Preparation and radiolabeling of surface-modified magnetic nanoparticles with rhenium-188 for magnetic targeted radiotherapy

Magnetite nanoparticles coated with silica were synthesized and characterized by electron microscopic methods (SEM and TEM) and crystal structure analysis (XRD). After surface modification with an amino silane coupling agent, N-[3-(trimethyoxysilyl) propyl]-ethylenediamine (SG-Si900), histidine was covalently linked to the amine group using glutaraldehyde as cross.-linker. The magnetic nanoparticles were then radiolabeled with Re-188 with a labeling yield of 91.4 +/- 0.3% and good stability in vitro. The labeling mechanism is suggested as fac-[Re-188(CO)(3)(H2O)(3)](+) core complexed with imidazolyl groups. (C) 2003 Elsevier B.V. All rights reserved.