Titanium Dioxide (TiO 2 ) Nanoparticle Toxicity in a Caenorhabditis elegans Model

Titanium dioxide is a compound that is used in the food, cosmetic, and paint industries; however, it is still toxic to humans and the environment. This study determined the toxicities of titanium dioxide nanoparticles (TiO NPs) in a ( ) model. The effects of commercially available (C-TiO ) and synthetically (S-TiO ) prepared TiO NP solutions on lethality, lifespan, growth, reproduction, locomotion, and gene expression were studied in . Exposure to TiO NPs (0.0, 0.01, 0.1, 1.0, and 10 mg/L) did not result in any change to the survival rate or body length of the nematodes, regardless of the concentration. However, there was a decrease in the reproduction (brood size) and locomotion (body bending and head thrashing) of the nematodes as the TiO NP concentration increased. The longevity of the nematodes was shortened following TiO NP exposure. The gene expression of sod-1, sod-3, ctl-1, ctl-2, cyp35A2, mlt-1, and mlt-2 in the nematodes showed that there was an overexpression of all genes when the worms were exposed to 1 mg/L C-TiO or 10 mg/L S-TiO . It was therefore concluded that compared with S-TiO , C-TiO possibly causes more toxicity or genotoxicity in the model.