Fig. 5

In vivo biodistribution imaging of siRNA/ELP variant complexes. a For in vivo IVIS imaging, Cy5.5 labelled siRNA (5 µg) was encapsulated by 200 µM of the ELPs. SiRNA/ELPs complexes were intravenously injected to 4T1 tumor bearing Balb/c wild type mice (n = 10). The tumors and organs were excised at 6 h post administration and fluorescence intensities were determined by IVIS imaging. Representative optical images of three independent experiments. b Quantification of the ex vivo fluorescence intensities of tumors and other organs at 6 h after injection (n = 10). *P < 0.05 (Student’s t-test), significant difference for Tat-A₁E₂₈ or Tat-A₄V₄₈ compared with free-siRNA. c Histological analysis of the localizations of siRNA/ELP variant complexes (red) in tumors at 6 h after injection. Nuclei were stained with Hoechst (blue), and IL-4R expression on cells was visualized by anti-IL-4 receptor antibody staining (green). The confocal images are representative of three experiments (Scale bar, 20 μm)