Monodisperse carboxylated polystyrene particles: synthesis, electrokinetic and adsorptive properties

Effect of conditions of styrene dispersion polymerization initiated by 4,4′-azo-bis-(4-cyanopentanoic acid) in ethanol solutions of polyvinylpyrrolidone was investigated. Suitable methods ensuring the control of final particle size, surface structure, and surface concentration of carboxylic groups in the polymerization process are discussed. Particle ability to interact with protein was also studied. Monodisperse particles of diameters up to 4 μm had a complex surface layer containing polyvinylpyrrolidone-graft-polystyrene copolymers as well as carboxylic groups of the initiator. The effect of this surface structure on the isotherms of adsorption and chemisorption of bovine serum albumin was revealed. Electrophoretic mobility of the particles and their isoelectric point values before and after protein binding depending on pH and ionic strength were determined. These data depend on conditions of particle preparation as well as on protein coating values.