Fig. 2

Drug-loaded SMPs have an enhanced ability to accumulate in tumours. A–C Uptake of PKH26-stained MPs by A549 cells at different times. PKH26-stained MPs were incubated with A549 cells, the cell uptake ratio and average fluorescence intensity were detected by flow cytometry at different times. A PKH26 positive ratio. B, C Mean fluorescence intensity (MFI) of PKH26. D Confocal fluorescence showed the subcellular localization of PKH26-MPs uptake by A549 cells. PKH26-stained MPs were incubated with CFSE-stained A549 cells, after 20 h, cells were stained with DAPI and observed under two-photon laser scanning fluorescence microscope. Scale bar = 20 μm. E In vivo distribution of MPs. Lewis cells were subcutaneously inoculated into C57 mice on Day 0, and DiR-labelled MPs were intravenously injected into the mice on Day 14, and fluorescence imaging of live and isolated organs was performed 24 h later. The organs in the left column were liver, lung and tumour from top to bottom, and the organs in the right column were spleen, kidney and heart from top to bottom. F Detection of drug loading in organs. Mice with Lewis subcutaneous tumours were injected intravenously with methotrexate-loaded MPs, and their organs and tissues were taken at different times, and the amount of methotrexate in each organ tissue was detected by high-performance liquid chromatography (n = 3)