Fig. 4.

In vitro cytotoxicity and cellular uptake. a Flow cytometry analysis of HeLa cells incubated with blank (left) and APTES-COF-1 (right). The four areas represent the different phases of the cells: necrotic (B1), late-stage apoptotic (B2), early apoptotic (B4), and live (B3). b Confocal images of HeLa cells recorded at 6 h after co-incubation with the three different DOX (red channel)-loaded PEG-CCM@APTES-COF-1 nanoparticles (NPs) (green channel). c Co-localization ratio analysis on HeLa cells between the red channel from DOX and green channel from CCM and that between the red channel from DOX and the blue channel from the stained nuclei. Each data point represents the average and SD (one above and one below for the error bars), as measured from five different analysis in a single experiment. d Confocal images of HeLa cells after treatment with DOX-loaded APTES-COF-1 at different times corresponding to in vivo release. The inset shows the corresponding large APTES-COF-1 aggregates of the area within the dotted circle on the cell surface. e Confocal images of HeLa cells after treatment with CCM-loaded APTES-COF-1 at different times corresponding to in vivo release. The inset shows the corresponding large APTES-COF-1 aggregates of the area on the cell surface. The blue channel was excited at 405 nm and collected between 450 and 500 nm; the green channel was excited at 488 nm and collected between 510 and 550 nm; the red channel was excited at 543 nm and collected between 590 and 650 nm. The scale bars are 20 μm. f Luminescent image of the CCM after addition of sample to the medium