3, Korea Institute of Science and Technology, Seoul, , Korea (the Republic of)
2, Ajou University, Suwon, Gyeonggi-do, , Korea (the Republic of)
Metal-doped titanium oxide (TiO2) nanoparticles were developed as enhanced photocatalysts with disinfection and purification potential. However, they can be hazardous to both the environment and human health. In this study, the toxicity of nickel (Ni) and platinum (Pt)-doped TiO2 nanoparticles (Ni-TiO2 and Pt-TiO2 nanoparticles) to skin and eye cells and a mouse skin model was evaluated. Physicochemical properties of nanoparticles were characterized using field emission-scanning electron microscopy, field emission-transmission electron microscopy, and X-ray photoelectron spectroscopy. Cytotoxicity was also evaluated at concentrations of 0.0001 to 10 mg/mL in HaCaT and ARPE-19. To investigate in vivo acute toxicity, 1 to 123 mg nanoparticles/1.5 cm2 were applied to hair-removed dorsal skin in a mouse model, and skin tissues and body condition were monitored. Metal-doped TiO2 nanoparticles had a spherical crystalline shape with nanoscale sizes less than 100 nm. In nanoparticles, 1.0% Ni2p and 0.26% Pt4f were detected at 871.2 eV and 74.4 eV for Ni-TiO2 and Pt-TiO2 nanoparticles, respectively. Cell viability in HaCaT was higher than that in ARPE-19 at a range of 0.1 - 10 mg/mL nanoparticles. In ARPE-19, superior cell viability was observed at 1.0 mg/mL and more than 1.0 mg/mL Ni-TiO2 nanoparticles compared with Pt-TiO2 nanoparticles. In vivo, body weight and AST/ALT levels were not significantly altered by Ni-TiO2 nanoparticle exposure. Histology, skin thickness, and inflammation grade were also comparable to control mice. Thus, metal-doped TiO2 nanoparticles show minimal toxicity in skin cells and a mouse skin model, indicating their potential for various applications.