Fig. 5From: Label-free cell based impedance measurements of ZnO nanoparticles—human lung cell interaction: a comparison with MTT, NR, Trypan blue and cloning efficiency assaysInteraction of ZnO NPs with A549 cells. Scanning electron microscopy observations. a and b A549 cells treated with 5 μg/cm2 ZnO NPs for 24 h. c A549 cells treated with 5 μg/cm2 ZnO NPs for 48 h. d A549 cells treated with 20 μg/cm2 ZnO NPs for 24 h. e and f A549 cells treated with 20 μg/cm2 ZnO NPs for 48 hBack to article page