表面增强拉曼散射强度与金纳米粒子粒径关系

表面增强拉曼散射（SurfaceenhancedRamanscattering,简称SERS）的增强机理主要分为两类’‘－‘’：电磁增强和化学增强．通常SERS活性表面的获得需要粗糙化．MOSkovitS最先提出,可将粗糙化的SERS活性表面模型化为平整金属基底上排列的金属胶体粒子“’．这样的模型与实际体系比较符合,同时给理论处理提供了便利．在这一模型基础之上,人们提出了一系列SERS电磁增强的理论计算方法’‘－“．在这些理论计算中,大多包含有SERS强度与粒径关系的结果．粒径对SERS强度的影响体现在两方面：1）SERS与粗糙度有关,粒径可视为粗…     

金纳米粒子修饰毛细管硅胶整体柱的制备及其电色谱性能研究

通过毛细管硅胶整体柱表面修饰十八烷基硫醇金纳米粒子,制备了一种新型毛细管电色谱固定相.制备金纳米粒子修饰整体柱时,采用溶胶-凝胶法制备毛细管硅胶整体柱,并在其表面化学修饰3-巯基丙基三甲氧基硅烷;通过巯基基团固载金纳米粒子于整体柱上,再共价键合十八烷基硫醇于金纳米粒子表面.以甲苯为探针,对理论塔板高度与流动相线速度之间...     

帽状金纳米结构的制备、表征及表面增强拉曼散射活性

采用真空离子溅射法在自组装的单层阵列二氧化硅纳米粒子表面沉积金薄膜, 制备了以SiO₂为核的帽状金纳米结构. 用透射电镜、扫描电镜、原子力显微镜、X 射线衍射仪和紫外-可见-近红外分光光度计对样品的表面形貌、结构及光学性质进行了表征. 以亚甲基蓝作为探针分子, 对金纳米帽的表面增强拉曼散射活性进行了研究, 结果显示, 吸附在金纳米帽上的分子拉曼散射信号得到显著增强, 增强因子达到10⁷数量级. 该基底在超灵敏生物和化学检测方面具有潜在的应用前景.     

帽状铜纳米粒子的制备及表面增强拉曼散射活性研究

采用真空热蒸发法在SiO₂纳米粒子自组装单层膜上沉积铜薄膜制备了帽状铜纳米粒子。用扫描电镜、原子力显微镜和紫外-可见-近红外分光光度计对帽状复合纳米粒子的表面形貌和光学性质进行了表征。以亚甲基蓝和吡啶-(2-偶氮-4)间苯二酚为探针分子,研究了该复合纳米粒子的表面增强拉曼散射(SERS)活性。通过比较吸附在不同基底上的吡啶-(2-偶氮-4)间苯二酚的谱峰强度,探讨了SERS效应与表面等离子体共振(SPR)的关系。     

调控金纳米花表面凸起的策略及其表面增强拉曼散射活性

以聚乙烯吡咯烷酮(PVP)与十二烷基硫酸钠(SDS)通过阳离子架桥形成的拟聚阴离子为软模板,通过改变PVP、SDS和纳米材料前驱体氯金酸(HAu Cl₄)浓度以及反应时间等因素,调控还原产物金纳米花形貌及粒径。表面张力、电导率、毛细管电泳及Zeta电位等实验结果表明PVP-SDS-HAu Cl₄形成新的拟聚阴离子,透射电子显微镜和X射线衍射结果表明SDS、PVP和HAu Cl₄的较低浓度组合更易获得表面凸起丰富的金纳米花。PVP-SDS拟聚阴离子发挥了二级软模板作用,在PVP (50 g·L^-1)-SDS (2 mmol·L^-1)-HAu Cl₄ (0.25 mmol·L^-1)溶液中调控合成的金纳米花为{111}晶面为主的面心立方结构,其平均等效粒径为108 nm,且表面上密集分布约16.5 nm的凸起。该金纳米花有较强的表面增强拉曼散射(SERS)活性,探针分子罗丹明6G的SERS信号强度依赖于金纳米花的表面凸起形貌。该研究中金纳米...     

