以新型银胶为衬底小鼠血清的表面增强拉曼光谱分析

针对以新型银胶体粒子为表面增强拉曼衬底获得的高信噪比的小鼠血清的表面增强拉曼光谱进行了分析,对小鼠血清拉曼光谱进行了初步指认。文章首先根据银胶体粒子形貌及特性,从电磁场物理增强的角度,分析了表面增强拉曼散射中有关银胶体粒子聚集形成“热点”导致局部电场增强效应的作用机理,并依据“热点”理论的分析,认为这种新型银胶体粒子具有很强的局域电场增强效果。同时运用表面增强拉曼中“热点”的现象,解释了小鼠血清的表面增强拉曼光谱中出现的低含量成分的拉曼光谱现象。希望通过表面增强拉曼光谱,了解血清中某些低含量成分的微小变化,进而能够及时获得机体的状况。研究结果为如何获得高信噪比生物大分子的表面增强拉曼散射光谱,了解丰富的生物分子结构信息提供了一种新的方法,同时也为开拓医学上利用血清进行疾病的早期检测提供了一种分子光谱学手段。     

以新型银胶为衬底的超低浓度R6G的拉曼光谱检测

利用柠檬酸钠还原硝酸银的原理,提出了一种微波加热制备银胶体粒子的新方法,得到了颗粒大小较均匀的灰色银胶体。以提纯后的银胶为表面增强拉曼散射衬底,研究了超低浓度染料大分子罗丹明6G分子的表面增强拉曼散射,得到浓度分别为10-12mol/L、10-13mol/L和10-14mol/L的罗丹明6G的表面增强拉曼散射光谱,初步实现了罗丹明6G的单分子检测,证明该新型银胶衬底有非常强的表面增强拉曼活性。同时根据表面增强拉曼散射“热点”的增强机理,分析了获得超低浓度R6G的表面增强拉曼光谱的原因。     

激光刻蚀银胶的制备及其SERS应用

激光刻蚀技术制备金属胶体是一种新兴的表面增强拉曼散射(SERS)活性衬底制备方法,本文利用激光刻蚀技术制备了'化学纯'银胶,并通过透射电镜、吸收光谱、表面增强拉曼散射光谱等手段对其进行研究,结果表明:银胶的等离子体共振吸收峰位于396nm;银粒子分布比较均匀,多数为球形颗粒,颗粒大小在20nm左右,并且有很好的分散性;吡啶的SERS谱分析显示此银胶具有很好的增强效果。     

基于“热点”效应的表面增强拉曼散射光谱研究

本文利用罗丹明6G在银胶体粒子聚集点上的表面增强拉曼光谱的强度变化,采用逐点扫描获得拉曼光谱的"Mapping"方法,获得了不同的银胶体粒子聚集点对吸附的R6G表面增强拉曼光谱强度的影响。分析了"热点"对拉曼散射的增强的作用,表明"热点"的增强强度和纳米粒子的聚集程度有关。     

混合正、负电性银胶体系的表面增强拉曼散射活性研究

通过化学还原的方法分别制备了具有正、负电性的纳米银胶 .利用透射电子显微镜表征了正、负电性银胶以及混合银胶体系中加入碱性品红分子后的聚集行为 .通过测定碱性品红分子在正、负电性银胶以及混合银胶体系中的表面增强拉曼光谱的变化 ,探讨了不同电性银胶基底对碱性品红表面增强拉曼活性的影响 .实验结果表明 ,混合溶胶体系所具有的不同于单一溶胶的聚集特性能有效的改善单银胶体系的表面增强拉曼散射活性 .     

全息干版银膜的制备、表征及其SERS活性的研究

报道了一种新的制备SERS基底的方法。通过对全息干版进行曝光、显影和定影,获得了具有良好稳定性的固体银膜。用紫外-可见光谱测量其表面等离子体共振吸收,发现其吸收谱线在420 nm处存在银粒子的特征吸收峰,且吸收峰具有较窄的半峰宽,这表明采用该方法制备的银膜表面分布着大小均一的银粒子。用扫描电子显微镜对其表面粒子形貌进行表征,发现银粒子分布均匀且平均粒径为100 nm左右。同时以结晶紫为探针分子测量了该银膜的表面增强拉曼光谱,结果表明该银膜具有良好的表面增强拉曼散射活性。采用这种方法制备的银膜稳定性好且易于保存,在常温下空气中放置数月,仍能保持原有的表面增强拉曼散射活性。     

