金和金银核壳纳米棒的表面增强荧光效应研究
发布时间：2019-03-29 19:57
【摘要】：荧光光谱技术被广泛应用于医学诊断、生物成像以及物质分析等领域,其检测极限取决于荧光信号的信背比。将荧光分子放置于特定构型的金属纳米结构附近,利用入射光场、金属纳米结构和荧光分子三者之间的相互作用对分子的荧光激发和发射过程进行调控,能够有效增加荧光信号强度,进而提高检测灵敏度。本论文利用金和金银核壳纳米棒溶胶为增强衬底,系统研究了单光子激发条件下金属纳米颗粒的局域表面等离激元共振模式与荧光分子发射光谱之间的耦合程度对荧光增强效应的影响规律；并对金属增强多环芳烃类化合物蒽的双光子激发荧光特性做了初步探索。论文主要工作包括以下四个部分：1.系统地介绍了金属纳米颗粒局域表面等离激元的产生和特性,以及基于表面等离激元的重要应用-表面增强荧光效应的产生机理和衬底分类。2.采用种子生长法合成金纳米棒溶胶；在此基础上,制备金银核壳纳米棒。通过调控反应过程中试剂的使用量,制备得到具有不同局域表面等离激元共振波长的金和金银核壳纳米棒。3.实验上选取具有不同局域表面等离激元共振波长的金和金银核壳纳米棒溶胶为增强衬底,基于激光光谱学方法,研究了金属纳米棒对VA嗪720分子的表面增强单光子激发荧光效应。研究表明,随着分子-金属纳米棒混合体系中纳米棒浓度的增加,荧光增强程度呈现先增大后减小的趋势,这归因于分子辐射衰减速率增加引起的荧光强度增大和自过滤效应带来的荧光强度减弱之间的竞争；通过进一步分析不同衬底的增强荧光效应发现,在考虑分子激发效率不受影响的情况下,金属纳米颗粒等离激元共振模式与荧光分子发射光谱之间的耦合程度对增强效果的影响强烈依赖于混合体系中金属纳米颗粒的浓度。在浓度较低时,具有最大耦合程度的金属纳米棒表现出最佳的荧光增强效果；而当浓度增加到一定量时,受到自过滤效应的影响,具有最大耦合程度的金属纳米棒反而有可能产生最弱的荧光增强。4.研究了金纳米棒对多环芳烃类化合物蒽的双光子激发荧光增强效应。利用相转移手段和缓慢挥发溶剂的方法制备得到蒽-金纳米棒混合体系,研究表明,由于金纳米棒在光场激发下对分子激发和发射行为的调控,蒽的双光子激发荧光信号明显增强。
[Abstract]:Fluorescence spectroscopy is widely used in medical diagnosis, biological imaging and material analysis, and its detection limit depends on the signal-to-back ratio of fluorescence signals. The fluorescence molecules are placed near the metal nanostructures of a specific configuration. The fluorescence excitation and emission processes of the molecules are regulated by the interaction among incident light field, metal nanostructures and fluorescent molecules. It can effectively increase the intensity of fluorescence signal, and then improve the detection sensitivity. In this thesis, gold and silver core-shell nanorods were used as reinforcing substrates. The influence of the coupling degree between the local surface plasmon resonance mode and the fluorescence emission spectrum on the fluorescence enhancement effect of metal nanoparticles under single photon excitation is studied systematically. The two-photon excited fluorescence properties of anthracene, a metal-enhanced polycyclic aromatic compound, were also studied. The main work of this paper consists of the following four parts: 1. In this paper, the generation and characteristics of the local surface plasmon of metal nanoparticles, the generation mechanism of the surface enhanced fluorescence effect and the substrate classification based on the surface isoplasmon are systematically introduced in this paper, as well as the generation mechanism and substrate classification of the surface enhanced fluorescence effect based on the surface plasmon. Gold nanorods were synthesized by seed growth method and gold-silver core-shell nanorods were prepared. Gold and gold-silver core-shell nanorods with different local surface plasmon resonance wavelengths were prepared by adjusting the amount of reagents used in the reaction. Gold and gold-silver core-shell nanorods with different local surface plasmon resonance wavelengths were selected as enhanced substrates based on laser spectroscopy. The surface-enhanced single-photon excitation fluorescence effect of metal nanorods on the VA pyrazine 720 molecule was studied. The results show that the fluorescence enhancement increases first and then decreases with the increase of the concentration of nanorods in molecular-metal nanorods. This is due to the competition between the increase of fluorescence intensity caused by the increase of molecular radiation attenuation rate and the decrease of fluorescence intensity caused by self-filtration effect. By further analyzing the enhanced fluorescence effect of different substrates, it is found that the molecular excitation efficiency is not affected by the molecular excitation efficiency. The coupling between the plasmon resonance mode of metal nanoparticles and the emission spectra of fluorescent molecules strongly depends on the concentration of metal nanoparticles in the mixed system. When the concentration is low, the metal nanorods with the maximum coupling degree show the best fluorescence enhancement effect. However, when the concentration increases to a certain amount, the metal nanorods with the maximum coupling degree may produce the weakest fluorescence enhancement due to the influence of the self-filtration effect. 4. The two-photon excitation fluorescence enhancement effect of gold nanorods on anthracene was studied. Anthracene-gold nanorods were prepared by phase transfer method and slowly volatile solvent method. The results showed that gold nanorods could regulate the molecular excitation and emission behavior under light field excitation. The fluorescence signal of anthracene excited by two-photon was enhanced obviously.
