title: Bilayer undulation dynamics in unilamellar phospholipid vesicles: effect of temperature, cholesterol and trehalose.
abstract: We report a combined dynamic light scattering (DLS) and neutron spin-echo (NSE) study on the local bilayer undulation dynamics of phospholipid vesicles composed of 1,2-dimyristoyl-glycero-3-phosphatidylcholine (DMPC) under the influence of temperature and the additives cholesterol and trehalose. The additives affect vesicle size and self-diffusion. Mechanical properties of the membrane and corresponding bilayer undulations are tuned by changing lipid headgroup or acyl chain properties through temperature or composition. On the local length scale, changes at the lipid headgroup influence the bilayer bending rigidity κ less than changes at the lipid acyl chain: We observe a bilayer softening around the main phase transition temperature Tm of the single lipid system, and stiffening when more cholesterol is added, in concordance with literature. Surprisingly, no effect on the mechanical properties of the vesicles is observed upon the addition of trehalose.
authors.affiliation: Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin, Hahn-Meitner Platz 1, 14109 Berlin, Germany; Radiation Science and Technology, Delft University of Technology, Mekelweg 15, JB 2629 Delft, The Netherlands. Electronic address: B.A.Bruning@tudelft.nl.
authors.forename: Beate-Annette
authors.initials: BA
authors.lastname: Brüning
authors.affiliation: Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin, Hahn-Meitner Platz 1, 14109 Berlin, Germany.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Prévost
authors.affiliation: Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin, Hahn-Meitner Platz 1, 14109 Berlin, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Stehle
authors.affiliation: Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin, Hahn-Meitner Platz 1, 14109 Berlin, Germany.
authors.forename: Roland
authors.initials: R
authors.lastname: Steitz
authors.affiliation: Time-of-Flight and High Resolution, Institut Laue Langevin, B. P. 156, 38042 Grenoble, Cedex 9, France.
authors.forename: Peter
authors.initials: P
authors.lastname: Falus
authors.affiliation: Time-of-Flight and High Resolution, Institut Laue Langevin, B. P. 156, 38042 Grenoble, Cedex 9, France.
authors.forename: Bela
authors.initials: B
authors.lastname: Farago
authors.affiliation: Physical and Biophysical Chemistry, Bielefeld University, Universitätsstr. 25, 33615 Bielefeld, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Hellweg
mesh_terms: D002784:Cholesterol / Q000737:chemistry*; D004134:Dimyristoylphosphatidylcholine / Q000737:chemistry*; D008051:Lipid Bilayers / Q000737:chemistry*; D014199:Trehalose / Q000737:chemistry*
chemical_list: D008051:Lipid Bilayers; D002784:Cholesterol; D014199:Trehalose; D004134:Dimyristoylphosphatidylcholine
keywords: Fluctuations; Neutron spectroscopy; Vesicles