Investigation of toxicity of TiO2 nanoparticles on glioblastoma and neuroblastoma as the most widely used nanoparticles in photocatalytic processes

Background: Titanium dioxide (TiO2) nanoparticles (NPs) are among the most important and usable photocatalysts. Recently, the biological properties of these NPs, particularly, its anticancer activity, have been considered. Glioblastoma and neuroblastoma are two fatal brain tumors with a high mortality rate in humans, the hope for treatment of which is weak by the common methods. Methods: In this study, the cytotoxicity effects of TiO2 alone and in combination with ultraviolet A (UVA) irradiation on two different cell lines, neuroblastoma (SH-SY5Y) and glioblastoma U87, were investigated. After administration of 10, 50, 100, and 500 μg/mL TiO2, 0.043 and 1.4 mW/cm2 UVA irradiation, cell viability was investigated after 4, 24, and 48 hours by 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT) assay. Results: MTT assay and light microscope demonstrated that the effect of TiO2 NPs varied based on the dose of the substance, the impact time, the cell type, and the amount of radiation. In this study, for NPs alone, both toxicity and non-toxicity of the substance were observed. For NPs in the presence of UV, based on the comparison with its status alone and the difference in the viability assay of the two groups, both the photocatalytic and the coating effect of the NPs were observed. Conclusion: According to the results, different concentrations of TiO2 can be used for different purposes. Low concentrations of TiO2 can be used to increase the efficiency of photodynamic therapy and high concentrations of TiO2 can be used to protect the normal cell. This strategy improves the photodynamic therapy and reduces the harmful effects.