【作者】 张小娟；

【导师】 李凤生；

【作者基本信息】 南京理工大学 ， 材料学， 2009， 博士

【摘要】 本文采用改进的一步细乳液共聚技术,制备出具有良好分散性、粒径分布范围窄、表面带有丰富官能团、高磁含量的超顺磁性高分子纳米球,并在磁性纳米球表面固载组氨酸,开展普通羰基铼的初步模拟标记实验。本研究为最终实现放射性核素¹⁸⁸Re的成功标记提供了详实的实验数据和坚实的理论基础。主要内容如下:首先,无机磁性核体材料的选择是影响磁性高分子纳米球性能的主要因素之一。本文采用盐助甘氨酸法制备了纳米铁氧体,并用改性共沉淀法制备了Fe₃O₄磁流体,对其性能进行了表征和分析对比。结果表明,相比纳米铁氧体而言,Fe₃O₄粒子不仅单分散、粒径小且均一、饱和磁化强度值更大、而且经修饰后与油相有很好的相容性,因此,更适于制备磁性高分子纳米球。其次,以Fe₃O₄磁流体为核,苯乙烯为聚合主单体,选用丙烯酰胺或甲基丙烯酸甲酯为功能单体,采用改进的一步细乳液共聚法分别制备出了表面酰胺基化、酯基化的核壳Fe₃O₄/聚合物纳米球。并探讨了功能单体和表面活性剂用量、交联剂用量、引发剂用量和磁流体浓度对磁性纳米球性能的影响。结果表明,通过工艺参数的调控,可以制得粒径小且均一、分散性好、磁含量高、功能基团丰富、饱和磁化强度达40-50emu/g的超顺磁性纳米球。而且,一步细乳液共聚法具有工艺简单、功能单体丰富可调、包覆完全等优点,可以推广为制备表面功能化磁性纳米球的普适性方法。此外,基于酯基化磁性纳米球的制备工艺,引入另一功能单体甲基丙烯酸缩水甘油酯进行细乳液共聚反应,制备出了表面环氧基化的磁性纳米球。结果表明,环氧基化磁性纳米球包覆完全、分散好、粒径分布窄,并显示超顺磁性,其平均粒径为60nm、磁含量为19.8wt.%、饱和磁化强度为18.54emu/g。此外,相比于酰胺基和羧基化磁性纳米球,环氧基化磁性纳米球更易进行氨基官能团的转化,所得的氨基化磁性纳米球球体完整,并能保持良好的分散性,可用于后续的标记实验。最后,严格在无水无氧的条件下,成功制备出了化合物[N（Et）₄][Re（CO）₃Br₃],将其溶于水后,得到了标记前体化合物普通羰基铼fac-[Re（CO）₃（H₂O）₃]⁺,并设计出普通羰基铼模拟标记氨基化磁性纳米球的技术路线。以自制的氨基化磁性纳米球为原料,戊二醛为交联剂,在氨基化磁性纳米球表面成功固载了组氨酸。结果表明,固载组氨酸后,磁性纳米球球体完整、分散性较好、且保持超顺磁性,其磁含量为20wt.%、饱和磁化强度值为9.43emu/g,可进行下步模拟标记实验。再以固载组氨酸的磁性纳米球作为磁靶向载体,开展普通羰基铼的初步模拟标记实验。结果表明,模拟标记产物分散性好,磁含量为16wt.%,超顺磁性且饱和磁化强度值为9.10emu/g。采用紫外分光光度计测试吸光度并计算出模拟标记率达80.4%。由此表明,普通羰基铼对固载组氨酸的磁性纳米球有较好的标记能力,有望实现放射性核素¹⁸⁸Re的成功标记。更多还原

【Abstract】 This dissertation is intended to prepare functionalized superparamagnetic nanospheres with small and uniform particle size,good dispersibility,high magnetite content and saturated magnetization by a modified one-step miniemulsion copolymerization.And histidine was covalently linked to the surface of magnetic nanospheres,and then the simulative labeling experiment of the resulting nanospheres with tri-carbonyl rhenium was primarily developed. Detailed experimental data and powerful theoretical evidence were obtained for realizing the successful radiolabeling of magnetic nanospheres with ¹⁸⁸Re.The details are described as below:Firstly,the inorganic magnetic particles are the key factors in influencing the properties of magnetic polymer nanospheres.In this paper,ferrite nanoparticles were prepared salt-assisted glycine combustion method,and Fe₃O₄ ferrofluids were prepared by modified coprecipitation. And their properties were characterized and analyzed.The resulted showed that compared with ferrite nanoparticles,Fe₃O₄ ferrofluids had better dispersibility,smaller and more uniform particle size,stronger magnetic responsiveness,better miscibility with oil phase,which were more fit for preparing magnetic polymer nanospheres.Secondly,the amide-functionalized and esterifiable Fe₃O₄/polymer core/shell magnetic nanospheres were prepared by a modified one-step miniemulsion copolymerization in presence of Fe₃O₄ ferrofluids,respectively.And styrene was polymerized monomer,and acrylamide and methyl methacrylate were chosen as functionalized monomer.The effects of various polymerization parameters,such as the functionalized monomer dosage,the surfactant dosage,the cross-linker dosage,the initiator dosage and the magnetic fluid concentration on the properties of magnetic nanospheres were discussed in detail.The resulted showed that by optimizing the technics parameters,superparamagnetic polymer nanopsheres with good dispersibility,small and uniform particle size,high magnetic content,large saturated magnetization（40-50 emu/g） and abundant functional groups were produced.Moreover,the miniemulsion copolymerization has the merits of simple process,tunable and abundant functional monomer and complete coverage,which can be introduced as a preferred method for preparing surface-functionalized magnetic nanospheres.On the basis of the synthesis technics of esterifiable nanospheres,the magnetic nanospheres with epoxy groups were prepared by introducing another functional monomer in the miniemulsion copolymerization.The resulted showed that epoxy nanopsheres had complete coverage,good dispersibility and small particle size.The average particle size was 60 nm, magnetic content was 19.8 wt.%and large saturated magnetization was 18.54 emu/g. Comparing with amide-functionalized and esterifiable magnetic nanospheres,epoxy magnetic nanospheres were transformed to amino-functionalized nanospheres more easily,and the amino-functionalized nanospheres remain well-dispersed and complete,which can be used in subsequent labeling experiment.Lastly,the compound[N（Et）₄][Re（CO）₃Br₃]was synthesized,and the labeling precursor fac-[Re（CO）₃（H₂O）₃]⁺ was obtained by dissolving[N（Et）₄][Re（CO）₃Br₃]in water.And the technology roadmap of labeling of magnetic nanopsheres with ordinary tri-carbonyl rhenium was designed.The histidine was covalently linked to the surface of amino-functionalized nanospheres using glutaraldehyde as cross-linker.The results showed that after immobilizing with histidine,magnetic nanospheres had complete structure,good dispersibility,high magnetic content（20 wt.%） and saturated magnetization（9.43 emu/g）,which can be used in the next simulative labeling experiment.Using the magnetic nanospheres immobilized with histidine as magnetic targeted carrier, the simulative labeling experiment of them with tri-carbonyl rhenium was primarily developed.The resulted showed that the labeled products has complete structure,good dispersibility,high magnetic content（16 wt.%） and saturated magnetization（9.10 emu/g）.The simulative labeling yield was tested by UV-spectrophotometer and calculated as 80.4%. These results exhibited that tri-carbonyl rhenium had good labeling ability for the magnetic nanospheres immobilized with histidine,which showed that it was hopeful in realizing the successful radiolableling with radionuclides ¹⁸⁸Re.更多还原