title: Lipid membrane with low proton permeability.
abstract: This work reports the production of a liposomal formulation, having a lipidic membrane with known chemical composition and a low proton permeability, as confirmed by physicochemical characterization of the maintenance of a transmembranic pH gradient. These liposomes consist of DSPC, DSPE-PEG, DSPG and cholesterol, with low internal pH. To verify the low proton permeability of these liposomal bilayers, a study of proton migration according to the fluorescence quenching of 9-aminoacridine (9AA), as well as CPT-11 encapsulation, were used to monitor the acidification of the intravesicular space. Both experiments showed that this liposomal formulation is able to maintain a transmembranic proton gradient.
authors.affiliation: Department of Physical Chemistry, Institute of Chemistry, State University of Campinas (UNICAMP), Cx Postal 6154, 13084-971 Campinas, SP, Brazil.
authors.forename: Débora Nakai
authors.initials: DN
authors.lastname: Biloti
authors.forename: Maria Helena Andrade
authors.initials: MH
authors.lastname: Santana
authors.forename: Francisco Benedito Teixeira
authors.initials: FB
authors.lastname: Pessine
mesh_terms: D000585:Aminacrine; D002166:Camptothecin / Q000031:analogs & derivatives* / Q000737:chemistry; D005456:Fluorescent Dyes; D006863:Hydrogen-Ion Concentration; D000077146:Irinotecan; D008081:Liposomes / Q000737:chemistry*; D008563:Membrane Lipids / Q000737:chemistry*; D010539:Permeability; D011522:Protons; D013050:Spectrometry, Fluorescence
chemical_list: D005456:Fluorescent Dyes; D008081:Liposomes; D008563:Membrane Lipids; D011522:Protons; D000077146:Irinotecan; D000585:Aminacrine; D002166:Camptothecin