【作者】 李双艳；

【导师】 常津； 康春生；

【作者基本信息】 天津大学 ， 材料学， 2007， 硕士

【摘要】 通过赖氨酸对壳聚糖进行修饰,增加了壳聚糖的氨基含量,改善了中性条件下的水溶性,对不同制备工艺条件下所制备的赖氨酸修饰壳聚糖进行了讨论,得出了赖氨酸修饰壳聚糖的最优条件:搅拌速度为1200 rpm、温度为20℃、油水相比为1、反应时间为6 h。通过对产物的溶解度、红外吸收光谱和核磁共振波谱测试,验证了赖氨酸化学键合于壳聚糖之上,并得出产物的溶解度为0.48 g,赖氨酸的取代度为32.78%。以制备的赖氨酸修饰壳聚糖为壳层材料,以四氧化三铁为核,用共沉淀法制备了磁性超微载体。透射电子显微镜和激光粒度仪分析表明载体粒子表面光滑,粒径分布均匀,为100nm左右;VSM磁性能分析仪和Zeta电位仪测试表明载体粒子具有良好的超顺磁性和较高正电性。然后将跨膜肽TAT和叶酸(Folate)连接到赖氨酸修饰壳聚糖超微磁性载体粒子表面,形成具有跨膜和磁性及受体介导复合靶向功能的超微磁性载体粒子(TAT-FA-LCMNPs),采用紫外分光光度计对构成复合功能载体系统的各组分进行了定量分析,证实了该复合功能超微载体系统的成功构建。在此基础上,将制备的四种磁性载体粒子:赖氨酸修饰壳聚糖超微载体(LCMNPs)、叶酸介导赖氨酸修饰壳聚糖超微载体(FA-LCMNPs)、具有TAT跨膜功能的赖氨酸修饰壳聚糖超微载体(TAT-LCMNPs)和具有复合靶向功能的超微载体(TAT-FA-LCMNPs)通过琼脂糖凝胶电泳,分别确定其与DNA的复合情况。然后以99mTc放射性标记不同载体粒子,对SD大鼠尾静脉和颈动脉分别进行注射,单光子发射型计算机断层显像仪(SPECT)检测,考察不同载体粒子携带质粒DNA通过大鼠血脑屏障的情况,并通过不同组别、不同给药方式、不同磁场作用时间及阴性对照组(放射性元素99mTc颈动脉注射)的对比确定了最优化治疗方法。结果显示,颈动脉给药、磁场作用于大鼠头部30min时,DNA-TAT-FA-LCMNPs具有最好的跨血脑屏障效果。更多还原

【Abstract】 Lysine Chemically modified chitoan with good water solubility was synthesized in this paper,and the coordination conditions(stirring rate、the reaction time、temperation、DMF/H2O)were optimized. The optimal swellen parameters were R= 1200 rpm、T=20℃、DMF/H2O=1、t= 6 h。Its composition and structure was characterized by FT-IR、1H-NMR and 13C-NMR, and the degree of substitution was 32.78% which was calculated by 1H-NMR.Then the lysine modified chitosan was used as matrix to prepare magnetic microspheres using co-precipitation method.The microspheres were analysised by XPS,TEM,XRD, VSM and Zeta Potential Analyzer. The results showed that the particles were spherical and uniform in dimension with particle diametrers of 100nm ,and had good supermagnetic characterization ,they also had many positive charge on their surface.We coupled TAT and folate on the surface of lysine modified chitosan magnetic micropheres to form TAT mediated magnetic nanoparticles having composite targeting function.And all of the components of the TAT-FA-LCMNPs was quantitively investigated by UV respectively .Additionally, combination of DNA and four kinds of MNPs was observed from agarose gel electrophoresis, suggesting that the LCMNPs could be a novel kind of magnetic targeting gene carriers. The biodistribution and the ability for crossing BBB of 99Tc-labeled MNPs and DNA complexes were further investigated by single photon emission computed tomography (SPECT). The results showed TAT-FA-LCMNPs and DNA complexes successfully passed the blood-brain barrier under the magnetic field for 30min after being injected through the carotid更多还原