Novel bilayer pickering emulsions stabilized by in situ modification of zein via selenium nanoparticles: Optimization, physicochemical properties and permeation

In this study, a novel bilayer Pickering emulsion stabilized by zein modification via selenium nanoparticles (Se NPs) was developed. Under the guidance of morphology and encapsulation efficiency of oil, the synthesis process of the Pickering emulsion was optimized. The formation mechanism of the Pickering emulsion was speculated based on the microstructure, distribution of selenium and competition adsorption at the oil/water interface. Then, the influence of the concentration of zein in the zein-selenium nanoparticles on Pickering emulsion was discussed according to the size of emulsion droplets, freeze-drying stability, rheology and lipid oxidation. Finally, an in vivo experiment was used to investigate the skin penetration and biodistribution of Pickering emulsion containing selenium. The results indicated that zein NPs were adsorbed on the surface of selenium and formed a bilayer Pickering emulsion. Under optimized conditions, the size of the emulsion droplets could remain 11.60 ± 0.13 μm, and no obvious coalescence or instability occurred after 60 days of storage. The increase in zein concentration had a positive effect on the encapsulation efficiency of oil, rheology and oxidation resistance of Pickering emulsion. In addition, this research provided a potential synthesis strategy for the introduction of other inorganic trace elements into Pickering emulsion and further applications.