Figure 5: Representative images of randomly selected microscopic fields of the colonies formed after 10 consecutive days exposure to increasing concentrations (0.05–100 μg/mL) of Cd-SiO2NPs, CdCl2, and SiO2NPs. SiO2NP colonies showed similar patterns at the all tested doses to the control (control data not shown). Few colonies with reduced size compared to control were observed at the lower concentrations (0.05–10 μg/mL) of Cd-SiO2NPs and CdCl2, while there was a total inhibition of the colonies at the higher tested doses (25–100 μg/mL) for both Cd-SiO2NPs and CdCl2. (Scale bar: 600 μm).