Evaluation of the interactions between multiwalled carbon nanotubes and caco-2 cells

The aim of this study was to determine whether multiwalled carbon nanotubes (MWNCT) are taken up by and are toxic to human intestinal enterocytes using the Caco-2 cell model. Caco-2 cells were exposed to 50 μg/ml MWCNT (oxidized or pristine) for 24 h, and experiments were repeated in the presence of 2.5 mg/L natural organic matter. Cells display yed many ofthe properties that characterize enterocytes, such as apical microvilli, basolateral basementmembrane, and glycogen. The cell monolayers also displayed tight junctions and electricalresistance. Exposure to pristine and oxidized MWCNT, with or without natural rganic matter,did not markedly affect viability, which was assessed by measuring activity of relea sed lactatedehydrogenase (LDH) and staining with propidium iodide. Ultrastructural ana lysis revealedsome damage to microvilli colocalized with the MWCNT; however, neither typ of MWCNT was taken up by Caco-2 cells. In contrast, pristine and oxidized MWCNT were taken up by the macrophage RAW 264.7 line. Our study suggests that intestinal enterocytes cells do not take up MWCNT.