Figure 3

(a) TEM image of an A549 cell after incubation with 10 μg/ml silica NPs for 24 hrs at 37°C. (b) Higher magnification image of the area indicated by the box in (a). (c) TEM image of A549 cells after incubation with 100 μg/ml silica NPs for 24 hrs at 37°C, showing a corner of one of the few remaining cells and surrounding it a large amount of cell debris, which was predominant throughout the sections. (d) EDX spectrum from the silica NP containing region of the A549 cell shown in (b).