Fig. 5: Intestinal barrier penetration mechanism and anti-tumor ability in vitro.

a Differential Gene Visualization Scatter Map and Volcano Map Display (FPKM). MSN/PB was applied to Caco-2 cells, irradiated under 808 nm laser for 5 min, and incubated for 4 h. b Column diagram of KEGG annotation of up-regulated and down-regulated differentially expressed genes. c Tightly connected signal path scheme. NO upregulates the cGMP/PKG signaling pathway by activating sCG. This step, in turn, inhibits RhoA/ROCK, resulting in downregulation of tight junction related proteins Claudin-1, Occludin, and ZO-1, thus opening the intestinal epithelial barrier. d, e Western blot and quantification of the expression levels of RhoA, ROCK, Claudin-1, Occludin and ZO-1 in Caco-2 cells incubated with different nanoparticles for different times (n = 3 independent experiments). 1, 4 h: control; 2, 4 h: MSN/PB; 3, 4 h: PB + NIR; 4, 4 h: MSN/PDA + NIR; 5, 4 h: MSN/PB + NIR; 6, 24 h: MSN/PB + NIR. f A diagram illustrating the mucus-producing transwell model, which is composed of Caco-2 and HT29-MTX cells. g CLSM images showing the CT26 cells in the basal chamber following a 4 h incubation period with various nanoparticles located in the apical chamber. h The MFI of CT26 cells in the basal chamber after being incubated with different nanoparticles in the apical chamber for 4 hours (n = 3 independent experiments). i The viability of CT26 cancer cells after being incubated with various nanoparticles for 24 hours (n = 3 independent experiments). j The proportion of dead CT26 cells after incubation with different nanoparticles for 24 h (5 μg mL⁻¹, based on CP content; n = 3 independent experiments). k Fluorescence images of live/dead cell staining of CT26 cells stained with Calcein AM/propidium iodide (PI) after incubation with different nanoparticles for 24 hours. The experiment was repeated independently and yielded similar results. l Flow cytometric analysis of CT26 cells in the mucus-producing transwell model after 24 h of incubation with various nanoparticles. Data are presented in the form of mean values ± SD. Significance was assessed via one-way ANOVA with Tukey’s post hoc test. Source data are provided as a Source Data file.