表面增强拉曼散射效应无标记、无分离检测三聚氰胺

利用纳米金的表面增强拉曼效应,建立了一种快速、灵敏、无标记、无分离的检测三聚氰胺的分析方法。通过柠檬酸钠还原法制得平均粒径为30 nm的纳米金溶胶,利用Au–S之间的共价键作用,将对巯基苯硼酸(4-MPBA)自组装到纳米金的表面,构建了一个三聚氰胺的检测平台。当溶液中存在三聚氰胺(MA)时,MA与4-MPBA之间存在强烈的氢键作用,使4-MPBA功能化的纳米金发生聚集。而且,MA的浓度越高,纳米金的聚集程度越大,形成的"热点"越多,4-MPBA和MA的拉曼信号越强。4-MPBA与MA的拉曼特征峰分别位于1076和715 cm!1处,若以I715与I1076的比值为依据,便可以实现三聚氰胺的定性及定量的检测,线性检测范围为0.1~1.5μmol/L,检出限(LOD)为0.02μmol/L。     

金纳米粒子的表面修饰及生物应用进展

近年来纳米材料被广泛应用于生物医学、航空航天和精细化工等领域。构成纳米材料的纳米粒子具有小尺寸效应、表面效应和宏观量子隧道效应等性质。其中金纳米粒子由于其独特的荧光特性、良好的生物相容性和表面等离子共振等性质,被广大科研人员进行深入研究。例如,在生物医学领域,科研人员构建了一系列新型的金纳米比色传感器、光学探针及各类载药体系等。然而,目前金纳米粒子仍存在水分散性差、肾清除效率低和量子发射产率低等问题,限制了其广泛应用。因此,研究人员对金纳米粒子表面进行多样化修饰,从而能有效克服上述缺点。本文就目前主流配体表面修饰金纳米粒子的研究进展进行了详细总结,着重介绍了功能化金纳米粒子在生物成像、生物检测、生物治疗三方面的应用,最后对金纳米粒子的临床治疗机制的探索以及商业化的应用进行了展望,希望能为相关领域的研究者们提供新思路。     

聚共轭亚油酸基网状纳米金的制备及表面增强拉曼散射和催化性能

以天然不饱和脂肪酸共轭亚油酸(CLA)为绿色单体, 通过简单的分子自组装和可控自交联反应制备聚共轭亚油酸(PCLA)聚集体. 透射电子显微镜(TEM)结果显示, PCLA聚集体的形貌呈现独特网状结构, 其联结单元为来自于CLA胶束的膨大颗粒. 采用氯金酸在极性聚合物表面原位还原, 2 d后在网状PCLA基底上制备得到以CLA胶束为核(20 nm)的网状纳米金结构, 而且网状PCLA的原位还原作用与模板作用相结合是获得PCLA基网状纳米金的充分必要条件. 与普通球形胶态金纳米颗粒[(5±1) nm]相比, PCLA基网状纳米金对苯硫酚具有更好的表面增强拉曼散射(SERS)效应, 对对硝基苯酚具有更好的催化还原效果.     

Au-Ag合金纳米粒子制备及其表面增强拉曼光谱研究

首先采用柠檬酸钠法制得Au-Ag合金纳米种子, 然后采用盐酸羟胺生长法得到不同组成的Au-Ag合金纳米粒子. 在其UV-Vis光谱中只观察到一个位于单金属银和金之间的等离子体共振峰, 表明Au-Ag合金纳米粒子已经形成. TEM结果表明, 合金纳米粒子的粒径约为60 nm, 且颜色均一, 没有明显的核壳结构. 用苯硫酚(TP)作为探针分子研究了合金纳米粒子的表面增强拉曼光谱(SERS). 结果表明, SERS强度与合金纳米粒子的组成和尺寸有关. 当纳米粒子粒径一定时, 除Au25Ag75外, 随着金的增加SERS强度增强. Au25Ag75的粒径比Ag小, 导致SERS强度比Ag低. Au50Ag50和Au75Ag25加入TP分子后, 其聚集方式与Au相似, 等离子体共振峰逐渐靠近1064 nm, 金含量较高时, TP的SERS归于聚集体的等离子体共振增强的贡献.     

