title: Association of sugar-based carboranes with cationic liposomes: an electron spin resonance and light scattering study.
abstract: The possibility of cationic (di-oleoyltrimethylammonium propane, DOTAP)/(L-alpha-dioleoylphosphatidyl-ethanolamine, DOPE) liposomes to act as carriers of boronated compounds such as 1,2-dicarba-closo-dodecaboran(12)-1-ylmethyl](beta-D-galactopyranosyl)-(1-->4)-beta-D-glucopyranoside and 1,2-di-(beta-D-gluco-pyranosyl-ox)methyl-1,2-dicarba-closo-dodeca-borane(12) has been investigated by Electron Spin Resonance (ESR) of n-doxyl stearic acids (n-DSA) and Quasi-Elastic Light Scattering (QELS). Both these carboranes have potential use in Boron Neutron Capture Therapy (BNCT), which is a targeted therapy for the treatment of radiation resistant tumors. They were shown to give aggregation both in plain water and in saline solution. Carborane aggregates were, however, disrupted when DOTAP/DOPE liposome solutions were used as dispersing agents. The computer analysis of the ESR spectra from carborane-loaded liposomes allowed to establish an increase of the order degree in the liposome bilayer with increasing carborane concentration, together with a decreased mobility. The same discontinuities of both correlation time and order parameter with respect to temperature variations were observed in carborane-containing and carborane-free liposomes. This suggested that a homogeneous dispersion of nitroxides and carboranes occurred in the liposome bilayer. The ESR line shape analysis proved that no dramatic changes were induced in the liposome environment by carborane insertion. QELS data showed that the overall liposome structure was preserved, with a slight decrease in the mean hydrodynamic radius and increase in polydispersity caused by the guest molecules.
authors.affiliation: Dipartimento di Chimica, Laboratorio di Chimica Fisica delle Interfasi, Università di Firenze, 50019, Sesto Fiorentino no, Florence, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Morandi
authors.forename: Sandra
authors.initials: S
authors.lastname: Ristori
authors.forename: Debora
authors.initials: D
authors.lastname: Berti
authors.forename: Luigi
authors.initials: L
authors.lastname: Panza
authors.forename: Aldo
authors.initials: A
authors.lastname: Becciolini
authors.forename: Giacomo
authors.initials: G
authors.lastname: Martini
mesh_terms: D016754:Boron Neutron Capture Therapy; D002241:Carbohydrates / Q000737:chemistry; D002412:Cations / Q000378:metabolism*; D004578:Electron Spin Resonance Spectroscopy; D005229:Fatty Acids, Monounsaturated / Q000494:pharmacology; D005456:Fluorescent Dyes / Q000494:pharmacology; D008027:Light; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism; D008081:Liposomes / Q000737:chemistry / Q000378:metabolism*; D008280:Magnetics; D008956:Models, Chemical; D009569:Nitric Oxide / Q000737:chemistry; D010714:Phosphatidylethanolamines / Q000737:chemistry; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology; D012542:Scattering, Radiation; D013229:Stearic Acids / Q000737:chemistry; D013696:Temperature; D013997:Time Factors
chemical_list: C410262:1,2-dioleoyl-glycero-3-phosphatidyl ethanolamine; D002241:Carbohydrates; D002412:Cations; D005229:Fatty Acids, Monounsaturated; D005456:Fluorescent Dyes; D008051:Lipid Bilayers; D008081:Liposomes; D010714:Phosphatidylethanolamines; D000644:Quaternary Ammonium Compounds; D013229:Stearic Acids; D009569:Nitric Oxide; C031183:stearic acid; C070046:1,2-dioleoyloxy-3-(trimethylammonium)propane