Synthesis Of Gold Magnetic Particles And Their Application

Gold magnetic particles are multifunctional magnetic composities whose core material is magnetic material and surface material is gold nanoparticles. Gold magnetic particles could quickly separate from the reaction system in external magnetic field, and quickly immobilize biological molecules. So more and more domestic and foreign scientists focus on the synthesis of gold magnetic particles and their application research. This paper systematically describes the preparation processes of core-shell Fe/Au magnetic composite nanoparticles, assembled structure Fe3O4/SiO2/Au magnetic composities and assembled structureγ-Fe2O3/SiO2/Au magnetic composities. The physical and chemical properties of the three kinds of gold magnetic particles were characterized. We also immobilized BSA on the surface of assembled structure gold magnetic composities. The concrete works of this paper are as follows:1. Synthesis of core-shell Fe/Au magnetic nanocompositiesThe Fe magnetic nanoparticles were prepared by temperature thermal decomposition method, and using the surface chemical reduction method synthesized core-shell Fe/Au magnetic nanocomposities, through ligand exchange make the core/shell Fe/Au nanocomposities disperse in water. The samples were characterized by UV-Vis spectrophotometer, TEM, Dynamic light scattering, Zeta potential instrument, FT-IR and XRD. The results showed the synthesized Fe magnetic nanoparticles and core-shell Fe/Au magnetic nanocomposities exhibited spherical shape, uniform particle size, with good magnetic responsiveness at room temperature; Fe magnetic nanoparticles exhibited good dispersion in hexane. The core-shell Fe/Au magnetic nanocomposities exhibited good dispersion both in THF and water.2. Synthesis of assembled structure Fe3O4/SiO2/Au magnetic compositiesThiol-functionalizedγ-Fe2O3/SiO2 magnetic composities and gold nanoparticles were first synthesized by methods of surface-chemically modifiedγ-Fe2O3/SiO2 magnetic composities and citrate reduction of the Au3+ to Au0, respectively. Interaction between these two types of particles prepared Fe3O4/SiO2/Au magnetic composities. The samples were characterized by TEM, UV-Vis spectrophotometer, Dynamic light scattering, Laser scattering particle size analyzer, Zeta potential instrument and XRD. The results showed the synthesized Fe3O4/SiO2/Au composities'size is about 340 nm, Zeta potential is about -30 mV, at room temperature with good magnetic responsiveness. 3. Synthesis of assembled structureγ-Fe2O3/SiO2/Au magnetic compositiesUsingγ-Fe2O3/SiO2 magnetic composite particles as precursor through self-assembly method synthesisedγ-Fe2O3/SiO2/Au magnetic composities. The samples were characterized by UV-Vis spectrophotometer, TEM, Zeta potential instrument, FT-IR and XRD. The results showed the synthesizedγ-Fe2O3/SiO2/Au composities'size is about 210 nm, Zeta potential is about -33.2 mV, at room temperature with good magnetic responsiveness.4. Immobilize BSA on the surface of assembled structure gold magnetic compositiesBovaine serum albumin (BSA) was immoblized on the surface of the two assembled structure gold magnetic composities in the Tris-HCl buffer and 1×PBST buffer, the immobilization amount of BSA onto the Fe3O4/SiO2/Au composites and y-Fe2O3/SiO2/Au composites'surface was 315μg/mg and 427μg/mg, respectively. The BSA immobilization study demonstrated the two assembled structure gold magnetic particles have potentially applied in many biological fields.