Role of modification route for zinc oxide nanoparticles on protein structure and their effects on glioblastoma cells.

Zinc oxide nanoparticles (ZnO) are presented as potential cancer therapeutic agent based on their surface properties. In this study, the most abundant blood proteins, albumin, fibrinogen and apo-transferrin, were covalently bound (c-ZnO NPs) and nonspecifically adsorbed (n-ZnO NPs) onto ZnO NPs to evaluate the role of modification route on protein structure and their effects on glioblastoma cells. The success of modification and structures of proteins on ZnO NPs were characterized with FT-IR. It was found that non-covalent interaction significantly damaged the secondary structure of proteins compared to those covalently attached to the ZnO nanoparticle. The effects of modified ZnO NPs were investigated by evaluating viability, cycle, and death mechanisms of glioblastoma (U373) cells. n-ZnO NPs were found more toxic compared to the pristine and c-ZnO NPs. However, c-ZnO NPs with albumin and apo-transferrin both perturbed the cell cycle function, and decreased the necrotic cell death rate of U373 cells below toxic concentration, suggesting their potential curative effect on glioblastoma cells.