In Vitro Evalution Of The Effect And Mechanism Of Carboxylated Multu-walled Carbon Nanotubes

Carbon nanotubes (CNTs) have attracted human beings’attention since they were discovered in 1991 owing to their fascinating electronic, optical, thermal, and mechanical assets. Thus, it is difficult to resist the phenomenon that extensive application of CNTs, as well as professional and public exposure to nanomaterials, is on the increase.The wide application of CNTs is on the increase. Thus, the potential harmful effects of CNTs on human health and the environment have been attracted serious concerns from academia, governments and our society. Generally, CNTs are divided into single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs). MWCNTs are more facile to be accostable than SWCNTs. So, there is a widespread concern over the ecological safety of MWCNTs. In addition, considering dispersion and biocompatibility, carboxyl multi-walled carbon nanotubes (MWCNTs-COOH) were chosen for the study.Studies have shown that the CNTs had a toxic effect on organism, possibly caused by oxidative stress. Oxidative stress have an effect on increasing of reactive oxygen species (ROS) When the content of reactive oxygen species (ROS) accumulated in the body reaches a certain amount, the body will result in severe oxidative damage, leading to the body of symptoms. Therefore, it is important to investigate the study of the mechanism of CNTs leading to the effect of oxidative stress for contributing to further research and understanding of the biological mechanisms of toxicity of CNTs. Moreover, it will provide the basis for the safety of CNTs.In this paper, in vitro under physiological conditions we investigated the effect and mechanism of oxidative stress caused by MWCNTs-COOH on molecular level and cellular level. The main contents of this paper included the following aspects:Firstly, by infrared spectroscopy and high-resolution transmission electron microscopy were used to characterize MWCNTs-COOH. Secondly, by the method of multiple spectroscopy and isothermal titration calorimetry means, we probed the interactions between MWCNTs-COOH and anti-oxidative stress key enzyme (catalase and Cu, Zn-superoxide dismutase).The results showed that the interactions between MWCNTs-COOH and two proteins are weak, and the hydrophobic force played a major role. In addition, results of activity determination showed that MWCNTs-COOH has no significant effect on the enzyme activity. We selected primary mouse hepatocytes as study object, using Muse Cell Analyzer to study the effect of MWCNTs-COOH on viability of hepatocytes. Subsequently, we studied the effects of MWCNTs-COOH on CAT activity and SOD activity in hepatocytes, respectively. In addition, we measured the content of MDA.The main conclusions: ①MWCNTs-COOH on cell viability in a time-dependent manner;②CAT, SOD activity have been suppressed, the intracellular antioxidant system is affected, MWCNTs-COOH-induced oxidative stress in the liver cells;③The content of MDA changed, but there was no significant difference, indicating that MWCNTs-COOH cells did not cause significant oxidative stress.In this paper, two in vitro levels (molecular, cellular) discussed the mechanism of oxidative stress induced by MWCNTs-COOH. This will provide more reference for further studies of biological toxicity of carbon nanotubes.