title: Properties of lipid electropores I: Molecular dynamics simulations of stabilized pores by constant charge imbalance.
abstract: Molecular dynamics (MD) simulations have become a powerful tool to study electroporation (EP) in atomic detail. In the last decade, numerous MD studies have been conducted to model the effect of pulsed electric fields on membranes, providing molecular models of the EP process of lipid bilayers. Here we extend these investigations by modeling for the first time conditions comparable to experiments using long (μs-ms) low intensity (~kV/cm) pulses, by studying the characteristics of pores formed in lipid bilayers maintained at a constant surface tension and subject to constant charge imbalance. This enables the evaluation of structural (size) and electrical (conductance) properties of the pores formed, providing information hardly accessible directly by experiments. Extensive simulations of EP of simple phosphatidylcholine bilayers in 1M NaCl show that hydrophilic pores with stable radii (1-2.5 nm) form under transmembrane voltages between 420 and 630 mV, allowing for ionic conductance in the range of 6.4-29.5 nS. We discuss in particular these findings and characterize both convergence and size effects in the MD simulations. We further extend these studies in a follow-up paper (Rems et al., Bioelectrochemistry, Submitted), by proposing an improved continuum model of pore conductance consistent with the results from the MD simulations.
authors.affiliation: Université de Lorraine, UMR 7565, F-54506 Vandoeuvre les Nancy, France; Department of Information Engineering, Electronics and Telecommunications (D.I.E.T), Sapienza University of Rome, 00184 Rome, Italy; Center for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia, 00161 Rome, Italy.
authors.forename: Maura
authors.initials: M
authors.lastname: Casciola
authors.affiliation: Université de Lorraine, UMR 7565, F-54506 Vandoeuvre les Nancy, France.
authors.forename: Marina A
authors.initials: MA
authors.lastname: Kasimova
authors.affiliation: University of Ljubljana, Faculty of Electrical Engineering, Tržaška 25, SI-1000 Ljubljana, Slovenia.
authors.forename: Lea
authors.initials: L
authors.lastname: Rems
authors.affiliation: Université de Lorraine, UMR 7565, F-54506 Vandoeuvre les Nancy, France; Department of Information Engineering, Electronics and Telecommunications (D.I.E.T), Sapienza University of Rome, 00184 Rome, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Zullino
authors.affiliation: Department of Information Engineering, Electronics and Telecommunications (D.I.E.T), Sapienza University of Rome, 00184 Rome, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Apollonio
authors.affiliation: Université de Lorraine, UMR 7565, F-54506 Vandoeuvre les Nancy, France; CNRS, UMR 7565, F-54506 Vandoeuvre les Nancy, France. Electronic address: mounir.tarek@univ-lorraine.fr.
authors.forename: Mounir
authors.initials: M
authors.lastname: Tarek
mesh_terms: D018274:Electroporation / Q000379:methods; D057927:Hydrophobic and Hydrophilic Interactions; D008051:Lipid Bilayers / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D010713:Phosphatidylcholines / Q000737:chemistry*
chemical_list: D008051:Lipid Bilayers; D010713:Phosphatidylcholines; C028694:1-palmitoyl-2-oleoylphosphatidylcholine
keywords: Conductance; Electroporation; Membrane model; Millisecond pulses; Pore