【作者】 刘春宇；

【导师】 徐蔚青； 徐抒平；

【作者基本信息】 吉林大学 ， 物理化学， 2013， 博士

【摘要】 贵金属纳米粒子具有很多独特的表面等离子体性质，这与金属纳米粒子的表面自由电子的集体振荡是密切相关的，它们都强烈的依赖金属纳米粒子的尺寸、形貌等因素，这使其在现代材料领域的研究中得到广泛的应用。光纤自出现之日起即引起科研工作者的极大关注，在诸多领域如通讯及传感等，有着重要的应用。光纤化学、生物传感器是传感领域中一个重要的研究方向，近十几年来取得的研究成果令人瞩目，它已广泛应用于化学传感以及生物体系中特异性识别、DNA等的快速检测，应用前景十分广阔。由于光纤具有信号的远程传输、低损耗及对外界环境干扰较小的优点，将光纤与SERS光谱技术相结合制备光纤SERS传感器，这种技术借助于SERS光谱技术可获得被测样品较为丰富的光谱信息，并实现实时、原位、在体、在线的光谱检测。光纤SERS传感器的灵敏度除了要求光纤本身要具备背景荧光底、传输效率高等优点外，对光纤探测端的形状、SERS活性层的修饰及在如何在光谱检测过程中提高信噪比都提出了比较高的要求。本文围绕高灵敏度SERS活性光纤的快速制备、应用技术而展开，主要研究内容如下：1.利用光化学法快速制备光纤SERS传感器，并将其应用于生物体系中Atto610标记的生物素与亲和素特异性识别过程的监测。利用光化学法在光纤尖端沉积银膜，探讨在相同激光功率下不同诱导时间对光纤沉积端形貌的影响。并根据Atto610的SERS信号强度变化对实验条件进行优化，寻找最佳的光诱导沉积时间、诱导生长液的最佳比例，调控光纤探测端LSPR的性质。在干扰极小的条件下时实测量生物素与亲和素特异性识别过程的SERS光谱，并利用干扰性实验证明这种识别的抗干扰能力。2.光纤探测端原位热聚合物多孔材料制备具有三维孔道结构基底，并利用光化学法快速沉积银纳米粒子使其具有SERS活性。利用SEM表征多孔材料的形貌结构，并分析热聚合温度、孔径、粒径对拉曼探针分子4-Mpy与4-MBA的SERS信号的影响，通过SERS信号的强度对比分析寻找理想的聚合温度。3. SERS光纤pH传感器的快速制备及应用。利用光化学法在快速制备光纤SERS传感器，并在其上组装4-Mpy拉曼探针分子，通过对比其在不同pH溶液中质子化特征峰强度变化的规律来确定pH值。在研究过程中，发现4-Mpy质子化特征峰在pH值增加的过程中有蓝移的现象，探讨拉曼探针分子4-Mpy频移变化与溶液pH值的关系。并据此推断4-Mpy分子在不同的pH溶液中与银膜的夹角有所不同，在酸性溶液中它垂直于银膜，中性及碱性溶液中与银膜产生一定的倾角。该SERS活性光纤具有较好的重复使用性，在实际检测中的具有潜在的应用价值。更多还原

【Abstract】 Surface-enhanced Raman scattering (SERS) is a fast and ultrasensitive scatteringspectra technique, has been widely applicable to single molecule detection, pesticidetracing, protein tests, pharmacy, biosensing, and art authentication, etc. SERS requiresminimal sample preparation and is non destructive to sample which allows real timeanalysis and great potential for multi components analysis. The morphology of themetallic structure plays a major role in determining the magnitude of signalenhancement and sensitivity of detection. The preparation of SERS substrates is anessential subject in SERS study. Some researchers employed the laser-induced Ag/Audeposition method to quickly construct an Au/Ag NP film on glass substrate for SERS.Optical fibers have long been the interest of analytical chemists. Through the fiber,signal and light can be transmitted to several kilometers without noticeable loss. It ischemically stable, and is not susceptible to environmental changes. Sensors based onsurface-enhanced Raman scattering (SERS) and optical fiber probes have been usedin chemical and biological detection and sensing due to their unique advantages, suchas their low cost, flexibility, reliability, and also remote sensing capabilities.Based on above view, my study is outlined as follows:1. Preparation of SERS-active optical fiber by laser-induced Ag depositionand its application for the bioidentification of biotin/avidinWe applied the SERS-active fiber prepared by the photochemical Ag NPdeposition to the bioidentification of avidin/biotin. First, we optimized thelaser-induced conditions for the fabrication of SERS-active Ag NP layer. The reflection spectroscopy and scanning electron microscope (SEM) were used tocharacterize the plasmonic property and the morphology of the formed SERS-activeAg NP layer. The optical fiber with laser-induced Ag film was used for monitoring thebiotin/avidin identification process. Since biotin gave weak Raman signals and nofingerprint information was provided in the direct detection of biotin, we used a dyemolecule labeled biotin (Atto610-biotin), which supported strong Raman activity dueto the fluorescent quenching effect when it was assembled on the Ag film surface bythe specific identification of avidin. The concentration-dependent SERS spectra ofAtto610-biotin were recorded and the working curve was obtained. The lowestdetection concentration of Atto610-biotin by using this SERS-active optical fiber wasas low as10-7mg/mL.2. Fabrication of SERS-acitve optical fiber sensor by in situ thermalpolymerization of porous material and its apllicationPolymer porous was preparing with the thermal polymerization method in the tipof the ordinary multimode fiber in situ. Silver nanoparticles film was deposited withthe laser-inducement method in the porous material of the tip fiber for preparation ofhigh SERS-active polymer porous fiber sensor. The metal nanoparticle aggregatescontaining many “hot spots” suspended in solution can present a large total surfacearea, thus facilitating effective interactions with analytes and generation of strongRaman scattering emission. In comparison to SERS sensing using nanostructuredmetal films, which are inherently planar detectors, this approach allows direct probingof analytes within a defined volume of solution, thereby providing higher sensitivity.Porous material laser-induce SERS-active fiber technology has high sensitivity,remotely, on line, real-time and non-destructive can apply the process monitoring,micro-fluidic chip, environmental testing, clinical monitoring and bio-pharmaceuticalfield.3. Preparation and study on the SERS-active fiber pH sensor withlaser-inducement deposition silver nanoparticle film We provide a method of photochemical modification of an optical fiber tip with asilver nanoparticle film.4-MBA and4-Mpy were absorbed by optical fiberSERS-active layer for pH sensor. SERS spectrum changes were monitored in differentpH values solution with SERS-active fiber. In the course of the study, we found that4-Mpy Raman peaks at1619cm-1was blue shift with pH value increases, inferred4-Mpy molecules in different pH solutions has vary the angle with the silver film.4-Mpy molecule was perpendicular with the silver film in acidic solution, and itproduces a certain inclination in the neutral and alkaline solution.更多还原