中文摘要：

目的 建立跨血脑屏障复合功能纳米载体系统。方法 以O-羧甲基壳聚糖（O-CMC）为原料，制备出具有超顺磁特性的纳米载体粒子，并将跨膜肽（Tat）、人转铁蛋白（Tf）和抗癌药物甲氨喋呤（MTX）与其结合，构建成兼具跨血脑屏障、磁性和受体介导双靶向及抗癌复合功能的纳米载体系统（MTX-O-MNPs-Tat-Tf）。应用透射电镜、原子力显微镜、震动样磁力计表征该纳米载体系统的形貌、粒径、磁性能并选择大鼠C6细胞考察MTX-O-MNPs-Tat-Tf载体粒子的抗肿瘤特性。结果纳米磁性粒子MTX-O-MNPs-Tat-Tf平均粒径为75nm，具有良好的抗肿瘤特性。初步动物实验表明，采用放射性元素锝标记，经单光子发射型计算机断层显像仪检测，复合功能载体系统成功跨越大鼠血脑屏障。结论MTX-O-MNPs-Tat-Tf裁体系统的建立为今后跨过血脑屏障治疗脑部疾病等提供了良好的应用前景．

英文摘要：

Objective To construct muhifunctonal nano-delivery system crossing the blood brain barrier （BBB）. Methods The magnetic nanoparticles were preprared with O-carboxylmethylated chitosan （O- CMC） and conjugated with a peptide sequence from the human immunodeficiency virus 1-tat protein and transferrin （ Tf）, and anti-tumor drug methotrexate （ MTX）, and thus constructed a O-CMC magnetic nanoparticles carrier system conjugating with Tat and Tf （O-MNPs-Tat-Tf） that combines multiple functions including crossing BBB, magnetism, receptor-mediated dual targets and anti-tumor capabilities. The appearance, diameter, and magnetism of MTX-O-MNPs-Tat-Tf carrier system were characterized with transmission electronic microscopy, atomic force microscopy and vibrating samples magnetometer. The cytotoxicity of MTX-loaded O-MNPs-Tat- Tf was investigated with C6 glioma cells. The ability of O-MNPs-Tat-Tf crossing BBB was investigated in rats by single photon emission computed tomography. Results The mean particle diameter was 75 nm, along with good anti-tumor property. The multi-functioned carrier system successfully crossed the BBB in rat. Conclusion The establishment of MTX-O-MNPs-Tat-Tf carrier model implies a promising future for its application in therapy of cerebral diseases.