竹红菌甲素在银胶中的电磁增强和荧光猝灭现象的研究

应用表面增强拉曼散射方法，首次获得了竹红菌甲素在黄银胶中的拉曼光谱；分析了电磁增强和荧光猝灭效应在银胶一竹红菌甲素体系中的作用。     

荧光/表面增强拉曼散射双模式纳米光学探针的构建及性能研究

提出一种新型的荧光及表面增强拉曼散射（SERS）双模式光学纳米探针。首先,通过再沉淀-包覆法合成二氧化硅包覆香豆素6的纳米颗粒,再在二氧化硅表面静电吸附多聚赖氨酸分子形成包覆层,随后通过原位还原的方法在多聚赖氨酸壳层复合银纳米颗粒,最后在银纳米颗粒表面吸附拉曼分子即形成双模式纳米探针。该探针通过二氧化硅包覆的荧光分子产生荧光信号,以多聚赖氨酸表面的银纳米颗粒作为SERS增强基底,利用拉曼分子获得SERS信号,实现了荧光及SERS双模式成像。荧光与表面增强拉曼散射相结合的双模式分析技术可同时发挥二者的优点,提高成像的分辨率和灵敏度,在生物医学领域具有重要的应用价值。     

竹红菌甲素在银胶中的电磁增强的和荧光猝灭现象的研究

应用表面增强拉曼散射方法，首次获得了竹红菌甲素在黄银胶中的拉曼光谱；分析了电磁增强和荧光猝灭效应在银胶－竹红菌甲素体系中的作用。     

一种新型表面增强拉曼活性基底的制备及表征

研究了一种新的表面增强拉曼活性银基底的制备方法,采用银增强剂和引发剂的混合溶液处理全铝表面制备了银基底,利用扫描电子显微镜分析了基底的表面形态和结构,测定结晶紫分子在基底表面的拉曼光谱.结果表明,这种基底具有很强的表面增强拉曼散射效应(SERS)活性和稳定性.     

基于整体柱的超灵敏表面增强拉曼检测

本文提出了一种全新的基于整体柱材料的SERS检测方法。通过将探针分子和银溶胶混合后滴加在整体柱上, 我们可以得到浓度低至10-18 mol/L的罗丹明6G(R6G)及10-16 mol/L的对巯基苯胺(PATP)的SERS信号。利用原子力显微镜(AFM)和扫描电镜(SEM)对银溶胶及整体柱材料进行了表征。通过实验结果可以初步推测, 整体柱材料的表面形态和孔结构可以促进银溶胶产生“热点”。     

A simple method for the preparation of ultrahigh sensitivity surface enhanced Raman scattering (SERS) active substrate

By immersing mica modified with cetyltrimethylammonium bromide (CTAB) into the silver colloid, a high efficient surface enhanced Raman scattering (SERS) active substrate was formed within 2 h at room temperature. The limit of detection of the substrate for Rhodamine 6G is up to 1×10⁻¹⁴ M. Changing the concentration of silver colloid and the treating time, various silver aggregates such as nanocrystals, clusters and films were found, and the SERS spectra of these aggregates were also obtained. The results of SERS revealed that CTAB could accelerate aggregation of the silver colloid and cause great Raman enhancement. Bilayer of CTAB is very important for aggregation of silver colloid and the aggregation extent is the main factor for the enormous enhancement on this substrate.     

表面增强拉曼光谱检测水中微量的芬太尼

通过化学法合成了具有表面增强拉曼散射(SERS)活性的银胶体,利用透射电子显微镜和紫外可见光谱仪分别对银胶体的形貌和光学性质进行了表征;采用这种衬底对水相中微量的芬太尼进行了SERS检测研究,并对芬太尼的SERS信号进行了归属,考察了各种实验条件对SERS检测的影响。实验结果表明,增大银胶体浓度有利于芬太尼SERS信号的检测;随着团聚剂氯化钠浓度增大芬太尼的SERS信号强度会先增大后减小,即团聚剂浓度存在一个最佳值;在优化的实验条件下芬太尼的检测限可以达到0.1ppm量级。     

应用银溶胶膜探测水中抗生素的表面增强拉曼光谱研究

以自组装法制备的银溶胶膜为表面增强拉曼散射活性基底实现了对水中抗生素的痕量检测。采用微波加热法制备银溶胶,自组装法制备银溶胶膜。通过改变银溶胶的pH值及镀膜的次数,研究其对抗生素增强效果的影响。实验发现,采用不同pH值的银溶胶镀膜所获得的银溶胶膜的增强效果有很大差异,当银溶胶pH=4,且镀膜次数为五次时,增强效果最佳。以此银溶胶膜为基底对三种抗生素(氯霉素、环丙沙星、恩诺沙星)进行了SERS检测,可以检测到的最低浓度分别为120,15,120 nmol·L-1。结果表明,利用改进方法制备的银溶胶膜,可以对水中抗生素进行痕量检测,为实现养殖水中残留抗生素的检测提供了方法。     

