Could Iron-Nitrogen Doping Modulate the Cytotoxicity of TiO Nanoparticles?

Titanium dioxide nanoparticles (TiO NPs) are found in several products on the market that include paints, smart textiles, cosmetics and food products. Besides these, TiO NPs are intensively researched for their use in biomedicine, agriculture or installations to produce energy. Taking into account that several risks have been associated with the use of TiO NPs, our aim was to provide TiO NPs with improved qualities and lower toxicity to humans and the environment. Pure TiO P25 NPs and the same NPs co-doped with iron (1%) and nitrogen atoms (P25-Fe(1%)-N NPs) by hydrothermal treatment to increase the photocatalytic activity in the visible light spectrum were in vitro evaluated in the presence of human lung cells. After 24 and 72 h of incubation, the oxidative stress was initiated in a time- and dose-dependent manner with major differences between pure P25 and P25-Fe(1%)-N NPs as revealed by malondialdehyde and reactive oxygen species levels. Additionally, a lower dynamic of autophagic vacuoles formation was observed in cells exposed to Fe-N-doped P25 NPs compared to the pure ones. Therefore, our results suggest that Fe-N doping of TiO NPs can represent a valuable alternative to the conventional P25 Degussa particles in industrial and medical applications.