Fig. 7.

CuO NM and CuSO₄ cellular uptake and translocation across the co-culture barrier. The Caco-2/Raji B and Caco-2/HT29-MTX co-cultures were exposed to CuO NMs or CuSO₄ at concentrations of 3.17, 6.34 or 12.68 Cu µg/cm² for 24 and 48 h. The level of Cu in the AP (a) and BL (b) compartments, and the cells (c) was evaluated by ICP-OES. Data are expressed as mean copper concentration (as a percentage of the exposed concentration) ± SEM (n = 3). Significance at p < 0.05 is indicted by * for comparison of CuO NMs at a concentration of 3.17 Cu µg/cm² to the other treatment concentrations within each time point or # for comparison of equivalent concentrations between 24 and 48 h time points