title: Bicosomes: bicelles in dilute systems.
abstract: Bicelles are discoidal phospholipid nanostructures at high lipid concentrations. Under dilute conditions, bicelles become larger and adopt a variety of morphologies. This work proposes a strategy to preserve the discoidal morphology of bicelles in environments with high water content. Bicelles were formed in concentrated conditions and subsequently encapsulated in liposomes. Later dilution of these new structures, called bicosomes, demonstrated that lipid vesicles were able to isolate and protect bicelles entrapped inside them from the medium. Characterization of systems before and after dilution by dynamic light-scattering spectroscopy and cryo-transmission electron microscopy showed that free bicelles changed in size and morphology, whereas encapsulated bicelles remained unaltered by the effect of dilution. Free and entrapped bicelles (containing the paramagnetic contrast agent gadodiamide) were injected into rat brain lateral ventricles. Coronal and sagittal visualization was performed by magnetic resonance imaging. Whereas rats injected with free bicelles did not survive the surgery, those injected with bicosomes did, and a hyperintensity effect due to gadodiamide was observed in the cerebrospinal fluid. These results indicate that bicosomes are a good means of preserving the morphology of bicelles under dilution conditions.
authors.affiliation: Departament de Tecnologia Química i de Tensioactius, Institut de Química Avançada de Catalunya, Consejo Superior de Investigaciones Científicas, Barcelona, Spain.
authors.forename: Gelen
authors.initials: G
authors.lastname: Rodríguez
authors.forename: Guadalupe
authors.initials: G
authors.lastname: Soria
authors.forename: Elisenda
authors.initials: E
authors.lastname: Coll
authors.forename: Laia
authors.initials: L
authors.lastname: Rubio
authors.forename: Lucyanna
authors.initials: L
authors.lastname: Barbosa-Barros
authors.forename: Carmen
authors.initials: C
authors.lastname: López-Iglesias
authors.forename: Anna M
authors.initials: AM
authors.lastname: Planas
authors.forename: Joan
authors.initials: J
authors.lastname: Estelrich
authors.forename: Alfons
authors.initials: A
authors.lastname: de la Maza
authors.forename: Olga
authors.initials: O
authors.lastname: López
mesh_terms: D000818:Animals; D001921:Brain / Q000033:anatomy & histology / Q000187:drug effects; D019786:Gadolinium DTPA / Q000008:administration & dosage / Q000494:pharmacology; D007276:Injections, Intraventricular; D008081:Liposomes / Q000737:chemistry* / Q000648:ultrastructure; D009682:Magnetic Resonance Spectroscopy; D008823:Micelles; D010743:Phospholipids / Q000737:chemistry*; D051381:Rats; D017208:Rats, Wistar; D012542:Scattering, Radiation; D014867:Water / Q000737:chemistry*
chemical_list: D008081:Liposomes; D008823:Micelles; D010743:Phospholipids; D014867:Water; C064925:gadodiamide; D019786:Gadolinium DTPA