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1.
We observed a strong, more than 16-fold, enhancement of Texas Red-labeled BSA fluorescence emission when deposited on silver colloid coated surfaces (SCCS). The same labeled protein deposited on silver island films (SIFs) showed an approximate 8-fold fluorescence enhancement. The lifetimes of Texas Red-BSA fluorescence are significantly shorter on silvered surfaces than on uncoated quartz substrate indicating a strong change in radiative decay rate of the dyes. We also observed a 36-fold increased brightness of overlabeled fluorescein-HSA deposited on silver colloid coated surface. Stronger enhancement observed for overlabeled Fl-HSA protein indicates that presence of silver particles partially decreased self-quenching. Our results indicate that surfaces coated with silver colloids are valuable substrates for metal-enhanced fluorescence. 相似文献
2.
Yuling Wang Wen Ren Shaojun Dong Erkang Wang 《Journal of Raman spectroscopy : JRS》2009,40(5):571-576
In this report, gold nanoparticles (AuNPs) labeled by Raman reporters (AuNPs‐R6G) were assembled on glass and used as the seeds to in situ grow silver‐coated nanostructures based on silver enhancer solution, forming the nanostructures of AuNPs‐R6G@Ag, which were characterized by scanning electron microscopy (SEM) and UV‐visible spectroscopy. More importantly, the obtained silver‐coated nanostructures can be used as a surface enhancement Raman scattering (SERS) substrate. The different SERS activities can be controlled by the silver deposition time and assembly time of AuNPs‐R6G on glass. The results indicate that the maximum SERS activity could be obtained on AuNPs‐R6G when these nanostructures were assembled on glass for 2 h with silver deposition for 2 min. In addition, the reproducibility of SERS signal on the fabricated nanostructures is very high with the intensity error lower than 15%, which has great promise as a probe for application in bioanalysis. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
3.
Matveeva EG Gryczynski I Malicka J Gryczynski Z Goldys E Howe J Berndt KW Lakowicz JR 《Journal of fluorescence》2005,15(6):865-871
We compared plastic (polycarbonate) and high-quality glass support materials for gold-coated slides, when performing a model
immunoassay against rabbit IgG using fluorescently labeled (AlexaFluor-647) anti-rabbit IgG, and detecting surface plasmon-coupled
emission (SPCE) signals. Both, glass and plastic slides were simultaneously coated with a 48-nm layer of gold and protected
with a 10-nm layer of silica. The maximum SPCE signal of AlexaFluor-647 was only two- to three-fold smaller on plastic slides
than on glass slides. A small difference in the SPCE angles on glass (θ
F = 55°) and plastic (θ
F = 52.5°) slides was observed and can be explained with a slightly smaller refractive index of the plastic. We have not found
any difference in the angle distribution (sharpness of the fluorescence signal at optimal SPCE angle) for the plastic slide
compared to the glass slide. The kinetics of binding was monitored on the plastic slide as well as on the glass slide. Optically
dense samples, a 4% red blood cell suspension and a 15% hemoglobin solution, are causing a reduction in the immunoassay SPCE
signal by approximately 15% and three times, respectively, and the percentage of the reduction is the same for plastic and
for glass slides. We believe that plastic substrates can be readily used in any SPCE assay, with only marginally lower total
signal compared to high-quality glass slides. 相似文献
4.
Chris D. Geddes Alexandr Parfenov David Roll Ignacy Gryczynski Joanna Malicka Joseph R. Lakowicz 《Journal of fluorescence》2003,13(3):267-276
Substantial increases in fluorescence emission from fluorophore-protein–coated fractal-like silver structures have been observed. We review two methods for silver fractal structure preparation, which have been employed and studied. The first, a roughened silver electrode, typically yielded a 100-fold increase in fluorophore emission, and the second, silver fractal-like structures grown on glass between two silver electrodes, produced a 500-fold increase. In addition, significant increases in probe photostability were observed for probes coated on the silver fractal like structures. These results further serve to compliment our recent work on the effects of nobel metal particles with fluorophores, a relatively new phenomenon in fluorescence we have termed both metal-enhanced fluorescence [1] and radiative decay engineering [2,3]. These results are explained by the metallic surfaces modifying the radiative decay rate () of the fluorescent labels. We believe that this new silver-surface preparation, which results in ultrabright and photostable fluorophores, offers a new generic technology platform for increased fluorescence signal levels, with widespread potential applications to the analytical sciences, imaging, and medical diagnostics. 相似文献
5.
Enhanced Lanthanide Luminescence Using Silver Nanostructures: Opportunities for a New Class of Probes with Exceptional Spectral Characteristics 总被引:2,自引:0,他引:2
The photophysical effects of europium tetracycline immobilized in thin polyvinyl alcohol films coated onto silver nanostructures have been investigated. Complimentary to recent reports from our laboratories that the close proximity of luorophores to silver nanostructures can enhance their intrinsic radiative decay rate, we show that up to a 16-fold enhancement in lanthanide luminescence is possible, accompanied by a notable reduction in luminescence lifetime. These results suggest the potential future development of a new class of significantly brighter lanthanide based probes with exceptional spectral properties, which can probably undergo significantly more excitation–emission event cycles due to the reduced lifetime, substantially increasing detectability. 相似文献
6.
