Molecular Dynamics Simulation of Interaction between Functionalized Nanoparticles with Lipid Membranes: Analysis of Coarse-Grained Models

Abstract

We compare atomistic and two popular coarse-grained (POL- and BMW-MARTINI) models by studying the interaction between a cationic gold nanoparticle functionalized with primary alkane amines and a lipid bilayer that consists of either zwitterionic lipids or a mixture of zwitterionic and anionic lipids. In the atomistic simulations, the nanoparticle does not exhibit any notable affinity to the zwitterionic bilayer but readily binds to the 9:1 zwitterionic:anionic bilayer, and nanoparticle adsorption leads to local segregation of anionic lipids and slowing down of their diffusion. At the coarse-grained level, the POL-MARTINI model does not lead to nanoparticle-membrane binding for either bilayer system, while the BMW-MARTINI model leads to nanoparticle binding to both bilayers; with the BMW-MARTINI model, nanoparticle binding leads to much less demixing of zwitterionic and anionic lipids and moderately <i>higher</i> rates of lipid diffusion. Analysis of nanoparticle properties in solution reveals notable discrepancies in the interfacial charge and water distributions at the coarse-grained level that are likely relevant to their limitations in describing binding interactions with other (bio)molecules.