Electrostatically induced undulations of lamellar DNA-lipid complexes

We consider DNA-cationic lipid complexes that form lamellar stacks of lipid bilayers with parallel DNA strands intercalated in beta-een. We calculate the electrostatically induced elastic deformations of the lipid bilayers. I t is found drat the membranes undulate with a periodicity that is set by th e DNA interaxial distance. As a consequence the lamellar repeat distance ch anges resulting in a swelling or compression of the lamellar stack. Such un dulations may be responsible for the intermembrane coupling between DNA str ands in different layers as it is observed experimentally.