Solid lipid-polymer hybrid nanoparticles prepared with natural biomaterials: A new platform for oral delivery of lipophilic bioactives

In this study, an innovative oral delivery system, solid lipid-polymer hybrid nanoparticles (SLPN), was prepared from all-natural biomaterials without use of synthetic surfactants, toxic chemicals, or organic solvents. SLPN were comprised of three components, solid lipid nanoparticles (SLN) as the inner core, bovine serum albumin (BSA)-dextran (BD) conjugate obtained through Maillard reaction as natural emulsifier anchored on the surface of SLN, and pectin as the secondary polymeric coating. Six types of solid lipids, including two glycerides and four saturated fatty acids, were comprehensively tested for their applicability to prepare SLN core and their compatibility with polymeric shells to form SLPN. SLPN prepared with glycerides exhibited superior colloidal properties, including smaller particle size, narrower size distribution, and better stability under simulated gastrointestinal fluids, compared to those prepared with fatty acids. Hydrophobic interactions were the driving force to form SLPN with BD conjugate, while pectin coating afforded greater surface hydrophilicity responsible for exceptional colloidal stability under gastrointestinal conditions. SLPN demonstrated high encapsulation efficiency and controlled release of curcumin, with glycerides as lipid core being more desirable than those prepared with fatty acids. Fluorescence microscope images revealed that encapsulation in SLPN significantly facilitated cellular uptake of curcumin by Caco-2 cells without any cytotoxicity. Collectively, this study provides a promising strategy to develop safe and effective oral delivery platform for lipophilic bioactives, which may open new avenues in functional foods.