Fig. 4
Induction of intracellular ROS generation by SiNPs in HUVECs. a, representative ROS images (green) measured with fluorescence microscopy. Both SiNP-20 and SiNP-100 induced ROS generation in a concentration (0–100 μg/mL)-dependent manner. As a positive control, H2O2 (7.5 mg/mL) increased the ROS level in HUVECs. Scale bar = 50 μm. b, flow cytometry assay for ROS detection, which showed the time course of ROS generation in HUVECs exposed to SiNPs at a fixed concentration (100 μg/mL). A rightward shift of the trace indicated ROS elevation. Both SiNP-20 and SiNP-100 induced significant ROS generation especially at 2–4 h after exposure. Counts, cell numbers