Figure 1.

Top view of lipid bilayer of initially ca. 25 × 29 nm (2304) lipids at six different times during the simulation: A) 1700 ps, onset of first pore formation B) 2040 ps, second pore forming, C) 2600 ps, D) 2800 ps, E) 2990 ps, F) 3600 ps. Sideviews, showing the increasing curvature of the bilayer: G) 0 ps, H) 1700 ps, I) 2040 ps, J) 3600 ps. The simulation cell is periodic, so that effectively an infinite stack of bilayers is simulated, but only the central simulation cell is actually simulated. The lipids are shown as spacefilling, with red for the headgroups and blue for the chains in the central simulation cell. For clarity, parts of the periodic images in the x, y plane are also shown, with the headgroups in yellow and the chains in green. The potential is positive at the top of snapshots G-J relative to the bottom. In the same reference frame, views of snapshots A-F are from the top. Water is not shown. Molecular graphics images were made with VMD [37]. Animations of this event and of the events in figures 2 are available as supplementary material. The time in each snapshot is only given as an indication of how fast defects develop; because the process is stochastic the exact values are not reproducible.