A Dissipative Particle Dynamics Study On The Interaction Between Cell Membrane And Graphene Nanocone

The interaction of graphene-based materials with cell membranes plays an important role in the development of graphene-enabled biomedical technologies as well as the management of graphene health and safety issues.Though the fundamental behavior of cell membranes exposed to graphene microsheets has been studied,very little is known about the behavior of graphene nanocone in cell environment.Graphene nanocone has special topology compared to ultrathin 2D synthetic materials.Here we perform coarse-grained molecular dynamics(CGMD)simulations to investigate the interactions between graphene nanocones with cell membranes.Graphene nanocones with five different apex angles are constructed as experimentally observed.The simulations show that nanocone can automatically penetrate into the cell membrane either from the apex or the bottom edge which are controlled by the apex angle and the size of nanocone.A penetration model is proposed for the energy barrier of these two entry modes,and the dependence of entry barrier on apex angle and size of nanocone are studied.For the apex entry mode,the nanocones tend to vertically penetrate into the cell membrane.And for the edge entry mode,the nanocones penetrate into the cell membrane at an inclined orientation to reduce entry barrier.In addition,we adopt dissipative particle dynamics simulations to analyze the evolution of interaction force and free energy as the graphene covered AFM probe indents across a lipid bilayer.Our results show that graphene covered on the AFM probe can cause severe deformation of cell membrane which drives the lipid molecule to adsorb and diffuse at the surface of graphene.Breakthrough force and free energy analysis are calculated for the effects of tip shape,size and surface hydrophobicity on the piercing behaviors of graphene covered AFM.The deformation of cell membrane can decrease the dependency of breakthrough force on tip shape.The analysis of surface functionalization suggests that the horizontal patterns on graphene can change the preferred orientation in the penetration process but the vertical patterns on graphene may disrupt the cell membrane.These findings provide useful guidelines for the molecular design of graphene materials for controllable cell penetrability.