Fig. 3

Cellular uptake of FITC-PT and FITC-SP. A Representative CLSM images of 143B cells and of 4T1 cells incubated with FITC-PT (20 µg mL⁻¹) for different time. Scale bar = 20 μm. Representative images and quantitative statistics of NIR-II fluorescence intensities of 143B or 4T1 cells incubated with different concentrations of SPN-PT (from left to right: 10 µg mL⁻¹, 20 µg mL⁻¹, 40 µg mL⁻¹) for 12 h (B) and 24 h (C). Flow cytometry analysis of 143B cells incubated with FITC-PT (20 µg mL⁻¹) (D) and FITC-SP (20 µg mL⁻¹) (E) for different time (from left to right: Con (control), 15 min, 30 min, 2 h, 4 h). Data were shown as mean ± SD, n = 3