Nanosecond field alignment of head group and water dipoles in electroporating phospholipid bilayers.
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.
Vernier
P Thomas
PT
Ming Hsieh Department of Electrical Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, California 90089-0271, USA. vernier@mosis.com
Ziegler
Matthew J
MJ
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*
D008051:Lipid Bilayers; D010743:Phospholipids; D014867:Water