A pore creation in a triangular network model membrane.

Membrane electroporation seems to be a useful method for delivery of biological active compounds into the cell. Although it is known that this phenomenon is sensitive to the electric field intensity, duration of the electric pulse and its shape, it is not fully understood. In some theoretical descriptions it is postulated that a hydrophobic pore appears at an early stage of pore creation. Here we show how to construct a hydrophilic pore structure connecting two parallel triangular networks modeling lipid membrane. It would be useful in Monte Carlo simulation studies on electroporation. In our model the pore appearance requires only movement of one lipid molecule. At the same time the chains of the second lipid molecule should occupy two nodes, one in each network to compensate the differences in chain packing densities when electric field is applied. In consequence the hydrated polar head should be placed in a hydrophobic part of the membrane giving rise to the hydrophilic pore. We also discuss the relation between the pore diameter and its shape.