Swelling of a Sponge Lipid Phase via Incorporation of a Nonionic Amphiphile: SANS and SAXS Studies

Small-angle X-ray scattering (SAXS) is employed to establish the structure of a self-assembled lipid/water system formed in excess aqueous phase by pharmaceutical-grade glycerol monooleate (GMO). A nonionic guest component (octyl glucoside) is incorporated with the purpose to study the swelling of the structure under full hydration. Small-angle neutron scattering (SANS) is used for characterization of the micellar properties of the octyl glucoside amphiphile and glycerol monooleate. The obtained SAXS and SANS patterns indicate a sponge-type supramolecular organization of the investigated lipid material. Their analysis allows determination of the average cell-cell distances in the bicontinuous bilayer sponge that are essential for the encapsulation of biomolecules and drugs. In the presence of the guest octyl glucoside (OG) the average size of the sponge cells is increased by about 14%. This would be an advantageous feature for the application of sponge-type liquid crystalline carriers as protein drug delivery vehicles, nanostructured bioreactors, and peptide-encapsulating fluid nanomaterials.