Surface-modified superparamagnetic iron-oxide nanoparticles

The generation of superparamagnetic iron-oxide nanoparticles bearing fluorescent ligands is described. gamma-Fe2O3 nanoparticles (radius similar to 4 and 8 nm) bearing octylamine or oleic acid as ligands were prepared by hydrothermal synthesis starting from Fe-cupferron and iron pentacarbonyl, respectively. Ligand exchange proceeds with 1,2-diols bearing omega-azido or omega-bromo ligands at elevated temperatures. Subsequent nucleophilic substitution reaction, followed by 1,3-dipolar cycloaddition reactions with 2,4,6-trinitro-1-O-propargyl-benzene yields superparamagnetic iron-oxide nanoparticles with a fluoresecent ligand on their surface.