Protein displacement dynamics on chromium oxide nanoparticles: Investigating the Vroman effect in a binary protein system

Metal exposure through environmental and biomedical sources poses significant risks to human health. Biomedical implants made of metal alloys, such as stainless steel, degrade chemically and mechanically over time, resulting in surrounding tissues being exposed to chromium oxide (Cr₂O₃) nanoparticles. These nanoparticles interact dynamically with biological fluids and tissues, leading to protein adsorption and the formation of a protein corona, which influences material biocompatibility and the immune response. This study investigates the interaction of Cr₂O₃ nanoparticles with two plasma proteins—bovine serum albumin (BSA) and fibrinogen—with a particular emphasis on the displacement dynamics governed by the Vroman effect. Using a variety of spectroscopic, analytical, and imaging techniques, the study reveals that neither Cr₂O₃ nanoparticles nor the displacement of BSA induce fibrinogen unfolding or breakage of its disulfide bonds. Fibrinogen was found to rapidly (< 1 minute) replace BSA on the nanoparticle surface and also to deposit on top of BSA, suggesting the mechanism of protein exchange follows the transient complex exchange model. These findings highlight the complex dynamics that modulate protein adsorption and displacement and contribute to the growing body of work that aims to advance the understanding of nanoparticle-protein interactions. • Fibrinogen rapidly displaces BSA on the surface of chromium oxide nanoparticles. • Chromium oxide nanoparticles do not induce BSA or fibrinogen unfolding. • Fibrinogen was found to deposit on top of initially adsorbed BSA. • The mechanism of the Vroman effect follows the transient exchange model.