Fig. 4

Cellular localization of GQDs and intracellular ROS generation. a, b Confocal microscopy images of GQDs-treated MCF-7 cells (a: scale bar: 50 µM, b:scale bar:10 µM). c Fluorescence intensity of DCF in 4T1 cell lines at 2, 15 and 24 h post-treatment of PBS, GQDs (100 µg/ml), TME (100 µM H₂O₂), GQD (TME) (100 µg/ml GQDs + 100 µM H₂O₂). d intracellular ROS level in 4T1 cells (green signals from DCF indicate ROS; blue signals from DAPI indicate nuclei), scale bar: 100 µm. e Quantified intracellular ROS level in 4T1 cells treated with agents: PBS, GQDs (100 µg/ml), TME (100 µM H₂O₂), GQD (TME) (100 µg/ml GQDs + 100 µM H₂O₂) for 2 h, measured by flow cytometry. Data are presented as mean ± standard deviation, and analyzed by unpaired Student’s two-tailed t-test, compared to PBS group. *p < 0.05, **p < 0.01, ***p < 0.001