Synthesis Of Superparamagnetic Iron Oxide Nanoparticles And Their Applications In Magnetic Resonance Imaging

We adopted thermal decomposition to prepare superparamagnetic iron oxide nanoparticles(SPIONs), in which iron resource was iron(III) acetylacetonate(Fe(acac)3). We determined the crystalline phase, particle size and shape of SPIONs by X-ray diffraction(XRD) and Transmission electron microscopy(TEM). The coated organics of SPIONs were recognized by Fourier transform infrared spectroscopy(FTIR). The hydrodynamic diameter and zeta potential of the SPIONs were determined by Malvern nano-particle and zeta potential analyzer. The magnetic properties of SPIONs were characterized by superconducting quantum interference device(SQUID). Inductively coupled plasma atomic emission spectrometer(ICP) was used to measure the iron concentration. In vivo T2*-weighted magnetic resonance imaging was measured by nuclear magnetic resonance spectrometer. The main contents are as follows:The PEG/PEI-SPIONs was synthesized by thermal decomposition of iron(III) acetylacetonate(Fe(acac)3) in poly(ethylene glycol)(PEG) containing poly(ethylene imine)(PEI) as modifying agents. We discussed the growth mechanism of SPIONs. The results indicated that the average size of the SPIONs was in the range of 10.3±1.9 nm. FTIR spectroscopic results showed that PEG and PEI are jointly attached to the surface of SPIONs. The M-H curves showed that the PEG and PEI coated SPIONs(PEG/PEISPIONs) have high stability and superparamagnetic property, the saturation magnetization was 50.4 emu/g. The SPIONs stability dispersed in the water more than 3 months, but also to maintain good stability in the phosphate buffer solution(PBS). In vivo T2*-weighted magnetic resonance imaging of the Kunming(KM) mouse brain after intravenous injection of the PEG/PEI-SPIONs showed good contrast effects.The Tween 80 was conjugated to PEG/PEI-SPIONs. The results showed that hydrodynamic diameter of SPIONs increased from 21.0 to 24.0 nm and zeta potentials reduced from 35.0 to 19.0 mV after the conjugation reaction. FTIR spectroscopic results showed that PEG, PEI and Tween 80 are jointly attached to the surface of SPIONs. The M-H curves showed that the PEG and PEI coated SPIONs(PEG/PEI-SPIONs) have high stability and superparamagnetic property. The SPIONs stability dispersed in the water more than 3 months, but also to maintain good stability in the phosphate buffer solution(PBS). In vivo T2*-weighted magnetic resonance imaging of the Kunming(KM) mouse brain after intravenous injection of the PEG/PEI/Tween 80-SPIONs showed good contrast effects.The polyaspartic acid(PASP) was coated to PEG/PEI-SPIONs. The results showed that hydrodynamic diameter of SPIONs increased from 21.0 to 23.4 nm and zeta potentials reduced from 35.0 to-20.4 mV after the conjugation reaction. FTIR spectroscopic results showed that PEG, PEI and PASP are jointly attached to the surface of SPIONs. The M-H curves showed that the PEG and PEI coated SPIONs(PEG/PEISPIONs) have high stability and superparamagnetic property. The SPIONs stability dispersed in the water more than 3 months, but also to maintain good stability in the phosphate buffer solution(PBS). In vivo T2*-weighted magnetic resonance imaging of the Kunming(KM) mouse brain after intravenous injection of the PEG/PEI/PASPSPIONs showed good contrast effects.The SPIONs(PEG-SPIONs、PEG/PVP-SPIONs) were successfully synthesized by thermal decomposition of Fe(acac)3 in PEG as modifying agent with PVP(0 or 0.3 g). Then were connected with N-(β-aminoethyl)-γ-aminopropylmethylbimethoxy silane(AEAPS) or maleic anhydride(Mal). The transferrin(Tf) or Angiopep-2(ANG) were coated on the PEG-SPIONs after connecting with Mal, respectively. The SPIONs were succeefully modified with the PEG/Mal/Tf and PEG/Mal/ANG(PEG/Mal/TfSPIONs and PEG/Mal/ANG-SPIONs).