Ligand-Mediated Interaction of Nanoparticles with Lipid Membranes

While many studies are performed on the effect of ligands on the adhesion and endocytosis of NPs, the effects of ligand length and surface density on the NPs' interaction with lipid membranes are poorly investigated. Here, a computational investigation is presented, based on molecular dynamics of a coarse-grained implicit-solvent model, of the interaction between ligand-decorated spherical NPs and lipid membranes. Specifically,the case is considered where the ligands interact attractively with lipid membranes only through their ends. In particular, the effects of ligand grafting density, ligand length, and strength of ligand-lipid interaction is investigated on the degree of wrapping of the NP by the membrane and on the morphology of the membrane close to the NP. Whereas the degree of wrapping is found to increase with increasing the grafting density for a given interaction strength and ligand length, it decreases with ligand length for a given grafting density and interaction strength. For moderate values of the adhesion strength and long ligands, it is found that the end ligands form long linear clusters, which lead to an anisotropic conformation of the membrane around the NP. For short ligands, the wrapping of the membrane around the NP is almost complete, with the wrapped NP showing a regular faceted structure for high adhesion strength.