Membrane Perturbation and Lipid Flip-Flop Mediated by Graphene Nanosheet.

Graphene nanosheets (GNs) may spontaneously insert into cell membranes and perturb the dynamic organization of the surrounding lipid bilayer. Understanding the interaction between GNs and cell membranes is vital for learning how to avoid adverse effects and nanomedical applications. To better understand the nature of such perturbations, we performed molecular dynamics simulations to provide molecular details about the molecular mechanism. In this study, we observed two typical interaction states of the GN-membrane systems. Both states have different effects on the cell membrane (lipid density, membrane thickness, and the mobility of phospholipids). Of great interest is that the insertion of GNs could generate a liquid-ordered domain and dramatically reduce the rate of lipid flip-flop. A similar phenomenon could be found in the GN adhesion states. Thus, these results could facilitate molecular-level understanding of the cytotoxicity of nanomaterials and help future studies on designing personalized drugs and therapeutics for diseases.