Fig. 4
a, b CLSM observation: the internalization process of 4T1 cells treated with FMS and PDGFB-FMS at a certain concentration of 10 μg/mL for 1, 2, and 4 h. c, d CLSM observation: the internalization process of 4T1 cells treated with different concentrations of FMS and PDGFB-FMS for 4 h. e T1WI and f T2WI of the cells treated with different samples (* and # represent PDGFB-FMS and FMS, respectively) at different time points, and h, i the corresponding T1 and T2 MRI SNR analysis. g T1WI and T2WI of 4T1 cells treated with PDGFB-FMS at the presence of different concentrations of GSH, and j the corresponding T1 and T2 MRI SNR analysis