Radiosensitizing performance of uncoated and citrate-coated SPIONs in cancerous and non-cancerous cells

Abstract

Superparamagnetic iron oxide nanoparticles were shown to exhibit a high performance as X-ray dosage \nenhancer in tumor cells. The radio-enhancing potential of uncoated and citrate-coated SPIONs was \ncomprehensively studied for tumor and healthy cells. Pristine and citrate-coated SPIONs drastically differ \nin their water dispersibility and adsorption affinity for proteins. The activities of antioxidant enzymes in the \nhealthy cells were shown to be significantly distinct from those in the tumor cells as containing a much \nhigher H2O2 concentration. Pristine SPIONs catalyzed the Fenton reaction of hydrogen peroxide to the \nhighly reactive hydroxyl radical in all cell types. In contrast, intracellular citrate-stabilized SPIONs were \nshown t \no be non-toxic and to do not affect the formation of reactive oxygen species. X-ray irradiation of citratestabilized SPIONs, when internalized by tumor cells, significantly boost the formation of hydroxyl radicals, \nwhereas the healthy cells preserved their initial levels of reactive oxygen species.