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.