【作者】 郇伟伟；

【导师】 杨宇翔；

【作者基本信息】 华东理工大学 ， 无机化学， 2013， 博士

【摘要】 Fe304因生物相容性、化学稳定性好,无毒副作用等特性,在生物医学领域的应用越来越广泛,常用于细胞磁分离及标记、临床诊断MRI造影剂、药物纳米导向剂和肿瘤磁热疗等方面。但是如何提高磁性能和载药率,如何实现靶向给药以及高效标记放射性核素示踪仍是目前科研工作者们所遇到的难题。本论文以FeCl3-6H2O和FeCl2-4H2O为铁源,分别采用溶剂热法、共沉淀法和回流法合成了磁性能优良的纳米Fe304及掺杂纳米Fe304,并将合成的纳米磁粒应用于丝裂霉素C (Mitomycin, MMC)负载、放射性元素99Tcrm标记、生物体内SPECT显像及磁靶向应用。论文主要包含以下工作：(一)采用溶剂热法制备了具有分散性良好、核壳结构明显的氨基化Fe3O4@SiO2。并进行了Eu3+和Sm3+掺杂纳米Fe304粒子的研究。发现Eu以+2和+3价掺杂于Fe3O4晶胞中,掺杂改变了纳米Fe304晶体的形貌和磁性质,随着掺杂量的增加,纳米Fe3O4先呈现空心球结构,再转化为球形,最后形成粒径为13nm均一的立方颗粒。形貌的变化影响了晶格的各向异性,导致了纳米颗粒的矫顽力和饱和磁化强度的不同。Sm3+的掺杂引起了磁偶极跃迁,而Eun+掺杂对磁偶极跃迁影响较小；两者的饱和磁化强度随掺杂量增加而出现不同的变化。(二)以四甲基氢氧化铵(TMAH)为沉淀剂和分散剂制备粒径均一,尺寸为20nm的纳米Fe3O4,首次分别与摩尔掺杂量为2%～10%的两种非磁性金属离子Mg2+和Al3+的含肼甲酸盐进行固固掺杂反应,制备了非磁性离子掺杂的强磁性纳米Fe3O4；用VSM磁强计测定了其饱和磁化强度(Ms),研究了Ms随掺杂量的变化,并通过穆斯堡尔谱图分析,研究了不同价态Fe在反尖晶石Fe304晶体A、B位置上的占位比例,结合磁性能测试和指标化计算晶胞参数的变化,研究了掺杂Mg2+和Al3+后纳米粒子磁性能的变化原因。并以毛细管模拟血管、球形玻璃球模拟血管周围肿瘤组织,研究了纳米Fe304在磁靶区干预部位的靶向性能。(三)用改进的StOber法制备了a-Fe203@Si02复合颗粒；并利用长链烷基三甲氧基硅烷极易水解缩合形成聚硅氧烷的特性,通过调节其链长、醇／水比,在复合颗粒表面包覆不同结构的介孔mSiO2,进一步采用选择性蚀刻技术气蚀Fe3O4@SiO2@mSiO2,制备了具有不同孔径和不同空腔体积的磁性纳米空心球(HMNPs-Cn, n=16,18)本文分别以HMNPs-C18和HMNPs-C16,对丝裂霉素C (MMC)进行了负载量和缓释动力学的研究,发现,HMNPs-C18的载药量高于HMNPs-C16,两者由于孔径和空腔体积不同,对MMC的缓释动力学模型也不同。此外,本文还以HMNPs-C18对放射性元素99Tcm标记进行了研究。(四)本文分别以溶剂热法、TMAH共沉淀法和回流法制备MNPs,并依次通过Sol-Gel过程,表面氨基化,DTPAA双酐等摩尔偶联,制备了带有DTPAA单酐的MNPs@SiO2-NH-DTPAA待标记化合物。筛选出以TMAH共沉淀法,并经A13+固固掺杂制备的待标记化合物,具有最高的饱和磁化强度(65.7emu/g),标记率最高为93.2%。分别以新西兰兔和腿部荷VX2肿瘤的新西兰兔为动物模型,采取耳后缘静脉注射,分别通过平面静态图像获得SPECT图像,首次研究了MNPs-DTPA-99Tcm在体内的自然分布和磁靶向分布。按感兴趣区技术(ROI)进行半定量分析,计算磁靶向干预的病变部位和未干预的病变部位的放射性计数比,评价MNPs在新西兰兔体内的靶向效果,为磁靶向载药系统提供重要参考。(五)本文通过戊二酸酐与丝裂霉素上活泼的亚胺基反应,制备了MMC-戊二酸衍生物,然后再与N-羟基琥珀酰亚胺(NHS)反应,经葡聚糖凝胶层析柱分离提纯,制备了MMC活化酯。另依次通过非磁性离子固固掺杂、Sol-Gel过程和表面氨基化,制备了具有高饱和磁化强度的Ald-Fe304@Si02-NH2复合颗粒。本文首次将MMC活化酯和表面带有氨基的复合颗粒在乙二醇二甲醚中偶联,进一步制备了负载MMC的纳米功能磁粒。通过核磁共振谱图、元素分析、紫外和红外光谱,证明了目标化合物的生成。更多还原

【Abstract】 Due to the good biocompatibility and the satisfactory chemical stability, the nano-particles have been widely used in the field of biomedicine. Especially, they are often used in cellular labeling and magnetic separation, MRI contrast agent, drug delivery agents, tumor thermotherapy and so on. However how to increase the magnetic performance and drug-loading capacity, and how to achieve MNPs-based targeted drug delivery and effective imaging with99Tcm-labelled are the main problem that researches facing.In this thesis, magnetic nano particles (MNPs) and dopped MNPs with excellent magnetic performance were synthesized by solvothermal method, coprecipitation method and reflux method, with FeCl3·6H2O and FeCl2·4H2O used as iron sources, anhydrous rare earth chloride and non-magnetic ion formate containing hydrazine as doping source respectively. The MNPs can be used for Mitomycin C drug loading, radioactive elements (99Tcm) labeling and In-vivo SPECT imaging, as well as application of magnetic targeting in humans. This thesis contains the following