title: Direct visualization of dispersed lipid bicontinuous cubic phases by cryo-electron tomography.
abstract: Bulk and dispersed cubic liquid crystalline phases (cubosomes), present in the body and in living cell membranes, are believed to play an essential role in biological phenomena. Moreover, their biocompatibility is attractive for nutrient or drug delivery system applications. Here the three-dimensional organization of dispersed cubic lipid self-assembled phases is fully revealed by cryo-electron tomography and compared with simulated structures. It is demonstrated that the interior is constituted of a perfect bicontinuous cubic phase, while the outside shows interlamellar attachments, which represent a transition state between the liquid crystalline interior phase and the outside vesicular structure. Therefore, compositional gradients within cubosomes are inferred, with a lipid bilayer separating at least one water channel set from the external aqueous phase. This is crucial to understand and enhance controlled release of target molecules and calls for a revision of postulated transport mechanisms from cubosomes to the aqueous phase.
authors.affiliation: Interdisciplinary Centre for Electron Microscopy, Swiss Federal Institute of Technology (EPFL), Lausanne 1015, Switzerland.
authors.forename: Davide
authors.initials: D
authors.lastname: Demurtas
authors.affiliation: Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne 1015, Switzerland.
authors.forename: Paul
authors.initials: P
authors.lastname: Guichard
authors.affiliation: Department of Health Science and Technology, ETH Zurich, Zurich 8092, Switzerland.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Martiel
authors.affiliation: Department of Health Science and Technology, ETH Zurich, Zurich 8092, Switzerland.
authors.forename: Raffaele
authors.initials: R
authors.lastname: Mezzenga
authors.affiliation: Interdisciplinary Centre for Electron Microscopy, Swiss Federal Institute of Technology (EPFL), Lausanne 1015, Switzerland.
authors.forename: Cécile
authors.initials: C
authors.lastname: Hébert
authors.affiliation: Nestlé Research Center, Vers-Chez-Les-Blanc, Lausanne 1000, Switzerland.
authors.forename: Laurent
authors.initials: L
authors.lastname: Sagalowicz
mesh_terms: D020285:Cryoelectron Microscopy; D055032:Electron Microscope Tomography; D021621:Imaging, Three-Dimensional; D008051:Lipid Bilayers; D008055:Lipids; D050866:Liquid Crystals / Q000648:ultrastructure*; D050178:Monoglycerides; D053838:Scattering, Small Angle; D014867:Water
chemical_list: D008051:Lipid Bilayers; D008055:Lipids; D050178:Monoglycerides; D014867:Water