title: Vesicles from docosahexaenoic acid.
abstract: In dilute aqueous solution and at room temperature, cis-4,7,10,13,16,19-docosahexaenoic acid (DHA) self-assembles into vesicles (self-closed bilayers), if the molar ratio of the neutral form of DHA to anionic DHA is kept between 1:1 and 1:3 (corresponding to a bulk pH between 8.5 and 9.2 for a system with 10 mM DHA). By using polycarbonate membrane extrusion, stable unilamellar DHA vesicles with an average diameter of 80 nm can be prepared at pH 8.8. Cryo-transmission electron microscopy indicates that the width of the DHA bilayers in the vesicles is clearly below twice the length of an extended DHA molecule, indicating a high conformational flexibility of DHA within the vesicle bilayer. These DHA bilayers have a similar thickness like bilayers of vesicles prepared at pH 8.5 from oleic acid (cis-9-octadecenoic acid). Using calcein as fluorescent reference compound, it is shown that water-soluble molecules can be encapsulated inside DHA vesicles which may make them interesting for medical or food applications.
authors.affiliation: Department of Materials, ETH, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich, Switzerland.
authors.forename: Trishool
authors.initials: T
authors.lastname: Namani
authors.forename: Takashi
authors.initials: T
authors.lastname: Ishikawa
authors.forename: Kenichi
authors.initials: K
authors.lastname: Morigaki
authors.forename: Peter
authors.initials: P
authors.lastname: Walde
mesh_terms: D003102:Colloids; D020285:Cryoelectron Microscopy; D004281:Docosahexaenoic Acids / Q000737:chemistry*; D005452:Fluoresceins / Q000737:chemistry; D046529:Microscopy, Electron, Transmission; D015394:Molecular Structure; D017186:Titrimetry
chemical_list: D003102:Colloids; D005452:Fluoresceins; D004281:Docosahexaenoic Acids; C007740:fluorexon