Effects of Oxidation on Protein-Nanoparticle Interactions

Abstract

Aims: Upon entrance into the blood stream most nanoparticles bind to an array of proteins forming a “protein corona”. Fibrinogen is the second most abundant blood protein and has been reported to bind to a variety of nanoparticles including metal oxides, polymeric nanoparticles and carbon nanotubes. Study Design: Study the effects of oxidation on the binding interactions between human serum fibrinogen and magnetic iron (III) oxide nanoparticles. Place and Duration of Study: Department of Chemistry, College of St. Benedict, 37 South College Avenue, St. Joseph, MN 56374, U.S.A., between June 2011 and May 2012. Methodology: Spectroscopic techniques (UV-Vis, IR, fluorescence, and circular dichroism) were used to study the binding interactions of magnetic nanoparticles with human serum fibrinogen and the effects of protein oxidation on its binding affinity. Results: Magnetic nanoparticles (MNP) formed stable complex with fibrinogen under physiological conditions. The binding constants (Ka) were determined as 1.91 (± 0.14) x10 M and 1.06 (± 0.09) x10 M at 300 K and 310 K respectively. The secondary structure of the protein was slightly affected by the formation of fibrinogen-MNP complex. When the protein was oxidized with metal catalyzed oxidation (MCO) system, significant changes in the protein structure was detected leading to decreased binding affinity for Original Research Article British Journal of Pharmaceutical Research, 4(2):172-185, 2014 173 MNP. Conclusion: Metal catalyzed oxidation of fibrinogen significantly affects its binding interactions with magnetic iron (III) oxide nanoparticles.