Background and PurposeThe objective of this study was to investigate the therapeutic effect of Folic Acid-Conjugated polyglycerol coated iron oxide nanoparticles on the radiosensitivity of HeLa cells when irradiated with 6 MeV electron beams. Materials and MethodsDifferent concentrations of iron oxide nanoparticles (PG-SPIONs and FA-PG-SPIONs (25, 50, 100, 200 μg ml−1)) were synthesized by the thermal decomposition technique. The effect of PG-SPIONs and FA-PG-SPIONs in combination with radiation (2, 4, 6 Gy) on the viability of cells and cell survival were estimated using the trypan blue dye exclusion test and MTT assay immediately and 48 h after irradiations, respectively. ResultsIt was observed that the penetration rate of uptake for cells treated with >50 μg ml−1 FA-PG-SPIONs was more than that of non-targeted nanoparticles. The data obtained by trypan blue dye exclusion test showed no significant reduction in cell viability for all groups in comparison with control group. The results revealed that increasing the radiation doses in the presence of the concentrations of the nanoparticles increased the value of radiosensitivity. The most radiosensitivity was obtained at the highest concentration of FA-PG-SPIONs (200 μg ml−1) as well as the longest radiation doses. ConclusionIt was revealed that higher concentrations of the FA-PG-SPIONs in combination with 6 MeV electron beams could enhance radiosensitization of HeLa cells.