Figure 4: Analysis of biodistribution of siRNA in various tissues after 4 hours of dose administration. (a) Histopathological images of heart, lungs, kidney, liver, and spleen obtained from a mouse xenograft model of colon cancer. The represented dark brown staining in the tissues emphasizes the presence of scrambled biotinylated siRNA (0.5 mg/kg) with different treatment formulations: chitosan-PEG-CP15, Unmodified chitosan nanoparticles, non-targeting biotin-siRNA alone, and control as untreated. (b) Image analysis of the mean percent area stained in the tumor tissues. The graph shows a representative result of the average of two random sections measured per animal tissue, mean ± SD. , .