Using Solution-Phase Nanoparticles, Surface-Confined Nanoparticle Arrays and Single Nanoparticles as Biological Sensing Platforms

The intense colors of noble metal nanoparticles have inspired artists and fascinated scientists for hundreds of years. In this review, we describe three sensing platforms based on the tunability of the localized surface plasmon resonance (LSPR) of gold and silver nanoparticles. Specifically, the color associated with solution-phase nanoparticles, surface-confined nanoparticle arrays, and single nanoparticles will be shown to be tunable and useful as platforms for biological sensing.     

基于适配体-表面等离子共振的生物传感技术及应用

适配体以其合成、修饰、固定等方面的优势,在生物分子识别领域有广泛的应用。基于表面等离子共振的传感技术具有非标记、无需前处理、实时监测等优点。适配体与表面等离子共振相结合研制的生物传感器在生物传感领域具有重要的应用价值,本文综述了基于适配体-表面等离子共振的生物传感技术及应用。     

银纳米颗粒对掺铒铋酸盐玻璃光谱性质的影响

采用传统熔融淬火技术制备了一系列Er3+离子掺杂复合银纳米颗粒的铋酸盐玻璃样品.研究了纳米银含量的改变对Er3+离子荧光发射特性的影响.研究发现,铒在1.53 μm处的荧光强度在银纳米颗粒质量分数为0.2%处取得最大值,为未掺杂银纳米颗粒时的4.6倍.其荧光增强的原因归结于银纳米颗粒表面等离子体共振导致局域场增强和Ag...     

Optical Detection of Some Hydrazine Compounds Based on the Surface Plasmon Resonance Band of Silver Nanoparticles

An indirect colorimetric method is presented for spectrophotometric determination of hydrazine, phenylhydrazine, and isoniazid. Reduction of silver ions to silver nanoparticles (AgNPs) by these analytes as active reducing agents in the presence of polyvinylpyrrolidone (PVP) and also cetyltrimethylammonium chloride (CTAC) as a stabilizer is the basis of the proposed method. The changes in plasmon absorbance of the AgNPs at λ = 415 nm in the presence of PVP were proportional to concentration of hydrazine, phenylhydrazine, and isoniazid in the ranges of 4.0–150.0 µM, 1.0–55.0 µM, and 2.0–30.0 µM, respectively, and the detection limit obtained was 0.79 µM. In the presence of CTAC, the linear ranges were 0.5–10.0 and 10.0–300.0 µM for hydrazine, 1.0–40.0 µM for phenylhydrazine, and 0.2–10.0 and 10.0–90.0 µM for isoniazid, and the detection limit was 0.12 µM. The method has been applied for determination of these analytes in different real samples such as boiler feed water and tablet.     

基于单个花状银纳米颗粒的表面增强拉曼散射效应研究

在室温下,以硝酸银为银源,抗坏血酸为还原剂,通过调节表面活性剂聚乙烯吡络烷酮的浓度,实现对花状银纳米颗粒的可控制备。利用扫描电子显微镜、原子力显微镜、X射线衍射和X射线能谱等手段检测并分析了材料的形貌结构和成分组成。实验结果表明,当聚乙烯吡络烷酮的浓度为0.1 mol/L时,所制备花状银纳米颗粒的表面结构达到最精细的状态且颗粒的尺寸达到微米量级,适合对单颗粒进行定位与光学性质研究。以结构最优化的花状银纳米颗粒为表面增强拉曼散射基底材料,以羟基苯甲酸为探针,对单个和少数颗粒的表面增强拉曼散射效应进行了研究,并借助暗场散射光谱分析了基底的表面增强拉曼散射机理。结果显示,该花状银纳米颗粒因其独特的表面结构为拉曼信号增强提供了大量“热点”。良好的拉曼性能以及较低的制备成本表明,该新型表面增强拉曼散射基底具有很大的应用前景。     

Evaluating the surface density and heterogeneity of a dithiobis (succinimidylpropionate) self-assembled monolayer on gold and its coupling with DNA embedded within a matrix

