Fig. 3

The impact of CuO NMs and CuSO₄ on Caco-2 cell morphology. a) Following differentiation, cell monolayers were exposed to cell culture medium (control) or 6.34 μg/cm² Cu of CuO NMs and CuSO₄ for 24 h and then fixed and stained for the tight junction protein ZO-1 (green) and nucleus with DAPI (blue). The images were obtained with Zeiss LSM880 confocal microscope using the Zen program for data analyses. Scale bar = 20 μm. b) Assessment of cell morphology using SEM. Differentiated and undifferentiated Caco-2 cells were exposed to 12.68 μg/cm² Cu of CuO NMs for 24 h and then were washed, fixed, dehydrated, dried and examined by FIB/SEM. i and ii are control differentiated Caco-2 cells enlarged X 5000 and X 10000 respectively. iii and iv are control undifferentiated Caco-2 cells enlarged X 5000 and X 10000 respectively. v and vi are differentiated Caco-2 cells exposed to 12.68 μg/cm² Cu of CuO NMs enlarged X 5000 and X 10000 respectively and vii and viii are undifferentiated Caco-2 cells exposed to 12.68 μg/cm² Cu of CuO NMs enlarged X 5000 and X 10000 respectively