Gastrin releasing protein receptor specific gold nanorods: Breast and Prostate tumor avid nanovectors for molecular imaging

Gastrin releasing protein receptor speci?c bombesin (BBN) peptide-gold nanoconjugates were successfully synthesized using gold nanorods and dithiolated peptide. The gold nanorod-bombesin (GNR-BBN) conjugates showed extraordinary in vitro stabilities against various biomolecules including NaCl, cysteine, histidine, bovine serum albumin, human serum albumin, and dithiothreitol. Quantitative measurements on the binding af?nity (IC50) of GNR-BBN conjugates toward prostate and breast tumor cells were evaluated. The IC50 values establish that GNR-BBN conjugates have strong af?nity toward the gastrin releasing peptide receptors on both the tumors. Detailed cellular interaction studies of GNR-BBN conjugates revealed that nanorods internalize via a receptor-mediated endocytosis pathway. The receptor speci?c interactions of GNR-BBN conjugates provide realistic opportunities in the design and development of in vivo molecular imaging and therapy agents for cancer.