Fig. 7

In vitro and in vivo MR/PA dual-modal Imaging a The linear relationship of T1 signal intensity and the concentration of MG@P NPs (0.5, 1.0, 2.0, 4.0 and 8.0 mg/mL); the inset was the T1-weighted MR images of MG@P NPs aqueous solutions at varied concentrations. b Time-dependent in vivo T1-weighted MR images of 4T1 tumor-bearing BALB/c mice after the intravenous injection of MG@P NPs. c Corresponding T1-weighted MR signal intensity of MG@P NPs in tumor varying with time. d Quantitative photoacoustic (PA) intensities of MG@P NPs in vitro. e The linear relationship of PA signal intensity and the concentration of MG@P NPs (0.5, 1.0, 2.0, 4.0 and 8.0 mg/mL); the inset was the PA images of MG@P NPs aqueous solutions at varied concentrations (λex = 690 nm). f Time-dependent PA images of 4T1 solid tumors after the intravenous injection of MG@P NPs. g The time-dependent PA signal intensity of MG@P NPs in tumor region