Enhanced fluorescence emission

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... 

Lim S-J, An B-K, Jung S-D, Chung M-A, Park SY (2004) Photoswitchable organic nanoparticles and a polymer film employing multifunctional molecules with enhanced fluorescence emission and bistable photochromism. Angew Chem Int Ed 43 6346-6350... 

Small Au NPs [189] and nanorods [190] display enhanced fluorescent emissions over the bulk metal that can be tuned as the size or the aspect ratio increases. 

Fig. 13. (A) Schematic representation of the interaction between neighboring residues of the His-tag (6 consecutive Histidine residues) and an NTA-complexed Ni2+ ion. (B) The performance of LHCII immobilization via chelating interaction. SPR kinetic curve of LHCII immobilization and regeneration cycles, monitored with an Nd YAG DPSS laser (X = 473 nm). (C) Surface plasmon field-enhanced fluorescence emission spectrum of surface attached LHCII compared with the fluorescence emission from free LHCII in solution, excited by an Nd YAG DPSS laser (X — 473 nm).

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. 

Ganesh N, Zhang W, Mathias PC et al (2007) Enhanced fluorescence emission from quantum dots on a photonic crystal surface. Nat Nanotechnol 2 515-520... 

We therefore assume that the major effect of the array is in increased collection of light within the apertures. In the simulation results of this section, we only consider briefly the excitation component to enhanced fluorescence emission. As already established by experiments, the light intensity within periodic arrangements of nanoapertures increases in association with EOT and is a result of aperture coupling effects via surface waves under external excitation. This coupling therefore modulates the response obtained for an isolated aperture. Simulations were performed in the same manner as described before, except for the fact that periodic boundary conditions were used along the sides of the simulaticHi space boundary. 

Pan, S. L., Rothberg, L.J., Nolte, A.J.,Rubner, M. F., Swager, T. M.(2005). Distance dependent investigation of surface plasmon resonance enhanced fluorescent emission using sequentially adsorbed polyelectrolyte mutilayer spacer. Proc. SPIE 5927 592705... 

The europium(III) methacycline complex 19 can be used for spectrofluori-metric determination of lysozyme [49]. The oxytetracycline and doxycycline complexes are both sensitive to ATP in that their luminescence emission is increased in presence of ATP [50, 51]. In addition, complex 17 can be used to determine heparin and NADP in aqueous solution [52,53]. The detection of these biomolecules occurs by means of an enhanced fluorescence emission. Bile acid quenches the luminescence of Eu " doxycycline in a concentration dependent manner [54]. 

Thiamin has also been determined using mercury(ii) (Martinez-Lozano et al. 1990). Mercury(ii) is used to oxidize thiamin to the fluorescent thiochrome compound. Based on this reaction, a flow injection method has been developed to analyze thiamin in commercial preparations. A fluorimetric method coupled with flow injection has been developed for determining thiamine based on the oxidation of thiamin to thiochrome by mercury(ii) (Perez-Ruiz et al. 2004). A high mercury(ii) concentration is utilized in this reaction for the largest yield of thiochrome and it produces an enhanced fluorescence emission signal at 440 nm when excited at 356 nm. The fluorescence intensity increases with the concentration of thiamin added, which exhibits outstanding results to determine vitamin Bj. 

Iron(iii) tetrasulfonatophthalocyanine (FeTSPc), a mimetic enzyme, is used to catalyse the oxidation reaction of thiamin to produce thiochrome in the presence of H2O2 (Chen et al. 1999). Thiamin is oxidized to thiochrome by the catalytic activity of FeTSPc in the presence of H2O2 in alkaline medium, which exhibits an enhanced fluorescence emission peak at 440 nm when excited at 375 nm with the fluorogenic substrate, L-tyrosine (Chen et al. 1999). The fluorescence intensity is increased linearly with the concentration of thiamin in the range of 1.0 x 10 to 1.0 x lO mol The limit of detection is 4.3 X 10 mol and the relative standard deviation is 2.2% for six repeated... 

Interestingly, the chiral bis-boronic acid sensor 4 show enhanced fluorescence emission towards one enantiomer of the tartaric acid, whereas fluorescence decreased in the presence of another enantiomer (Figures 6.4 and 6.5). This enhancement/reduction in fluorescence response for chiral recognition of enantiomers was rarely reported. Both the fluorescence... 

The most complex situation is sketched in Figure 7(b) for intermediate separation distances the chromophores excited either by plane waves from the dielectric side or by a surface plasmon mode excited from the prism side relaxes vibronically to the bottom of the excited state level of the chromophore but then can back-couple to the metal, thereby exciting a red-shifted siuface plasmon mode. This mode in turn can re-radiate via the prism (or the grating) and lea to an enhanced fluorescence emission. The optimum dye-metal separation for this decay mechanism has been reported to be in the range of d = 20 nm . 

Figure 7. Enhanced fluorescence emission is a through space interaction as compared to SERS. Adapted from reference 5.

In this review Chapter, we have shown the favorable effects of enhanced fluorescence emission intensity, (quantum yield), reduced lifetime (increased photostability) for fluorophores in close proximity to appropriately sized metallic silver nanostructures. Our findings have indeed revealed that 500-fold enhancement in emission intensity can be realized, which is likely to offer multifarious applications to medical diagnostics and the clinical sciences. Metal-fluorophore interactions are... 

Pathak RK, Ibrahim SM, Rao CP (2009) Selective Recognition of Zn by Salicylaldimine appended triazole-linked Di-derivatives of Calix[4]arene by Enhanced fluorescence emission in aqueous-organic solutions role of terminal -CH2OH moieties in conjunction with the imine in recognition. Tetrahedron Lett 50 2730-2734... 

Further on, different ILs with various structures were confined into the supercage of silica gel and extensively characterized by Brunauer-Emmett-Teller (BET), Fourier transform infrared spectroscopy (FT-IR), temperature-programmed desorption (TPD), differential scanning calorimetry (DSC), and inverse gas chromatography (ICC) [67]. Compared to the bulk IL and silica gel-supported IL film, the silica gel-confined IL displayed remarkably low specific heat capacities, disordered vibrational conformations, stronger interactions with hydrocarbon solutes, and greatly enhanced fluorescence emission. Furthermore, it could be applied in the separation of CO2 from CO2/N2 mixtures and thiophene from thiophene/octane mixtures. 

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