Development of 99mTc(CO)3-dendrimer-FITC for cancer imaging

Study of fluorophore and technetium labeling of poly(amido)-amine (PAMAM) generation 4 (G4) dendrimer and its evaluation as potential molecular imaging agent in both normal and melanoma-bearing mice, are described. Dendrimers were first conjugated with FITC (fluorescein isothiocyanate). Dendrimer-FITC was then incubated with the intermediate [Tc-99m(CO)(3)(H2O)(3)](+) and purified by gel filtration. Biodistribution and scintigraphy images were performed administrating Tc-99m(CO)(3)-dendrimer-FITC to normal mice (NM) or melanoma-bearing mice (MBM). Cryostat tissue sections from MBM mice were analyzed by confocal microscopy. Radiolabeling yield of dendrimer was approx. 90%. The Tc-99m(CO)(3)-dendrimer-FITC complex was stable for at least 24 h. Biodistribution studies in NM showed blood clearance with hepatic and renal depuration. MBM showed a similar pattern of biodistribution with high tumor uptake that allowed tumor imaging. Confocal microscopy analysis showed cytoplasmic distribution of Tc-99m(CO)(3)-dendrimer-FITC. (C) 2011 Elsevier Ltd. All rights reserved.