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Water activity in lamellar stacks of lipid bilayers: "Hydration forces" revisited

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Autor(es):
Rubim, R. Leite ; Gerbelli, B. B. ; Bougis, K. ; Pinto de Oliveira, C. L. ; Navailles, L. ; Nallet, F. ; de Oliveira, E. Andreoli
Número total de Autores: 7
Tipo de documento: Artigo Científico
Fonte: EUROPEAN PHYSICAL JOURNAL E; v. 39, n. 1, p. 11-pg., 2016-01-25.
Resumo

Water activity and its relationship with interactions stabilising lamellar stacks of mixed lipid bilayers in their fluid state are investigated by means of osmotic pressure measurements coupled with small-angle X-ray scattering. The (electrically neutral) bilayers are composed of a mixture in various proportions of lecithin, a zwitterionic phospholipid, and Simulsol, a non-ionic cosurfactant with an ethoxylated polar head. For highly dehydrated samples the osmotic pressure profile always exhibits the "classical" exponential decay as hydration increases but, depending on Simulsol to lecithin ratio, it becomes either of the "bound" or "unbound" types for more water-swollen systems. A simple thermodynamic model is used for interpreting the results without resorting to the celebrated but elusive "hydration forces". (AU)

Processo FAPESP: 11/16149-8 - Interações entre bicamadas de lipídios - o papel da constante de rigidez da membrana
Beneficiário:Rafael Leite Rubim
Modalidade de apoio: Bolsas no Brasil - Mestrado