Impact of Lipid Structural Variations on Bilayer Properties: A Coarse-Grained Molecular Dynamics Study

Abstract: The supramolecular assembly of lipids into bilayer membranes is essential for cellular structure and function. However, the impact of lipid structural variations such as acyl chain length, degree of unsaturation, and headgroup type on bilayer properties remains incompletely understood. This study employs coarse-grained molecular dynamics simulations using the Martini force field to investigate seven distinct lipid species, aiming to compute critical bilayer parameters including area per lipid, bilayer thickness, and lateral diffusion coefficients. Our simulations reveal that lipids with longer acyl chains exhibit increased bilayer thickness, while unsaturation introduces kinks in the acyl chains, generally reducing bilayer thickness and increasing the area per lipid. Lipids with unsaturated chains demonstrate higher lateral diffusion coefficients, enhancing membrane fluidity. Variations in headgroup chemistry significantly influence lipid packing and membrane dynamics. This investigation advances our understanding of membrane biophysics and has significant implications for the design of lipid-based systems in biomedical applications.