Physicochemical\nProperties of Seed Oil Blends and\nTheir Potential for the Creation of Synthetic Oleosomes with Modulated\nPolarities

There is an increasing demand within the pharmaceutical\nand cosmetic\nindustries for biofriendly lipid-based active ingredient delivery\nsystems. Micelles, liposomes, and lipid nanoparticles are currently\nthe most used systems despite their limitations. Oleosomes, also known\nas lipid droplets, are promising alternatives to the existing strategies.\nOleosomes are typically found in plant cells and are characterized\nby a nonpolar triacylglycerol core surrounded by a phospholipid monolayer\npunctuated with the protein oleosin. Producing oleosomes synthetically\nallows the customization of their lipid content, size, protein content,\nand oil core characteristics, expanding their versatility. Herein\nwe demonstrate a proof of concept for the use of synthetic oleosomes\nto sequester polar molecules by modulating their core polarity with\nblends of sunflower and castor oils. The physical properties (density,\nrefractive index, and permittivity) of the oil blends are characterized\nand demonstrate ideal mixing of the oils, which is supported by molecular\ndynamics simulations. Spectroscopic examination of the oil blends\nusing fluorescent probes shows that the polarity of oil blends increases\nas the fraction of castor oil increases. Finally, we show that the\nuptake of a polar fluorescent probe (NBD-glucose) into synthetic oleosomes\nis enhanced by increasing the polarity of the oil core, but large\ncharged molecules are excluded from the core regardless of polarity.\nThese experiments show that synthetic oleosomes with tunable oil cores\ncan expand the range of molecules that can be loaded into a biofriendly\npackage as desired for biotechnology applications.