PNNL

Abstract

surfactant interaction pose experimental limitations and most often do not provide the overall picture, motivating the use of in silico models to study such phenomena at molecular scale. In this work, coarse grained molecular dynamics simulations have been employed to investigate how nonionic (alcohol ethoxylate (AE)) and anionic surfactants (alcohol ethoxy sulphate (AES)) interact with lipid bilayer liposome that mimic corneal epithelial membranes. The spherical liposome is composed of dipalmitoylphophatidylchline (DPPC), dioleoylphophatidylethanolamine (DOPE), dioleoylphosphatidylserine (DOPS), and cholesterol resembling the composition of the corneal epithelial cells’ membrane bilayer. The simulation consisted of varying degrees of representative surfactant compositions and two initial types of surfactant configurations within or outside the liposome. Our results reveal that both surfactants induce outer leaflet bulging, agreeing with membrane solubilization models. The higher ethoxylated of the two surfactants, AE, caused more consistent inner leaflet disruption than AES, resulting in significantly more water permeation and membrane thinning. In addition, both surfactants increase the later diffusion of lipids within the membrane layers, with higher ethoxylated AE showing stronger effect than AES. This study demonstrates how surfactant’s structure and localization influence bilayer membrane integrity, offering mechanistic insights into the irritation potential, thus guiding the rational design of effective surfactant-based formulations.