Physics of nanoporation and water entry driven by a high-intensity, ultrashort electrical pulse in the presence of membrane hydrophobic interactions

Abstract

The electroporation process in response to a high-intensity, ultrashort (\ensuremath{\sim}ns) electric pulse is probed based on molecular-dynamics simulations and shown to be a very rapid, twofold process. The electric driving force produces a Maxwell stress at the membrane and works to rearrange lipid dipoles and cause openings. However, water entry, which is essential for useful transport, is facilitated by electrowetting, which is an important component of the overall process. The molecular system can thus function as an electrically driven hydrophobic toggle switch that changes the water permeability. Furthermore, our results show that once they are fully formed, the nanopores do not close rapidly after cessation of the external electric field, in keeping with recent experiments. Finally, it is suggested that multiple pore formation in close proximity, as in situations involving high driving electric fields, is likely to be a rapid sequential process.