Interaction between immunoglobulin G and peroxidase-like iron oxide nanoparticles: Physicochemical and structural features of the protein.

The study is devoted to the oxidative modification of immunoglobulin G (IgG) on the surface of peroxidase-like iron oxide magnetic nanoparticles (MNPs) under conditions of induced reactive oxygen species (ROS) generation and without them. A pronounced change of thermodynamic parameters of denaturation has been detected for IgG in solutions containing MNPs under hydrogen peroxide action during 24 h of incubation. Dynamic light scattering measurements and UV-Visible spectrophotometry have been used to show aggregation in these solutions. Ferromagnetic resonance (FMR) was used to compare IgG coating thickness on individual MNPs under conditions of induced ROS generation and without them. The similarity between IgG adsorption on MNPs under these conditions after 24 h of incubation has been confirmed by the fluorescence measurements. The sites of IgG oxidative modifications that take place on MNPs surface and some evidences of the influence of oxidative modification and adsorption on the chemical structure of IgG were revealed by HPLC MS/MS analysis.