Toxicity of nano and bulk forms of cerium oxide in different cell lines

In recent years, nanotechnology has gained serious attention for diagnosis, prevention and treatment roles. In this study we synthesized nanoceria or CeO2NPs (cerium oxide nanoparticles) and compared toxicity of cerium oxide powder in nano and bulk forms in two cancerous and one normal cell lines. The cell lines were cultured in a standard humidified incubator, at 37 °C in a 5% CO2 atmosphere, in RPMI 1640 medium. The cells were incubated with different concentrations of cerium oxide (from 2 μg/mL to 64 μg/mL) in bulk and nano forms.  To determine the effect of cerium oxide on cell viability after 24 h, 48 h, and 72 h incubation, a MTT assay was performed using SKBR3 (human breast cancer cell line), A431 (Human epidermoid carcinoma cell line) and C2Cl2 (ATCC mouse skeletal muscle cell line) cells. Analysis of variance followed by Sidak post-hoc test, shows the toxicity of nanoceria is significantly deferent from bulk form on three cell lines in this study and is more on cancerous cells in compared to normal cells especially in higher level of concentrations after 24, 48 and 72 hours (All P<0.05). Additionally, the effect of cell lines, cerium oxide forms and concentrations cerium oxide leads in significantly the lowest amount of viability after 72 hours compared with 24 hours and 48 hours.