Preparation and characterization of magnetic poly(styrene-glycidyl methacrylate) microspheres for highly efficient protein adsorption by two-stage dispersion polymerization

Micrometer-sized superparamagnetic poly(styrene-glycidyl methacrylate)/Fe3O4 spheres were synthesized by two-stage dispersion polymerization with modified hydrophobic Fe3O4 nanoparticles, styrene (St), and glycidyl methacrylate (GMA). The morphology and properties of the magnetic Fe3O4-P (St-GMA) microspheres were examined by scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometry, thermogravimetric analysis, and attenuated total reflectance. The average size of the obtained magnetic microspheres was 1.50 mu m in diameter with a narrow size distribution, and the saturation magnetization of the magnetic microspheres was 8.23 emu/g. The magnetic Fe3O4-P (St-GMA) microspheres with immobilized iminodiacetic acid-Cu2+ groups were used to investigate the adsorption capacity and selectivity of the model proteins, bovine hemoglobin (BHb) and bovine serum albumin (BSA). We found that the adsorption capacity of BHb was as high as 190.66 mg/g of microspheres, which was 3.20 times greater than that of BSA, which was only 59.64 mg/g of microspheres as determined by high-performance liquid chromatography. With a rather low nonspecific adsorption, these microspheres have great potential for protein separation and purification applications. (C) 2015 Wiley Periodicals, Inc