【作者】 方修忠；

【导师】 梁宏； 沈星灿；

【作者基本信息】 广西师范大学 ， 无机化学， 2005， 硕士

【摘要】 第一章:综述了磁性四氧化三铁纳米粒子的合成方法及其在生物医药领域的应用前景;由于磁性纳米粒子有着很大的比表面,容易发生团聚现象,针对如何提高纳米溶胶的稳定性和分散性,引入了纳米粒子的表面修饰技术的概念并介绍了在表面修饰领域取得的一系列的研究进展;DNA 的固定化已广泛用于检测分析、分离纯化,在核酸化学、生物计算、分子遗传学及生物工程的研究中有着不可替代的重要作用。本章节还介绍了DNA 在纳米粒子表面固定化的研究进展及研究展望。 第二章: 由于磁性Fe3O4纳米粒子有着很大的比表面,磁性偶极间的相互吸引都易导致团聚现象的产生,如何制备出粒径小、分散性好的超细Fe3O4纳米粒子已成为当今倍受关注的研究热点。本章以γ-氨丙基三乙氧基硅烷作分散稳定剂,改善了磁性Fe3O4纳米粒子表面的疏水环境,成功地制备出稳定性好、单分散的磁性Fe3O4/氨基硅烷复合纳米微球,有效地阻止了四氧化三铁纳米粒子团聚的发生。经IR、XRD、TEM、VSM 及UV-Vis 测试结果表明,该种复合微球具备粒径小、粒径分布范围窄(10 ±2 nm)、比饱和磁化强度和超顺磁性等优良性能;经表面改性后,氨基作为功能性基团成功的负载到磁性Fe3O4纳米粒子表面,增强了微球的生物兼容性,因此该种磁性微球在酶的固定、细胞分选、靶向给药等领域有着广泛的应用前景。 第三章: 采用化学共沉淀法和表面化学修饰的方法制备了以Fe3O4为磁核,氨基硅烷为外壳的超顺磁性硅壳磁纳米粒子。通过氨基硅烷化后,在纳米粒子表面带上氨基碱性基团,在低的pH 值条件下带正电,与DNA 片段中的磷酸根负离子通过静电作用将DNA 固定,构建了一种具超顺磁性的DNA 纳米富集器。应用更多还原

【Abstract】 Part one: The preparation methods of nanosized magnetite particles such as precipitation and hydrothermal method are summarized, and its widely uses in the fields such as biotechnology was reported, for example, in bio-separation, immunoassays, and DNA immobilization. In this part, surface modification is also introduced as a new nano-technology. the modification methods, modification kinetics and the recent research in surface modifications of nanoparticles was reported. Part two: The amino-silane modified magnetite nanoparticles were synthesized by the coprecipitation and surface modification with 3-aminopropyl-triethoxysilane （APTTS）. Characterized by TEM and UV-vis, the ultrafine APTTS/Fe3O4 nanospheres had well dispersion and stabilization in aqueous fluids, The superparamagnetic APTTS/Fe3O4 nanospheres with an average diameter of 10 nm were characterized significantly with functional group, as well as a maximized saturation magnetization of 63.54 emu/g, and the optimal surface modification molar ratio of APTTS to Fe3O4 was found to 4:1. Displaying functional group of –NH2, high saturation magnetization, the superparamagnetic APTTS-modified Fe₃O₄ NPs are of significance for magnetic applications in biomedicine. Part three: Adsorption of DNA on magnetic nanoparticles was carried out, the interaction between magnetite and DNA and kinetics of the adsorption process were studied. Fe3O4 nanoparticles were prepared by the chemical precipitation method and modified with 3-Aminopropyltriethoxysilane on the surface of magnetite NPs. Characterization of magnetic particles were carried out using transmission electron microscopy and a vibrating sample magnetometer. Fourier-transform infrared spectroscopy was used to confirm the attachment of DNA on magnetic particles. Effect of pH and salt concentrations were investigated on the adsorption process. The experiment results show the adsorption of DNA on magnetic particles was effected greatly by the pH and ionic strength. Adsorption kinetics were analyzed by a linear driving force mass-transfer model.更多还原