银纳米粒子修饰三维碳纳米管阵列SERS实验

为了使表面增强拉曼散射(SERS)基底的三维聚焦体积内包含更多的“热点”,能吸附更多探针分子和金属纳米颗粒,以便获得更强的拉曼光谱信号,提出了银纳米粒子修饰垂直排列的碳纳米管阵列三维复合结构作为SERS基底,并对其进行了实验研究。利用化学气相沉积(CVD)方法制备了垂直排列的碳纳米管阵列;采用磁控溅射镀膜方法先在碳纳米管阵列上形成一层银膜,再通过设置不同的高温退火温度,使不同粒径的银纳米粒子沉积在垂直有序排列碳纳米管阵列的表面和外壁。SEM结果表明：在有序碳纳米管阵列的表面和外壁都均匀地负载了大量银纳米粒子,并且银纳米颗粒的粒径、形貌及颗粒间的间距随退火温度的不同而不同。采用罗丹明6G(R6G)分子作为探针分子,拉曼实验结果表明：R6G浓度越高,拉曼强度越强,但是R6G浓度的增加与拉曼强度增强并不呈线性变化;退火温度为450 ℃,银纳米颗粒平均粒径在100～120 nm左右,退火温度为400 ℃,银纳米颗粒平均粒径在70 nm左右,退火温度为450 ℃的拉曼信号强度优于退火温度400和350 ℃。     

自组装银纳米粒子及其SERS增强效应

采用柠檬酸三钠还原硝酸银方法制备出银纳米粒子, 并通过在玻璃表面修饰3-氨基丙基-三乙氧基硅烷( APTES)对银纳米粒子进行自组装。利用紫外-可见(UV-Vis)吸收光谱和扫描电子显微镜(SEM)测试手段对样品进行分析和表征。由测试结果可知银纳米粒子的尺寸比较均匀, 组装致密度较高, 基本以亚单层的形式分布于基底表面。进一步研究了以结晶紫(CV)为探针分子的自组装基底的表面增强拉曼光谱(SERS), 计算发现该基底的拉曼增强因子数量级达106。结果表明: 银纳米粒子自组装基底具有良好的SERS增强效应, 为痕量CV的检测提供了有效的方法。     

银和去合金银-金纳米粒子的SERS活性研究

用乙二醇还原硝酸银,聚乙烯吡咯烷酮作表面活性剂合成了大量的银纳米颗粒。银纳米颗粒和HAuCl4发生置换反应后形成去合金银-金纳米粒子。以吡啶和SCN-作为探针分子研究了它们的SERS活性。结果表明,当探针分子吸附于银纳米颗粒和去合金银-金纳米粒子上时,探针分子的特征振动峰强度增强、频率发生位移。SERS可表征纳米粒子物理和化学性质的变化。     

种子法制备三角形银纳米粒子及其性能表征

 以十六烷基三甲基溴化胺(CTAB)为软模板剂，采用种子法制备出三角形银纳米粒子，应用透射电镜、能量散射X射线谱仪、紫外 可见分光光度计研究了粒子的性能。结果表明：所得三角形银纳米粒子是面心立方单晶，边长随着种子加入量的减少而递增，可在20～100 nm范围内调节；CTAB以薄膜形式包覆于粒子表面阻止其氧化，粒子胶体的吸收光谱呈现典型的三角形粒子吸收峰。用扫描电镜观测到粒子在硅片上自组装成一定的2维阵列结构。     

种子法制备三角形银纳米粒子及其性能表征

以十六烷基三甲基溴化胺(CTAB)为软模板剂,采用种子法制备出三角形银纳米粒子,应用透射电镜、能量散射X射线谱仪、紫外 可见分光光度计研究了粒子的性能。结果表明：所得三角形银纳米粒子是面心立方单晶,边长随着种子加入量的减少而递增,可在20～100 nm范围内调节;CTAB以薄膜形式包覆于粒子表面阻止其氧化,粒子胶体的吸收光谱呈现典型的三角形粒子吸收峰。用扫描电镜观测到粒子在硅片上自组装成一定的2维阵列结构。     

银纳米粒子对抗生素诺氟沙星的荧光猝灭效应

以β-环糊精(β-CD)为稳定剂,葡萄糖为还原剂,采用"绿色化学方法"合成了平均粒径约为31nm的类球形银纳米粒子。研究了其对水溶液中痕量诺氟沙星荧光行为的影响,实验结果表明,制得的银纳米粒子对诺氟沙星具有较强的荧光猝灭效应,且随着加入银纳米粒子量的增加荧光猝灭效果逐渐增强。初步探讨了银纳米粒子对诺氟沙星的荧光猝灭机理。     

