Cu(II)-incorporated histidine-containing, magnetic-metal-complexing beads as specific sorbents for the metal chelate affinity of albumin

N-Methacryloyl-(L)-histidine methyl ester (MAH) was synthesized from metharyloyl chloride and histidine. Spherical beads with an average size of 150-250 mum were obtained by the suspension polymerization of ethylene glycol dimethacrylate and MAH in an aqueous dispersion medium. Magnetic poly(ethylene glycol dimethacrylate-co-N-Methacryloyl-(L)-histidine methyl ester) [m-p(EGDMA-co-MAH)] microbeads were characterized with swelling tests, electron spin resonance, elemental analysis, and scanning electron microscopy. The specific surface area of the beads was 80.1 m(2)/g. m-p(EGDMA-co-MAH) microbeads with a swelling ratio of 40.2% and 43.9 mumol of MAH/g were used for the adsorption of bovine serum albumin (BSA) in a batch system. The Cu(II) concentration was 4.1 mumol/g. The adsorption capacity of BSA on the Cu(II)-incorporated beads was 19.2 mg of BSA/g. The BSA adsorption first increased with the BSA concentration and then reached a plateau, which was about 19.2 mg of BSA/g. The maximum adsorption was observed at pH 5.0, which was the isoelectric point of BSA. The BSA adsorption increased with decreasing temperature, and the maximum adsorption was achieved at 4degreesC. High desorption ratios (>90% of the adsorbed BSA) were achieved with 1.0M NaSCN (pH 8.0) in 30 min. The nonspecific adsorption of BSA onto the mp(EGDMA-co-MAH) beads was negligible. (C) 2004 Wiley Periodicals, Inc.