Controllable Silver Plating on Silica for Surface-enhanced Raman Scattering

We proposed a facile and rapid method for preparing silica-silver core-shell(SSCS) substrates to use Ag electroless plating on SiO2@Au-seed particles.UV-Vis-NIR absorption spectrometer and SEM were employed to monitor the reaction process of the formation of Ag on the surfaces of silica beads,and the optical resonance of the substrate could shift from visible to NIR region.It has been found that surface-enhanced Raman scattering(SERS) enhancement changes with the electroless plating time and the SSCS substr...     

基于Au/SiO2纳米粒子的结晶紫表面增强拉曼特性研究

采用自组装-化学镀法制备了以SiO2为核,Au为壳层的核壳结构纳米粒子(Au/SiO2),以生物染色剂结晶紫为探针分子,研究了Au/SiO2的表面增强拉曼散射(SERS)效应,并考察了Cl-对SERS增强效应的影响。实验表明,Cl-对SERS有明显的增强效果,这主要是由于Cl-的加入使得Au/SiO2发生团聚,产生大量"热点",从而使SERS增强效果进一步加强。以Au/SiO2(5×1010 mL-1)为活性基底,KCl(0.01 mol/L)为额外增强剂,在水溶液中实现了对结晶紫(CV)的痕量检出,最低检测浓度可达到5×10-10mol/L。     

Raman and Surface-enhanced Raman Scattering of Chlorophenols

Raman spectrum is a powerful analytical tool for determining the chemical information of compounds. In this study, we obtained analytical results of chlorophenols(CPs) molecules including 4-chlorophenol(4-CP), 2,6-dich- lorophenol(2,6-DCP) and 2,4,6-trichlorophenol(2,4,6-TCP) on the surface of Ag dendrites by surface-enhanced Raman scattering(SERS) spectra. SEM images indicate that the SERS substrate of Ag dendrites is composed of a large number of polygonal nanocrystallites, which self-assembled into a 3D hierarchical structure. It was found that there were distinct differences for those three molecules from Raman and SERS spectra. This indicates that SERS could be a new tool of detection technique regarding trace amounts of CPs.     

Improved Surface Enhanced Raman Scattering for Nanostructured Silver on Porous Silicon for Ultrasensitive Determination of 2,4,6-Trinitrotoluene

Label-free and low-cost surface-enhanced Raman scattering-active substrates of silver nanostructures on porous silicon have been synthesized. The morphology and spectroscopic properties were investigated as a function of concentration and immersion time. The enhancement factor of optimized silver-porous silicon substrate was estimated to be 2.18 × 10⁸ by the use of p-thiocresol as a Raman probe. The optimized substrate was used to determine 50 pg of 2,4,6-trinitrotoluene. These results demonstrate that the prepared silver-porous silicon substrates are promising for the ultra-sensitive determination of organic molecules.     

Comparison of Surface-enhanced Raman Scattering Spectra of Two Kinds of Silver Nanoplate Films

Surface-enhanced Raman scattering(SERS) spectra of different silver nanoplate self-assembled films at different excitation wavelengths were fairly compared. Shape conversion from silver nanoprisms to nanodisks on slides was in situ carried out. The SERS spectra of 4-mercaptopyridine(4-MPY) on these anisotropic silver nanoparticle self-assembled films present that strong enhancement appeared when the excitation line and the surface plasmon resonance(SPR) band of silver substrate overlapped. In this model, the influence of the crystal planes of silver nanoplates on SERS enhancement could be ignored because the basal planes were nearly unchanged in two kinds of silver nanoplate self-assembled films.     

