Influence of the multibody interactions in a lipidic membrane model

Abstract

This work presents a new model of lipid membrane that introduces multibody lateral interactions in the cooperative parameter ω. The traditional and widely-used assumption of pairwise interactions between neighboring lipids is replaced by a more general approach. In the literature, most models consider ω as a single interaction parameter while ignoring multibody interactions, where van der Waals forces, hydrogen bonding, and ionic bonding between acyl chains and head groups are present. In this study, a two-state model is considered where the gel-fluid interaction energy is parameterized and depends on the number of gel-fluid pairs in their nearest neighbors. Monte Carlo simulations in the grand canonical ensemble are used to analyze order parameters, heat capacity, and other parameters in the vicinity of the gel-fluid phase transition. The behavior is analyzed and discussed in terms of domain formation and the emergence of new ordered structures in the system.