银纳米粒子上苯甲酸吸收行为的实验(FT-Raman)和理论(DFT)研究(英文)

1IntroductionSurface-enhanced Raman scattering(SERS)has been widely used in studying interaction mecha-nismof the molecules withthesurface of thesubstrateand molecular orientation1-3·However,with thevariation of the characteristics of the surface of thesubstrates,the SERSspectrumof adsorbates will alsobe different,which makes the analyses difficult·Thecommon analytical methodis basedontheshift of Ra-man bands,enhancement or weakness of intensity toguessthe adsorption orientation,geometry…     

镧与真空沉积银纳米粒子的金属间化合

根据HumeRothery规则,分析了银与镧两元素之间形成金属间化合物的倾向性,并根据真空蒸发沉积的条件,分析了在真空蒸发沉积情况下镧与银之间形成金属间化合物的可能性.用X射线光电子能谱化学位移方法对真空蒸发沉积的银、镧薄膜进行了分析,结果表明在真空沉积条件下镧与银之间的确形成了金属间化合物. 关键词： 金属间化合物 镧 银 纳米粒子     

氯离子刻蚀三角银纳米粒子及其拉曼光谱的研究

在硼氢化钠和双氧水共存的体系中还原硝酸银,以聚乙烯吡咯烷酮(PVP)为表面活性剂,在柠檬酸钠的作用下合成三角银纳米粒子,随后加入氯离子,研究其作用下三角银纳米粒子的形貌变化.结果表明:随着氯离子浓度不断增大,三角银纳米粒子逐渐被刻蚀成圆盘粒子,且吸附生物分子多巴胺后,SERS信号随着粒子减小而增强,原因可能在于粒子形状发生转化的同时还生成了大量的银团簇物质,这些银团簇的存在活化了溶胶体系的性质.     

银纳米粒子上对硝基苯甲酸的催化还原

采用银纳米粒子为催化剂,研究了银纳米粒子对硝基苯甲酸还原的催化性能.结果表明,纳米尺度的银粒子在室温下可极大地加速对硝基苯甲酸的还原过程.其中,银纳米粒子被认为起着电子媒介体作用,即还原剂硼氢酸根优先将电子传递到银纳米粒子,继而吸附的对硝基苯甲酸获取电子发生还原.     

银镜法制备具有表面增强红外活性Ag纳米粒子的探讨

利用银镜法在玻璃基底上沉积金属银制得表面增强红外材料,扫描电镜显示,沉积在基片上的银为球状颗粒,且平均直径在100nm左右,银纳米粒子形成一个个不相连的金属岛。以邻硝基苯胺为探针分子,用衰减全反射法(ATR)考察了邻硝基苯胺在银镜基底上的表面增强红外光谱。结果表明:邻硝基苯胺的最小检出质量约为40ng,增强因子约为70。制备银膜的最佳条件为:A gNO3质量分数为1%,反应温度为60℃,且加入表面活性剂可使银纳米粒子分散均匀。     

银纳米微粒荧光猝灭法测定水中痕量ClO2

在pH 9.1的NH4Cl-NH3·H2O缓冲溶液中,银纳米微粒在470 nm处产生一个荧光峰;它能被ClO2氧化导致体系的荧光发生猝灭.ClO2浓度在0.001 1～0.185μg·mL-1范围内与荧光猝灭强度成良好的线性关系,检测限为0.004 7μg·mL-1 ClO2.据此建立了测定ClO2的荧光分析新方法,用于饮用水中ClO2的测定,结果满意.     

Sensitized Fluorescence of Silver Nanoparticles in the Presence of Pyrene

The fluorescence of pyrene adsorbed onto the surface of the cetyltrimethylammonium-coated silver nanoparticles was studied. Pyrene molecules adsorbed on freshly prepared silver particles were found to be in close proximity to silver surface thus providing the possibility of energy transfer from excited pyrene to silver cores of the particles. In that case along with the expected fluorescence of pyrene we observed the fluorescence of the silver nanoparticles induced by the excited pyrene molecules. In due course the restructuring of the cetyltrimethylammonium layer resulted in moving of pyrene molecules away from silver surface and simultaneous disappearance of the silver nanoparticles fluorescence band. These data strongly support the recent hypothesis of fluorophore-plasmon coupled emission.     

