Study of Phospholipid/Graphene interfaces and the effect of substrate curvature on lipid morphology and dynamics.

Abstract

Phospholipids are an important class of lipids which are widely used as model platforms to study biological processes and interactions. They have been known to form stable interfaces with solid substrates like graphene, and these interfaces have potential applications in bio-sensing and targeted drug-delivery. In this paper, we perform molecular dynamics simulations of graphene supported lipid monolayers to characterize lipid properties in such interfaces. We observed substantial differences in lipid properties like tail order-parameter, density profile, diffusion rate, etc., between lipids in a supported monolayer and free-standing bilayer. Further, we studied these interfaces on sinusoidally deformed graphene substrates to understand the effect of curvature on the supported lipids. Here, we observed that the nature of substrate curvature—concave, convex or flat—can affect the lipid/substrate adhesion strength as well as induce structural and dynamical changes in the adsorbed lipid monolayer. Together, these results help characterize the properties of lipid/graphene interfaces, as well as understand the effect of substrate curvature on these interfaces, which can enable tuning of lipid properties for various sensor device and drug delivery applications.