Toxic effects of titanium dioxide nanoparticlesand multi-walled carbpn nanotubes in vitro and in vivoPatinya Sukwong
( Ph.D. )
Nanomaterials are of interest in various applications. Titanium dioxide nanoparticles (TiO2-NPs) and multi-walled carbon nanotubes (MWCNTs) are one of the versatile nanomaterials used in nanotechnology products such as sunscreen, cosmetics, electronic devices, paint, and sports gear. Therefore, workers and consumers are potentially exposed to TiO2-NPs and MWCNTs. Since these particles have a small size at a nanoscale level they are capable of penetrating biological structures. An increase in the use of TiO2-NPs and MWCNTs is therefore raising concerns in possibly adverse effects on human health. Due to this reason, the main purpose of this thesis is to investigate the toxic effect of TiO2-NPs and MWCNTs in vitro and in vivo. The impact of TiO2-NPs on the induction of toxicity in immune (RAW 264.7) and brain cancer (C6 glioma) cells is investigated in this thesis. Cell viability, DNA fragmentation, apoptosis cell death, and inflammatory response molecules were measured after treating RAW 264.7 and C6 glioma cells with various concentrations of TiO2-NPs. The results in this thesis showed that TiO2-NPs at concentrations 25 g/ml could strongly induce toxicity in both cells. However, it was found that the RAW 264.7 cell is more sensitive to TiO2-NPs than C6 cells.
Following in vitro investigation, in vivo toxicity of TiO2-NPs and MWCNTs in mice was examined. Intranasal exposure of mice with TiO2-NPs and MWCNTs for 6 and 24 h was performed. Inflammatory response molecules in bronchoalveolar lavage fluid were determined. The results showed that MWCNTs induced higher toxicity in treated mice than TiO2-NPs at the same concentration and exposure time. In addition, another useful information of TiO2-NPs and MWCNT characterization is described in this thesis. The information on characterization of both nanoparticles could help explain how particles are associated with the induction of toxicity in vitro and in vivo. The overall results of this thesis provide useful information for using these nanomaterials effectively with health concerns.