TiO<sub>2</sub> Nanoparticle-Induced Oxidation of the Plasma Membrane: Importance of the Protein Corona.

TitleTiO2 Nanoparticle-Induced Oxidation of the Plasma Membrane: Importance of the Protein Corona.
Publication TypeJournal Article
Year of Publication2017
AuthorsS Runa, M Lakadamyali, ML Kemp, and CK Payne
JournalThe journal of physical chemistry. B
Start Page8619
Pagination8619 - 8625
Date Published09/2017

Titanium dioxide (TiO<sub>2</sub>) nanoparticles, used as pigments and photocatalysts, are widely present in modern society. Inhalation or ingestion of these nanoparticles can lead to cellular-level interactions. We examined the very first step in this cellular interaction, the effect of TiO<sub>2</sub> nanoparticles on the lipids of the plasma membrane. Within 12 h of TiO<sub>2</sub> nanoparticle exposure, the lipids of the plasma membrane were oxidized, determined with a malondialdehyde assay. Lipid peroxidation was inhibited by surface passivation of the TiO<sub>2</sub> nanoparticles, incubation with an antioxidant (Trolox), and the presence of serum proteins in solution. Subsequent experiments determined that serum proteins adsorbed on the surface of the TiO<sub>2</sub> nanoparticles, forming a protein corona, inhibit lipid peroxidation. Super-resolution fluorescence microscopy showed that these serum proteins were clustered on the nanoparticle surface. These protein clusters slow lipid peroxidation, but by 24 h, the level of lipid peroxidation is similar, independent of the protein corona or free serum proteins. Additionally, over 24 h, this corona of proteins was displaced from the nanoparticle surface by free proteins in solution. Overall, these experiments provide the first mechanistic investigation of plasma membrane oxidation by TiO<sub>2</sub> nanoparticles, in the absence of UV light and as a function of the protein corona, approximating a physiological environment.

Short TitleThe journal of physical chemistry. B