International Journal of Nanomedicine (Apr 2019)
68Ga-radiolabeled bombesin-conjugated to trimethyl chitosan-coated superparamagnetic nanoparticles for molecular imaging: preparation, characterization and biological evaluation
Abstract
Maliheh Hajiramezanali,1 Fatemeh Atyabi,2,3 Mona Mosayebnia,1 Mehdi Akhlaghi,4 Parham Geramifar,4 Amir Reza Jalilian,4 Seyed Mohammad Mazidi,5 Hassan Yousefnia,6 Soraya Shahhosseini,7 Davood Beiki4 1Department of Radiopharmacy, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran; 2Department of Pharmaceutical Nanotechnology, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran; 3Nanotechnology Research Centre, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran; 4Research Center for Nuclear Medicine, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran; 5Radiation Application Research School, Nuclear Science and Technology Research Institute (NSTRI), Tehran, Iran; 6Material and Nuclear Fuel Research School, Nuclear Science and Technology Research Institute (NSTRI), Tehran, Iran; 7Department of Radiopharmacy and Pharmaceutical Chemistry, School of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran Introduction: Nowadays, nanoparticles (NPs) have attracted much attention in biomedical imaging due to their unique magnetic and optical characteristics. Superparamagnetic iron oxide nanoparticles (SPIONs) are the prosperous group of NPs with the capability to apply as magnetic resonance imaging (MRI) contrast agents. Radiolabeling of targeted SPIONs with positron emitters can develop dual positron emission tomography (PET)/MRI agents to achieve better diagnosis of clinical conditions.Methods: In this work, N,N,N-trimethyl chitosan (TMC)-coated magnetic nanoparticles (MNPs) conjugated to S-2-(4-isothiocyanatobenzyl)-1,4,7,10-tetraazacyclododecane tetraacetic acid (DOTA) as a radioisotope chelator and bombesin (BN) as a targeting peptide (DOTA–BN–TMC–MNPs) were prepared and validated using fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), and powder X-ray diffraction (PXRD) tests. Final NPs were radiolabeled with gallium-68 (68Ga) and evaluated in vitro and in vivo as a potential PET/MRI probe for breast cancer (BC) detection.Results: The DOTA–BN–TMC–MNPs with a particle size between 20 and 30 nm were efficiently labeled with 68Ga (radiochemical purity higher than 98% using thin layer chromatography (TLC)). The radiolabeled NPs showed insignificant toxicity (>74% cell viability) and high affinity (IC50=8.79 µg/mL) for the gastrin-releasing peptide (GRP)-avid BC T-47D cells using competitive binding assay against 99mTc–hydrazinonicotinamide (HYNIC)–gamma-aminobutyric acid (GABA)–BN (7–14). PET and MRI showed visible uptake of NPs by T-47D tumors in xenograft mouse models.Conclusion: 68Ga–DOTA–BN–TMC–MNPs could be a potential diagnostic probe to detect BC using PET/MRI technique. Keywords: superparamagnetic iron oxide nanoparticles, trimethyl chitosan, bombesin, gallium-68, PET/MRI