In vitro and in vivo toxicological evaluation of transition metal-doped titanium dioxide nanoparticles: Nickel and platinum

Transition metal-doped titanium dioxide nanoparticles (M-TiO₂ NPs) have been studied to enhance the activity of TiO₂ NPs in biomedical applications. In this study, in vitro and in vivo toxicological aspects of M-TiO₂ NPs were reported to assess the safety of these materials. M-TiO₂ NPs were synthesized via a photo-deposition technique. Nickel (Ni) and platinum (Pt) were used as dopants. Physicochemical properties, cytotoxicity, phototoxicity, gene ontology (GO) and dermal toxicity of M-TiO₂ NPs were investigated. Ni-TiO₂ (Ni, 1.02%) and Pt-TiO₂ (Pt, 0.26%) NPs were sphere shape crystals with nanoscale size. ARPE-19 cells were more susceptible to Pt-TiO₂ NPs (EC50, 0.796 mg/mL) than Ni-TiO₂ NPs (EC50, 2.945 mg/mL). M-TiO₂ NPs were rated as probably phototoxic to phototoxic. GO suggested binding function and metabolic processes as a risk mechanism of M-TiO₂ NPs. In vivo toxicological effects of Ni-TiO₂ NPs were not observed on body weight, serum aspartate transaminase/alanine transaminase levels, and skin histology at 61.5–6150 mg/kg. Specifically, skin thickness was not significantly modified (max. 33.2 ± 8.7 μm) and inflammation grade was less than level 2 (max. 1.2 ± 0.4). From these results, Ni-TiO₂ and Pt-TiO₂ NPs show promise as enhanced photocatalysts for safe and sustainable usage.