Fig. 2
Cellular uptake, subcellular distribution, and cytotoxicity. A, B Subcellular distribution of the liposomes in tumor cells. Nucleus, lysosomes, and mitochondrion were stained with Hoechst 33,342 (blue), LysoTracker Green (green), and MitoTracker Green (green), respectively. Scale bar = 50 μm. C The cellular uptake of Cy5-labeled liposomes in MC38 cells was examined by flow cytometry. D Quantification of fluorescence intensity of the cellular uptake in a time-dependent manner. E Cell viability was measured by CCK-8 assay after treatment with CPT11, PBSN38L, and CPBSN38L in MC38 cells without or with ultrasound irradiation under different SN38-equivalent concentrations. The cells were incubated with drugs for 6 h, followed by US irradiation under the intensity of 0.8 W/cm2, 3 MHz, 50% of the duty cycle for 5 min, followed by incubation for 42 h. F Flow cytometry analysis of cell apoptosis after different treatments, and the G representative flow cytometry dot plot in each group. The SN38-equivalent concentration is 10 µM