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

Abstract

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.

Effect of hydrophobic/hydrophilic characteristics of magnetic microspheres on the immobilization of BSA

“…Therefore, our results seemed to suggest that hydrophobic interaction played an important role in increasing the immobilized ratio of BSA, which was also pointed out in Hou et al's work [20]. They even suggested that hydrophilic amide group might resist BSA molecules from approaching through the hydrophobic interaction [20]. In addition, Gruüttner et al also pro- posed that the surface of magnetic polystyrene microspheres was very hydrophobic, which resulted in a high amount binding of proteins on the microspheres' surface [24].…”

“…Apparently, type 8 microsphere had the highest immobilized ratio. Therefore, our results seemed to suggest that hydrophobic interaction played an important role in increasing the immobilized ratio of BSA, which was also pointed out in Hou et al's work [20]. They even suggested that hydrophilic amide group might resist BSA molecules from approaching through the hydrophobic interaction [20].…”

“…Dispersion polymerization is a very attractive method for preparing micron-size polymeric microspheres because of its simplicity and single-step process [20]. It is especially suitable for preparing microspheres of 0.1-15 m in diameter, often of fairly good monodispersity [21].…”

“…These results indicated that, during the process of immobilization, the type 8 microsphere was more easy to touch and subsequently covalently bind BSA molecule than other types of microsphere. It is generally believed that the microspheres' surface may represent three main interactions between microspheres and protein molecules [20]: hydrophobic interaction, hydrogen bond, electrostatic force. It should be noticed that the net charge on the surface of all types of microspheres is zero since there is no ionization for the activated polymer microspheres.…”

Synthesis and preparation of nanoparticles composed of amphiphilic poly(γ-glutamic acid) with different hydrophobic side chains and their potential of membrane disruptive activity

“…Therefore, to investigate the hemolytic mechanisms of γ-PGA-AAE NPs, the surface hydrophobicity of γ-PGA-AAE NPs was evaluated based on the adsorption of RB, a hydrophobic dye [17]. It has been reported that the adsorbed amount of RB marks the difference in surface hydrophobicity of NPs [28,29]. As shown in Fig.…”