Schematic structures of lipid cubic phases. Ia3d, Pn3m and Im3m are the inverse bicontinuous cubic phases reported so far experimentally. Fd3m is an inverse micellar cubic phase found with mixtures of DOPC and glycerol. The two types of inverse micelle (open and grey spheres) with their polyhedral shapes are indicated on each site of the cubic lattice. Adapted from reference . Reproduced by permission of the PCCP Owner Societies.