Fig. 5: Catalytic activity and cytotoxicity of VPCaNPs.

a Cell viability of VPQDs, CaNPs, and VPCaNPs by cck8 assays. Data are presented as the mean with SD (n = 4 biologically independent cells). Statistical differences were analyzed by a two-way ANOVA with Tukey’s multiple comparisons test. b Representative fluorescence quantification of intracellular cy5-labled VPCaNPs with different incubation time. c Representative fluorescence image of 4T1 cells incubation with cy5-labeled VPCaNPs for 4 h. This experiment was repeated three times independently with similar results. Representative fluorescence quantification of intracellular level of (d) ROS, (e) O₂, (f) ·O₂⁻, (g) H₂O₂, and (h) ·OH of 4T1 cells incubation with saline, VPQDs, CaNPs, and VPCaNPs for 6 h by FCM. Representative FCM images of (i) JC−1, (j) red/green ratio of lipid peroxidation probe, C11-BODIPY(581/589), and (k) PI and annexin V-FITC of 4T1 cells incubation with saline, VPQDs, CaNPs, and VPCaNPs for 12 h. The saline groups were control groups. Each experiment was repeated three times independently with similar results.