The role of iron oxide nanoparticles in the radiosensitization of human prostate carcinoma cell line DU145 at megavoltage radiation energies

Purpose: To examine the radiosensitizing effects of iron oxide nanoparticles in the presence of 6 MV (megavoltage) X-ray radiation. Materials and methods: Iron oxide nanoparticles with two different modifications - dextran coating (plain) and amino-group dextran coating - were used. The rate of iron oxide penetration was monitored using Prussian blue staining, magnetic resonance imaging and atomic adsorption spectroscopy. The effect of iron oxide on the viability of cells was determined using trypan blue dye exclusion assay followed by evaluating the cytotoxicity effect of amino-group iron oxide nanoparticles and ionizing radiation. Radiation dose enhancement studies were carried out on DU145 human prostate carcinoma cell line with 1 mg/ml amino-group iron oxide nanoparticles and different doses of 6 MV X-ray radiation. Results: The uptake of amino-group coated nanoparticles by DU145 cells was significantly more than the plain nanoparticles. In addition, cell viability was decreased with the increase of iron oxide concentration. The dose enhancement factor (DEF) is approximately 1.2 at different doses in the range of 2-8 Gy of 6 MV X-ray radiation. Conclusions: It was demonstrated that iron oxide nanoparticles with the appropriate surface modifications can enter the DU145 cells and it can be used as a cell sensitizer to megavoltage ionizing radiations in radiation therapy.