Dissipative particle dynamics simulation of poly(ethylene oxide)–poly(ethyl ethylene) block copolymer properties for enhancement of cell membrane rupture under stress

Magnetic Fluid Hyperthermia (MFH) is an encouraging cancer treatment involving superparamagnetic nanoparticles coated with bio-active molecules. When placed in an oscillating magnetic field, the particles release heat into the tumor environment. The generally accepted mechanism of cell death is through hyperthermia, but it is plausible that destruction of the cell through mechanical means could also play a significant role. In this study, we examine mechanical disruption of a model cell membrane in the presence of a representative magnetic nanoparticle coating, the copolymer poly(ethylene oxide)–poly(ethyl ethylene) (PEO–PEE). Our goal is to determine the effect of polymer properties on the mechanical rupture of a cell membrane under stress. Using dissipative particle dynamics, we create an interacting system of dipalmitoylphosphatidylcholine lipids, PEO–PEE polymers, and water and apply an incremental tension until bilayer rupture occurs. Our findings show that the optimal structure of the block copolymers to enhance rupture is relatively short polymers with a hydrophobic–hydrophilic–hydrophobic block structure containing a high hydrophilic content. Additionally, we compare the energy necessary to rupture a cell membrane with the magnetostatic energy of magnetic nanoparticles in MFH and our results indicate that nanoparticle sizes of the order of those currently used in standard MFH treatment produce enough energy for mechanical rupture, thus suggesting that mechanical means may be exploited in MFH to enhance the destruction of tumor cells.

► We developed a coarse-grained molecular model in magnetic fluid hyperthermia.
► Polymers coating magnetic nanoparticles interact with a lipid bilayer under stress.
► Hydrophobic triblock-copolymers are most effective at rupturing a lipid bilayer.