Figure 6.

Translocation of p(4VP)-MWCNTs across alveolar epithelial cell monolayers depends on temperature, cell type and exposure time. (a) Uptake of non-fMWCNTs and p(4VP)-MWCNTs (300nm and 700nm long) by TT1 cells observed at 4 and 37°C. A significant decrease (**p<0.001, n=3 experiments with 300 total observed cells) in percentage of cell uptake of 300 and 700nm p(4VP)-MWCNTs was observed at 4°C. (b) Both the 300 and 700nm p(4VP)-MWCNTs were detected in the basal chambers of the TT1 cell models after 24h exposure. The p(4VP)-MWCNTs did not cross AT2 monolayer (panel b and c; n= 5 subject samples). (c) The rate of p(4VP)-MWCNT transport was plotted against time; there was no translocation across AT2 cells (n=5subject samples). Translocation across TT1 cells increased significantly over 24 hours for both lengths of MWCNTs (*p<0.01,**p<0.001, n=3 experiments). (d) TT1 cell viability was unaffected by 300 and 700nm p(4VP)-MWCNTs over 7 days treatment. (e) TT1 TEER values decreased significantly (*p<0.01,**p<0.001, n=3) at days 1, 3 and 7. (f) The percent TT1 cell uptake of applied p(4VP)-MWCNTs depended on the length of the p(4VP)-MWCNTs and exposure time. More uptake was observed with 300nm p(4VP)-MWCNTs (d;**p<0.001, n=3 experiments), and cell uptake increased as a function of time in TT1 cells.