Build-Up of a 3D Organogel Network within the Bilayer Shell of Nanoliposomes. A Novel Delivery System for Vitamin D3: Preparation, Characterization, and Physicochemical Stability

The inherent thermodynamic instability of liposomes during production and storage has limited their widespread applications. Therefore, a novel structure of food-grade nanoliposomes stabilized by a 3D organogel network within the bilayer shell was developed through the extrusion process and successfully applied to encapsulate vitamin D3. A huge flocculation and a significant reduction of zeta potential (−17 mV) were observed in control nanoliposomes (without the organogel shell) after 2 months of storage at 4 °C, while the sample with a gelled bilayer showed excellent stability with a particle diameter of 105 nm and a high negative zeta potential (−63.4 mV), even after 3 months. The development of spherical vesicles was confirmed by TEM. Interestingly, the gelled bilayer shell led to improved stability against osmotically active divalent salt ions. Electron paramagnetic resonance confirmed the higher rigidity of the shell bilayer upon gelation. The novel liposome offered a dramatic increase in encapsulation efficiency and loading of vitamin D3 compared to those of control.