介孔二氧化硅包覆的纳米金棒在生物检测和光热治疗中的应用

发布时间：2018-02-28 00:14

本文关键词： 纳米金棒 AuNRs@SiO_2 等离子共振传感器生物检测药物释放　出处：《华中农业大学》2017年硕士论文　论文类型：学位论文

【摘要】：纳米金棒(AuNRs)作为贵金属纳米粒子中形貌独特的一种,由于其独特的局域等离子共振(LSPR)特性及其衍生出的光热效应,被广泛应用于传感检测及癌症治疗等方面。然而,由于AuNRs表面官能团单一、生物毒性强、比表面积小等缺陷,限制了AuNRs的应用。本文利用生物相容的介孔二氧化硅对AuNRs表面进行修饰,在改善AuNRs性能的同时扩展在生物检测及癌症治疗中的应用。将AuNRs与介孔二氧化硅(Si O_2)结合,本文的研究工作主要分为以下几个方面:(1)基于AuNRs@Si O_2复合材料构建等离子共振(LSPR)传感器,用于检测大肠杆菌。以稳定AuNRs的表面活性剂十六烷基三甲基溴化铵(CTAB)为模板,在AuNRs表面沉积介孔二氧化硅层,通过调控CTAB的浓度和正硅酸四乙酯(TEOS)加入量,合成了不同厚度的介孔二氧化硅层包覆的AuNRs。通过改变周围环境折射率,对不同厚度的AuNRs@Si O_2复合材料的灵敏度进行了评估,实验证明较薄厚度的AuNRs@Si O_2复合材料的灵敏度更高,最高可达390 nm/RIU。将具有最优灵敏度的AuNRs@Si O_2复合材料用于大肠杆菌的检测,实验结果表明大肠杆菌浓度与AuNRs@Si O_2复合材料的等离子共振峰的位移呈现线性关系,并且,检测限可达10CFU,灵敏度相对于传统方法高出了两个数量级,为大肠杆菌的量化以及高灵敏地检测大肠杆菌奠定了基础。(2)基于温敏性高分子包覆的AuNRs@Si O_2复合材料可控药物释放平台。通过自引发光接枝光聚合(SIPGP)的方法,将温敏性的嵌段共聚物p(NIPAM-co-AAm)接枝到AuNRs@Si O_2复合结构的表面。纳米金棒本身的光热效应为该体系用于光疗化疗结合杀死癌细胞提供了基础,介孔二氧化硅的存在在提高稳定性和生物相容性的同时大幅提高了载药量,温敏性聚合物赋予了该复合结构开关响应性能。为了深入探究该复合体系的药物可控释放性能,以盐酸阿霉素(DOX)为模型药物,通过该体系在体外的药物释放性能研究发现,在不同的温度和p H刺激下,DOX的缓释性能呈现出明显的差别。并且,为了进一步研究其开关响应性能,通过外加近红外光源的刺激发现,同等时间内相对于无激光刺激,DOX的缓释量明显增大。这为解决传统可控缓释难的问题、实现细胞内开关响应药物缓释性能提供了研究基础。
[Abstract]:AuNRs are widely used in sensing detection and cancer therapy because of their unique local plasmon resonance (LSPR) properties and their photothermal effects. The application of AuNRs is limited because of its single functional group, strong biotoxicity and small specific surface area. In this paper, the surface of AuNRs is modified by biocompatible mesoporous silica. In addition to improving the performance of AuNRs and expanding its applications in biological detection and cancer therapy, AuNRs is combined with mesoporous silica and SiO2. The research work in this paper is divided into the following aspects: 1) the plasmon resonance (LSP) sensor based on AuNRs@Si O\ -2 composite material is constructed for the detection of Escherichia coli. The surfactant cetyltrimethylammonium bromide (cetyltrimethylammonium bromide) stabilizing AuNRs is used as a template for the detection of Escherichia coli. The mesoporous silica layer was deposited on the surface of AuNRs. By adjusting the concentration of CTAB and the amount of tetraethyl tetraethyl orthosilicate (TEOS), AuNRscoated with different thickness of mesoporous silica layer was synthesized by changing the refractive index of the surrounding environment. The sensitivity of AuNRs@Si O _ 2 composite with different thickness was evaluated, and the results showed that the sensitivity of AuNRs@Si _ O _ 2 composite with thin thickness was higher, up to 390nm / r RIU. The most sensitive AuNRs@Si O _ 2O _ 2 composite was used for the detection of Escherichia coli. The experimental results show that there is a linear relationship between the concentration of Escherichia coli and the displacement of plasmon resonance peak of AuNRs@Si O\ -2 composite, and the detection limit can reach 10 CFU, and the sensitivity is two orders of magnitude higher than that of the traditional method. It lays a foundation for the quantification and highly sensitive detection of Escherichia coli. It is based on a controllable drug release platform of AuNRs@Si O _ 2 composite coated with thermo-sensitive polymer. The thermosensitive block copolymers (pNPAM-co-AAmA) were grafted onto the surface of AuNRs@Si O _ 2 composite structure. The photothermal effect of the nanocrystalline gold rods provided the basis for the phototherapy chemotherapy combined with the killing of cancer cells. The presence of mesoporous silica improves the stability and biocompatibility of the composite structure and greatly increases the drug load. The thermo-sensitive polymer gives the switch response performance of the composite structure. Using doxorubicin hydrochloride (DOX) as a model drug, the release properties of doxorubicin hydrochloride in vitro were studied. It was found that the slow release performance of doxorubicin hydrochloride was significantly different under different temperature and pH stimulation. In order to further study the switching response performance, it was found that the sustained release of DOX was obviously increased in the same time compared with that without laser stimulation, which was a solution to the problem of traditional controllable slow release. It provides a basis for the study of the slow release of intracellular switch-responsive drugs.
【学位授予单位】：华中农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O614.123;TB383.1

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