Fig. 3: MRI/SPECT/CT imaging, pharmacokinetics and biodistribution of Mb@Gd-NTs.

a In vitro phantom MRI contrast images of different concentrations of Mb@Gd-NTs. b Linear fitting of R₁ (1/T₁) values as a function of different concentrations of Gd-Tex-lipid and the r₁ value of the intact or dissociated Mb@Gd-NTs. c In vivo T₁-weighted MRI imaging of LLC tumor-bearing mice before and 4 h, 24 h, and 48 h after the injection of Mb@Gd-NTs. d SPECT/CT images of LLC tumor-bearing mice acquired at 2–72 h after i.v. injection of Mb@¹⁷⁷Lu/Gd-NTs. These experiments (a–d) were repeated three times independently with similar results. e Biodistribution of Mb@¹⁷⁷Lu/Gd-NTs in tumors and major organs measured at 6, 24, 48, and 72 h post-injection. The data (e) are shown as the mean ± SD (n = 4 mice). f In vivo fluorescence imaging of LLC tumor-bearing mice 0.5–72 h after i.v. injection of free Cy5.5-Mb, Cy5.5-Mb@NTs and Cy5.5-Mb@Gd-NTs (n = 4 mice, cf. Supplementary Fig. 9). g The content of Cy5.5- Mb or Cy5.5-Hb in lungs, muscles, and tumors 2 h after the injection of free Cy5.5-Mb and 24 h after the injection of Cy5.5-Mb@NTs, Cy5.5-Hb@NTs, and Cy5.5-Mb@Gd-NTs. The data (g) are shown as the mean ± SD (n = 4 mice). h Pharmacokinetic studies of Cy5.5-labeled different agents. The data (h) are shown as the mean ± SD (n = 4 mice). i, j Immunofluorescent staining of the hypoxic region (pseudo-red color) of tumor tissue sections and the corresponding semi-quantification results (j). Cell nuclei were stained with DAPI (pseudo-blue color). Tumors were excised from mice 2 h after the injection of free Mb and 24 h after the injection of different liposomes. Scale bar, 60 μm. The data (j) are shown as the mean ± SD (n = 6 mice). Statistical analysis was performed by a two-tailed unpaired t test (g, h, j). ^*P < 0.05; ^**P < 0.01^{; ***}P < 0.001. Source data are provided as a Source Data file.