A new model for lipid monolayer and bilayers based on thermodynamics of irreversible processes

PINTO, A. E.; , DISALVO. E ANIBAL

PLOS ONE

PUBLIC LIBRARY SCIENCE

Lugar: San Francisco; Año: 2019 vol. 14 p. 1 - 25

1932-6203

O. A. Pinto1, E. A. DisalvoID2*1 Instituto de Bionanotecnologı´a del NOA (INBIONATEC), Universidad Nacional de Santiago de Estero(UNSE- CONICET), Villa el Zanjo´n, Santiago del Estero, Argentina, 2 Laboratorio de Biointerfases ySistemas Biomime´ticos, Centro de Investigaciones en Biofisica Aplicada y Alimentos (CIBAAL) (UNSECONICET), Villa el Zanjo´n, Santiago del Estero, Argentina* disalvoanibal@yahoo.com.arAbstractLipid monolayers are used as experimental model systems to study the physical chemicalproperties of biomembranes. With this purpose, surface pressure/area per molecule isotherms provide a way to obtain information on packing and compressibility properties of thelipids. These isotherms have been interpreted considering the monolayer as a two dimensional ideal or van der Waals gas without contact with the water phase. These modelisticapproaches do not fit the experimental results. Based on Thermodynamics of IrreversibleProcesses (TIP), the expansion/compression process is interpreted in terms of coupledphenomena between area changes and water fluxes between a bidimensional solution ofhydrated head groups in the monolayer and the bulk solution. The formalism obtained canreproduce satisfactorily the surface pressure/area per lipid isotherms of monolayer in different states and also can explain the area expansion and compression produced in particlesenclosed by bilayers during osmotic fluxes. This novel approach gives relevance to the lipidwater interaction in restricted media near the membrane and provides a formalism to understand the thermodynamic and kinetic response of biointerphases to biological effectors.