title: Nanosecond field alignment of head group and water dipoles in electroporating phospholipid bilayers.
abstract: To investigate the mechanism of biological cell membrane electroporation at the nanosecond and nanometer scale, we tracked pore-forming lipids and water in molecular dynamics simulations of a palmitoyloleoylphosphatidylcholine bilayer in a minimum porating electric field. Although the field-generated torque tilts the mean head group dipole a few degrees away from its equilibrium, zero-field position relative to the bilayer plane, this change in conformation does not appear to contribute directly to the development of the pore-initiating aggregation of lipid head groups and water that leads to the formation of a membrane-spanning hydrophilic pore. Field-directed rotation of the head group dipoles in the plane of the incipient pore wall, in combination with water dipole and solvation interactions at the aqueous-lipid interface, is one component in the coordinated ensemble of electroporation events.
authors.affiliation: Ming Hsieh Department of Electrical Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, California 90089-0271, USA. vernier@mosis.com
authors.forename: P Thomas
authors.initials: PT
authors.lastname: Vernier
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Ziegler
mesh_terms: D003198:Computer Simulation; D018274:Electroporation / Q000379:methods; D057927:Hydrophobic and Hydrophilic Interactions; D008051:Lipid Bilayers / Q000737:chemistry*; D008958:Models, Molecular; D010743:Phospholipids / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D008051:Lipid Bilayers; D010743:Phospholipids; D014867:Water