title: Capacious and programmable multi-liposomal carriers.
abstract: Spherical polycationic brushes (SPBs) were synthesized by grafting polycationic chains onto 100 nm polystyrene particles. These particles were exposed to unilamellar egg-lecithin (EL) liposomes with a mean diameter of 40 nm that had been rendered anionic via the presence of 10 molar% of phosphatidylserine (PS(1-)). The liposomes also contained 30 mole% of a morpholinocyclohexanol-based lipid (MOCH) that undergoes a conformational flip when the pH is decreased from 7.0 to 5.0. Mixtures of SPBs and liposomes at pH 7 gave an electrostatically-driven complex possessing, on average, about 40 liposomes for each SPB particle. It was found that the bound liposomes rapidly release much of their contents when the pH is reduced from 7.0 to 5.0 owing mostly to a MOCH conformational change that creates defects in the bilayer membrane. The drop in pH does not, however, induce a separation of the liposomes from the SPBs. Around 50-60% of the liposome contents escape before, it is reasoned, lateral and transmembrane motion of the membrane components heals the defects and prevents further release. Remarkably, the liposomes complexed with SPB release their cargo much faster than the identical but non-complexed liposomes.
authors.affiliation: Department of Chemistry, M.V. Lomonosov Moscow State University, Leninskie Gory 1-3, 119991 Moscow, Russian Federation. yaroslav@genebee.msu.ru.
authors.forename: Alexander A
authors.initials: AA
authors.lastname: Yaroslavov
authors.forename: Andrey V
authors.initials: AV
authors.lastname: Sybachin
authors.forename: Olga V
authors.initials: OV
authors.lastname: Zaborova
authors.forename: Vasiliy A
authors.initials: VA
authors.lastname: Migulin
authors.forename: Vyacheslav V
authors.initials: VV
authors.lastname: Samoshin
authors.forename: Matthias
authors.initials: M
authors.lastname: Ballauff
authors.forename: Ellina
authors.initials: E
authors.lastname: Kesselman
authors.forename: Judith
authors.initials: J
authors.lastname: Schmidt
authors.forename: Yeshayahu
authors.initials: Y
authors.lastname: Talmon
authors.forename: Fredric M
authors.initials: FM
authors.lastname: Menger
mesh_terms: D000838:Anions / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D054709:Lecithins / Q000737:chemistry; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism; D008081:Liposomes / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D010316:Particle Size; D010718:Phosphatidylserines / Q000737:chemistry; D011073:Polyamines / Q000737:chemistry; D000071228:Polyelectrolytes; D011137:Polystyrenes / Q000737:chemistry; D055672:Static Electricity
chemical_list: D000838:Anions; D054709:Lecithins; D008051:Lipid Bilayers; D008081:Liposomes; D010718:Phosphatidylserines; D011073:Polyamines; D000071228:Polyelectrolytes; D011137:Polystyrenes