Effects of SWCNT fiber length and functionalization on ROS and collagen production.
Manke-A; Stueckle-TA; Wang-L; Dinu-DA; Rojanasakul-Y
Toxicologist 2014 Mar; 138(1):155
Single-walled carbon nanotubes (SWCNTs) present a significantly higher chance of occupational and environmental exposure owing to their widespread use in technology and commercial products. Currently, there is a lack of consensus on the various CNT characteristics that induce pulmonary toxicity. Therefore, our aim was to study the effect of SWCNT length and chemical functionalization on ROS production and collagen synthesis in human lung fibroblasts. SWCNTs with varying functionalization including carboxylic acid, amine and hydroxyl, and varying lengths, i.e. long 5-30 nm and short 1-2 nm, obtained from Cheap Tubes Inc. were used. SWCNT dimension and elemental composition characterization was conducted using atomic force microscopy and energy dispersive X-ray spectroscopy respectively. SWCNT toxicity in normal human lung fibroblast were first determined using WST-1 assay and sub-toxic concentrations of SWCNTs were selected for further experiments. Cellular ROS production was determined fluorometrically using DCF-DA as fluorescent probes for peroxide measurement. Type I Collagen expression was determined by western blotting in the presence and absence of ROS inhibitors. Cellular collagen content was determined by Sircol assay. Our results showed that: 1) Pristine > COOH > NH2 > OH SWCNT in ROS and collagen production in a dose- and time-dependent manner; 2) longer length SWCNTs induced higher ROS generation and collagen I expression than those of short length; and 3) SWCNT-induced collagen expression was significantly blocked by various ROS inhibitors revealing a role for oxidative stress in SWCNT-induced fibrogenesis. These results suggest that SWCNT length and functionalization impact lung fibroblast ROS and collagen synthesis, which contribute to SWCNT-induced pulmonary fibrosis. Disclaimer: Research findings and conclusions are those of the authors and do not necessarily represent the views of the National Institute for Occupational Safety and Health.
Toxicology; Cell-function; Cellular-function; Cell-damage; Nanotechnology; Lung; Exposure-levels; Pulmonary-disorders; Pulmonary-function; Pulmonary-system; Pulmonary-system-disorders; Fibrosis; Molecular-structure
The Toxicologist. Society of Toxicology 53rd Annual Meeting and ToxExpo, March 23-27, 2014, Phonex, Arizona