Oxidative and Binding Effect of Nano-TiO2 on Plasmid DNA and Pepsin

With the development of nano material industry, more and more attention has been paid on the biological effect of nano materials. However, little research focused on the effect of nano TiO₂ on protein level. In this study, we detected the toxic effect of nano TiO₂ (50~60 nm) on DNA and functional proteinase. The oxidative damage of nano TiO₂ on DNA was detected by gel electrophoresis and HPLC. Anson method was used to study the inhibition of nano TiO₂ on pepsin, and the mechanism of the reaction was further researched by the method of UV-Vis scan and TEM. The results showed that the ratio of super-coiled DNA decreased significantly both under UV radiation and visible light. Levels of 8-OHdG generated from DNA increased from 27.66 8- OHdG/104 dG to 296.69 8-OHdG/104 dG after treated with nano TiO₂. After water incubated with nano TiO₂ at 37degC, the activity of pepsin decreased with the increase of the concentration of particels, UV-Vis scan and TEM detection proved the binding effect of nano TiO₂ on pepsin, which indicated potential usage for oral drug delivery of nano TiO₂.