【作者】 洪霞；

【导师】 白玉白； 李铁津；

【作者基本信息】 吉林大学 ， 物理化学， 2004， 博士

【摘要】 近年来，磁性纳米材料无论从理论研究的角度，还是从实际应用的角度，都引起了人们极大的兴趣。当磁性材料的尺寸减小到一定的临界尺寸以下时，将表现出特殊的磁性质，其中超顺磁性在生物、医药和临床诊断等领域具有广阔的应用前景。在已报道的各类磁性纳米材料中，Fe₃O₄纳米粒子由于制备工艺简单、价格低廉、饱和磁化强度高等特点，同时又对人体不产生毒副作用，无免疫原性，可随人体代谢排除体外，易穿过各种生理屏障到达指定部位，因此，在免疫检测和药物靶向等方面具有无可比拟的优势。目前，Fe₃O₄纳米材料已经成为磁性纳米材料在生物应用领域中的首选材料。 本论文以Fe₃O₄磁性纳米材料为主线，系统研究了Fe₃O₄磁性纳米粒子的合成、复合及组装，探索了其在生物方面的应用，取得一些创新性结果。 1．Fe₃O₄磁性纳米晶的制备。 磁性纳米材料的磁性质与其组分、形状、尺寸以及纳米晶的有序性有关。然而，由于磁性纳米粒子间具有很强的相互作用，要想制得单分散的、形状规则的材料一般很难，这就大大阻碍了它们的进一步应用。为此，我们在传统制备方法的基础上进行了部分改进，采用MaSsan水解法、Fe²⁺氧化水解法和反相胶束法三种方法，分别探索了合成高质量Fe₃O₄纳米晶的最佳条件，制得了一系列单分散、尺寸可控、形状可变（球形或方形）、磁性可调的Fe₃O₄纳米晶，为Fe₃O₄纳米晶的表面修饰及进一步功能化奠定了良好的基础。 2．Fe₃O₄磁性纳米晶与高分子材料复合物的制备。百林大学博士学位论文 相对于单组分的磁性纳米粒子而言，磁性纳米粒子通过与高分子的复合，能有效地改变表面电荷、功能性质和反应活性，能增强材料的稳定性和分散性，易于与生物分子进行偶联，因此，作为分离介质和磁性载体而被广泛应用于细胞分离、固定化酶、免疫检测及靶向药物治疗等方面。本文分别研究了合成高分子和天然高分子与Fe3O;磁性纳米晶的复合。 （1）Fe3O4/聚苯乙烯磁性纳米复合微球的制备。 聚苯乙烯是一种最常用的合成高分子材料，本文设计并合成了三明治型和核壳型两种Fe3O4/聚苯乙烯磁性纳米复合材料，分别对材料的合成及其物理化学性质进行了系统研究。实验证明，Fe3O4磁性纳米晶通过与聚苯乙烯材料的复合，不仅能有效地防止Fe30;纳米晶的氧化，使其能在一个更宽的pH值范围内稳定存在（p十3一12），而且还提供了大量的梭基和表面负电荷，有利于与生物分子的进一步偶联，使其有可能应用于生物、临床等方面。 （2）Fe3O4/葡聚糖磁性纳米复合材料的制备及应用。 葡聚糖属于天然高分子，材料本身无毒，具有良好的水溶性、化学稳定性和生物相容性，是一种很好的生物载体试剂。基于免疫检测的目的，选用葡聚糖包覆超顺磁性的Fe3O4纳米粒子，通过葡聚糖表面的醛基化实现与单克隆抗体的偶联，最终制得了Fe304/葡聚糖/Ig伽磁性纳米生物探针。利用酶联免疫分析技术对磁性纳米生物探针的免疫活性进行了研究，分别采用BSA和甘氨酸对偶联产物进行封闭，并比较了二者的封闭效果。实验结果表明，这种磁性纳米生物探针保持有较高的反应活性，B SA的封闭效果要好于甘氨酸。为了进一步验证上述结果，进行了免疫层析试纸实验。结果表明，所制备的磁性纳米生物探针完全适用于快速免疫检测的需要，为进一步的临床诊断奠定了可靠的实验基础。 3 .Fe3O4/醛基葡聚糖/Ig饰的免疫组装及检测。 利用抗体与抗抗体间的特异性识别作用，通过层层组装技术，将B SA封闭的磁性葡聚糖八g咙纳米生物探针组装到抗抗体（即位一IgGH）修饰的镀金的硅基底上，并用灯M、红外光谱和x一光电子能谱区PS)跟踪监测了整个组装中文摘要过程。首次将横向力显微镜（LF玛技术和磁力显微镜（NIFM）技术与原子力显微镜（A卫哟技术结合，用于检测磁性纳米生物探针的特异性识别事件，大大提高了检测的准确性和灵敏性，为免疫检测开拓了新的思路。 4.利用层层组装（LbL）方法制备磁性荧光纳米复合材料。 近年来，半导体荧光纳米晶由于其独特的光学特性，吸引了人们的广泛关注，并已作为新一代荧光标记物被广泛应用于光学、生物、医学等领域。其与磁性纳米粒子结合，必将兼具二者的优点，在生物和医学等领域发挥更大的作用。为此，本文首次利用LbL技术，设计并合成了同时具有高发光和强磁性的新型水溶性磁性荧光纳米复合材料任e3o在即CdTe和Fe30了口马/C dTe）n）。通过调整Fe3O4纳米粒子和CdTe纳米晶间的距离（即改变聚电解质的层数）或增加CdTe纳米晶在Fe3O4纳米粒子表面的沉积数量（即改变CdTe量子点的沉积循环次数），优化了材料的光致发光性质。此外，利用这种磁性荧光纳米复合材料对单克隆抗体Ig咙进行标记，并对标记物实行了免疫层析检测实验，结果表明，标记后的Ig饰仍然保持较高的反应活性。同时，由超顺磁性带来的快速分离为磁性荧光纳米复合材料及其与IgGH的偶联产物的纯化提供了极大的便利。更多还原

