Fig. 4: Intracellular behaviors of CAA-PEG NSs in colorectal tumor cells.

a Confocal microscopy images of CT-26 cells treated with ICG or ICG-labeling CAA-PEG NSs for 4 h incubation. b Bio-TEM images of CT-26 cell sections after incubation with CAA-PEG NSs for different time intervals. c Valence transition of As^V to As^III of CAA-PEG NSs in CT-26 cells and cell apoptosis causing by As^III. Created in BioRender. Jiang, L. (2025) https://BioRender.com/b39z422d Valence transition efficiency of As^V to As^III in CT-26 cells (Data are presented as mean values +/− SD, n = 3 independent experiments). e Western blot analysis of cell apoptosis-related proteins (P53, P21) after different treatments (One representative gel from three repeated gels). H₂S content change in CT-26 cells after treatment with CAA-PEG NSs for different time intervals observed by confocal microscopy (f) and flow cytometry (g), and its quantitation. h Western blot analysis of CBS in CT-26 cells after treatment with CAA-PEG NSs (One representative gel from three repeated gels). i CT-26 cell viability treated with different concentrations of CAA-PEG NSs with or without laser irradiation (Data are presented as mean values +/− SD, n = 3 independent experiments. Two-way ANOVA analysis and Sídík’s Multiple Comparison Test was used to compare the Laser +/− groups, P values were presented in absolute value in the figures). j Live/dead cell staining assay of CT-26 cells after treatment with CAA-PEG NSs with or without laser irradiation.