中文摘要：

制备了一种新的基因载体材料——赖氨酸修饰的壳聚糖（CTS-lys）包裹的磁性纳米颗粒.优化制备了CTS-lys原料,红外（IR）和核磁（1H-NMR）检测结果表明壳聚糖的大量氨基被赖氨酸修饰.通过共沉淀方法,制备了赖氨酸修饰的壳聚糖磁性纳米颗粒（CTS-lys-MNPs）.利用透射电镜（TEM）、激光粒度分析仪、磁力计（VSM）和X射线衍射（XRD）对CTS-lys-MNPs进行了表征,并通过U293细胞,研究了CTS-lys-MNPs的细胞毒性.结果表明,CTS-lys-MNPs的平均粒径为100nm,具有较好的超顺磁性和较低的细胞毒性;在此基础上,通过凝胶电泳实验观察了CTS-lys-MNPs和DNA的结合情况,并通过单光子发射型计算机断层显像仪（SPECT）研究了CTS-lys-MNPs和DNA的复合物在动物体内跨越血脑屏障的能力.结果表明,CTS-lys-MNPs是一种较好的磁靶向基因载体并能成功地跨越血脑屏障.

英文摘要：

In recent times,as nonviral gene vectors,chitosan and its derivations have attracted many researchers＇ attentions.The preparation of a novel gene vector-magnetic nanoparticle coated with a novel polymer-lysine modified chitosan（CTS-lys）is described in this article.Initially,the correlation conditions of preparing CTS-lys were optimized,and it was demonstrated that lots of amines of chitosan were modified by lysine,which was indicated by infrared spectroscopy（IR）and proton nuclear magnetic resonance（1H-NMR）.Subsequently,through the coprecipitation method,the lysine modified chitosan magnetic nanospheres（CTS-lys-MNPs）were attained.The characterizations of nanospheres were measured by transmission electron microscopy（TEM）,dynamic laser light scattering,vibrating samples magnetometer（VSM）,and X-ray diffraction（XRD）.The cytotoxicity of CTS-lys-MNPs was also investigated with U293 cells.The results indicated that the average size of nanospheres was about 100 nm,and they had narrower size distribution,good superparamagnetic property,and perfect crystallinity,and they also retained low toxicity.Additionally,the combination of DNA and CTS-lys-MNPs was observed via agarose gel electrophoresis,and the ability of complexes of CTS-lys-MNPs and DNA crossing blood-brain barrier（BBB）in rats was studied by single photon emission computed tomography（SPECT）.The results showed that the gene vector was a superior material,which had the ability of targeting and avoiding the caption of BBB.