In this short paper we report the interactions of silver island films with chemiluminescing species. Our findings show that silver island films can increase the detectability of chemiluminescent reactions/species, with an approximately 5-fold increase in signal intensity. This finding not only suggests the use of silver nanostructures to amplify chemiluminscent signatures in assay platforms, and therefore increase the detectability of analytes or biospecies, but more importantly, suggests that surface plasmons can be directly excited by chemically induced electronically excited molecules. This finding is of significance towards our understanding of fluorophore–metal interactions, a relatively new near-field fluorescence concept, recently named metal-enhanced fluorescence and also radiative decay engineering. 相似文献
7.
Advances in Surface-Enhanced Fluorescence 总被引:4,自引:0,他引:4
Lakowicz JR Geddes CD Gryczynski I Malicka J Gryczynski Z Aslan K Lukomska J Matveeva E Zhang J Badugu R Huang J 《Journal of fluorescence》2004,14(4):425-441
We report recent achievements in metal-enhanced fluorescence from our laboratory. Several fluorophore systems have been studied on metal particle-coated surfaces and in colloid suspensions. In particular, we describe a distance dependent enhancement on silver island films (SIFs), release of self-quenching of fluorescence near silver particles, and the applications of fluorescence enhancement near metalized surfaces to bioassays. We discuss a number of methods for various shaped silver particle deposition on surfaces. 相似文献
8.
André Anders Eungsun Byon Dong-Ho Kim Sunnie H.N. Lim 《Solid State Communications》2006,140(5):225-229
The nucleation and coalescence of silver islands on coated glass was investigated by in situ measurements of the sheet resistance. Sub-monolayer amounts of niobium and other transition metals were deposited prior to the deposition of silver. It was found that in some cases, the transition metals lead to coalescence of silver at nominally thinner films with smoother topology. The smoothing or roughening effects by the presence of the transition metal can be explained by kinetically limited transition metal islands growth and oxidation, followed by defect-dominated nucleation of silver. 相似文献
9.
Oxygen deficient zinc oxide (ZnO) thin films were deposited electrochemically on glass substrates which are pre-sputtered with pure zinc (Zn) metal. Well-arranged flower-like nanostructures are observed from the SEM micrographs. The purity and crystallinity of the deposited films were confirmed from X-ray diffraction studies supported by Raman studies. The broad and intense defect induced green emission confirms the high oxygen deficiency in the nanostructures. The flower-like structures as well as the oxygen defects present in the system are indeed very suitable for gas and chemical sensing applications. These films were used for room temperature sensing of three different chemicals viz. acetone, ethanol and ammonia. The sensor was found to be insensitive to the change in different concentrations of acetone while it was found to be sensitive to different concentrations of ethanol and ammonia. The sensor is most suitable for sensing ammonia at room temperature. 相似文献
10.
Alexandre Merlen Virginie Chevallier Jean Christophe Valmalette Lionel Patrone Philippe Torchio Sylvain Vedraine François Flory Golam Moula 《Surface science》2011,605(13-14):1214-1218
We compared the surface enhanced spectroscopy signal arising from dye molecules (methylene blue, crystal violet and octadecylrhodamine B) deposited on gold nanostructures fabricated onto two kinds of substrates: silicon wafer or glass. For any molecule and excitation wavelength, the observed signal was always higher on glass compared to silicon. This experimental result is confirmed by Finite-Difference Time Domain calculations: the enhancement in the electric field is much higher with gold nanoparticles on glass than on silicon, even if a thin oxide layer is present. These results clearly demonstrate that the nature of the substrate, independently of metallic nanoparticles, is important for the preparation of highly efficient SERS nanostructures. 相似文献
11.
12.
Antonín Vašíček 《Czechoslovak Journal of Physics》1954,4(2):204-219
Formulas for the reflection of light from glass (i. e. a dielectric) coated with a thin non-metallic film are generalized for the case of the reflection of light from a metal coated with a thin non-metallic film, e. g. a film of aluminium oxide on aluminium. It is shown how the refractive index and the thickness of the aluminium oxide film on an aluminium mirror can be determined by measurements in polarized light. In conclusion the results of Drude's classical theory of thin non-metallic films on metallic mirrors are compared with the results obtained by the author on the basis of the interference of light in thin films. 相似文献
13.
The metal-enhanced fluorescence is measured with different thickness of emission film. Silver nanoparticles are immobilized on glass slide by chemical self-assembly method. Rhodamine B molecules are dispersed in the polymer matrix of Poly(methyl methacrylate) (PMMA), then spin coated on prepared silver particles substrate with different thickness from 15 nm to 70 nm. The enhanced fluorescence is observed depending on the thickness of emission film since the average distance between rhodamine B molecules and silver nanoparticles is altered by the PMMA matrix. The 5-fold enhancement is attained. The experiment was explained qualitatively by an integral fluorescence enhancement. 相似文献
14.
