To assess the biological effects of low level, water dispersible, functionalised carbon nanotube (f-CNT) exposure in an in vitro model simulating the digestive tract, cellular protein expression was quantified and compared using label-free quantitative mass spectrometry (LFQMS). Co-cultured cells were exposed to well-characterised SWCNT-COOH, MWCNT-COOH, and MWCNT-PVP. The relative expression of 2,282 unique proteins was compared across the dose groups. 428 proteins were found to be differentially expressed. At the high dose, the extent of differential protein expression was CNT-specific and directly related to CNT colloidal stability. Cells responded to low level MWCNT-PVP exposure with three-fold greater differential expression. Bioinformatic analysis indicated significant and f-CNT-specific effects on relevant molecular and cellular functions and canonical pathways, with little overlap across f-CNT type and in the absence of overt toxicity.
Keywords: CNT; carbon nanotube; colon; in vitro; intestinal cells; label-free quantitation; mass spectrometry; poly(4-vinylpyrrolidone); proteomics.