Study On Toxicology And Biological Activity Of Nano-TiO₂

Nanoscale titanium dioxide (TiO₂) has inherent physical and chemical advantages which decide its especial toxicology characters. TiO₂ nanoparticles may enter into the soil, air and water, and finally enter into human body by various ways. So, the estimate of security and fatalness of TiO₂ nanoparticles has become the new toxicological task in 21 century. The paper discussed the toxic effects of TiO₂ nanoparticles and micon-TiO₂ on mammals and its safety to aquatics via the stydy with mouse and Daphnia Magna.The main study contents and conclusions including:(1) The study on toxic effects of nano-TiO₂ and micon-TiO₂ with mice. The result showed all indexes of nano-10mg/kg bw group were obviously higher than others (P<0.01 or P<0.05). ALB, TP, ACP and ALP of nano-1mg/kg bw group were higher than the control group, micon-10mg/kg bw and micon-1mg/kg bw groups (P<0.01 or P<0.05). ALP of micon-1mg/kg bw and micon-10mg/kg bw were markedly different from the control group, but other indexes of micon-1mg/kg bw and micon-10mg/kg bw had no obvious difference. The results indicated the lung scathe caused by nano-TiO₂ was more serious than one caused by micon-TiO₂. Nano-TiO₂ induced the change of osmosis of gas/blood barrier and lung early fibrosis, and existed size-dependence.(2) The study on urgent toxic effects of three sized TiO₂ nanoparticles(5±1,25±5,100±5nm)with mice. Blood serum indexes and contents of Ti in brain, lung, liver, kidney and spleen were measured. TP, AKP and LDH indicated all treatments except for high dose of 100nm TiO₂ group may lead to different degree liver damage. Three indexes all great increased at high dose of 5nm TiO₂, it implied liver damage of mice of this treatment may be the most serious. MDA, GSH-Px and SOD showed 5nm and 25nm TiO₂ particles led oxidative stress at low and high dose, and three sized TiO₂ particles induced oxidative damage at high dose. Tissue distribution of Ti showed:â‘ The titanium content in brain increased with decrease of the concentration and size;â‘¡In the 5nm and 25nm TiO₂ nanoparticles treatments, especially at mid and low dose, more TiO₂ nanoparticles were retained in lung, and TiO₂ nanoparticles more easily translocated to other organs,such as spleen, kidney and liver. This may relate to aggregation characteristic of TiO₂ nanoparticles.(3) Take Daphnia Magna as mode bilolgy to Study the Toxicity affect of nano-TiO₂ at the time of its revealment. The result showed, the death reason was difference at its different states.When nano- TiO₂ was in suspending state, Daphnia Magna was died because of eating too much nano- TiO₂ or asphyxia as the low oxygen content.