works:First, the amino-functionalized MNPs@SiO2core/shell nanoparticles with high dispersibility were synthesized by solvothermal method, and the doping of Eu+and Sm3+into nano Fe3O4was studied. The results show that Eu ions had doped in the Fe3O4cell in mixed-valence of Eu3+/Eu2+, the doping could change morphologies and magnetic properties of the Fe3O4cell. When the Eu and Sm doping amount were increased, the doped Fe3O4nanoparticles changed from hollow nanospheres into spherical particles, and finally changed into uniform cube-shaped particles with13nm in diameter, resulting in change of shape anisotropy, which may affect their coercivity and saturation magnetization. It was found that higher Sm3+-doping amount led to stronger magnetic dipole transitions, while the Eun+-doping amount had little effect on the magnetic dipole transitions, thus resulting in different changes in their saturation magnetization with doping amount.Second, Fe3O4magnetic nanoparticles with uniform particle size about20nm were prepared by co-precipitation method with tetramethyl ammonium hydroxide (TMAH) as precipitant and dispersing agent. Then the as-synthesized Fe3O4particles were first taken to react with non-magnetic ion (magnesium or aluminum ion) formate containing hydrazine at2%～10%molar doping ratio to prepare strong magnetic non-magnetic ion dopped MNPs by solid-solid reaction. Their saturation magnetization (Ms) was determined by vibrating sample magnetometer (VSM), the changes of Ms with Mg2+and Al3+doping amount was also studied. By analysis of the magnetic Mossbauer spectra of non-magnetic ion dopped MNPs, the ratio of the relative population of A-site Fe atoms to B-site Fe atoms in the inverse spinel structure of Fe3O4was studied. The reason why Ms changed after doping Mg2+and Al3+can be explained by considering the VSM determination results and changes of unit-cell parameters obtained from the indexing of the experimental XRD pattern. Moreover, the targeting performance of MNPs at magnetic targeting interfered sites was studied by capillary simulating vein, and spherical glass balls simulating perivascular tumor tissue also.Third, based on the fact that long alkyl chain trimethoxysilane has the characteristic of being easily hydrolysized and condensed into polysiloxane, the α-Fe2O3@SiO2composite particles were synthesized by a modified StOber method, and further covered by mesoporous mSiO2on their surface with different structure through adjusting alcohol/water ratio and chain-length of long alkyl chain trimethoxysilane. Finally, the magnetic hollow spheres (HMNPs-Cn, n=16,18) with different pore diameter and cavity volume were obtained by using selective etching technique to treat Fe3O4@SiO2@mSiO2. In this thesis, the loading and release kinetics of mitomycin C (MMC) on HMNPs-C18and HMNPs-C16were studied, the results showed, HMNPs-C18has a higher