【学位授予单位】：陕西师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1;O657.3
[Abstract]:Fluorescence spectroscopy is widely used in medical diagnosis, biological imaging and material analysis, and its detection limit depends on the signal-to-back ratio of fluorescence signals. The fluorescence molecules are placed near the metal nanostructures of a specific configuration. The fluorescence excitation and emission processes of the molecules are regulated by the interaction among incident light field, metal nanostructures and fluorescent molecules. It can effectively increase the intensity of fluorescence signal, and then improve the detection sensitivity. In this thesis, gold and silver core-shell nanorods were used as reinforcing substrates. The influence of the coupling degree between the local surface plasmon resonance mode and the fluorescence emission spectrum on the fluorescence enhancement effect of metal nanoparticles under single photon excitation is studied systematically. The two-photon excited fluorescence properties of anthracene, a metal-enhanced polycyclic aromatic compound, were also studied. The main work of this paper consists of the following four parts: 1. In this paper, the generation and characteristics of the local surface plasmon of metal nanoparticles, the generation mechanism of the surface enhanced fluorescence effect and the substrate classification based on the surface isoplasmon are systematically introduced in this paper, as well as the generation mechanism and substrate classification of the surface enhanced fluorescence effect based on the surface plasmon. Gold nanorods were synthesized by seed growth method and gold-silver core-shell nanorods were prepared. Gold and gold-silver core-shell nanorods with different local surface plasmon resonance wavelengths were prepared by adjusting the amount of reagents used in the reaction. Gold and gold-silver core-shell nanorods with different local surface plasmon resonance wavelengths were selected as enhanced substrates based on laser spectroscopy. The surface-enhanced single-photon excitation fluorescence effect of metal nanorods on the VA pyrazine 720 molecule was studied. The results show that the fluorescence enhancement increases first and then decreases with the increase of the concentration of nanorods in molecular-metal nanorods. This is due to the competition between the increase of fluorescence intensity caused by the increase of molecular radiation attenuation rate and the decrease of fluorescence intensity caused by self-filtration effect. By further analyzing the enhanced fluorescence effect of different substrates, it is found that the molecular excitation efficiency is not affected by the molecular excitation efficiency. The coupling between the plasmon resonance mode of metal nanoparticles and the emission spectra of fluorescent molecules strongly depends on the concentration of metal nanoparticles in the mixed system. When the concentration is low, the metal nanorods with the maximum coupling degree show the best fluorescence enhancement effect. However, when the concentration increases to a certain amount, the metal nanorods with the maximum coupling degree may produce the weakest fluorescence enhancement due to the influence of the self-filtration effect. 4. The two-photon excitation fluorescence enhancement effect of gold nanorods on anthracene was studied. Anthracene-gold nanorods were prepared by phase transfer method and slowly volatile solvent method. The results showed that gold nanorods could regulate the molecular excitation and emission behavior under light field excitation. The fluorescence signal of anthracene excited by two-photon was enhanced obviously.
【学位授予单位】：陕西师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1;O657.3
【共引文献】
相关期刊论文 前10条
1 曾伟成,黄颖,樊希承;植物凝集素稳定性的荧光光谱分析[J];海峡药学;2005年02期
2 曾伟成;黄颖;樊希承;陈勇攀;;FDA-EB双色荧光分析法检测细胞活性的变化[J];海峡药学;2007年01期
3 佘家Y，
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