Sodium, fluorescent indicators

A number of experimental techniques by measurements of physical properties (interfacial tension, surface tension, osmotic pressure, conductivity, density change) applicable in aqueous systems suffer frequently from insufficient sensitivity at low CMC values in hydrocarbon solvents. Some surfactants in hydrocarbon solvents do not give an identifiable CMC the conventional properties of the hydrocarbon solvent solutions of surfactant compounds can be interpreted as a continuous aggregation from which the apparent aggregation number can be calculated. Other, quite successful, techniques (light scattering, solubilization, fluorescence indicator) were applied to a number of CMCs, e.g., alkylammonium salts, carboxylates, sulfonates and sodium bis(2-ethylhexyl)succinate (AOT) in hydrocarbon solvents, see Table 3.1 (Eicke, 1980 Kertes, 1977 Kertes and Gutman, 1976 Luisi and Straub, 1984 Preston, 1948). 

Sodium-binding benzofuran isophthalate (SBFI) 272 is a fluorescent indicator developed to measure intracellular Na concentrations <1989JBC19449>. Its structure incorporates a diaza crown ether portion for cation binding and... 

The single-cell imaging on microfluidic device helps to quantitatively monitor intracellular sodium ion (Na+) concentration, potassium channel permeability, and apoptosis or necrosis and thus provides an advantage over the patch clamp system [58], The inhibition of potassium channels is monitored by using the FluxOR thallium detection kit. FluxOR dye is cleaved by endogenous esterases to thallium-sensitive fluorescent indicator inside the cells, and... 

Daniell LC (1992) Determination of the intravesicular ionized sodium concentration in a cell-free brain membrane vesicle preparation using the fluorescent indicator, SBFI. Anal Biochem 202 239-244... 

Deri Z, Adam-Vizi V (1993) Detection of intracellular free Na concentration of synaptosomes by a fluorescent indicator, Na -binding benzofuran isophthalate the effect of veratridine, ouabain, and a-latrotoxin. J Neurochem 61 818-825 Dubois JM, Bergman C (1975) Late sodium current in the node of Ranvier. Pfliigers Arch 357 145-148... 

Minta, A. Tsien. R.Y. Fluorescent indicators for cytosolic sodium. J. Biol. Chem. 1989, 264, 19449-19457. de Silva, A.P. Gunaratne, H.Q.N. Gunnlaugs.son. T. Nieuwenhuizen, M. Fluorescent switches with high selectivity towards sodium ions Correlation of ion-induced conformation switching with fluorescence function. Chem. Commun. 1996. 1967-1968. 

Procedure. 0.005 ml of the test solution is transferred to a Whatman No. 1 filter paper by micropipette. After quickly drying the spot in hot air, the paper is sprayed with a 15 % solution of sodium tungstate and examined under u.v. light. A whitish-pink fluorescence indicates the presence of dysprosium. 

Martin, V. V. Rothe, A. Gee, K. R. Fluorescent metal ion indicators based on benzoannelated crown systems a green fluorescent indicator for intracellular sodium ions. Bioorg. Med. Chem. Lett. 2005,15, 1851-1855. 

Minta, A. Tsien, R. Y. Fluorescent indicators for cytosolic sodium. J. Biol. Chem. 1989, 264, 19449-19457. 

M. Yamazaki, N. Quantification of intracellular free sodium ions by using a new fluorescent indicator, sodium-binding benzofuran isophthalate in guinea pig myocytes. Biochem. Biophys. Res. Commun. 1991, 175, 611-616. 

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