The homogeneity of a self-assembled monolayer (SAM) on a surface is an important parameter which affects the ability of a SAM to fulfill its intended function. As an example, SAMs formed from octanethiols can form an impermeable surface, while SAMs based on a bifunctional coupling reagent can form a surface with uniform reactivity. Exposure of gold nanoparticles or gold surfaces to solutions of dithiobis (succinimidylpropionate) (DSP) gives rise to a surface which can react with DNA. Atomic force microscopy, UV-vis and gel electrophoresis experiments indicate that a self-assembled monolayer of DSP on gold nanoparticles can attenuate aggregation, inhibit the “lying down” of covalently-bound single-stranded (ss) DNA and promote more efficient hybridization. The determination of the point of aggregation after reacting DSP with colloidal gold yields 2.86 × 10⁻¹⁰ mol/cm² or 42% of the value determined from molecular modeling. Cyclic voltammetry experiments validate that DSP on a gold quartz crystal (6.3 × 10⁻¹⁰ mol/cm²) forms a fairly uniform SAM that is within 94% of maximum coverage when compared with results obtained from molecular modeling (6.67 × 10⁻¹⁰ mol/cm²). Surface plasmon resonance experiments indicate that the reaction of a DSP coated gold surface with (ss) DNA yields 2.4 × 10⁻¹² mol/cm² or reaction with about 1% of the available surface area. Subsequent reactions of the DSP surface with the filler, n-boc-1,4-phenylene diamine (n-boc), yield a total surface coverage of 1.8 × 10⁻¹¹ mol/cm². The surrounded (ss) DNA yields a surface with 97% hybridization efficiency toward the complement.     

Silver‐Based Nanoparticles for Surface Plasmon Resonance in Organic Optoelectronics

Organic optoelectronic devices including organic light‐emitting diodes (OLEDs) and polymer solar cells (PSCs) have many advantages, including low‐cost, mechanical flexibility, and amenability to large‐area fabrication based on printing techniques, and have therefore attracted attention as next‐generation flexible optoelectronic devices. Although almost 100% internal quantum efficiency of OLEDs has been achieved by using phosphorescent emitters and optimizing device structures, the external quantum efficiency (EQE) of OLEDs is still limited due to poor light extraction. Also, although intensive efforts to develop new conjugated polymers and device architectures have improved power conversion efficiency (PCE) up to 8%–9%, device efficiency must be improved to >10% for commercialization of PSCs. The surface plasmon resonance (SPR) effect of metal nanoparticles (NPs) can be an effective way to improve the extraction of light produced by decay of excitons in the emission layer and by absorption of incident light energy within the active layer. Silver (Ag) NPs are promising plasmonic materials due to a strong SPR peak and light‐scattering effect. In this review, different SPR properties of Ag NPs are introduced as a function of size, shape, and surrounding matrix, and review recent progress on application of the SPR effect of AgNPs to OLEDs and PSCs.     

Saccharide Sensing Using Gold and Silver Nanoparticles-A Review

We review new methodologies for glucose sensing from our laboratories based on the specific biological interactions between Con A, dextran-coated gold nanoparticles and glucose, and the interactions between dextran, glucose, and boronic-acid capped silver nanoparticles in solution. Our new approaches promise new tunable glucose sensing platforms. Dextran-coated gold nanoparticles were aggregated with the addition of Con A resulting in increase an in absorbance of nanoparticles at 650 nm, where the post-addition of glucose caused the dissociation of the aggregates and thus a decrease in the absorbance at 650 nm. The interaction of glucose and dextran with boronic acid-capped silver nanoparticles in solution resulted in enhanced luminescence intensity cumulatively due to surface-enhanced fluorescence and the decrease in absorbance at 400 nm, with an increase in absorbance at 640 nm. Lifetime measurements were used to distinguish the contribution from the surface-enhanced fluorescence. TEM was employed to assess the aggregation of nanoparticles.     

金复合纳米微粒的消光特性

基于Mie光散射理论,研究了金壳介质芯的金复合纳米球壳微粒在光散射与吸收中的消光特性.对微粒增大时的多极子特性以及内半径变动时共振峰的移动作了计算和分析,证实了共振峰位置随内外半径比增大而增大的规律.还对纯金纳米微粒的多极子特性作了计算,并讨论了总消光效率中散射和吸收各自的贡献.     

Optimized Synthetic Protocols for Preparation of Versatile Plasmonic Platform Based on Silver Nanoparticles with Pentagonal Symmetries

