Real-Time Monitoring of Curcumin Release with a Lipid-Curcumin-Loaded Silica Colloidal Crystal Film Using Optical Interferometry

A novel efficacious strategy for real-time monitoring of the release of hydrophobic cargo curcumin (molecule model nutraceuticals) from a lipid-curcumin-loaded silica colloidal crystal (L(Cur)-SCC) film controlled by lipase was developed. Curcumin was dispersed in a proportion of a digestible lipid complex (glycerol trioleate and glycerol tristearate) to prepare a lipid-curcumin complex and then loaded into the SCC film by a capillary to prepare an L(Cur)-SCC film. Lipase-triggered degradation of the digestible lipid complex resulted in curcumin release being tracked in real-time by ordered porous layer interferometry (OPLI). The optical thickness changes (ΔOT) of the L(Cur)-SCC film depend on the mass changes of the lipid-curcumin complex due to the migration of interference fringes caused by the lipase degradation of the digestible lipid complex. Curcumin release from the L(Cur)-SCC film was characterized and analyzed in combination with an ultraviolet-visible spectrophotometer, a nanoparticle size analyzer, and an attenuated total reflection infrared spectrometer. The introduction of a soluble dietary fiber (pectin) into the L(Cur)-SCC film delayed the release rate of curcumin. Furthermore, the real-time sustained release of curcumin from the L(Cur)-SCC film in the simulated digestive fluids was tracked. This study provides an early exploration of the real-time controlled release of lipid-soluble nutraceuticals in the gastrointestinal tract.