乙二醛诱导细胞凋亡的近红外表面增强拉曼光谱

将60 nm金纳米粒子导入到活的人骨肉瘤细胞中, 用近红外表面增强拉曼散射(SERS)技术获取细胞内化学成分的高分辨SERS信息. 对正常活性细胞和乙二醛诱导的凋亡细胞的比较研究表明, 对于正常活性的细胞, 金纳米探针主要分布在细胞质内(围绕细胞核), 而凋亡细胞内的金纳米探针的分布较为均匀, 在遍布凋亡细胞内的各个位置包括细胞表面均容易找到DNA片段的信息.     

Surface-enhanced Raman scattering for perchlorate detection using cystamine-modified gold nanoparticles

Perchlorate (ClO₄⁻) has recently emerged as a widespread environmental contaminant found in groundwater and surface water, and there is a great need for rapid detection and monitoring of this contaminant. This study presents a new technique using cystamine-modified gold nanoparticles as a substrate for surface-enhanced Raman scattering (SERS) detection of perchlorate at low concentrations. A detection limit of 5 × 10⁻⁶ M (0.5 mg/L) has been achieved using this method without sample preconcentration. This result was attributed to a strong plasmon enhancement by gold metal surfaces and the electrostatic attraction of ClO₄⁻ onto positively charged, cystamine-modified gold nanoparticles at a low pH. The methodology also was found to be reproducible, quantitative, and not susceptible to significant interference from the presence of anions such as sulfate, phosphate, nitrate and chloride at concentrations <1 mM, making it potentially suitable for rapid screening and routine analysis of perchlorate in environmental samples.     

SnO2纳米粒子作为SERS基底的研究

采用溶胶-水热法制备了不同尺寸的SnO2纳米粒子, 并将其作为表面增强拉曼散射(Surface-enhanced Raman scattering, SERS)活性基底, 重点探讨了表面缺陷能级与SERS性能的关系. 观察到4-巯基苯甲酸(4-MBA)吸附在150 ℃水热合成的SnO2纳米粒子上的SERS 信号最强, 随着在空气中煅烧温度的升高, SERS信号逐渐减弱. 分别用透射电子显微镜、 紫外-可见光谱、 荧光光谱、 X射线衍射和X射线光电子能谱对SnO2纳米粒子进行了表征. 结果表明, SnO2纳米粒子的表面氧空位和缺陷等表面性质在增强拉曼散射性能中发挥着重要的作用, 表面氧空位和缺陷等含量越高其SERS信号就越强.     

Surface-enhanced Raman Scattering from Molecules Adsorbed on Mixed Silver/Gold Nanoparticle Surfaces

Introduction Since the first discovery of Surface-Enhanced Raman Scattering(SERS) from pyridine molecules adsorbed at roughened silver electrodes in 1974 by Fleischmann et al.[1],the research of SERS has made tremendous progress in applications of it to various fields of science and technology[2-8].     

基于Kretschmann结构的金银合金薄膜的SERS效应

利用Kretschmann棱镜耦合结构和532 nm激光光源,测试了金银合金薄膜的表面增强拉曼散射(SERS)效应,并与纯金薄膜的测试结果进行了比较.结果显示,在激发光为p偏振态且入射角近似等于表面等离子体共振(SPR)角时,附着于金银合金薄膜表面的Nile Blue分子的SERS信号达到最强,比利用纯金薄膜测得的SERS信号高约2倍.实验结果还表明,在金银合金薄膜表面自组装金纳米粒子后,Nile Blue吸附层的SERS信号比自组装纳米金之前测得的信号增强了至少3倍,比利用纳米金修饰的纯金薄膜测得的信号高出2倍多.在棱镜底面沿薄膜法线收集的SERS信号是完全非偏振光,而从棱镜侧面收集的SERS信号是p偏振光,是拉曼光借助SPR效应产生的定向发射.