Fabrication And Properties Of Magnetic Nanocomposites For Dual-modality Magnetic Resonance/X-ray Imaging And Sustained Drug Delivery

nanoparticles have been applied widely in magnetic resonance imaging (MRI) of clinical diagnosis owing to unique properties of superparamagnetism, biodegradability and biocompatibility. In order to compensate for the deficiencies of unitary modality imaging of Fe3O4nanoparticles, the functionalized modifications of X-ray imaging were performed using polyvinylpyrrolidone-iodine and2,3,5-triiodobenzoic acid, respectively, and the potentials of MRI and X-ray imaging of the obtained nanocomposite particles were also studied. In order to deal with the limitations on unitary function imaging of Fe3O4nanoparticles, magnetic graphene nanocomposites and magnetic polymer nanocomposites were prepared via in situ method and the applications in MRI and sustained drug delivery of the nanocomposites were also examined. The main contents and results are summarized as follows:1) The Fe3O4nanoparticles were functionalized modified by polyvinylpyrrolidone-iodine (PVPI) and2,3,5-triiodobenzoic acid (TIBA) to obtain X-ray imaging function. The effects of PVPI and TIBA coating on particle size, crystal structure, thermal stability and magnetization properties of Fe3O4nanoparticles were investigated using TEM, XRD, FTIR, XPS, TGA and SQUID in detail. The magnetization curves of PVPI and TIBA modified Fe3O4composite particles are in accordance with Langevin’s equation and both the composite particles show typical superparamagnetism, high saturation magnetization and excellent MRI effect at room temperature, and also TIBA functionalized Fe3O4nanoparticles exhibit good biocompatibility and favorable X-ray imaging ability.2) The exfoliated graphene oxide (GO) nanosheets were synthesized by improved Hummer’s method, and then the Fe3O4nanoparticles were in situ decorated on the surface of GO nanosheets via chemical co-precipitation method. Growth mechanism and dispersion principles of Fe3O4nanoparticles on the surface of GO nanosheets were examined and the effects of GO on the crystal structure, thermal stability and magnetization properties of Fe3O4nanoparticles were also studied using TEM, XRD, FTIR, Raman, XPS, TGA and SQUID in detail. The magnetization curve of Fe3O4/GO is in accordance with Langevin’s equation and the nanocomposites exhibit typical superparamagnetism, good water dispersibility and high saturation magnetization at room temperature. Fe3O4/GO nanocomposites show excellent MRI effect and great potential in drug delivery with5-fluorouracil (5-FU) saturation drug loading of0.361mg/mg. Drug release behavior within24h agrees with Higuchi kinetic function and its half-time of release is10.32h.3) Magnetic poly(ε-caprolactone)(PCL) nanocomposites based on Fe3O4nanoparticles and Fe3O4@GO hybrid nanoparticles were prepared using a facile in situ polymerization method. The dispersion principles of Fe3O4and Fe3O4@GO nanoparticles within PCL matrix were examined and the effects of Fe3O4and Fe3O4@GO on crystal structure, crystallization properties, thermal stability and magnetization properties of PCL matrix were studied using SEM, XRD, FTIR, DSC, POM, TGA and SQUID in detail. The magnetization curve of PCL/Fe3O4@GO is in accordance with Langevin’s equation and the nanocomposites display superparamagnetism and MRI effect at room temperature. The drug loading and entrapment efficiency of PCL/Fe3O4@GO with5-FU initial concentration of50mg/mL are0.143mg/mg and56.6%, respectively. Drug release behavior within30d agrees with biphase kinetic function and its half-time of release reaches29.25h.