Chain length dependence of anomalous swelling in multilamellar lipid vesicles

Abstract

Using small-angle X-ray scattering, the repeat distance vs. temperature is measured for a homologous series of multilamellar vesicles of lecithins with varying acyl chain length in excess water condition around the lipid main transition. A systematic chain length dependence is found which is in accordance with a bending rigidity renormalization and critical unbinding of the lamellae close to the transition, as previously suggested in Hønger et al. [Phys. Rev. Lett. 72, 3911 (1994)].PACS. 87.16.-b Subcellular structure and processes -64.70.Md Transitions in liquid crystals -61.10.Eq X-ray scattering (including small-angle scattering)

Phase Behavior of Model Lipid Bilayers

“…2,24 Experimental work and theories suggest that the swelling could be caused by increased interactions between bilayers due to changes in the Helfrich undulation forces. [45][46][47][48][49][50] Approaching the transition temperature T m , the bilayer has a reduced bending rigidity and as a result the fluctuations of the bilayer increase. Due to these increased bilayer fluctuations the steric repulsion between bilayers increases.…”

Direct Visualization of Asymmetric Behavior in Supported Lipid Bilayers at the Gel-Fluid Phase Transition

“…The phase transition behavior from gel to fluid phase (L b to L a ) of phosopholipid membranes has been studied in great depth in the past (Korrenman and Posselt, 2000;Lewis et al, 1987;Marsh et al, 1977;Morrow and Davis, 1988;Prenner et al, 1999). However, due to the accessibility of sample forms, such studies are mainly conducted with lipid vesicles, both multilamellar (Janiak et al, 1976;Lewis and McElhaney, 1990) and unilamellar (Marsh et al, 1977;Metso, 2003).…”

DC13PC bilayers from anomalous swelling to main transition: An X-ray scattering investigation

“…The concept of a critical behavior intercepted by the first order chain melting transition has been proposed, criticalities being reduced and finally canceled as lipids with increasing chain length are considered [6]. Nonetheless, the interest in the description of the main transition in terms of a first order broadened one is long lived and, independently from the observation of the anomalous swelling behavior, it rather relies on calorimetric measurements on short-chain phosphocholines [11][12][13].…”

“…Apart from the overall change from an ordered to a disordered arrangement within the hydrocarbon core across the melting temperature region, the details of this transition depend on a number of parameters, first on the lipid and on its nano-organization [1]. Moreover, if observed in multilamellar structures, the transition seems to be accompanied by some criticalities, a feature that has strongly attracted the attention of both experimental and theoretical groups [2][3][4][5][6][7][8][9][10]. In particular, the observation of an anomalous swelling in multilayers, both dispersed (MLV, multilayer vesicles) or supported on flat surfaces (multistacks) in the region of the chain melting transition has been thoroughly addressed, and deserved a lot of experimental effort with various spectroscopic techniques, in order to verify which of the invoked structural and dynamic properties is at the basis of this peculiar behavior.…”