Fig. 3
PDA NPs ameliorate UVR-induced Cell Death and Scavenge UVR-induced ROS in keratinocytes. (A, B) Flow cytometry analysis plots and quantifications of cell death of HaCaT cells pretreated with PDA NPs (0, 20,40, 60 mg/mL) for 24 h followed by UV irradiation (UVB 50 mJ/cm2). (C, D) Representative fluorescent images and quantification of ROS level in HaCaT cells pretreated with 20 mg/mL PDA NPs for 24 h followed by UV irradiation (UVA 200 mJ/cm2 + UVB 10 mJ/cm2, or UVA 400 mJ/cm2 + UVB 20 mJ/cm2). The ROS level was probed by DCFH-DA (green). Scale bar = 100 μm. (E, F) Flow cytometry analysis plots and quantifications of ROS level in HaCaT cells pretreated with 20 mg/mL PDA NPs for 24 h followed by UV irradiation (UVA 200 mJ/cm2 + UVB 10 mJ/cm2, or UVA 400 mJ/cm2 + UVB 20 mJ/cm2). The ROS level was detected by DHE fluorescent probes (PE-TexasRed). All data represent the mean ± SD. *p < 0.05, **p < 0.01 and ***p < 0.001