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类型 基础研究 预答辩日期 2018-03-23
开始(开题)日期 2011-03-31 论文结束日期 2018-01-09
地点 东南大学丁家桥校区江苏省生物材料与器件重点实验室会议室 论文选题来源 973、863项目     论文字数 7.2 (万字)
题目 Fe3O4/Ag复合纳米结构的可控制备及其磁致热疗的基础研究
主题词 磁性纳米颗粒,银,复合纳米材料,形貌可控,磁致热 疗
摘要 癌症是世界范围内发病和死亡的主要原因,攻克癌症是全球医学领域的研究热点。 磁致热疗是肿瘤热疗的重要分支之一,通常利用瘤内超顺磁性氧化铁纳米颗粒在适用的 交变磁场(ACMF)激励下产热,将肿瘤温度升至40~46 oC以杀死肿瘤细胞,从而起到 治疗作用。磁致热疗作为治疗肿瘤的一种新方法,具有微创、低毒副作用等优点,亦存 在氧化铁纳米颗粒的磁热转换效率和传/加热效率较低,临床实验给药浓度高剂量大等不 足。研究者们不断研发具有治疗性能的载药磁性复合纳米材料,以进一步提高肿瘤磁致 热疗疗效。 癌细胞对化疗药物易产生耐药性问题,这也是成功治愈癌症的主要障碍之一。在众 多纳米材料中,银纳米颗粒作为有前途的新型抗癌纳米药物,是化疗药物的潜在候选物。 本论文将纳米Fe3O4和纳米Ag可控地构建在一个纳米结构单元中,获得了不同形 貌的Fe3O4/Ag复合纳米结构:核壳型Fe3O4@Ag和异聚体型和Fe3O4-Ag复合纳米颗粒, 并改善了纳米银的生物相容性;进而将具有超顺磁性和抗癌活性的Fe3O4/Ag 复合纳米 结构作为先进的产热介质,在细胞水平和动物水平上进行肿瘤磁致热疗的验证,磁致热 和抗癌活性协同作用,显著地提高了热疗疗效。主要工作包括以下几个方面: 1. 设计了一种新颖的原位还原合成方法:为了跨越晶格失配的Fe3O4和Ag异质间 较高的界面能垒,利用在预制成的Fe3O4纳米颗粒表面修饰上对Ag +有强亲和力的–COO -作为位点去接收过量Ag +源,然后利用中间产物Fe3O4-COOAg纳米颗粒的沉淀-溶解平 衡性质,直接原位还原Ag +,制备出Fe3O4/Ag复合纳米结构,并且形貌可控。本论文推 测形貌可控制备的机制是控制Fe3O4-COOAg纳米颗粒的[-COO -]和[Ag + ]的解离程度。依 据勒夏特列原理,移动Fe3O4-COOAg纳米颗粒的电离平衡,即调控[-COO -]和[Ag + ]的解 离程度,从而改变Fe3O4-COOAg纳米颗粒表面位点结合Ag +的密疏程度,再原位还原, 得到核壳型或异聚体型的Fe3O4/Ag复合纳米结构。当Fe3O4-COOAg纳米颗粒溶液饱和 时,[-COO -]和[Ag + ]的解离程度在溶液中处于最小状态,Ag +大量结合在颗粒表面的 -COO -上,经原位还原后生成核壳型Fe3O4@Ag复合纳米颗粒。当Fe3O4-COOAg纳米颗 粒溶液被适当稀释,[-COO -]和[Ag + ]的解离程度适当增大,Ag +仅部分还结合在颗粒表面 的-COO -上,经原位还原后生成异聚体型Fe3O4-Ag复合纳米颗粒。研究结果表明,相比 较单一材料的Fe3O4-PAA纳米颗粒,纳米Ag并入到Fe3O4@Ag和Fe3O4-Ag复合纳米 东南大学博士学位论文 2 结构,这两种复合纳米颗粒的超顺磁性、磁感应加热、MRI阴性造影的性能指标并未受 到明显地影响,仍保持了纳米Fe3O4的磁学性能,这为Fe3O4@Ag和Fe3O4-Ag复合纳米 颗粒的肿瘤磁致热疗研究奠定了基础。 2. 以人肝癌SMMC-7721细胞为模型,对Fe3O4/Ag复合纳米结构进行了一系列体 外细胞实验和体外磁致热疗研究。体外细胞毒性实验结果显示,Fe3O4-PAA、Fe3O4-Ag 和Fe3O4@Ag纳米颗粒在0~60 μg Fe/mL或当量0~24.83 μg Ag/mL的浓度范围内对人肝 癌7721细胞和人正常肝L02细胞活性没有显著影响;而24.83 μg Ag/mL是单一材料的 Ag纳米颗粒细胞毒性浓度的1倍多,因此本论文认为纳米银合并入Fe3O4/Ag复合纳米 结构后降低了银的毒性。进而,一系列非毒性浓度条件下的7721肿瘤细胞磁致热疗研 究显示,相比于单一材料的Fe3O4-PAA纳米颗粒,Fe3O4-Ag和Fe3O4@Ag复合纳米颗 粒在ACMF(390 KHz, 18 A, 20 min)激励下对肿瘤细胞的生长抑制作用呈浓度依赖性 的显著增强,表明具抗癌活性的纳米银合并入Fe3O4/Ag复合纳米结构后显著地提高了 磁致热疗效果。基于磁致热能够促进Fe3O4-Ag和Fe3O4@Ag复合纳米颗粒表面的银离 子释放,本论文认为Fe3O4/Ag复合纳米结构显著增强的肿瘤细胞生长抑制作用,可能 归因于磁致热和热辅助银离子释放的协同作用。 3. 以人肝癌7721细胞裸鼠皮下异种移植瘤为模型,对Fe3O4/Ag复合纳米结构进行 了动物体内磁致热疗研究,包括疗效评价及组织病理学分析。在以Fe3O4-PAA、Fe3O4-Ag 和Fe3O4@Ag纳米颗粒作为磁性介质产热,瘤内注射剂量为15 mg Fe/kg体重,给药2 次(每次间隔2天),连续肿瘤磁致热疗6天(20-min ACMF, 390 KHz, 18 A, 每次间隔 24 h)的条件下,肿瘤生长曲线、HE染色、TUNEL染色和CD31染色结果显示:Fe3O4-Ag 和Fe3O4@Ag复合纳米颗粒在ACMF激励下,对7721肿瘤组织生长的抑制作用、诱导 肿瘤细胞凋亡和抑制肿瘤新生血管形成作用,显著强于单一材料的Fe3O4-PAA纳米颗粒。 通过分析上述数据统计学差异的程度,本论文认为Fe3O4/Ag复合纳米结构显著增强的 诱导肿瘤细胞凋亡、抑制肿瘤新生血管形成和抑制肿瘤生长作用,可能归因于磁致热和 纳米银抗癌活性的协同作用
英文题目 Shape-controlled fabrication of magnetite silver hybrid nanostructure and their fundamental study of magnetic hyperthermia
英文主题词 Magnetic nanoparticles, Silver, Nanocomposites, Hybrid, Shape control, Hyperthermia
