Shape modification of phospholipid vesicles induced by high pressure: influence of bilayer compressibility.

Laurent Beney (1) , Jean-Marie Perrier-Cornet (1) , M. Hayert (1) , P. Gervais (1)

1 Laboratoire de génie des procédés alimentaires et biotechnologiques

Giant vesicles composed of pure egg yolk phosphatidylcholine (EYPC) or containing cholesterol (28 mol%) have been studied during a high hydrostatic pressure treatment to 285 MPa by microscopic observation. During pressure loading the vesicles remain spherical. A shape transition consisting of budding only occurs on the cholesterol-free vesicles during pressure release. The decrease in the volume delimited by the pure EYPC bilayer between 0.1 and 285 MPa was found to be 16% of its initial volume, whereas the bulk compression of water in this pressure range is only 10%. So the compression at 285 MPa induced a water exit from the pure EYPC vesicle. The shape transition of the EYPC vesicle during pressure release is attributed to an increase in its area-to-volume ratio caused by the loss of its water content during compression. Because bulk compression of the cholesterol-containing vesicle is close to that of water, no water transfer would be induced across the bilayer and the vesicle remains spherical during the pressure release.

Mots clés: Cholesterol; Lipid Bilayers; Microscopy; Phase-Contrast; Phosphatidylcholines; Surface Properties

Mots clés: Hydrostatic Pressure; Molecular Conformation

Domaines: Biophysique [physics.bio-ph]; Génie des procédés; Bactériologie

Laurent Beney, Jean-Marie Perrier-Cornet, M. Hayert, P. Gervais. Shape modification of phospholipid vesicles induced by high pressure: influence of bilayer compressibility.. Biophysical Journal, 1997, 72 (3), pp.1258-63. ⟨10.1016/S0006-3495(97)78772-1⟩. ⟨hal-00687309⟩