The effect of nano-scale Zn-doped TiO2 and pure TiO2 particles on Hydra magnipapillata

Abstract

Zn-doped nano-scale TiO2 is a useful material in the production of both hydrogen energy and LEDs. However, scientists have raised concerns regarding the toxicity of nano-scale materials. In this study, we investigated the biological toxicity of nano-scale Zn (0.1, 0.5, and 1 mol%)-doped TiO2 and pure TiO2 nanoparticles using the freshwater cnidarian Hydra magnipapillata as our model organism. Zn-doped TiO2 nanoparticles were prepared using a conventional hydrothermal method for the insertion of zinc into the TiO2 framework. The character of Zn-doped TiO2 (0.1%, 0.5%, 1% Zn) and pure TiO2 was 7-8 nm with a positive surface charge. The size was smaller than that used in previous research on the toxicity of nano-scale materials. Although, in this study, we found no significant biological toxicity in Hydra magnipapillata, there was some damage under Zn-doped TiO2 and pure TiO2 UV-A photocatalysis conditions. We assessed that the damage was not linked to the nanoparticles, but rather due to the photocatalytic reaction. Moreover, Zn-doped TiO2 and pure TiO2 nanoparticles were not shown to cause cytotoxic effects, like apoptosis and necrosis that are the major markers of toxicity in organisms exposed to nanomaterials. There was no difference in necrosis or apoptosis, as viewed with a confocal laser microscope, between the Zn-doped TiO2 nanoparticleexposed group and control groups. This study suggests that particles under 10 nm in size do not exhibit biological toxicity and that the small particle size of Zndoped TiO2 and TiO2 nanoparticles decreases photocatalytic photocatalytic effect.