15.
光纤与生物分子界面上固定FITC标记抗体的荧光光谱 总被引:3,自引:3,他引:0
采用化学方法把FITC标记羊抗人抗体IgG共价固定到三氨基三乙氧基硅烷和戊二醛(APTES-Glu)修饰的石英光纤纤芯表面。通过研究未经过任何修饰的纤芯表面的吸附以及共价固定的FITC标记羊抗人抗体的荧光光谱性质发现:共价结合到纤芯表面的FITC荧光光谱相对于溶液中FITC的荧光峰位红移约9nm,而物理吸附的FITC的荧光峰位移动约4nm,而且两者相对荧光强度相差6倍。而在固定的人血清蛋白进行免疫反应后,FITC的荧光峰位只移动3~4nm,除此之外,研究了抗体共价键固定的稳定性问题。结果表明:共价键结合抗体的数量要大于表面吸附,共价键固定的FITC标记羊抗人抗体与光纤表面间的相互作用较吸附于光纤表面的FITC标记羊抗人抗体间的相互作用更强。这对于建立一种通过荧光光谱识别固体表面与生物分子的吸附还是共价结合的判据提供了物理基础。 相似文献
16.
Perforated nanocap array: Facile fabrication process and efficient surface enhanced Raman scattering with fluorescence suppression
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Recently, individual reduced-symmetry metal nanostructures and their plasmonic properties have been studied extensively. However, little attention has been paid to the approach to fabricating ordered reduced-symmetry metal nanostructure arrays. In this paper, a novel perforated silver nanocap array with high surface-enhanced Raman scattering (SERS) activity and fluorescence suppression is reported. The array is fabricated by electron beam evaporating Ag onto the perforated barrier layer side of a hard anodization (HA) anodic aluminum oxide (AAO) template. The morphology and optical property of the perforated silver nanocap array are characterized by an atomic force microscope (AFM), a scanning electron microscope (SEM), and absorption spectra. The results of SERS measurements reveal that the perforated silver nanocap array offers high SERS activity and fluorescence suppression compared with an imperforated silver nanocap array. 相似文献
17.
以经过硅烷化后玻璃片为基底,之后吸附金纳米种子,采用柠檬酸钠为还原剂,在荧光灯照射条件下还原硝酸银,制备出基底表面具有银纳米粒子聚集结构的材料。采用透射电镜、扫描电镜和紫外可见分光光度计对产物的形貌和性质进行了表征,并考察银纳米粒子的形貌对其薄膜基底SERS活性的影响。结果表明:随着光照时间增加至16 h,金种子长大为平均粒径110 nm的不规则状多晶银纳米粒子,且出现双层粒子堆积。基底上纳米粒子的吸收光谱上出现了由银粒子的表面等离子体激元偶极子耦合引发的强烈吸收峰:随着光照时间的变化,耦合峰在600~813 nm波段内移动。光照时间为12 h后得到的SERS活性基底具有最强的SERS信号。 相似文献
18.
以经过硅烷化后玻璃片为基底,之后吸附金纳米种子,采用柠檬酸钠为还原剂,在荧光灯照射条件下还原硝酸银,制备出基底表面具有银纳米粒子聚集结构的材料。采用透射电镜、扫描电镜和紫外可见分光光度计对产物的形貌和性质进行了表征,并考察银纳米粒子的形貌对其薄膜基底SERS活性的影响。结果表明:随着光照时间增加至16 h,金种子长大为平均粒径110 nm的不规则状多晶银纳米粒子,且出现双层粒子堆积。基底上纳米粒子的吸收光谱上出现了由银粒子的表面等离子体激元偶极子耦合引发的强烈吸收峰:随着光照时间的变化,耦合峰在600~813 nm波段内移动。光照时间为12 h后得到的SERS活性基底具有最强的SERS信号。 相似文献
19.
20.
G. A. Gachko 《Journal of Applied Spectroscopy》2001,68(5):766-775
The spectra of giant Raman scattering of light and surfaceenhanced fluorescence of certain chromophores absorbing light in the visible spectrum region are investigated. The factors that have an effect on the enhancement of secondary radiation of chromophores adsorbed on the surface of rough silver films under conditions of resonance excitation are determined. The spectra of mirror reflection of light by the substrates used are considered. The coefficients of diffuse and mirror reflection, absorption, and transmission of light by thin silver films at wavelengths of 488 and 633 nm are determined. The scheme of an experimental system for observation of the spectra of giant Raman scattering and surfaceenhanced fluorescence on the source side of a transparent substrate is proposed. Conclusions on the predominant contribution of the resonance excitation of surface plasmons to the enhancement of the signal of the giant Raman scattering and surfaceenhanced fluorescence of molecules adsorbed on the rough metal surface are drawn. 相似文献