The assessment of tumor cell uptake capacity for RTD. (A) Representative fluorescent microscopy images of SU-DHL-4 (scale bar, 50 μm). (B) Representative fluorescent microscopy images of U2932 (scale bar, 50 μm). (C) Flow histogram of Cy5 positivity after incubating SU-DHL-4 cells with Cy5-labeled TDN/RTD. (D) Flow histogram of Cy5 positivity after incubating U2932 cells with Cy5-labeled TDN/RTD. (E) Statistical analysis of Cy5 positive cells from panel C. (F) Statistical analysis of Cy5 positive cells from panel D. The results of histogram from panels E-F are shown as mean ± SD (n = 3; ∗∗∗P < .001; ∗∗∗∗P < .0001), compared to control group by 1-way ANOVA. Unpaired t test was used for comparison between 2 groups.