Bio-distribution of sCA-siRNA in normal and tumor tissues.

<p>(A) CT imaging of Alexa Fluor 750 labeled siRNA in FaDu tumors at 4 and 12 h. The red dashed circles indicate tumors. (B) <i>Ex vivo</i> imaging at 9 and 16 h comparing sCA with IF and Atelo. (C) Detection of siRNA in HCT116 tumor at 4 h by light sheet fluorescence microscopy. The microvasculature was visualized as red signals by intravenous injection of Texas Red conjugated dextran. Green: 6-FAM labeled siRNA. Scale bar, 10 μm. (D) IVIS spectrum CT imaging 12 h after treatment. Mice were treated with 40 μg of Alexa Fluor 750 labeled siRNA delivered with Invivofectamine 2.0 (IF), AteloGene (Atelo), or sCA by intravenous administration via tail vein. Left panel: whole mouse imaging; right panel: CT scan images of lung and liver. (E) Detection of 6-FAM labeled siRNA distribution by fluorescence microscopy in liver 4 h after intravenous injection. The microvasculature was visualized with red signals by intravenous injection of Texas Red conjugated dextran. Left, 6-FAM labeled siRNA; right, merged images of the left panel and Texas Red stained blood vessels with DAPI. Scale bar, 50 μm. (F) Quantitative analysis of fluorescence intensity at 4 and 12 h. Fluorescence of 6-FAM was calculated as fluorescence intensity/area and normalized against that of control sections. Data represent mean ± SEM. Liver: n = 12∼15 fields of view (FOV) from 4 mice; Spleen: n = 12∼20 FOV from 4 mice; Kidney: n = 8∼16 FOV from 4 mice; HCT116: n = 21∼24 FOV of 6 tumors; HT29: n = 8∼24 FOV of 6 tumors (Wilcoxon rank test).