Nanoscale assembly of amine-functionalized colloidal iron oxide

We demonstrate a single-step facile approach for highly water-stable assembly of amine-functionalized Fe3O4 nanoparticles using thermal decomposition of Fe-chloride precursors in ethylene glycol medium in the presence of ethylenediamine. The average size of nanoassemblies is 40±1 nm, wherein the individual nanoparticles are about 6 nm. Amine-functionalized properties are evident from Fourier transform infrared spectrometer (FTIR), thermal and elemental analyses. The saturation magnetization and spin-echo r2 of the nanoassemblies were measured to be 64.3 emu/g and 314.6 mM−1 s−1, respectively. The higher value of relaxivity ratio (r2/r1=143) indicates that nanoassemblies are a promising high-efficiency T2 contrast agent platform.