Dipolar interactions between domains in lipid monolayers at the air-water interface

A. BANCHIO; N. WILKE; E. RUFEIL FIORE

SOFT MATTER

ROYAL SOC CHEMISTRY

Lugar: CAMBRIDGE; Año: 2016 vol. 12 p. 4769 - 4777

1744-683X

A great variety of biologically relevant monolayers present phase coexistence characterized bydomains formed by lipids in an ordered phase state dispersed in a continuous, disordered phase.The difference in surface densities between these phases originates inter?domain dipolar interactions,which are relevant for the determination of the spacial distribution of domains, as wellas their dynamics. In this work, we propose a novel manner of estimating the dipolar repulsionusing a passive method that involves the analysis of images of the monolayer with phase coexistence.The method is based on the comparison of the pair correlation function obtained fromexperiments with that obtained from Brownian dynamics simulations of a model system. As anexample, we determined the difference in dipolar density of a binary monolayer of DSPC/DMPCat the air?water interface from the analysis of the radial distribution of domains, and the resultsare compared with those obtained by surface potential determinations. A systematic analysisfor experimentally relevant parameter range is given, which may be used as a working curve forobtaining the dipolar repulsion in different systems.