Synthesis And Characterization Of Composite Magnetic Nanoparticles

With the research in the field of biomedicine and bioengineering, people are exploring various functional composite microspheres which can serve as intelligent tools for drug delivery, biomacromolecules purification, biosensor and enzyme immobilization, etc.; Based on the research and the development of composite microspheres, our works focused on the preparation of functionalized magnetic composite microspheres, which involves in three parts, i.e. the preparation and surface modification of magnetite nanoparticles, preparation of Fe3O4/SiO2 nanoparticles, preparation of Fe3O4/Au nanoparticles. The results are listed as follows:(1) Magnetite nanoparticles were prepared by chemical co-precipitation process. Different reaction parameters including reactant concentrate, molar ratio, pH and reaction temperature were found to dramatically influence the properties of the products. Finally, magnetite nanoparticles of about 35 nm were obtained by using proper reaction conditions. The characterization results of XRD, SEM and laser granularity instrument confirmed that magnetite particles were prepared. The magnetic property was charactered by transmittance of suspension in given time and magnetic field.(2) Stable magnetic fluid was prepared by treating magnetic nanoparticles with trisodium citrate aqueous solution. Using the modified magnetic nanoparticles as seeds,Fe3O4/SiO2 were prepared via a modified Stober method. It was found that the size of Fe3O4/SiO2 particles is related with the amount of TEOS and the extent of modification of Fe3O4 particles. The particles'modality and size was tested with SEM and laser granularity instrument. The magnetic property was charactered by transmittance of suspension in given time and magnetic field.(3) Fe3O4/Au composite particles were prepared via seed-growth method. In the coating process, MPA-Na was injected to make Fe3O4/Au particles more stable. The influence of concentration of HAuCl4 and Fe3O4 seeds number on Fe3O4/Au particles'propertise were analysed. The UV-vis spectra show absorption peak in evidence, which is character peak of nanogold, proved the produced particles'surfaces were wrapped by Au. The particles' modality and size was tested with SEM and laser granularity instrument. The magnetic property was charactered by transmittance of suspension in given time and magnetic field.