Sliding Columnar Phase of DNA-Lipid Complexes

Abstract

We introduce a simple model for DNA-cationic-lipid complexes in which galleries between planar bilayer lipid lamellae contain DNA 2D smectic lattices that couple orientationally and positionally to lattices in neighboring galleries. We identify a new equilibrium phase in which there are long-range orientational but not positional correlations between DNA lattices. We discuss properties of this new phase such as its x-ray structure factor $S\left(\mathbf{r}\right)$, which exhibits unusual $\exp (-\mathrm{const}\times {ln}^2|\mathbf{r}|)$ behavior as a function of in-plane separation $\mathbf{r}$.