TiO2 Nanoparticles and Their Effects on Eukaryotic Cells: A Double-Edged Sword

Nanoparticulate TiO2 (TiO2 NPs) is a widely used material, whose potential toxicity towards eukaryotic cells has been addressed by multiple studies. TiO2 NPs are considered toxic due to their production of reactive oxygen species (ROS), which can, among others, lead to cellular damage, inflammatory responses, and differences in gene expression. TiO2 NPs exhibited toxicity in multiple organs in animals, generating potential health risks also in humans, such as developing tumors or progress of preexisting cancer processes. On the other hand, the capability of TiO2 NPs to induce cell death has found application in photodynamic therapy of cancers. In aquatic environments, much has been done in understanding the impact of TiO2 on bivalves, in which an effect on hemocytes, among others, is reported. Adversities are also reported from other aquatic organisms, including primary producers. These are affected also on land and though some potential benefit might exist when it comes to agricultural plants, TiO2 can also lead to cellular damage and should be considered when it comes to transfer along the food chain towards human consumers. In general, much work still needs to be done to unravel the delicate balance between beneficial and detrimental effects of TiO2 NPs on eukaryotic cells.