Nanostructure Formation\nin Glycerolipid Films during\nEnzymatic Hydrolysis: A GISAXS Study

Responsive nanostructured films from food-grade lipids\ncan be valuable\nfor food, pharmaceutical, and biotechnological science. Lyotropic\nliquid crystalline structures that respond to enzymes in their environment\ncan, for instance, be innovated as drug delivery platforms or biosensors.\nHowever, the structural changes that such films undergo during enzymatic\nreactions with lipase are not yet understood. This work demonstrates\nthe preparation of mesostructured lipid films from the food-grade\nlipids glycerol monooleate (GMO) and triolein on silicon wafers and\ntheir digestion with pancreatic lipase using time-resolved synchrotron\ngrazing incidence small-angle X-ray scattering (GISAXS). The film\nstructure is compared with the corresponding GMO/triolein bulk phases\nin excess water. Increasing the GMO/triolein ratio in the film makes\nit possible to modulate the structure of the films from oil coatings\nto inverse hexagonal and inverse bicontinuous cubic films. Pancreatic\nlipase triggered swelling of the internal film nanostructure and eventually\nstructural transformation inside the film. Orientation and reorientation\nof the internal film structure relative to the silicon wafer surface\nwere observed during the preparation of the films and their digestion.\nThe findings contribute to the understanding of self-assembly in thin\nfilms and guide the development of enzyme-responsive coatings for\nthe functional modification of various substrates.