The key findings in the synthesis and transformation of silver nanoparticles with pentagonal symmetries arising from regular multiple twinning are reported, researched in the last 5 years. In a one‐stage photochemical synthesis of silver decahedral (pentagonal bipyramid, J₁₃ solid) nanoparticles (AgDeNPs), oxidative etching by hydrogen peroxide is implemented to achieve complete conversion of the small silver platelet precursor NPs. The concentration of hydrogen peroxide is found to be optimal at 0.2 m . Such high peroxide concentration can be rationalized by its slow reactivity in a red‐ox equilibrium with borohydride and citrate. We have also adapted light‐emitting diodes (LEDs) as a light source and documented optimal exposure time, LED power, and wavelength range for convenient laboratory synthesis of high‐purity size‐selected AgDeNPs. In the absence of platelet impurities, AgDeNPs produce by the new‐generation procedure can be conveniently re‐grown into larger sizes using silver ions as a precursor. Thermal regrowth of new‐generation AgDeNPs into pentagonal silver nanorods (AgPRNPs, J₁₅ solid) can be reliably accomplished with the precise variation in rod length (by varying amounts of added silver) and width (by using different seed AgDeNPs). With the reported reproducible synthetic protocols that can be readily implemented in any chemistry laboratory, AgDeNPs and AgPRNPs should serve as a versatile plasmonic platform with a precisely tunable surface plasmon resonance (SPR) from ca. 430 nm (rounded AgDeNPs) to 1100+ nm (longitudinal SPR of longer AgPRNPs). The plasmonic platform based on the reported AgNPs with pentagonal symmetries should be practical for a diverse range of applications, especially plasmonic sensing and surface‐enhanced Raman spectroscopy.     

不同密度银纳米粒子对氧化锌基发光二极管发光的增强

采用分子束外延法制备不同密度的银纳米粒子(AgNPs)修饰的局域表面等离子体共振增强n-ZnO/iZnO/MgO/p-GaN异质结发光二极管(LEDs),并对其电学及光学性质进行表征。结果显示:LEDs中引入适当浓度的AgNPs有利于AgNPs局域表面等离子体激元与ZnO激子相耦合,可以显著提高器件的电致发光性能;随着AgNPs浓度的增加,LEDs发光增强倍数先增大后减小,分析认为这是AgNPs局域表面等离子体共振耦合增强过程和AgNPs的消光过程两者之间相互博弈而导致的结果。     

金银纳米粒子的电化学性质及联苯胺的SERS研究

采用柠檬酸钠还原氯金酸,硼氢化钠还原硝酸银分别制备了较小粒径的金、银纳米粒子。运用紫外可见吸收光谱(UV-Vis)、扫描电子显微镜(SEM)、循环伏安法(CV)对金、银纳米粒子进行了表征。结果表明：所得金、银纳米粒子粒径分别约为16和10 nm,并能以亚单层形式组装于导电玻璃(ITO)表面;CV图显示金、银纳米粒子分别有一对不对称的氧化还原峰,而且纳米粒子的浓度对其氧化还原电位存在一定的影响。采用自组装方法,以联苯胺为偶联分子, 在粗糙金基底表面构筑了金/银纳米粒子的双层有序结构。表面增强拉曼光谱研究表明, 在有序金银纳米粒子组装体中偶联分子的拉曼散射得到了增强。     

金-二氧化钛（Au-TiO_2）复合薄膜的制备及局域表面等离子体共振（LSPR）效应

利用溶胶凝胶法在玻璃衬底上制备了金-二氧化钛（Au-TiO2）复合纳米薄膜,研究了热处理温度对复合薄膜表面纳米颗粒沉积的影响。利用原子力显微镜对样品进行了形貌表征,结果显示：复合薄膜是由纳米微晶组成的致密膜,温度越高越有利于Au粒子的形成。在550℃的热处理温度下,薄膜表面沉积的纳米微晶的粒径约为100nm。利用紫外-可见分光光度计测量了反射谱线,结果表明：由于局域表面等离子体共振（LSPR）的产生,在不同的热处理温度下,第一个反射峰（短波长处）不发生变化,第二个反射峰（长波长处）发生漂移（红移）。     

基于银掺杂钠钙玻璃的荧光染料自发辐射增强

本文通过离子交换和后续热处理的方法在钠钙玻璃中引入Ag纳米颗粒, 并将Ag掺杂的钠钙玻璃作为衬底增强了钠钙玻璃和荧光染料罗丹明6G(R6G)的荧光辐射。Ag纳米颗粒的表面等离激元散射增强了掺杂玻璃的荧光, 而R6G的增强荧光辐射则源于掺杂玻璃与荧光染料之间的辐射共振能量转移。     

海胆状金纳米粒子表面形貌对表面增强喇曼散射特性的影响

采用改进的一步还原法合成了多种海胆状金纳米粒子,并对它们的表面增强喇曼散射特性与其表面形貌的关系进行了实验研究.实验表明,合成的海胆状金纳米粒子的直径及表面的尖刺大小可以通过改变加入到氯金酸溶液中的硝酸银的量来调节.当加入到氯金酸溶液中的硝酸银为1μL时,合成的海胆状金纳米粒子的直径最小而尖刺最长.同时测量的紫外-可见-近红外吸收光谱表明,海胆状金纳米粒子的局域表面等离子体共振带会随着加入到氯金酸溶液中的硝酸银量的增加而变宽.此外,通过喇曼标记分子对巯基苯甲酸(4MBA)的喇曼光谱测量发现,较小直径和较长尖刺的海胆状金纳米粒子具有更强的表面增强喇曼散射活性.     

