【作者】 田志卿；

【导师】 杨仕平； 杨红；

【作者基本信息】 上海师范大学 ， 应用化学， 2011， 硕士

【摘要】 磁性纳米材料,特别是超顺磁性的纳米材料,由于其特有的物理和化学性质而受到人们的重视,并因此在机械、电学、光学、磁学、化学和生物学领域有着广泛的应用前景。特别是近年来,磁性纳米粒子在磁共振成像（MRI）领域的研究更是人们关注的重点。MRI技术能对细胞或人体组织进行“无创的”、清晰的3D成像,提供精确的解剖学信息,因此在许多领域发挥了重要作用。磁性纳米粒子在MRI领域中常常作为造影剂使用,以此提高MRI图像的对比度和清晰度。磁性纳米粒子的发展对MRI技术的发展带来新的活力和进展。本论文分为两个部分,分别研究了MnFe₂O₄和Fe₃O₄磁性纳米粒子在磁共振成像领域的一些应用。第一部分是对MnFe₂O₄磁性纳米粒子形貌和磁学性质的研究。实验以Fe（acac）3和Mn（acac）2为前驱体,以油酸、油胺和1, 2-十六烷二醇及其混合物为表面活性剂,在有机溶液中,用高热分解法制备铁酸锰纳米粒子。实验研究了各种表面活性剂对铁酸锰纳米粒子的粒径大小、形态和磁学性质的影响。通过配体交换,使油溶性的铁酸锰磁性纳米粒子表面带有亲水性分子——多巴胺（Dopamine）,使得纳米粒子具有水溶性,进一步研究了材料对于HeLa细胞的磁共振成像实验。第二部分研究了Fe₃O₄磁性纳米粒子对Hg²⁺的MR传感效应。我们先用Fe（acac）3为前驱体,以油胺为表面活性剂,用高热分解法制备Fe₃O₄纳米粒子,然后分别用两种方法对其进行表面修饰。第一种方法采用配体交换法,使纳米粒子表面带有亲水基团——氨基,使材料具有水溶性。然后通过共价修饰接,接上胸腺嘧啶（Thymine）,合成Fe₃O₄ @Dopamine@Thymine （Fe₃O₄ @DA@T）纳米材料。第二种方法对材料进行包二氧化硅和氨基化的修饰,通过共价键接上Thymine,合成了Fe₃O₄ @SiO2@Thymine （Fe₃O₄ @ SiO2@T）纳米材料。通过各种表征手段研究两种纳米粒子的大小、形态、表面官能团和磁性以及材料在Hepes缓冲溶液中对Hg²⁺的传感效应。实验证明,两种材料都可以作为Hg²⁺的MR传感器使用,但是用第二种方法合成的该材料对汞离子的灵敏度和选择性都比第一种材料好。总之,我们合成了一些铁酸盐纳米粒子,分别研究了它们作为磁共振成像造影剂在Hela细胞成像和汞离子传感方面的应用,取得了较为理想的效果。更多还原

【Abstract】 Magnetic nanomaterials, especially superparamagnetic nanomaterials, are paid more attention on by people because of their special physical and chemical properties, and therefore they have a broad prospect of application in mechanical, electrical, optical, magnetism, chemical and biological field, especially in recent years, more people have been intrested in magnetic resonance imaging （MRI）. MRI technology frequently can realize "non-inasie", clear 3D imaging of the cells or human tissue, so it plays an important role in many fields. Magnetic nanoparticles are often used as the contrast agent in the field of MRI, and improve the contrast and clarity of MRI images. The development of magnetic nanoparticles brings new vitality and progress to the MRI technology.The experiments are divided into two parts, and we separately studied some applications of MnFe₂O₄ and Fe₃O₄ magnetic nanoparticles in MRI fields. The first part is the research of morphology and magnetic properties of MnFe₂O₄ magnetic nanoparticles. We used Fe（acac）3 and Mn（acac）2 as precursors; oleic acid, oleylamine and 1,2-hexadecane glycol and their mixture as surfactant. In organic solution, we synthesised the MnFe₂O₄ magnetic nanoparticles by high thermal decomposition. We studied the effect of various surfactants on the size of MnFe₂O₄ magnetic nanoparticles, shape and magnetic properties. Through the ligand exchange, exchange oil-soluble surfactants on iron acid manganese magnetic nanoparticles surface with hydrophilic molecules—dopamine, make nanoparticles is water-soluble, the materials were used for the further research on magnetic resonance imaging experiments of HeLa cells. The second part is Hg²⁺ MR sensing effect of Fe₃O₄ magnetic nanoparticles. First, we use Fe（acac）3 as precursors, oleylamine as surfactant, in organic solution, with high thermal decomposition to synthesis Fe₃O₄ magnetic nanoparticles. Then, the experiments were divided into two parts. The first method was ligand exchange, which made hydrophilic groups—amino on the surface of nanoparticles, then the material became soluble in aqueous solution. Through covalent modifition with Thymine, we synthesized Fe₃O₄@DA@T nanomaterials. The second method was to coat the shell of silica and modify amino on the surface of tne materials, and then we connected thymine through covalent bond, Fe₃O₄@SiO2@T nanomaterials were prepared at last. We conducted characterizations about size, shape, surface functional groups and magnetic and effect of Hg²⁺ selective—MR nanosensor in Hepes buffer solution of two nanoparticles through various methods. Experiments proved that two kinds of materials could be used as Hg²⁺ selective—MR nanosensor, but the materials synthesed by the second method was more selective and sensitivite as nanosensor than the other nanoparticles.In conclusion, we synthesized some iron chromate salt nanoparticles, separately studied them as MRI applications in Hela cells imaging and mercury ion sensing, and achieved the ideal effect.更多还原