Fabrication and characterization of SERS‐active silver clusters on glassy carbon

In this article, a novel technique for the fabrication of surface enhanced Raman scattering (SERS) active silver clusters on glassy carbon (GC) has been proposed. It was found that silver clusters could be formed on a layer of positively charged poly(diallyldimethylammonium) (PDDA) anchored to a carbon surface by 4‐aminobenzoic acid when a drop containing silver nanoparticles was deposited on it. The characteristics of the obtained silver clusters have been investigated by atomic force microscopy (AFM), SERS and an SERS‐based Raman mapping technique in the form of line scanning. The AFM image shows that the silver clusters consist of several silver nanoparticles and the size of the clusters is in the range 80–100 nm. The SERS spectra of different concentrations of rhodamine 6G (R6G) on the silver clusters were obtained and compared with those from a silver colloid. The apparent enhancement factor (AEF) was estimated to be as large as 3.1 × 10⁴ relative to silver colloid, which might have resulted from the presence of ‘hot‐spots’ at the silver clusters, providing a highly localized electromagnetic field for the large enhancement of the SERS spectra of R6G. The minimum electromagnetic enhancement factor (EEF) is estimated to be 5.4 × 10⁷ by comparison with the SERS spectra of R6G on the silver clusters and on the bare GC surface. SERS‐based Raman mapping technique in the form of line scanning further illustrates the good SERS activity and reproducibility on the silver clusters. Finally, 4‐mercaptopyridine (4‐Mpy) was chosen as an analyte and the lowest detected concentration was investigated by the SERS‐active silver clusters. A concentration of 1.6 × 10⁻¹⁰ M 4‐Mpy could be detected with the SERS‐active silver clusters, showing the great potential of the technique in practical applications of microanalysis with high sensitivity. Copyright © 2006 John Wiley & Sons, Ltd.     

Thiol‐immobilized silver nanoparticle aggregate films for surface enhanced Raman scattering

We report a novel method for the fabrication of films of silver nanoparticle aggregates that are strongly attached to Si substrates (Thiol‐immobilized silver nanoparticle aggregates or TISNA). The attachment is achieved by chemically modifying the surface of a Si(100) surface in order to provide SH groups covalently linked to the substrate and then aggregating silver nanoparticles on these thiol covered surfaces. The transmission electron microscopy (TEM), scanning electron microscopy (SEM) and atomic force microscopy (AFM) characterization show a high coverage with single nanoparticles or small clusters and a partial coverage with fractal aggregates that provide potential hot spots for surface enhanced Raman scattering (SERS). We have confirmed the SERS activity of these films by adsorbing rhodamine 6G and recording the Raman spectra at several concentrations. By using the silver‐chloride stretching band as an internal standard, the adsorbate bands can be normalized in order to correct for the effects of focusing and aggregate size, which determine the number of SERS active sites in the focal area. This allows a quantitative use of SERS to be done. The adsorption–desorption of rhodamine 6G on TISNA films is reversible. These features make our TISNA films potential candidates for their use in chemical sensors based on the SERS effect. Copyright © 2008 John Wiley & Sons, Ltd.     

三维金字塔立体复合基底表面增强拉曼散射特性

表面增强拉曼散射(SERS)是一种广泛应用于化学反应检测、医学诊断和食品分析等领域的高灵敏度光谱技术.基底结构的构建对提高探针分子的SERS信号有非常重要的影响.本文利用聚甲基丙烯酸甲酯(PMMA)包裹银纳米颗粒制备了一种三维金字塔立体复合SERS基底,实现了对罗丹明6G (R6G)分子的高灵敏度检测.通过调节银纳米颗粒在PMMA丙酮溶液中的分散密度,实现了光在金字塔谷内的有效振荡,既保证了三维结构高密度的"热点"效应,又避免了由于金属-分子相互作用引起的吸附探针分子变形导致的信号失真等问题.同时,有效防止了银纳米颗粒的氧化,为探针分子提供更大的电磁增强作用范围,使增强的拉曼信号产生稳定的输出.此研究结果不仅提供了一种高性能、可重复使用的SERS基底的有效策略,也会对未来设计改进三维结构的SERS基底有指导意义.     

Photonic Crystal Fibre SERS Sensors Based on Silver Nanoparticle Colloid

A photonic crystal fibre （PCF） surface enhanced Raman scattering （SERS） sensor is developed based on silver nanoparticle colloid. Analyte solution and silver nanoparticles are injected into the air holes of PCF by a simple modified syringe to overcome mass-transport constraints, allowing more silver nanoparticles involved in SERS activity. This sensor offers significant benefit over the conventional SERS sensor with high flexibility, easy manufacture. We demonstrate the detection of 4-mercaptobenzoic acid （4-MBA ） molecules with the injecting way and the common dipping measurement. The injecting way shows obviously better results than the dipping one. Theoretical analysis indicates that this PCF SERS substrate offers enhancement of about 7 orders of magnitude in SERS active area.     

正、负电性纳米银吸附阴、阳离子型分子的SERS比较

使用表面带负电的胶态纳米银,分别进行阴,阳离子型分子的SERS效应研究,并与表面带正电的胶态纳米银比较,当阳离子型分子盐酸副玫瑰苯胺吸附在正,负电性纳米银表面上时,后者SERS较强,当阴离子型分子吲哚丁酸分别吸附在这两种胶态纳米银上时,后者无SERS效应。