Fig. 1

Synthesis and cellular-level evaluations of ¹³¹I-MnO₂-BSA. a The synthesis and action procedures of radionuclide labeled MnO₂-BSA (i.e., ¹³¹I-MnO₂-BSA) and the enhanced IRT. b TEM images with low- and high- (inset) magnifications of MnO₂-BSA; c Size distribution of ¹³¹I-MnO₂-BSA determined by DLS in PBS. d UV–Vis absorbance spectra of ¹³¹I-MnO₂-BSA with different concentrations in PBS. e Narrow-band XPS spectrum of ¹³¹I-MnO₂-BSA, and Mn 2p XPS spectra with high resolution were recorded. f Oxygen dissolution level of ¹³¹I-MnO₂-BSA after incubation with H₂O₂ (5 mM) for different durations. g Radiolabeling stability tests of ¹³¹I-MnO₂-BSA at 37 °C in PBS, FBS and serum. h, i Fluorescence images (h) and the corresponding mean fluorescence intensity (MFI) (i) of ROS in 4T1 cells stained with DCFH-DA after various treatments. j Flow cytometry (FCM) patterns of 4T1 cells stained with propidium iodide (PI) and annexin V-FITC after various treatments for determining the apoptosis level. P values were calculated by ANOVA (***p < 0.001). Data are expressed as mean ± standard deviation (SD) (n = 3)