Silver nanoparticles fluorescence

Corrigan, T, Guo, S., Phaneuf, R., and Szmacinski, H. (2005) Enhanced fluorescence from periodic arrays of silver nanoparticles,/. Fluoresc., 15, 777-784. 

The commercially available dicyanomethylene squaraine dye Seta-670-mono-NHS showed extremely low blinking effects and good photostability when used in single-molecule studies of multiple-fluorophore labeled antibodies [113]. Seta-670-mono-NHS and Seta-635-NH-mono-NHS were covalently labeled to antibodies and used in a surface-enhanced immunoassay [114]. From the fluorescence intensity and lifetime changes determined for a surface that had been coated with silver nanoparticles, both labeled compounds exhibited a 15- to 20-fold... 

A 2 1-fold increase in fluorescence intensity was demonstrated for the long-wavelength hydrophilic bis-trimethine label 29 (original silver nanoparticles coated with a cryolite spacer [96], A 20-fold increase of fluorescence intensity and a sixfold decrease of the mean decay time were obtained for heptamethine cyanine dye 30 on silver nanoparticles [97],... 

Sprensen TJ, Laursen BW, Luchowski R, Shtoyko T, Akopova I, Gryczynski Z, Gryczynski I (2009) Enhanced fluorescence emission of Me-ADOTA+ by self-assembled silver nanoparticles on a gold film. Chem Phys Lett 476 46-50... 

In this chapter, we discuss first how the silver clusters relate to silver atoms and silver nanoparticles. Then we overview the formation of fluorescent silver clusters in aqueous solution, using silver salts as precursors and various scaffolds as stabilizers. Finally we discuss applications of silver clusters in fluorescent labeling of biological tissues, and their use as fluorescent probes for sensing of molecules. 

In 2007, Dickson et al. found that it is possible to stain fixed cells with fluorescent silver clusters instead of silver nanoparticles by tuning the staining conditions [57]. The new approach consists of staining fixed cells with a low concentrated silver nitrate solution 20-100 mM, within 20 h at ambient conditions, and reducing the silver by photoactivation, with the result of small silver clusters that present a broad emission band between 500 and 700 nm (Fig. 8a-d). The discovery that fluorescent silver clusters can be generated by photoactivation of cells fed with silver salt, opens up new paths for the application of silver clusters in biological systems. 

In a more simple and cheap way, silver clusters can be prepared in aqueous solutions of commercially available polyelectrolytes, such as poly(methacrylic acid) (PM A A) by photo activation using visible light [20] or UV light [29]. Ras et al. found that photoactivation with visible light results in fluorescent silver cluster solutions without any noticeable silver nanoparticle impurities, as seen in electron microscopy and from the absence of plasmon absorption bands near 400 nm (F = 5-6%). It was seen that using PMAA in its acidic form, different ratios Ag+ MAA (0.15 1-3 1) lead to different emission bands, as discussed in the next section (Fig. 12) [20]. When solutions of PMAA in its sodium form and silver salt were reduced with UV light (365 nm, 8 W), silver nanoclusters were obtained with emission band centered at 620 nm and [Pg.322]

Figure 27.1 Principle of silver nanoparticle enhanced fluorescence applied to artificial cell surfaces.

Lochner, N., Pittner, F., Wirth, M., Gabor, F., Wheat germ agglutinin binds to the epidermal growth factor-receptor of artificial Caco-2 membranes as detected by silver nanoparticle enhanced fluorescence. Pharm Res 20, 833-839 (2003). 

The mechanistic route followed for the reduction process was different in the case of Ag/mycelium and Ag/media. In media, glucose was found mainly responsible for the reduction whereas in the case of mycelium, it was mainly the S-H group responsible for the same. The photoluminescence spectrum of these protein-stabilized silver nanoparticles also showed much enhanced fluorescence emission intensity. 

Chen Y, Munechika K, Ginger DS (2007) Dependence of fluorescence intensity on the spectral overlap between fluorophores and plasmon resonant single silver nanoparticles. 

K. Aslan, P. Holley, and C. D. Geddes. Metal-enhanced fluorescence from silver nanoparticle-deposited polycarbonate substrates Journal of Materials Chemistry, 2006, 16, 2846-2852. 

Zhang, J., Malicka, J., Gryczynski, I., and Lakowicz, J. R. (2005). Surface-enhanced fluorescence of fluorescein-labeled oligonucleotides capped on silver nanoparticles, yowrno/ of Physical Chemistry B 109 7643-7648. 

Chen, Y., Munechika, K., and Ginger, D. S. (2007). Dependence of Fluorescence Intensity on the Spectral Overlap between Fluorophores and Plasmon Resonant Single Silver Nanoparticles. Nano Letters 7 690-696. 

Sabanayagam, C.R. and Lakowicz, J.R. (2007) Increasing the sensitivity of DNA microarrays by metal-enhanced fluorescence using surface-boimd silver nanoparticles. Nucleic Acids Res 35 el3. 

Figure 7.1 (A) Sdiematic representation of the Metal-Enhanced Fluorescence phenomena (B) FDTD calculations for two silver nanoparticle arrays...

Chowdhury, M. H., Gray, S. K., Pond, J., Geddes, C. D., Aslan, K., and Lakowicz, J. R. (2007). Computational study of fluorescence scattering by silver nanoparticles Journal of the Optical Society of America B-Optical Physics 24 2259-2267. 

Both Geddes and the Lakowicz group s have investigated the metal-enhanced fluorescence of fluorophores on silver island films (SIFs) [11,26,27] and variously aggregated silver nanoparticles in solution [28,29]. One example of enhancement on SIFs is discussed below [26]. In this work the distance-dependent MEF of a monolayer of sulforfiodamine B (SRB) on SIFs was studied. A SRB monolayer was electrostatically incorporated into the Langmuir-Blodgett (LB) layers of octadecylamine (ODA) deposited... 

Metal nanoparticles have attracted considerable interest due to their properties and applications related to size effects, which can be appropriately studied in the framework of nanophotonics [1]. Metal nanoparticles such as silver, gold and copper can scatter light elastically with remarkable efficiency because of a collective resonance of the conduction electrons in the metal (i.e., the Dipole Plasmon Resonance or Localized Surface Plasmon Resonance). Plasmonics is quickly becoming a dominant science-based technology for the twenty-first century, with enormous potential in the fields of optical computing, novel optical devices, and more recently, biological and medical research [2]. In particular, silver nanoparticles have attracted particular interest due to their applications in fluorescence enhancement [3-5]. 

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