-hydroxyapatite(HAP) or micro-scale chitosan(CTS) fibers were also fabricated,the morphology,mechanical performance,pH changes in vitro degradation and protein adsorption of the scaffolds were also investigated.Incorporation of HAP into the PLLA matrix significantly enhanced the scaffold, effectively retarded the pH decline in vitro degradation and increased the ability of protein adsorption of the composite scaffold.Through the surface modification of HAP by silane A174,it increased the interracial connection between the PLLA and HAP.As a result,the silane modified HAP could be more homogeneously dispersed in the scaffold and enhanced the PLLA matrix more effectively than non-modified HAP did.Similarly,incorporation of CTS fibers into the PLLA matrix significantly enhanced the scaffold,effectively retarded the pH decline in vitro degradation and increased the ability of protein adsorption of the composite scaffold.Through the condensation reaction between PLLA and CTS fibers,it increased the interfacial connection between the PLLA and CTS fibers.Therefore,the surface modified CTS fibers could be more evenly distributed in the scaffold.In all,the nano-fibrous PLLA scaffold reinforced by HAP or CTS fibers had excellent performance of morphology,mechanical strength,pH changes in vitro degradation and protein adsorption,this new composite scaffold might be a very promising scaffold for tissue engineering.更多还原