title: Spectroscopic studies of D-alpha-tocopherol concentration-induced transformation in egg phosphatidylcholine vesicles.
abstract: The effects of embedding up to 60 mol% of alpha-tocopherol (alpha-Toc) on the morphology and structure of the egg phosphatidylcholine (PC) membrane were studied using spectroscopic techniques. The resulting vesicles were subjected to turbidometric and dynamic light scattering measurements to evaluate their size distribution. The alpha-Toc intrinsic fluorescence and its quenching was used to estimate the tocopherol position in the membrane. Optical microscopy was used to visualize morphological changes in the vesicles during the inclusion of tocopherol into the 2 mg/ml PC membrane. The incorporation of up to 15 mol% of tocopherol molecules into PC vesicles is accompanied by a linear increase in the fluorescence intensity and the simultaneous formation of larger, multilamellar vesicles. Increasing the tocopherol concentration above 20 mol% induced structural and morphological changes leading to the disappearance of micrometer-sized vesicles and the formation of small unilamellar vesicles of size ranging from 30 to 120 nm, mixed micelles and non-lamellar structures.
authors.affiliation: Department of Physics, Poznań, Poland. polewski@au.poznan.pl
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Dwiecki
authors.forename: Paweł
authors.initials: P
authors.lastname: Górnas
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Wilk
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Nogala-Kałucka
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Polewski
mesh_terms: D004305:Dose-Response Relationship, Drug; D004530:Egg Yolk / Q000737:chemistry* / Q000187:drug effects / Q000528:radiation effects; D008027:Light; D009391:Nephelometry and Turbidimetry; D010713:Phosphatidylcholines / Q000378:metabolism*; D012542:Scattering, Radiation; D013050:Spectrometry, Fluorescence; D053835:Unilamellar Liposomes / Q000378:metabolism* / Q000528:radiation effects; D024502:alpha-Tocopherol / Q000494:pharmacology*
chemical_list: D010713:Phosphatidylcholines; D053835:Unilamellar Liposomes; D024502:alpha-Tocopherol