Figure 3.

CCL21a/Exo^GM‐CSF+Ce6@nanoGel in combination with SDT induces cancer cell death. A) Scanning electron micrographs of Exo^GM‐CSF@Gel and Exo^GM‐CSF@nanoGel. Scale bars, 100 nm. B) Releasing profile of Exo^GM‐CSF from the hydrogels. Data are expressed as mean ± S.E.M of three independent experiments. **, P ＜0.01 by two‐way ANOVA. C) Schematic showing the experimental procedure of tracking exosome engulfed by the cells in the hydrogel. D) The intracellular distribution of DiI‐labeled exosomes in hydrogels was analyzed by fluorescence microscopy. Nuclei were counterstained with Hoechst. Cell membranes were labeled with DiO. Scale bar, 50 µm. E) Schematic showing composited hydrogel formation. F) Profile of CCL21a released from the indicated hydrogels. Data are expressed as mean ± S.E.M of three independent experiments. *, p < 0.05 by two‐way ANOVA. G) Schematic illustration of sonodynamic therapy effect in vivo. CT26.WT‐GFP tumor‐bearing mice were randomly divided into six groups: None@nanoGel (G1′), None@nanoGel/US group (G1), CCL21a/Exo^Ctrl@nanoGel (G2′), CCL21a/Exo^Ctrl@nanoGel/US group (G2), CCL21a/ Exo^Ctrl+Ce6 @nanoGel/US group (G3), and CCL21a/Exo^GM‐CSF+Ce6@nanoGel/US group (G4). On the 7th day of subcutaneous tumor inoculation, hydrogels with different components were injected beside the tumor. Ultrasound irradiation was performed every 4 h for three times on day 8. The mice were sacrificed and hydrogels were harvested for further analysis on day 10. H) Representative images of TUNEL staining of hydrogel slices from different groups. Nuclei, blue; CT26.WT‐GFP, Green; TUNEL, red. Scale bar, 30 µm. I) Percentages of CT26.WT‐GFP in the hydrogel on day 10. Data are expressed as mean ±S.E.M of three independent experiments. ***, p < 0.001 by one‐way ANOVA. J) Percentage of apoptotic CT26.WT‐GFP cells in indicated groups. Data are expressed as mean ± S.E.M of three independent experiments. ***, p < 0.001; ns, no significance by one‐way ANOVA.