Fluctuations of Quasi-Two-Dimensional Smectics Intercalated between Membranes in Multilamellar Phases of DNA-Cationic Lipid Complexes

We theoretically elucidate lamellar phases of DNA-cationic lipid complexes as the very first realization of a decoupled phase of strongly fluctuating 2D smectic DNA manifolds weakly interacting across membranes. Because of couplings between adjacent 2D smectic Lₓ×Ly planes, recently observed ordinary 2D smectic behavior of DNA in-plane undulations, with 〈u²〉~Ly1/2~Lₓ, must cross over, at long scales, to a novel fluctuation behavior, with 〈u²〉~(lnLy)²~(lnLₓ)².