Adsorptive separation of hemoglobin by molecularly imprinted chitosan beads

A simply hemoglobin (Hb) molecularly imprinted polymer (MIP) was prepared using Hb as the imprinted molecule, acrylamide as the functional monomer and cross-linked chitosan beads as the supporting matrix. The MIP was achieved by entrapment of the selective soft polyacrylamide gel in the pores of the cross-linked chitosan beads by letting acrylamide monomer and the protein diffuse into the pores of chitosan beads before starting the polymerization. The chitosan beads were freed from the surrounding polyacrylamide gel by washing. The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms. Langmuir analysis showed that an equal class of adsorption was formed in the MIP and the adsorption equilibrium constant and the maximum adsorption capacity were evaluated. The MIP has much higher adsorption capacity for Hb than the non-imprinted polymer with the same chemical composition, and the MIP also has a higher selectivity for the imprinted molecule. The MIP can be reused in an easy way and the reproduction coefficient was approximately 100% at low concentration. (C) 2004 Elsevier Ltd. All rights reserved.