Figure 4.

ZnO NPs induced the production of ROS in HaCaT cells.

Notes: Cells grown in a culture plate were treated with nanoparticles at 20 μg/mL for (A) 0, (B) 6, or (C) 24 hours, or (D) 10 days, washed with cold phosphate-buffered saline, and then incubated with DCFH-DA. The samples were measured by flow cytometry. (E) Relative analysis of each sample by software FlowJo 7.6. The x-axis shows the intensity of fluorescence representing the level of ROS, and the y-axis shows the measured cell quantity.

Abbreviations: ROS, reactive oxygen species; DCFH-DA, 2′,7′-dichlorodihydrofluorescein diacetate.