中文摘要：

采用共沉淀法制备了复合转化生长因子-β1（TGF-β1）的磺化壳聚糖/聚赖氨酸纳米粒子（SCS/PLL/TGF-β1）,研究了磺化壳聚糖的浓度对纳米粒子粒径和表面电位的影响.所得纳米微粒的粒径在240~290nm、表面电位在-0.4~-1.3 mV之间可调.采用透射电子显微镜表征了磺化壳聚糖/聚赖氨酸（SCS/PLL）和SCS/PLL/TGF-β1纳米粒子的形貌.通过体外骨髓间充质干细胞（BMSCs）培养实验,分别考察了SCS/PLL/TGF-β1纳米粒子对BMSCs的增殖、氨基葡聚糖（GAGs）分泌和Ⅱ型胶原基因表达的影响.结果显示,相对于等量的SCS/PLL或同浓度的自由TGF-β1,SCS/PLL/TGF-β1纳米粒子可有效保护TGF-β1的活性,促进BMSCs向软骨细胞分化,可望应用于软骨修复材料等领域的研究.

英文摘要：

To protect the activity of transform growth factor-β1（TGF-β1）,the sulfated chitosan /polylysine / TGF-β1（SCS / PLL / TGF-β1） nanoparticles were prepared by a co-precipitation method.Along with the increase of sulfated chitosan concentration,the nanoparticles with larger size and more negatively-charged surface were obtained.Both the SCS / PLL and SCS / PLL / TGF-β1 nanoparticles had a round morphology observed by transmission electron microscopy（TEM）,with a dry size of（177 ± 26） nm and（195 ± 35） nm,respectively.In vitro cell culture was performed to evaluate the differentiation of bone mesenchyrnal stem cells（BMSCs） induced by the SCS/PLL/TGF-β1 nanoparticles.The result of cell proliferation showed that the addition of TGF-β1 either in a free state or as nanoparticles could block the proliferation of BMSCs to some extent.However,compared to the blank,SCS / PLL and free TGF-β1 groups,the SCS / PLL / TGF-β1 group secreted the highest amount of glycosaminoglycans（GAGs）.Moreover,the results of quantitative reverse transcription-polymerase chain reaction（qRT-PCR） also showed that the BMSCs seeded with the SCS / PLL / TGF-β1 nanoparticles expressed significantly higher amount of collagen type II gene at day 14.All these results confirm that the bioactivity of TGF-β1 can be largely preserved in the form of SCS / PLL / TGF-β1 nanoparticles,leading to the preferential differentiation of BMSCs toward chondrocytes.