PEG coated bismuth oxide nanorods induced radiosensitization on MCF-7 breast cancer cells under irradiation of megavoltage radiotherapy beams

Abstract Gold nanoparticles have been introduced to increase the radiotherapy therapeutic efficacy. In this study, bismuth oxide nanorods coated with polyethylene glycol (Bi2O3-PEG) was applied as radiosensitizer for megavoltage photon and electron beams. Bi2O3-PEG nanorods of size 60 nm were synthesized using hydrothermal method and characterized using XRD and FESEM. Cytotoxicity evaluation was conducted on MCF-7 cells using 0.5 µMol/L of Bi2O3-PEG nanorods for 24, 48 and 72 hours of incubation time. The cells with and without Bi2O3-PEG were irradiated with 6 and 10 MV photon beams as well as electron beams of energy 6 and 12 MeV. Post-irradiation cell survival were quantified using clonogenic assays. The radiosensitization effects of Bi2O3-PEG nanorods were elucidated by extrapolating the sensitization enhancement ratio (SER) from the cell survival curves. Size and morphological characterization confirm the Bi2O3-PEG nanorods average size was 60 nm with surface modification of PEG. The cytotoxicity results show the Bi2O3-PEG nanorods are biocompactible to MCF-7 cells. The irradiation results demonstrate that Bi2O3-PEG nanorods produce radiosensitization effects when irradiated with photon beams with SER value of 1.12 for 6 MV and 1.15 for 10 MV. Meanwhile for electron beam, the SER obtained are 1.13 for 6 MeV and 1.06 for 12 MeV. In conclusion, the Bi2O3-PEG nanorods positively induced radiosensitization when irradiated with megavoltage radiotherapy beam indicating potential future clinical application as radiosensitizer.