Preparation and characterization of PVPI-coated Fe3O4 nanoparticles as an MRI contrast agent

Polyvinylpyrrolidone-iodine (PVPI)-coated Fe3O4 nanoparticles were prepared by using inverse chemical co-precipitation method, in which the PVPI serves as a stabilizer and dispersant. The wide angle X-ray diffraction (WAXD) and selected area electron diffraction (SAED) results showed that the inverse spinel structure pure phase polycrystalline Fe3O4 was obtained. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results exhibited that the resulted Fe3O4 nanoparticles were roughly spherical in shape with narrow size distribution and homogenous shape. Fourier transform infrared spectroscopy (FTIR) results suggested that PVPI interacted with Fe3O4 via its carbonyl groups. Results of superconducting quantum interference device (SQUID) indicated prepared Fe3O4 nanoparticles exhibited superparamagnetic behavior and high saturation magnetization. T2-weighted MRI images of PVPI-coated Fe3O4 nanoparticles showed that the magnetic resonance signal was enhanced significantly with increasing nanoparticles concentration in water at room temperature. These results indicated that the PVPI-coated Fe3O4 nanoparticles had great potential for application in MRI as a T2 contrast agent.