Influence of Lipid’s Main Transition Temperature on the Stability of Chimeric Liposomal Systems

Abstract

Background: The incorporation of polymeric components into liposomes promotes structural rearrangement of the lipid bilayers that could affect their properties and their behavior. Therefore, by mixing phospholipids with polymeric compounds the, socalled chimeric liposomal nanosystems are produced and could be advantageous, compared with conventional (e.g. composed of pure phospholipids) liposomal nanostructures. Objective: In this work, we used lipids with different main transition temperature (Tm) i.e 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC, Tm=55°C), L-α-phosphatidylcholine, hydrogenated (Soy) (HSPC, Tm=52 °C) and egg phosphatidylcholine (EggPC, Tm=23 °C) and we studied and compared the physicochemical characteristics and the stability of conventional with that of chimeric liposomes. Methods: Thin-film hydration method (TFH) was used as the preparation protocol for all systems. Dynamic and electrophoretic light scattering (DLS and ELS) were utilized in order to elucidate the physicochemical characteristics of all systems. All liposomal systems exhibited sizes below 100nm while the ζ-potential was around zero, indicating the absence of surface charge. Results: The results revealed that the Tm of each phospholipid influences the biophysical behavior of the lipidic membrane, which contributes to the physicochemical characteristics and affects the physical stability of the liposomal nanosystems. The nature and physicochemical properties of each phospholipid seem to play a key role, regarding the structural characteristics and the formation process of the liposomal nanosystems. Conclusion: : Comparing the physicochemical properties of the conventional liposomes with those of the chimeric liposomal systems, we conclude that the complexity of the latter, due to the incorporation of the polymeric guest into the lipidic bilayer, revealed new properties, which correspond to increased physical stability.