Investigating Liposome Membrane Properties: Insights from Langmuir Monolayer Studies in the Corona Protein Environment

Most nanoparticles approved for medical applications are liposome formulations. In the environment of biological fluids, the corona protein was found to alter both the surface of the liposome and its size and zeta potential. As a result, it can also affect the stability of the carrier and its ability to hold a drug and release it sustainably into the cell. The key element of novelty of this research is the introduction of the Langmuir-Blodgett technique together with imaging microscopy to study the interactions between the monolayer corresponding to one liposome leaflet and the corona protein. We applied this approach to study the properties of individual lipid monolayers, which constitute the bilayers of PEGylated or non-PEGylated liposomes exposed to human serum albumin solutions. The thermodynamic parameters obtained from these measurements reflect changes in the properties of the lipid layer under the influence of the corona protein. Polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS) spectra visualized the differences of these interactions, depending on the composition of the lipid layer. Liposome properties were also characterized in the PBS solution before and after incubation in human serum albumin solutions. The antirheumatic drug, iguratimod, was chosen as the cargo of the liposomes, and changes in its release kinetics in the presence and absence of the corona protein confirmed the advantages of the selected PEGylated lipid carrier.