title: Impact of membrane fluidity on steric stabilization by lipopolymers.
abstract: In this work, the impact of lipid lateral mobility on the steric interaction between membranes containing poly(ethylene glycol) (PEG) functionalized lipids was investigated using the surface force apparatus. The force-distance profiles show the presence of electrostatic and steric repulsion that arise from the presence of negatively charged PEG functionalized lipids. Fluid-phase bilayers have high lateral diffusion relative to gel-phase bilayers; however, a quantitative comparison of the interaction forces between membranes in these two different phase states demonstrates a reduced rate of diffusion in the fluid phase for the PEG-lipids under constrained geometries. Thus, the amount of polymer in the contact zone can be modulated and is reduced with fluid membranes; however, complete exclusion was not achieved. As a result, the steric repulsion afforded by PEG chains or binding affinity of ligated PEG chains can only be modestly tailored by the phase state of the liposome.
authors.affiliation: Department of Chemical Engineering and Materials Science, University of California, Davis, One Shields Avenue, Davis, California 95616, USA.
authors.forename: Raquel
authors.initials: R
authors.lastname: Orozco-Alcaraz
authors.forename: Tonya L
authors.initials: TL
authors.lastname: Kuhl
mesh_terms: D008051:Lipid Bilayers / Q000737:chemistry*; D008560:Membrane Fluidity; D011092:Polyethylene Glycols / Q000737:chemistry*; D055672:Static Electricity
chemical_list: D008051:Lipid Bilayers; D011092:Polyethylene Glycols