Preparation of magnetic poly(styrene-co-acrylic acid) microspheres with adsorption of protein

Monodisperse cross-linked superparamagnetic poly(St-AA)/Fe3O4 microspheres with carboxyl group on the surface were prepared via miniemulsion copolymerization. The morphology, composition, magnetic properties, and crystalline structure of the magnetic microspheres were characterized by transmission electron microscopy, vibrating sample magnetometer, X-ray diffraction, Fourier transform infrared spectroscopy and thermogravimetric analysis methods, respectively. The effect of crosslinker during polymerization on the particle morphology was studied. The relationship between the adsorbed weight of bovine serum albumin (BSA) on microspheres and adsorption time and pH was also investigated. Moreover, poly(St-AA)/Fe3O4 microspheres displayed excellent adsorption capabilities on BSA and the adsorbed weight of BSA was improved with the increasing AA content in the poly(St-AA)/Fe3O4 microspheres.