英文摘要 Cancer is one of the leading causes of morbidity and mortality worldwide. Cancer therapy is a research focus in the modern medical field. Magnetic hyperthermia is one of the important branches of tumor hyperthermia, which treats a tumor by heat proceeding from intra-tumor magnetic nanoparticles (NPs) such as superparamagnetic iron oxide NPs when an alternating current magnetic field (ACMF) is applied to them. A range of 40 to 46 oC is considered as valid hyperthermia temperatures, which can selectively kill cancer cells more sensitive to heat than normal cells. Magnetic hyperthermia as a new approach for cancer therapy has the advantages of non-invasiveness, low toxicity and none side-effect. However, due to the relatively poor heat transfer efficiency of current Fe3O4 NPs, the very high concentrations or doses of iron oxide NPs usually are applied in clinical trial in order to obtain the efficient cancer thermal treatment, which is bound to limit the development of their practical applications. Therefore, the better magnetic nanoparticle-based magnetic mediators have been expected to raise the magnetic hyperthermia efficiency. Besides, drug resistance of chemotherapy almost inevitably emerges and continues to be a major obstacle towards cancer therapy. As a promising and novel anticancer nanomedicine, silver nanoparticles are recognized as being a potential candidate for chemotherapeutic drugs. In this dissertation, an in situ reduction strategy was designed to shape-controlled fabricate the lattice-mismatched Fe3O4 and Ag into a single nano-unit. By this method, the morphology of the magnetite silver (Fe3O4/Ag) hybrid nanostructure could be readily altered to a core-shell (Fe3O4@Ag) or heteromer (Fe3O4-Ag) structure. These two types of Fe3O4/Ag hybrid structure integrated the properties of nano Fe3O4 and Ag, which also proved to be better biocompatible than the individual Ag NPs. Importantly, this is the first report in which the anticancer activity-loaded superparamagnetic magnetite silver hybrid nanostructure is used as the advanced hyperthermia mediator for in vitro and in vivo magnetic hyperthermia. All the results show that the core-shell Fe3O4@Ag or heteromer Fe3O4-Ag hybrid NPs could significantly improve the hyperthermia efficiency. The main contents of this doctoral dissertation are summarized as follows: 1. A new in situ reduction method was used to shape-controlled prepare the magnetite silver hybrid nanostructure. The pre-prepared Fe3O4 NPs were modified with carboxyl groups being a strong affinity to Ag+ ion as inorganic bonding junctions to carry Ag+, which could bypass the high interfacial energy barrier between lattice-mismatched Fe3O4 and Ag. The carboxyl group-capped Fe3O4 NPs (Fe3O4-PAANPs ) were precipitated by excess of AgNO3 added, which resulted in the Fe3O4-COOAg NPs precipitate. And then, this precipitate was redissolved to yield a saturated or diluted concentration Fe3O4-COOAg NPs solution, which could be in situ reduced to magnetite silver hybrid nanostructure with different morphology: core-shell Fe3O4@Ag or heteromer Fe3O4-Ag hybrid NPs. Encouraged by the existing precipitation-dissolution behavior of Fe3O4-COOAg NPs precipitate, the ionization equilibrium of the