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Interactions between lipid bilayers - the role of the membrane bending rigidity constant

Grant number: 11/16149-8
Support type:Scholarships in Brazil - Master
Effective date (Start): October 01, 2012
Effective date (End): April 30, 2014
Field of knowledge:Physical Sciences and Mathematics - Physics - Condensed Matter Physics
Principal researcher:Elisabeth Andreoli de Oliveira
Grantee:Rafael Leite Rubim
Home Institution: Instituto de Física (IF). Universidade de São Paulo (USP). São Paulo , SP, Brazil


Changes in the chemical composition of the membrane are responsible for changes in their mechanical properties that are manifested in different forms of three-dimensional organization and influence several biological processes such as, for example, the fusion of membranes. In addition to the van der Waals forces and the hydration force, undulation fluctuations contribute to a steric repulsive force that results in an effective potential of interaction in which certain conditions the secondary minimum may disappear by setting a seamless transition from one state connected of the membranes to a state not connected with the membranes separated. The objective of this study is to investigate experimentally the role of flexibility of the membrane in the structure of the lamellar phase. We intend to systematically vary the composition of the membrane, introducing co-surfactant which makes it more flexible. Through experiments of X-ray scattering (SAXS), with samples under a given osmotic pressure, we have access to experimental structural parameters that characterize the arrangement of the bilayers, such as lamellar periodicity, thickness of the aqueous layer, thickness of the bilayer and average quadratic width of the fluctuations. Using theoretical models available in the literature we can determine parameters that characterize the interactions, as the Hamaker constant, the bending rigidity modulus of the membrane and the extent of hydration forces. (AU)

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Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
RUBIM, R. LEITE; GERBELLI, B. B.; BOUGIS, K.; PINTO DE OLIVEIRA, C. L.; NAVAILLES, L.; NALLET, F.; DE OLIVEIRA, E. ANDREOLI. Water activity in lamellar stacks of lipid bilayers: ``Hydration forces{''} revisited. EUROPEAN PHYSICAL JOURNAL E, v. 39, n. 1 JAN 25 2016. Web of Science Citations: 3.
BOUGIS, K.; RUBIM, R. LEITE; ZIANE, N.; PEYENCET, J.; BENTALEB, A.; FEVRIER, A.; OLIVEIRA, C. L. P.; ANDREOLI DE OLIVEIRA, E.; NAVAILLES, L.; NALLET, F. Stabilising lamellar stacks of lipid bilayers with soft confinement and steric effects. EUROPEAN PHYSICAL JOURNAL E, v. 38, n. 7 JUL 16 2015. Web of Science Citations: 4.
GERBELLI, BARBARA B.; RUBIM, RAFAEL L.; SILVA, EMERSON R.; NALLET, FREDERIC; NAVAILLES, LAURENCE; OLIVEIRA, CRISTIANO L. P.; DE OLIVEIRA, ELISABETH A. Steric-Induced Effects on Stabilizing a Lamellar Structure. Langmuir, v. 29, n. 45, p. 13717-13722, NOV 12 2013. Web of Science Citations: 4.
Academic Publications
(References retrieved automatically from State of São Paulo Research Institutions)
RUBIM, Rafael Leite. Study of interactions between lipid membranes by SAXS experiments: the role of the composition. 2014. Master's Dissertation - Universidade de São Paulo (USP). Instituto de Física (IF/SBI) São Paulo.

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