Lys3-Bombesin Conjugated to99mTc-Labelled Gold Nanoparticles for In Vivo Gastrin Releasing Peptide-Receptor Imaging
The gastrin releasing peptide-receptor (GRP-r) is over-expressed in breast and prostate cancer and lymph node metastases. Lys3-bombesin is a peptide that binds with high affinity to GRP-r. The aim of this research was to prepare a multifunctional system of technetium-99m labelled gold nanoparticles conjugated to Lys3-bombesin/HYNIC-GGC and to evaluate its biological behaviour as a potential radiopharmaceutical for in vivo GRP-r imaging. Methods: Lys3-bombesin and hydrazinonicotinamide-Gly-Gly-Cys-NH2 (HYNIC-GGC) peptides were conjugated to gold nanoparticles (AuNP, 20 nm) to prepare a multifunctional system of HYNIC-GGC-AuNP-Lys3-bombesin by means of spontaneous reaction of the thiol (Cys) present in HYNIC-GGC sequence and the amine of Lys3-bombesin. The nanoconjugate was characterized by transmission electron microscopy (TEM), IR, UV–Vis, Raman, and X-ray photoelectron spectroscopy (XPS). Technetium-99m labelling through the HYNIC-GGC ligand was carried out using EDDA/tricine as coligands and SnCl2 as reducing agent with further size exclusion chromatography purification. Radiochemical purity was determined by size exclusion HPLC and ITLC-SG analyses. In vitro binding studies were carried out in human prostate cancer PC-3 cells (GRP-r positive cells). Biodistribution studies were accomplished in athymic mice with PC-3 induced tumours and images obtained using a micro-SPECT/CT system. Results: TEM and spectroscopy techniques demonstrated that AuNPs were functionalized with HYNIC-GGC-NH2 and Lys3-bombesin through interactions with thiol groups of Cysteine and the N-terminal and -amine of Lysine respectively. Radio-chromatograms showed radiochemical purity higher than 95%.99mTc-EDDA/HYNIC-GGC-AuNP-Lys3-bombesin (99mTc-AuNPLys3-bombesin) showed specific recognition for GRP-r over-expressed in PC-3 cells. After administration of99mTc-AuNP-Lys3-bombesin in mice the pancreas-to-blood ratio was 36 at 1 h demonstrating ability to target in vivo GRP receptor-bearing cells. In vivo micro-SPECT/CT images in mice showed an evident tumour uptake (6.39± 0.83% IA/g at 1 h). Conclusions: This study demonstrated that the99mTc-AuNP-Lys3-bombesin multifunctional system shows specific recognition for GRP-r and suitable properties to be used as a molecular imaging agent.
No Reference information available - sign in for access.
No Citation information available - sign in for access.
No Supplementary Data.
No Article Media
Document Type: Research Article
Publication date: August 1, 2010
More about this publication?
- Journal of Biomedical Nanotechnology (JBN) is a peer-reviewed multidisciplinary journal providing broad coverage in all research areas focused on the applications of nanotechnology in medicine, drug delivery systems, infectious disease, biomedical sciences, biotechnology, and all other related fields of life sciences.
- Editorial Board
- Information for Authors
- Subscribe to this Title
- Terms & Conditions
- Ingenta Connect is not responsible for the content or availability of external websites