Stabilization of membrane pores by packing.

We present a model for pore stabilization in membranes without surface tension. Whereas an isolated pore is always unstable (since it either shrinks, tending to reseal, or grows without bound until membrane disintegration), it is shown that excluded volume interactions in a system of many pores can stabilize individual pores of a given size in a certain range of model parameters. For such a multipore membrane system, the distribution of pore size and associated pore lifetime are calculated within the mean-field approximation. We predict that, above the temperature T(m), when the effective line tension becomes negative, the membrane exhibits a dynamic sievelike porous structure.