Adsorption Kinetics of Oppositely Charged Hard and Soft Nanoparticles with Phospholipid Membranes

Nanoparticles (NPs) have great potential for biological applications as typically they exhibit strongly size-dependent properties. Specifically, the interaction of NPs with phospholipid membranes is significantly relevant to nanomedicine and the related field of nanotoxicology. Therefore, the investigation of interactions of NPs with model membranes is not only fundamentally important but also practically valuable to understand interactions of NPs with more complex cell membranes. Here, we report on the interaction of anionic vesicles of different charge densities and cationic SiO₂ NPs, either covered by a bare surface functionalized with amino moieties (-NH₂) or covered by poly[2-(dimethylamino) ethyl methacrylate]. We studied the kinetics of binding of NPs to the vesicle surface by time-resolved scattering experiments. A key result of the study is that binding is favored in the presence of electrostatic attraction, but the polymer layer decreases the binding rate drastically.