EDTA-induced self-assembly of cationic lipid-DNA multilayers near a monolayer-covered air-water interface.

The presence of EDTA in the suspending buffer can induce the formation of multilayer structures from a mixture of the cationic lipid 3beta[N-(N',N'-dimethylaminoethane)-carbamoyl] cholesterol and the zwitterionic 'helper' lipid 1, 2-dimyristoyl-sn-glycero-3-phosphocholine with DNA. The resulting structures consist of stacks of alternating sheets of lipid bilayer with intercalated DNA. In the absence of EDTA, only a single layer of DNA adsorbs to the lipid membrane. The buffer composition therefore influences the morphology of the lipid-aggregate/DNA assembly, which was not known to date.