drug loading than HMNPs-C16, both of them have different drug release kinetics model for MMC, due to their different pore diameter and cavity volume. Besides, the labeling of radioactive element99Tcm by HMNPs-C18was also studied.Fourth, the solvothermal method, TMAH coprecipitation method and reflux method were employed to prepare MNPs respectively. After that, the MNPs@SiO2-NH-DTPAA (un-labeled compound) with DTPAA monoanhydride was prepared successively with the following procedures on the MNPs surface:(a) Sol-Gel process,(b) surface amination process and (c) equimolar coupling of c-DTPAA bis-anhydride on the surface of amino-functionalized nano magnetic particles. Among these un-labeled compounds, the Al3’ion dopped MNPs@SiO2-NH-DTPAA prepared by TMAH coprecipitation and following Al3+doping, solid-solid reaction was screened out to have the highest saturation magnetization (65.7emu/g), and labeling efficiency (93.2%).In this thesis, Tumor-Free New Zealand white rabbit and Leg-VX2Tumor-Bearing New Zealand white rabbit were selected as experimental animal model, which are all treated by the injection of labeled compound in one ear vein, after that, the SPECT images were obtained from two-dimensional static images respectively. Based on the information from the images, the natural distribution and magnetic targeting distribution were first studied. Semiquantitative analysis can be achieved by calculation of region of interest ratios (ROI) using liver or lung for comparison, and according to the semiquantitative analysis, in vivo radioactivity count ratio of magnetic targeting interfered lesion’s site to non-interfered lesion’s site was calculated to evaluate in vivo targeting effects of labeled compound in Tumor-Bearing New Zealand white rabbit. The results will offer important references for magnetic targeting drug-loaded system.Fifth, by reaction of glutaric anhydride with an active imino group in mitomycin C (MMC), the MMC-glutaric acid derivatives can be prepared. Then the obtained products underwent esterification with N-hydroxysuccinimide (NHS) followed by passing them through a column of dextran gel to isolate and purify the activated ester of glutaric MMC.On the other hand, Ald-Fe3O4@SiO2-NH2composite particles with high saturation magnetization were prepared successively with the procedures:(a) non-magnetic ion doping, solid-solid reaction,(b) Sol-Gel process and (c) surface amination process.In this thesis, by first coupling the activated ester of glutaric MMC with the amino-functionalized Ald-Fe3O4@SiO2-NH2composite particles in the1,2-dimethoxyethane, the MMC grafted Ald-Fe3O4@SiO2-NH2composite particles were further prepared, which provides reference of the route for preparing this targeted drugs. The targeting compounds were demonstrated by nuclear magnetic resonance (NMR) spectra, elemental analysis, UV and FT-IR spectra.更多还原