Preparation and characterization of comb type polymer coated poly(HEMA/EGDMA) microspheres containing surface-anchored sulfonic acid: Application in γ-globulin separation

Poly(2-hydroxyethyl methacrylate/ethylenglycol dimethacrylate), poly(HEMA/EGDMA) microspheres was prepared via suspension polymerization. After activation of the hydroxyl groups of poly(HEMA/EGDMA) by bromination, surface-initiated atom transfer radical polymerization (ATRP) of glycidylmethacrylate was conducted in dioxane/bipyridine mixture with CuBr as catalyst at 65 °C. The epoxy groups of the poly(glycidylmethacrylate) comb polymer were converted into sulfonic acid groups (as proton-exchange groups) with reaction of sodium sulfite. Synthesized microspheres were characterized by swelling studies, FT-IR spectroscopy, scanning electron microscopy (SEM) and elemental analysis. The microspheres were used as ion-exchange support for adsorption and purification of human γ-globulin (IgG). The maximum γ-globulin adsorption on the ion-exchange adsorbents was observed at between pH 5.0 and 6.0. The IgG adsorption onto the poly(HEMA/EGDMA) microspheres was negligible. The maximum amount of adsorbed γ-globulin was found to be 230.1 mg/g microspheres. The ion-exchange adsorbents allowed one-step separation of IgG from human plasma. The γ-globulin molecules could be repeatedly adsorbed and desorbed with this ion-exchange support without noticeable loss in their IgG adsorption capacity.