title: Substituted 4-[4-(dimethylamino)styryl]pyridinium salt as a fluorescent probe for cell microviscosity.
abstract: In aqueous solution, 4-[4-(dimethylamino)styryl]pyridine (DMASP) derivatives displayed dual fluorescence, in which excitation at either 469 or 360 nm produced an emission band near 600 nm. Increasing the viscosity of the environment intensified the fluorescence emission obtained at the longer wavelength of excitation, whereas the emission at the lower wavelength of excitation showed little change in intensity. Thus, using the ratio of the 600 nm emission obtained by exciting at 469 nm to that obtained with 360 nm excitation, it is possible to obtain a value related to the local viscosity that does not depend on the system parameters. The fluorescence emission of the dye in aqueous solution, as well as in living cells, is well suited for use with visible fluorescence spectroscopy. The N-carboxymethyl butyl ester DMASP derivative (1) was found to be irreversibly loaded into living smooth muscle cells, presumably because it is hydrolyzed by cellular esterases, transforming it into a membrane-impermeable fluorescent carboxylate DMASP derivative. (2) After calibrating 2 against glycerol/water and sucrose/water mixtures of known viscosity, the fluorescence ratio generated from cultured smooth muscle cells in dual-excitation mode gave an average intracellular viscosity of 4.5 cP. This value corresponds to those reported in the literature.
authors.affiliation: Department of Molecular Physics, Faculty of Chemistry, Technical University of Łodź, Zeromskiego 116, Łódź 90 924, Poland. bwandelt@ck-sg.p.lodz.pl
authors.forename: Barbara
authors.initials: B
authors.lastname: Wandelt
authors.forename: Alina
authors.initials: A
authors.lastname: Mielniczak
authors.forename: Petra
authors.initials: P
authors.lastname: Turkewitsch
authors.forename: Graham D
authors.initials: GD
authors.lastname: Darling
authors.forename: Brent R
authors.initials: BR
authors.lastname: Stranix
mesh_terms: D000818:Animals; D018929:Cell Culture Techniques / Q000295:instrumentation / Q000379:methods*; D002478:Cells, Cultured; D003593:Cytoplasm / Q000502:physiology*; D005434:Flow Cytometry / Q000379:methods*; D005456:Fluorescent Dyes; D006863:Hydrogen-Ion Concentration; D032389:Myocytes, Smooth Muscle / Q000737:chemistry / Q000502:physiology*; D011726:Pyridinium Compounds / Q000737:chemistry* / Q000378:metabolism; D051381:Rats; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014783:Viscosity
chemical_list: C475681:1-methyl-4-(4-aminostyryl)pyridinium; D005456:Fluorescent Dyes; D011726:Pyridinium Compounds