【Abstract】 Recently, the nanomagentic materials have gained increasing attention in the fundamental studies and the technological applications. When the size decreased down to a critical value, the magnetic materials would exhibit an interesting magnetic property. Superparamagnetic property, as one of the special properties makes it possible to apply in the wide technological areas, including biology, pharmacy and diagnostics. Among a variety of the reported nanomagnetic materials, the magnetite (Fe3O4) nanoparticles show many outstanding advantages in immunoassay and targeting drug-delivery system not only due to their simple preparation techniques, lower cost and higher saturation magnetization, but also because they are nontoxic, nonimmunogenic, biodegradable and are easily transported though serials of physiological barrier to the site of choice. At present, the magnetite nanomagnetic materials have become the preferred materials for the biological applications.In the present dissertation, we investigated the preparation, modification and assembly of the Fe3O4 nanoparticles, and explored the possibilities for their biological applications. Some novel results are obtained from our experiments.1. Preparation of the Fe3O4 nancrystals.The magnetic properties of the nanomagnetic materials would be influenced by their component, shape, size and the ordering of the nanocrystal. However, it is very difficult to obtain the monodisperse magnetic nanocrystals with the regular shape, which would greatly hinder their further development. As the result, a serialof the monodisperse Fe3O4 nanocrystals with the controlled size, changeable shape and tunable magnetic properties were prepared following the modified methods derived from Massart’s method, oxidation of ferrous ions and the inverted micelles technique. The relative optimal conditions to synthesize high quality nanocrystals were found. These work laid the foundations of the success to further modification and functionalization of the Fe3O4 nanocrystals.2. Preparation of Fe3O4 magnetic polymer nanocomposites.Compared with the single-component magnetic nanoparticles, the magnetic polymer nanocomposites possess more advantages. For example, the surface charge, functional properties and the reaction activity could be well tuned. The stability and the dispersing could be improved. It would be helpful for their future applications as biolabeling. Furthermore, they could be used as the separation medium and magnetic carrier in cell separation, immobility of enzymes, immunoassay and targeting drug delivery, etc. Based on that, two polymers, natural polymer and synthesis polymer, were chose to coat the magnetite nanocrytals, respectively.(1) Preparation of Fe3O4/ polystyrene nanocomposite microspheres.Since it is a most common synthesis polymer, polystyrene was used to coating the Fe3O4 nancrystals. Two structures were designed and fabrication including sandwiched and core-shell structures. Their physical and chemical properties were investigated in detail. It was found that the polystyrene outermost layers could not only prevent the further oxidation of the Fe3O4 nanocrystals, but made them stable over a large range of pH value (pH=3~12). In addition, they could also offer large amount of carbonyl groups and negatively charged, which was useful for the further labeling of the biomolecules to employ in biology and clinic, etc.(2) Preparation and application of the Fe3O4/dextran nanocomposites. Dextran belongs to the natural polymer. It is nontoxic, water-soluble,chemically stable and biocompatible, thus it is an excellent biocarriers. For the purpose of immunoassay, dextran-coated superparamagnetic Fe3O4 nanoparticles were prepared. A periodate oxidation method was used to further activate the magnetic dextran, forming magnetic polyaldehyde-dextran, which could be conjugated to monoclonal antibody. The nanomagnetic biological probes ofFe3O4/dextran/IgGH were finally prepared. BSA and glycin were chose to block the conjugates. And their blocking effects were compar更多还原