Supramolecular Liquid Crystallinity: Spherical Coils of Levan Surrounding Cylindrical Rods of DNA

Abstract

Levan, which adopts a compact spherical conformation in aqueous solution, can form a liquid crystalline phase if DNA is also present. We propose that supramolecular rodlike structures, assembled by the noncovalent aggregation of levan around DNA, stabilize the lyotropic phase. We describe a geometric model for the aggregates. The model is quantitatively consistent with the relative amounts of DNA and levan needed for liquid crystallinity, and it agrees qualitatively with the shape of the boundary between the isotropic and heterogeneous fields on an experimentally determined phase diagram.[S0031-9007 (97)05063-1] PACS numbers: 87.15.Da, 36.20.Fz, 61.25.Hq, 64.70.Md

Dense packing of spheres around rods in supramolecular aggregates

“…Recently, a new class of supramolecular liquid crystal (figure 1, centre) has been described, combining intrinsic rods and globular molecules [8]. The shape anisotropy of the aggregates is ensured by their rod-like molecular core (DNA in the model system), which is present at concentrations significantly lower than those normally associated with liquid crystalline solutions.…”