Influence of surface properties of polymeric nanoparticles on their membrane affinity

Biodegradable polylactic/glycolic acid copolymers are widely used as colloidal drug delivery systems. PLGA nanoparticles were prepared using non-ionic, PEO-containing block copolymer (Pluronic) and charged polymeric (PEI) surface modifiers. Physicochemical properties such as size, size distribution, zeta potential, surface composition, and colloid stability were compared to their behavior at interfaces. Adhesion of the PLGA nanoparticles to solid surface, accumulation at water surface and their cell membrane affinity (using a Langmuir lipid monolayer as a model system) were characterized. Significant differences were observed in surface activity and adhesion as well as in membrane affinity of nanoparticles depending on their surface composition. The interplay of electrostatic and steric effects resulted in sufficient colloid stability and maximum membrane affinity for the system stabilized with the mixture of Pluronic and PEI.