Binding of antibodies to concanavalin A-modified monolithic cryogel

Abstract

Binding of human immunoglobulin-G (IgG) from aqueous solutions and human plasma to concanavalin A (Con A) immobilized poly(acrylamide-allyl glycidyl ether) [poly(AAm-AGE)] monolithic cryogel has been studied. Poly(AAm-AGE) cryogel was prepared by bulk polymerization which proceeds in aqueous solution of monomers frozen inside a column (cryo-polymerization). After thawing, the monolithic cryogel contains a continuous polymeric matrix having interconnected pores of 10–100 μm size. Con A was immobilized by covalent binding onto poly(AAm-AGE) cryogel via epoxy groups. The maximum IgG adsorption on the Con A-poly(AAm-AGE) cryogels was observed at pH 7.4 from aqueous solutions. The non-specific IgG adsorption onto the plain poly(AAm-AGE) adsorbents was about 0.25 mg/g. Up to 6.7 mg/g IgG were bound to Con A-poly(AAm-AGE) cryogels from aqueous solutions. The large pore size of the cryogel makes it possible to process blood cells without blocking the column. Higher adsorption capacity was observed from human plasma (up to 25.6 mg/g). Bound IgG was eluted using 2.0 M NaCl with a purity of 85%. Adsorption capacities of other blood proteins were obtained as 1.0 mg/g for fibrinogen and 1.7 mg/g for albumin. The total protein adsorption was determined as 28.6 mg/g. Con A-poly(AAm-AGE) cryogels was used for repetitive adsorption/desorption of IgG molecules without noticeable loss in IgG adsorption capacity after 10 cycles.