Synthesis of Zn-Doped Manganese Ferrite Nanoparticles Via Coprecipitation Method for Magnetic Resonance Imaging Contrast Agent

Abstract

Two different preparations of biocompatible magnetic nanoparticles (MNPs), both (MnFe2O4 and Mn0.91Zn0.09Fe2O4) coated with methoxy polyethylene glycol aldehyde (m-PEG-CHO) were prepared through coprecipitation method. The prepared powder was reanalyzed for material structure with an X-ray diffractometer (XRD) and for particle size using a transition electron microscope (TEM). Magnetic saturation (MS) and coercivity (HC) of the formed particles were examined by a vibrating sample magnetometer (VSM). Surface structure of the samples was characterized by Fourier transform infrared spectroscopy (FTIR). Biocompatible ferrofluids were intravenously injected into four rabbits. Then the magnetic resonance (MR) images of brain were obtained by magnetic resonance imaging (MRI) experiments before and after intravenous injection of ferrofluids. The MNPs demonstrate super paramagnetic behavior with a spinel structure measuring 30–40 nm in size. Doping of these magnetite nanoparticles with zinc resulted in decreases in crystallite size from 24.23 nm to 21.15 nm, the lattice parameter from 8.45 A to 8.43 A and the coercivity from 41.20 Oe to 13.07 Oe. On the other hand, saturation magnetization increased from 50.12 emu/g to 57.36 emu/g following zinc doping. Image exposure analysis revealed that the reduction of MR signal intensity for zinc-doped magnetite nanoparticles was more than nondoped nanoparticles (shorter T2 relaxation time) thereby making the images darker.