Curvature and Charge Modulations in Lamellar DNA−Lipid Complexes

To model the possible formation of coupled spatial corrugations and charge density modulations in lamellar DNA−lipid complexes, we use a free energy functional which includes the electrostatic, lipid mixing, and elastic degrees of freedom in a self-consistent manner. We find that the balance of forces favors membrane corrugations that are expected to be stable with respect to thermal membrane undulations for a certain range of lipid (charged and uncharged) composition. This may lead to locking between DNA strands in adjacent galleries of the complex. Furthermore, the possibility of membrane corrugations renders the lamellar complex more stable with respect to another, hexagonal, DNA−lipid phase.