Fe3O4-COO-Ag+ NPs may be a key factor for the possible shape control mechanism of magnetite silver hybrid nanostructure. According to the Le Chatelier’s principle, when the Fe3O4-COO-Ag+ NPs solution is saturated implying that the equilibrium moves to the left, the minimized dissociation of [-COO-] and [Ag+] is kept on the surface of NPs tending to result in the core-shell Fe3O4@Ag hybrid NPs. When the Fe3O4-COO-Ag+ NPs solution is diluted implying that the equilibrium moves to the right, the greater dissociation of [-COO-] and [Ag+] is kept on the surface of NPs tending to result in the heteromer Fe3O4-Ag hybrid NPs. The characterizations indicated that the incorporation of Ag into Fe3O4@Ag and Fe3O4-Ag hybrid NPs had no obvious influence on their superparamagnetic properties and magnetically induced heating properties compared to individual Fe3O4-PAA NPs, which shows the promising potentiality for magnetic hyperthermia of magnetite silver hybrid nanostructure. 2. Using human hepatoma SMMC-7721 cells as a model, a series of in vitro experiments and in vitro magnetic hyperthermia were performed on magnetite silver hybrid nanostructure as magnetic mediators. MTT assays showed Fe3O4@Ag and Fe3O4-Ag hybrid NPs had no obvious cytotoxicity against both human hepatoma SMMC-7721 cells and human normal hepatocyte L02 cells at the concentrations up to 60 μg Fe/mL or 24.83 μg Ag/mL, while individual Ag NPs had significant cytotoxicity at the concentrations ≥ 10.35 μg Ag/mL. It is suggested the hybridization of nano Fe3O4 and Ag reduces the toxicity of Ag. Furthermore, in vitro magnetic hyperthermia study demonstrated that both Fe3O4-Ag and Fe3O4@Ag hybrid NPs under ACMF excitation exhibited significantly higher inhibition effects on SMMC-7721 cells than individual Fe3O4-PAA NPs at a series of non-cytotoxic concentrations. Based on the fact that magnetically induced heating could boost the Ag+ release from the hybrid NPs surface, the magnetic hyperthermia efficiency of the magnetite silver hybrid nanostructure is greatly enhanced due to the synergistic effect of magnetically induced heating and heat-assisted silver ions release. 3. Using human hepatoma SMMC-7721 xenograft tumor as a model, in vivo magnetic hyperthermia were performed on magnetite silver hybrid nanostructure as magnetic mediators with a regimen of intra-tumor injection (single dose 15 mg Fe/kg body weight) repeated once every 3 days and ACMF treatment (390 KHz, 18 A, 20 min) repeated for successive 6 days. The results demonstrated that both Fe3O4-Ag and Fe3O4@Ag hybrid NPs under ACMF excitation exhibited significant higher tumor growth inhibition, apoptosis and angiogenesis than individual Fe3O4-PAA NPs. Statistical therapeutic evaluation based on the results of tumor growth curve, TUNEL staining and CD31 staining reveals that the combination of magnetically induced heating and anticancer activity of nano Ag could synergistically contribute to obtain the enhanced effect.
