Poration of Lipid Bilayers by Shock-Induced Nanobubble Collapse

Abstract

Sonoporation is a promising noninvasive drug- and gene-delivery approach, in which cavitation bubbles generated by ultrasound are used to enhance the cell membrane permeability. We have performed multimillion-atom molecular dynamics (MD) simulations to study the impact of shock waves on nanobubbles in the vicinity of a dipalmitoylphosphatidylcholine (DPPC) bilayer. The MD simulations reveal that the nanojet impact generates shear flow of water on bilayer leaflets and pressure gradients across them, which transiently enhance the bilayer permeability by creating nanopores and water molecules translocation across the bilayer. Effects of nanobubble size and temperature on the porosity of lipid bilayers will be discussed.Fig.: Nanojet (blue, green and red are velocity streamlines) impact deforming the lipid membrane (yellow). The nanopore created in the membrane (blue) is shown in the bottom inset. The top inset shows the time evolution of lateral flow on the lipid membrane surface.View Large Image | View Hi-Res Image | Download PowerPoint Slide