Fig. 3

In Vitro Cellular Assay. a Fluorescence microscopy images of MNNG/HOS cells after 4 h incubation with ICG, ICG@HTP and ICG@HTPR NPs. b Co-localization of the test NPs into mitochondria of MNNG/HOS cells. c Corresponding fluorescence microscopy images of MNNG/HOS cells stained with Calcein-AM and PI. d Flow cytometry apoptosis experiment based on annexin V-FITC/PI staining of MNNG/HOS cells after incubation with different formulations for 24 h, including control group, PBS, AIBI (50 μg/mL), AHPR (120 μg/mL, equivalent AIBI dosage of 50 µg/mL), AHTPR (120 μg/mL, equivalent AIBI dosage of 50 µg/mL), and 808 nm laser (1.0 W cm⁻², 5 min). Cells without treatment were used as control. e Apoptosis ratios of cells after corresponding treatment was quantified. (*P < 0.05, **P < 0.01, ***P < 0.001)