Fig. 4

Cellular uptake and therapeutic efficacy of PEG/Cu-BDC against 4T1 breast tumor cells. a CLSM images of 4T1 breast tumor cells after incubated with FITC-labeled PEG/Cu-BDC for various durations (1, 2, 4, and 6 h). Scale bars: 30 μm. b Intracellular ROS generation in 4T1 breast tumor cells after cultured with various concentrations of PEG/Cu-BDC (0, 20, 50, and 100 μg mL⁻¹). Scale bars: 50 μm. c Cellular viability of the 4T1 breast tumor cells after incubated with PEG/Cu-BDC for 24 and 48 h, respectively (n = 5 biologically independent samples). d Live/dead staining of 4T1 breast tumor cells with calcein AM and PI, respectively. Scale bars: 100 μm. e Flow cytometry analysis showing apoptosis of 4T1 breast tumor cells after incubation with different concentrations (0, 20, 50, and 100 μg mL⁻¹) of PEG/Cu-BDC for 24 h