Preparation And Property Research Of Surface-Functional Magnetic Polymer Microspheres

Magnetic polymer microsphere is a kind of hybrid microsphere with magnetic property, which is composed of polymer and inorganic magnetic particles. It is quite fit for application in biological system because of their small particle size, large specific surface area, great capacity of coupling biology molecules, and good suspension in disperse system. The magnetic polymer microspheres can be applied in various aspects in biotechnology and biomedical engineering, such as cell separation, immobilized enzyme, protein separations, target drug, and biochemical assays etc.Fe₃O₄ with the hydrophilic-hydrophobic property was used to be the core material of the microspheres, which was prepared by co-precipitation method. Magnetic polymer microspheres were prepared through polymer encapsulation of small Fe₃O₄ particles by microsuspension polymerization. The effects of monomer, magnetic fluid, stabilizer on the particle size and reaction process were investigated, and solve the difficulty of the low output in the polymerization. The size, dispersion and morphological characterizations of the magnetic microspheres were carried out with SEM. The magnetism can be observed clearly using a magnet of magnetic field about 3000 GS. The magnetic properties of the microspheres were evaluated using a vibrating sample magnetometer (VSM). The functional groups on the surface were carried out with Fourier transfer infrared (FTIR). The degree of the thermal stability of the magnetic microspheres was carried out with a thermo gravimetric analysis. Ultraviolet spectrum was used to analysis conjugation rate of magnetic microspheres with protein, and the fluorescence microscope was used to investigate the quantum dot labeled antibody coupled with antigen labeled magnetic microspheres.The results indicated that the magnetic microspheres were superparamagnetic, well shaped spheres, mono-dispersed with abundant functional groups on the surfaces of the magnetic microspheres and good thermal stability. The microspheres could be linked well with the protein.