学术讨论
主办单位时间地点报告人报告主题
江苏省颗粒学会2010年年会 2010年11月26日-28日 江苏泰州 丁琪 新型核壳结构氧化铁-银纳米粒子的制备
The 6th Asia-Pacific Conference on Transducers and Micro/Nano Technologies 2012年7月8日-11日 江苏南京 丁琪 Preparation of Ag/Fe3O4nano-flowers by coupling chemistry
2014年第三届全国全国纳米生物与医学博士生学术论坛 2014年08月25-28日 江苏苏州 丁琪 Tailored-made Ag/Fe3O4 hybrid nanocomposites
2015年第四届全国生物与医学纳米技术博士生学术论坛 2015年7月 江苏苏州 丁琪 shape-controlled magnetite silver hybrid nanoparticles
第二届亚洲纳米生物技术研讨会 2016年12月1-2号 江苏苏州 丁琪 Enhanced Magnetic Hyperthermia of Magnetite Silver Hybrid Nanoparticle
江苏省生物材料与器件重点实验室 2015年5月7日 东南大学丁家桥校区基一楼201 胡克 纳米材料/水凝胶复合材料研究进展及其在生物医学中的应用
江苏省生物材料与器件重点实验室 2016年4月25日 东南大学丁家桥校区基二201 孙剑飞 纳米颗粒介导的电磁生物医学效应
江苏省生物材料与器件重点实验室 2016年5月7日 东南大学丁家桥校区基二101 杨芳 微气泡的制备研究
东南大学生物科学与医学工程学院 2015年11月17日 南京东郊国宾馆 都有为 仿生纳米磁性材料及其生物医用基础
东南大学生物科学与医学工程学院 2014年11月25日 东南大学榴园宾馆 詹熙 肿瘤转移、肿瘤标志物及药物组学筛选
     
学术会议
会议名称时间地点本人报告本人报告题目
The 2016 International Conference of nanobiology and Nanomedicine 2016年12月8日-10日 福建福州 Fabrication of Magnetite Silver Hybrid Nanoparticles with High Performance Magnetic Hyperthermia
2017年第六届全国生物与医学纳米技术博士生学术论坛 2017年5月 江苏苏州 形貌可控的磁银复合纳米颗粒构建及其磁热疗应用探讨
生物与医学纳米技术研讨会(20160727) 2016年7月27日 江苏南京 磁银纳米复合结构的构建与机制探讨
生物与医学纳米技术研讨会(20161119) 2016年11月19日 江苏南京 Fe3O4/Ag复合纳米粒子的磁致热疗研究
     
代表作
论文名称
Shape-controlled fabrication of magnetite silver hybrid nanoparticles with high performance magnetic
 
答辩委员会组成信息
姓名职称导师类别工作单位是否主席备注
华子春 正高 教授 博导 南京大学
胡勤刚 正高 教授 博导 南京市口腔医院
冯继锋 正高 教授 博导 江苏省肿瘤医院
章非敏 正高 教授 博导 南京医科大学
张宇 正高 教授 博导 东南大学
      
答辩秘书信息
姓名职称工作单位备注
张淼 其他 讲师 东南大学