Representative images of Ana-1 cells subjected to silver staining and TEM. (a) Negative control cells treated with PBS buffer and the cells incubated with PEGylated Au DENPs (at the Au concentration of 100 μM (b) and 300 μM (c) for 24 h). The image (d) shows TEM images of cells incubated with PEGylated Au DENPs at the Au concentration of 300 μM for 24 h; and the image (e) shows the magnified view of the square area in (d). The black arrow in (e) shows the domain of Au DENPs. Scale bar measures 100 μm.