title: Short-lived fluorescence component of DPH reports on lipid--water interface of biological membranes.
abstract: Fluorescence measurements of 1,6-diphenyl-1,3,5-hexatriene (DPH) in large unilamellar phospholipid vesicles were performed to characterize the influence of the membrane physical properties on the short-lived lifetime component of the fluorescence decay. We have found that the short-lived component of DPH significantly shortens when the membrane undergoes a temperature-induced phase transition as it is known for the long-lived component of DPH. We induced membrane phase transitions also by alcohols, which are reported to be distributed different way in the membrane--ethanol close to the membrane-water interface and benzyl alcohol in the membrane core. A different effect of the respective alcohol on the short and long decay component was observed. Both the time-resolved fluorescence spectra of DPH taken during lipid vesicle staining and the lifetime dependences caused by changes of temperature and/or induced by the alcohols show that the short-lived fluorescence originates from the population of dye molecules distributed at the membrane-water interface.
authors.affiliation: Department of Genetics and Microbiology, Faculty of Science, Charles University, Vinicná 5, CZ-128 44 Prague 2, Czech Republic. konop@natur.cuni.cz
authors.forename: Ivo
authors.initials: I
authors.lastname: Konopásek
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Vecer
authors.forename: Kazimierz
authors.initials: K
authors.lastname: Strzalka
authors.forename: Evzen
authors.initials: E
authors.lastname: Amler
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000494:pharmacology; D019905:Benzyl Alcohol / Q000494:pharmacology; D004161:Diphenylhexatriene / Q000032:analysis* / Q000737:chemistry*; D000431:Ethanol / Q000494:pharmacology; D005453:Fluorescence; D005454:Fluorescence Polarization; D008055:Lipids / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry*; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry*
chemical_list: D008055:Lipids; D008081:Liposomes; D014867:Water; D004161:Diphenylhexatriene; D015060:1,2-Dipalmitoylphosphatidylcholine; D000431:Ethanol; D019905:Benzyl Alcohol