Figure 5. (A) In vivo imaging of mice injected peritumoral with poly(ethylene imine) (PEI)-PSiO₂ nanoparticles ( = MSNPs) or FA-MSNPs. Images of the abdominal and dorsal area demonstrate accumulation of fluorescence in the bladder and in the tumors, respectively. Images of the abdominal area show elimination of fluorescence within 48 h after injections. (B) Ex vivo analyses (left) and quantification of fluorescence intensity (right) in organs from mice injected intravenous with FA-MSNPs. (C) Histological analysis of brain, kidney, spleen, liver, and lungs of untreated mice and FA-MSNPs-treated mice showed no morphological changes. PSiO₂ nanoparticles accumulated in the tumors were biocompatible, biodegradable and eliminated through renal excretion. Reprinted with permission from reference 33.