Fig. 1.

Cell viability and intracellular ROS levels of HaCaT cells treated with GrDENs. (A and B) HaCaT cells were treated alone with GrDENs (0–2 × 10⁹ particles/mL) for 24 h in panel A. For panel B, HaCaT cells were pre-treated with GrDENs (0–2 × 10⁹ particles/mL) for 30 min and stimulated with UVB irradiation for 24 h. Cell viability was examined by MTT assay. (C and D) HaCaT cells were pre-treated with GrDENs (0–2 × 10⁹ particles/mL) for 30 h and irradiated by UVB for 24 h, and the cells were incubated with H2DCFDA (C) or DCFH-DA (D) for 20 min. Intracellular ROS levels were determined by fluorescent imaging (C) and flow cytometry (D). Fluorescent intensity was measured with ImageJ (C). Data in (A), (B), and (C) are presented as mean ± standard deviation of at least three independent experiments. Results in (D) are representative images from three independent experiments. ##p < 0.01 compared to the normal group (non-treatment), and *p < 0.05, **p < 0.01 compared to the control group (UV irradiation).