title: Influence of High Pressure on the Bending Rigidity of Model Membranes.
abstract: Curvature is a fundamental lipid membrane property that influences many membrane-mediated biological processes and dynamic soft materials. One of the key parameters that determines the energetics of curvature change is the membrane bending rigidity. Understanding the intrinsic effect of pressure on membrane bending is critical to understanding the adaptation and structural behavior of biomembranes in deep-sea organisms as well as soft material processing. However, it has not previously been possible to measure the influence of high hydrostatic pressure on membrane bending energetics, and this bottleneck has primarily been due to a lack of technology platforms for performing such measurements. We have developed a new high-pressure microscopy cell which, combined with vesicle fluctuation analysis, has allowed us to make the first measurements of membrane bending rigidity as a function of pressure. Our results show a significant increase in bending rigidity at pressures up to 40 MPa. Above 40 MPa, the membrane mechanics become more complex. Corresponding small and wide-angle X-ray diffraction shows an increase in density and thickness of the bilayer with increasing pressure which correlates with the micromechanical measurements. These results are consistent with recent theoretical predictions of the bending rigidity as a function of hydrocarbon chain density. This technology has the potential to transform our quantitative understanding of the role of pressure in soft material processing, the structural behavior of biomembranes, and the adaptation mechanisms employed by deep-sea organisms.
authors.affiliation: †Department of Chemistry, Imperial College London, South Kensington Campus, London SW7 2AZ, U.K.
authors.forename: Sowmya
authors.initials: S
authors.lastname: Purushothaman
authors.affiliation: ‡Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, U.K.
authors.forename: Pietro
authors.initials: P
authors.lastname: Cicuta
authors.affiliation: †Department of Chemistry, Imperial College London, South Kensington Campus, London SW7 2AZ, U.K.
authors.forename: Oscar
authors.initials: O
authors.lastname: Ces
authors.affiliation: †Department of Chemistry, Imperial College London, South Kensington Campus, London SW7 2AZ, U.K.
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Brooks
mesh_terms: D002462:Cell Membrane; D055595:Mechanical Phenomena; D011312:Pressure; D013696:Temperature; D053835:Unilamellar Liposomes
chemical_list: D053835:Unilamellar Liposomes