Exposure of human bronchial epithelial cells to carbon nanotubes caused oxidative stress and cytotoxicity

Carbon nanotubes are new members of carbon allotropes similar to fullerenes and graphite. Because of their unique electrical, mechanical and thermal properties, carbon nanotubes are highly important for the development of novel applications in the electronics, aerospace and computer industries. Occupational exposure to both natural and man-made graphite during mining and milling can cause pneumoconiosis with clinical/radiographic manifestations similar to those in coal miners. We investigated the adverse effects of single wall carbon nanotubes (SWCNT) using a cell culture of human bronchial epithelial cells (BEAS-2B). Exposure of BEAS-2B cells to SWCNT caused ultra-structural and morphological changes, cellular toxicity, and apoptosis. In addition, exposure to SWCNT induced oxidative stress as shown by the formation of free radicals, accumulation of peroxidative products, and depletion of cell antioxidants. These data indicated that exposure to unrefined SWCNT may lead to pulmonary toxicity due to accelerated oxidative stress in the lung of exposed workers.