二维自组装结构中银纳米粒子的吸收光谱特征

通过静电相互作用在聚乙烯吡啶修饰的玻璃表面组装了银纳米粒子的二维结构。吸收光谱结果表明,组装银粒子间的相互作用导致银粒子的偶极子表面等离子体共振发生较大的位移,但基本不改变四极子表面等离子体共振。银粒子表面吸附分子及周围介质直接影响其表面等离子体共振。     

Fluorescence Modulation of Acridine and Coumarin Dyes by Silver Nanoparticles

Silver nanoparticles were synthesized by chemical reduction of silver ions by sodium borohydride in the presence of poly-(N)-vinyl-2-pyrrolidone in solution of short chain alcohols. The nanoparticles are stable in 2-propanol, and the average diameter of the Ag colloid obtained in this solvent is about 6 nm. The photophysical properties of acridinium and coumarin dyes in 2-propanol are affected by the presence of silver nanoparticles. The interaction of silver nanoparticles with acridinium derivative leads to a spectral change of its intramolecular charge transfer (ICT) absorption band. The dye emission increases suddenly with the initial addition of the Ag metal nanoparticles, but at a high concentration of the colloid, static fluorescence quenching occurs with a progressive decrease of the fluorescence efficiency. Amino coumarin fluorescence is only quenched by the silver nanoparticles in solution.     

表面分子功能化银纳米粒子的光谱特征

通过玻片表面构筑银纳米粒子二维组装结构研究吸附分子对银粒子表面等离子体共振的影响.吸收光谱结果表明银纳米粒子表面吸附二硫代乙二酰胺分子可导致金属粒子的表面等离子体共振吸收红移,主要与金属粒子的微环境改变以及吸附分子与金属间电荷转移而导致的金属粒子内部电子密度改变有关.二硫代乙二酰胺分子通过其氨基和巯基共同吸附于金属表面.     

Spontaneous Agglomeration of Silver Nanoparticles Deposited on Carbon Film Surface

The spontaneous aggregation of silver nanoparticles on a two-dimensional surface at room temperature is investigated. The nanoparticles were deposited on a carbon film and have been observed by a transmission electron microscope (TEM) for over one year. These particles were about 10nm, spherical and well dispersed initially, and an obviously spontaneous agglomeration was observed at the 12th day, the values, coverage rate of the silver particles on carbon film, were increased with time (before 40th day), but reduced with time (after 40th day). These show that the aggregates of the particles tend to have the smallest surface to reduce their surface free energy and are compact three-dimensional cluster in which the most size is above 100nm. Agglomerating is a successively slow diffusion-limited aggregation (DLA) growth. Another phenomenon, a big aggregate gathering some particles and a small aggregate to form a still bigger one, is observed. This indicates that the aggregating processes are controlled by migration of the particles on carbon film surface and surface energy of the particles.     

纳米银与表面吸附荧光素的荧光性能的影响

研究了纳米银粒子对表面吸附荧光素(fluorescein,Fl)的荧光性能的影响。Fl溶液中加入纳米银粒子,Fl分子包覆在纳米银粒子表面形成Fl_n-Ag复合物使纳米银相互桥连形成类似网络的结构,且Fl分子吸收峰随着纳米银浓度的增加发生红移。纳米银通过产生的强局域场将能量传输给Fl发光中心,实现了Fl的荧光增强,荧光增强效率随着纳米银浓度的增加具有最大值。较大粒径的纳米银使Fl获得最大荧光增强效率所需浓度较低且最大荧光增强效率值较高。研究结果表明,纳米银与Fl间的能量传输主要由Fl分子附近局域电磁场增强和分子到金属表面无辐射跃迁能量转移过程所决定并与纳米银的浓度、尺寸密切相关。     

Silver Enhancement of Gold Nanoparticles for Biosensing: From Qualitative to Quantitative

Abstract

The establishment and rapid progress in sensitive biosensing using immunogold silver enhancement has occurred in the past 30 years. Its high sensitivity and simplicity have made immunogold silver enhancement a revolutionary technique for signal amplification in biosensing. This review focuses on the major applications of immunogold silver enhancement, with special emphasis on quantitative biosensing. In this review, the combinations of immunogold silver enhancement with a series of quantitative techniques, such as colorimetry, electrical and electrochemical methods, gravimetry, chemiluminescence, Raman spectroscopy, and inductively coupled plasma–mass spectrometry (ICP-MS), are discussed in detail. Immunogold silver enhancement has become one of the most useful methods in highly sensitive quantitative bioanalysis. The recent development of ICP-MS detection shows great potential in combination with immunogold silver enhancement.