Directed self-assembly of lipid A-phosphate lattices

Non-spherical lipid A-phosphate and approximants self-assembled to form body-centered and face centered cubic liquid crystals. These materials were isolated as defined clusters by size exclusion chromatography (SEC) and density gradient centrifugation and were studied as electrostatically stabilized aqueous dispersions. High resolution transmission electron microscopy (HRTEM), selected area diffraction (SADP) experiments, light scattering (LS) and small-angle X-ray scattering (SAXS) measurements on the various self-assembled lipid A-phosphate nanocrystals reveal equilibrium phase structures, which appear as crystal approximants of dodecahedra, icosahedra or truncated octahedral structures. A volume-fraction-sensitive transition of lipid A-diphosphates is observed between phase-separated-fatty-acid chains and a mixed honeycomb phase (Kagomé lattice).