Fig. 3

Tumor microenvironment responsive ability of MRf NCs. a DCF fluorescence (ROS level) images of 4T1 cells after different treatment. b DCF fluorescence intensity in different treatment groups (Ex/Em = 488 nm/525 nm). c pH changes of different pH PBS solutions after PEI-MnCO₃ and commercial MnCO₃ treatment. d BCECF fluorescence intensity in different treatment groups (Ex/Em = 430 nm/530 nm). Data are represented as mean ± SD; n = 4; Statistical significance was analyzed by the two-tailed Student’s t-test. *p < 0.05, **p < 0.01. All light treated groups were compared to the dark treated group in c. And all groups are compared to control group in e. e BCECF fluorescence (pH changes) images of 4T1 cells after different treatment