Dye–ligand and metal chelate poly(2-hydroxyethylmethacrylate) membranes for affinity separation of proteins

Abstract

Cibacron Blue F3GA was covalently immobilized onto poly(2-hydroxyethyl methacrylate) (pHEMA) membranes via the nucleophilic reaction between the chloride of its triazine ring and the hydroxyl group of pHEMA. Then, Fe 3+ ions were complexed by chelation with the immobilized Cibacron Blue F3GA molecules. Different amounts of Fe 3+ ions were loaded on the membranes by changing the concentration of Fe 3+ ions and pH of the reaction medium. Membranes with or without Fe 3+ were used in the adsorption of glucose oxidase, catalase and bovine serum albumin. The adsorption capacities of these membranes were determined by changing pH and the concentration of the proteins in the adsorption medium. The adsorption phenomena appeared to follow a typical Langmuir isotherm. The maximum capacities ( q m) of the Fe 3+ complexed membranes for glucose oxidase, catalase and bovine serum albumin (8.70·10 − 3 μmol m − 2, 2.15·10 − 3 μmol m − 2 and 2.21·10 − 3 μmol m − 2) were greater than those of the untreated membranes (6.79·10 − 3 μmol m − 2, 1.34·10 − 3 μmol m − 2 and 1.94·10 − 3 μmol m − 2) respectively. The nonspecific adsorption of the enzymes and the protein on the pHEMA membranes was negligible.