Synthesis and protein immobilization of monodisperse magnetic spheres with multifunctional groups

Monodisperse magnetic spheres with multifunctional groups were synthesized by spraying suspension polymerization. The effects of stabilizer type and its concentration on the monodispersity of magnetic spheres were investigated. The results showed that polyvinyl alcohol (PVA) was satisfactory as a stabilizer in this spraying suspension polymerization, and the magnetic spheres showed good monodispersity when the concentration of PVA was increased to above 20 wt%. It was also found that the monodispersity of magnetic spheres could be improved with increase of the amount of initiator. Scanning electron microscopy and vibrating sample magnetometer verified that the magnetic spheres obtained were monodisperse with small size (about 9.8 μm) and displayed superparamagnetic characteristics. Data of Fourier transform infrared (FT-IR) spectroscopy and surface chemical reaction method indicated that the extensive epoxy groups existed on the surface of magnetic spheres. Bovine serum albumin (BSA) was covalently immobilized onto the glutaraldehyde treated and untreated magnetic spheres, respectively. The results showed that the maximum BSA immobilization capacity onto the magnetic spheres was about 57 mg/g.