Water Bridges in Electropermeabilized Phospholipid Bilayers

Pulsed electric field permeabilization of living cell membranes forms the basis for widely used biotechnology protocols and an increasing number of therapeutic applications. Experimental observations of artificial membranes and whole cells and molecular and analytical models provide evidence that a membrane-spanning, hydrophilic, conductive pore can form in nanoseconds. An external electric field lowers the energy barrier for this stochastic process, reducing the mean time for pore formation and increasing the pore areal density. Molecular dynamic simulations reveal the key role played by interfacial water in electropermeabilization. These model systems, validated in the laboratory, are deepening our understanding of the factors governing pore initiation, construction, and lifetime, knowledge that will translate to enhanced utilization of this method in biomedicine and bioengineering.