【作者】 郑元青；

【导师】 李丹；

【作者基本信息】 湖南大学 ， 生物化学与分子生物学， 2009， 硕士

【摘要】 本文对天然高分子聚合物修饰的磁性纳米颗粒的制备方法及其应用进展进行了综述。通过大量实验研究了天然高分子聚合物修饰的磁性淀粉纳米颗粒的制备和生物学效应。实验从磁性纳米颗粒（γ-Fe₂O₃）入手,经天然的高分子聚合物淀粉包被,再经多聚赖氨酸和叶酸修饰,考察其理化性质,并进行了进一步的肿瘤细胞磁热疗方面的应用研究。本文采用反相微乳液法制备了包裹磁流体的淀粉纳米颗粒（StNP@Fe₂O₃）,再经多聚赖氨酸（PLL）和叶酸活性物质（FA-PEG-NH2）修饰,得到多聚赖氨酸-磁性淀粉纳米颗粒（PLL-StNP@Fe₂O₃）和叶酸-磁性淀粉纳米颗粒（FA-StNP@Fe₂O₃）。然后通过透射电子显微镜显示颗粒形貌,激光粒度分析仪检测显示所得颗粒平均粒径和电位大小。邻菲罗啉法检测颗粒的铁含量。经过改性的磁性纳米颗粒在交变磁场下作用30 min可使环境温度（37℃）升高到42⁴3℃,显示其具有一定的磁热效应。进一步将纳米颗粒与肿瘤细胞株Hela细胞共培养,经交变磁场作用后,进一步通过MTT实验、Hochest-PI双染色分析、流式细胞仪技术检测纳米颗粒在细胞水平的生物学效应,结果表明磁性纳米颗粒在未加磁场时,在一定浓度范围内对细胞的增殖无明显影响;而在一定交变磁场强度作用下则能有效地诱导细胞凋亡。普鲁士蓝染色实验中,在与正常细胞对比的情况下,显示了经过靶向修饰PLL和叶酸有助于纳米颗粒靶向识别肿瘤细胞。研究表明靶向修饰的纳米颗粒具有良好的肿瘤靶向磁热治疗效果,其中,FA-StNP@Fe₂O₃颗粒经过表面叶酸修饰后更能实现对肿瘤细胞的靶向识别和细胞内的富集,使肿瘤细胞凋亡显著,是一种很有潜力肿瘤靶向热疗载体,可望应用于肿瘤的靶向治疗。更多还原

【Abstract】 This thesis describes current approaches for the preparation of biodegradable polymers nanoparticles and their applications research in medical field. Experimental magnetic nanoparticles start fromγ-Fe₂O₃, with natural starch polymer coating. And two kinds of natural macromolecules biodegradable polymers, Poly-L-lysine（PLL） and Folic acid （FA-PEG-NH2）, were used in this experiments to modify starch magnetic nanoparticles. Study its physical and chemical properties, and further biological medical application for magnetic hyperthermia.Modified magnetic starch nanoparticles （PLL-StNP@ Fe₂O₃&FA-StNP@ Fe₂O₃） were synthesized by conjugating PLL&FA-PEG-NH2 onto the surface of magnetic starch nanoparticles（StNP@ Fe₂O₃） prepared by reverse microemulsion method. The synthesized nanoparticles were investigated by transmission electron microscopy and zeta potential analysis. The average size of its well dispersed particles and the iron concentration detected by phenanthroline method were gained. Placing these nanoparticles in alternating magnetic field for 30 min could result in an increase in the suspension temperature from ambient temperature （37 oC） to a value between 42 and 43 oC. Co-cultured nanoparticles and Hela cell line or normal HUEC-12 cell line, and the biological effects at cellular level were investigated in alternating magnetic field using MTT assay, Hochest-PI double staining and flow cytometry analysis. Experimental results showed that functional nanoparticles within certain concentration range has no obvious effect on cell proliferation. When treated in magnetic field, apoptosis on Hela induced by these nanoparticles were obvious. Prussian blue staining analysis confirmed that the nanoparticles modified with PLL &FA had improved ability in tumor cell-targeting, compared with HUCE-12,and therefore, potential applications in biomedical and magnetocaloric areas. It is expected to be applied to tumor targeting therapy in the near future.更多还原