Summary:
When nanoparticles enter into the bloodstream, they interact and come into contact with biomolecules, which modify the surface properties and affect the biological behavior of nanoparticles. The aim of the present study is to evaluate the physicochemical and biological stability of liposomal systems, the role of lipid composition and concentration in protein binding, and the effect of protein absorption on the properties of liposomal nanosystems. Neutral, anionic lipids and Poly(Ethylene Glycol)-Lipid Conjugates (PEG-lipid conjugates) were used for the preparation of liposomal systems. Liposomes of different lipid composition were prepared in two concentrations by lipid - film hydration method. Thereafter, the liposomes were diluted in aqueous and biological media and their physicochemical characteristics were determined using Dynamic and Electrophoretic light scattering. Our results show that the conventional neutral liposome systems were not stable in the aqueous and biological media, whereas the anionic liposomal formulations showed better stability in the two dispersion media. In addition, the incorporation of cholesterol appears to confer physical and biological stability by regulating the lipid membrane fluidity. Liposomes containing cholesterol and PEG-lipid conjugates retained their size in the presence of serum proteins due to steric stabilization. In the present study, we propose a new parameter, Fraction of stealthiness (Fs), to investigate the extent of protein binding in liposomes. This paramete depends on the changes in the size of the liposomes after the incubation in the serum, while the liposomes exhibit stealth properties when the Fs approaches the value 1. In conclusion, this study could help to understand the interfacial phenomena and the interactions of proteins - nanoparticles, which are the keys to the development of Advanced Drug Delivery Nanosystems (aDDnSs).
Keywords:
Liposomes, protein corona,stealth, Dynamic Light Scattering
