Monodisperse polystyrene microspheres by dispersion copolymerization of styrene and other vinyl comonomers: characterization and protein adsorption properties.

Dispersion polymerization is a very attractive method for preparing micron-size monodisperse polymeric microspheres. The applications of microspheres have been greatly extended by using comonomers. In the present study, five kinds of polystyrene microspheres of 4-6 microm in diameters bearing different surface functional groups were synthesized by copolymerization of styrene and various vinyl comonomers. Their surface physicochemical characteristics were examined, including average particle size and size distribution, concentration of surface functional groups, as well as hydrophobicity. Concentration of FT-IR spectra of different samples were also discussed. The effects of microspheres' surface physicochemical properties on the isotherms of adsorption and chemisorption of BSA were determined. The results show that microspheres bearing different surface function groups have different capacity of protein adsorption. Besides, since the protein adsorption behaviors were more complex than the ideal adsorption model, the isotherms could not fit Freundlich model very well. Possible reasons were discussed. Knowledge gained from these results may be utilized for rational design of carriers of receptors and antibodies used in solid-phase immunoassay, especially Scintillation proximity assay in High-throughput Screening. Copyright (c) 2007 Wiley Periodicals, Inc.