Assessment of pulmonary toxicity of functionalized multiwall carbon nanotubes in vitro.
Mishra-A; Stueckle-T; Derk-R; Schwegler-Berry-D; Wu-N; Rojanasakul-Y; Castranova-V; Wang-L
Toxicologist 2012 Mar; 126(Suppl 1):276
Multi-walled Carbon nanotubes (MWCNT), with their unique physico-chemical properties such as diameter less than 100 nm and a large surface area, have a number of current and proposed applications in health care and consumer products. MWCNT can also be toxic due to fiber shape and large surface area. Previous studies have reported that MWCNT exposure in mice caused rapid and progressive interstitial lung fibrosis within a few weeks. Physical-chemical properties of MWCNT e.g. solubility, dispersion status etc. certainly mediate their bio-effects. However, mechanisms involved are largely unknown. Therefore, in vitro methods should be developed which allow mechanistic studies. For this present study, two types of MWCNT were used: purified (p) and COOH-functionalized (f ) MWCNT. Particle characterization was performed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and zeta potential measurement. Cultured human bronchial epithelial cell and lung fibroblast cells were exposed to p-MWCNT or f-MWCNT. Cytotoxicity was measured using the tryphan blue assay and lactate dehydrogenase (LDH) assay. Levels of collagen, an indicator of fibrogenicity, were evaluated by ELISA and western blotting. Results showed that 1) f-MWCNT was more hydrophilic than p-MWCNT due to the presence of surface attached COOH functional groups; 2) at physiologically relevant exposure concentrations (0.02-0.6 microg/cm2), f-MWCNT showed less cell damage compared to p-MWCNT in lung epithilial cells in vitro; 3) both p-MWCNT and f-MWCNT induced collagen I in fibroblast cells in vitro. Our data suggests that COOH-functionalization modulates the bio-effects of MWCNT in vitro which have important implications in nanotoxicology.
Nanotechnology; Toxic-materials; Health-hazards; Chemical-properties; Physical-properties; Surface-properties; Laboratory-animals; Laboratory-testing; Exposure-assessment; Exposure-chambers; Exposure-methods; Fibrous-bodies; Biological-effects; In-vitro-study; Analytical-methods; Microscopic-analysis; Spectroscopes; Lung-fibrosis; Lung-disorders; Pulmonary-disorders; Respiratory-system-disorders; Particulates; Lung-cells; Bioassays; Cytotoxic-effects; Collagen-fibrils; Cell-damage; Fibrogenicity
The Toxicologist. Society of Toxicology 51st Annual Meeting and ToxExpo, March 11-15, 2012, San Francisco, California