Ag nanoparticles obtained by pulsed laser ablation in water: surface properties and SERS activity

We studied the surface properties and reactivity of silver nanoparticles obtained by picosecond or nanosecond pulsed laser ablation in water and with 1064‐nm wavelength. Ultraviolet–visible spectroscopy results and subsequent modelling by Mie theory indicated the presence of an oxide layer on the nanoparticle surface, which favours the colloidal stability, but reduces the interaction with the environment. The oxide layer is also responsible for the reduced surface enhanced Raman spectroscopy (SERS) activity of these colloids with respect to those obtained by chemical reduction. However, SERS activation can be efficiently obtained by addition of chloride ions to the colloids, leading to SERS enhancement factors that are comparable with those of the chemically prepared counterparts. Copyright © 2015 John Wiley & Sons, Ltd.     

金膜表面等离激元诱导邻巯基苯甲酸脱羧反应的表面增强拉曼光谱研究

贵金属纳米结构表面等离激元共振(SPR)因其广泛的用途而备受关注,它不仅可以催化某些特殊的表面反应,同时还能产生表面增强拉曼散射效应(SERS),极大增强分子的表面拉曼信号,因此两者结合后可在纳米结构表面采用SERS光谱跟踪SPR催化反应.目前此类研究主要集中在氮氮(N N)偶联,因此亟待拓展SPR反应种类及提高催化活...     

金属纳米颗粒对有机太阳能电池光吸收效率影响的研究

借助时域有限差分法,对几种常见金属纳米颗粒影响有机太阳能电池光吸收效率的因素及其内部物理机制进行了研究.首先对金属纳米颗粒激发局域表面等离子共振的场分布特点进行分析,对比其在电池不同功能层中对光吸收率的影响;其次基于米氏理论与电共振效应,得出金属纳米颗粒的结构参量对局域表面等离子共振位置及强度的影响规律,并以此进行优化设计.结果表明,具有高对称性形貌的金属纳米颗粒以小尺寸密堆积结构引入电池活性层,能够促进电池光吸收增强三倍以上.     

金属纳米颗粒对有机太阳能电池光吸收效率影响的研究

借助时域有限差分法,对几种常见金属纳米颗粒影响有机太阳能电池光吸收效率的因素及其内部物理机制进行了研究.首先对金属纳米颗粒激发局域表面等离子共振的场分布特点进行分析,对比其在电池不同功能层中对光吸收率的影响;其次基于米氏理论与电共振效应,得出金属纳米颗粒的结构参量对局域表面等离子共振位置及强度的影响规律,并以此进行优化设计.结果表明,具有高对称性形貌的金属纳米颗粒以小尺寸密堆积结构引入电池活性层,能够促进电池光吸收增强三倍以上.     

基于银纳米粒子的局域表面等离子体共振效应提高草甘膦基于茚三酮间接检测的灵敏度（英文）

常规的农药残留检测一般存在前处理操作复杂,耗时较长,方法不够灵敏等问题。根据氨基与茚三酮显色原理和局域表面等离子体共振(LSPR)增强光吸收原理,利用紫外-可见吸收光谱对水样品中草甘膦含量进行定量分析,并利用密度泛函理论进一步分析了显色的类似罗曼紫产物的光吸收增强机理。草甘膦与茚三酮在钼酸钠催化下反应生成类似罗曼紫产物;该物质在紫外–可见吸收光谱570nm处有最大吸收峰,当其吸附在银纳米粒子(Ag NPs)表面上时,最大吸收峰蓝移至568nm处,同时吸收强度显著提高;本研究中检出限为2.017 4×10^-11 mol·L^-1,显著低于文献中约6.5×10^-7 mol·L^-1的检出限。Gaussian 09软件计算得出,类似罗曼紫产物经由茚三酮的C=O基团垂直吸附在Ag NPs表面,静电势表明茚三酮的C=O基团优先与Ag稳定相互作用并形成Ag—O键,C=O基团和C—N基团构成了π键共轭系统;连接草甘膦和茚三酮之间的C—N键是类似罗曼紫产物的生色团。因此,茚三酮衍生法可用于间接检测水样品中草甘膦,银纳米...