We studied the combination between seven kinds of drugs and the bovine serum albumin (BSA) using Methyl Green (MG) as fluorescent probe. These drugs were Streptomycin sulphate, Kanamycin sulfate, Gentamicin, Amikacin, Neomycin, Thiamphenicol and Florfenicol. And after reaction of these drugs, the fluorescence intensity of BSA had no obvious change. Research has shown that in Tris-HCl (pH=7.40) ...

The mechanism of the fluorescence quenching of aqueous thionine by various metal ions (Ce3+_, Fe2+, Mn2+, Mg2+, Cs+ and Na+) was studied at pn = 2.5. The following Stern-Volmer constants (K s v) were determined: XSv(Fe2+) == 1.13 dm3 mol -1 , Ksw(Mn2+) = 0.24 dm3 mol"1, Ksv(Ce3+) = 0.24 dm3 mol -1, i£sv(Cs~) — 0.03 dm3 mol -1 . At concentrations below 1 mol.dm -3 Na2S04 and MgS04 are very weak ...

The aggregation dependent correlation between fluorescence quenching and the electronic carotenoid– chlorophyll interactions, / S1 Chl Coupling , as measured by comparing chlorophyll fluorescence observed after twoand one-photon excitation, has been investigated using native LHC II samples as well as mutants lacking Chl 2 and Chl 13. For native LHC II the same linear correlation between / S1 Ch...

Wavelength- and time-resolved fluorescence experiments have been performed on the photoactive yellow protein, the E46Q mutant, the hybrids of these proteins containing a nonisomerizing "locked" chromophore, and the native and locked chromophores in aqueous solution. The ultrafast dynamics of these six systems is compared and spectral signatures of isomerization and solvation are discussed. We f...

The photoluminescence (PL) quantum yield of single-walled carbon nanotubes (SWNTs) is relatively low, with various quenching effects by metallic species reported in the literature. Here, we report the first case of metal enhanced fluorescence (MEF) of surfactant-coated carbon nanotubes on nanostructured gold substrates. The photoluminescence quantum yield of SWNTs is observed to be enhanced mor...

An Mn metal-organic framework (Mn-MOF), Mn-L, based on a pyrene-tetraacid linker (H4 L), displays a respectable fluorescence quantum yield of 8.3% in spite of the presence of the paramagnetic metal ions, due presumably to fixation of the metal ions in geometries that do not allow complete energy/charge-transfer quenching. Remarkably, the porous Mn-L MOF with ∼25% solvent-accessible volume exhib...

The development of activatable photodynamic therapy (PDT) has demonstrated a utility for effective photosensitizer quenchers. However, little is known quantitatively about Forster resonance energy transfer (FRET) quenching of photosensitizers, even though these quenchers are versatile and readily available. To characterize FRET deactivation of singlet oxygen generation, we attached various quen...

Artificially mediated linear (methylviologen) and cyclic (phenazine methosulfate) electron transport induced zeaxanthin-dependent and independent (constitutive) nonphotochemical quenching in osmotically shocked chloroplasts of pea (Pisum sativum L. cv Oregon). Nonphotochemical quenching was quantitated as Stern-Volmer quenching (SV(N)) calculated as (F(m)/F'(m))-1 where F(m) is the fluorescence...

INTRODUCTION When bound to proteins and membranes, fluorescence probes can provide valuable information about the environment of the binding site (Edelman & McClure, 1968; Brand & Gohlke, 1972). Recently much interest has been shown in aromatic hydrocarbons as fluorescence probes. Because they are non-polar molecules, they should not interact as strongly with charged groups as the amino-napthal...

In the work discussed in this paper, the effect of a high surface-to-volume ratio of a microfluidic detection cell on fluorescence quenching was studied. It was found that modification of the geometry of a microchannel can provide a wider linear range. This is a phenomenon which should be taken into consideration when microfluidic systems with fluorescence detection are developed. The dependenc...