Cibacron blue F3GA and Zn(II) containing poly(ethylene glycol dimethacrylatehydroxyethyl methacrylate) microbeads for albumin adsorption

Swellable poly (ethylene glycol dimethacrylate-hydroxyethyl methacryate) [poly(EGDMA-HEMA] microbeads, in the size range of 150-200 mu m, were produced by a modified suspension copolymerization of EGDMA and HEMA. Cibacron Blue F3GA was attached, then Zn(II) ions were incorporated within the microbeads by chelating with the Cibacron Blue F3GA molecules. The maximum amount of Cibacron Blue F3GA attachment was 16.5 mu mol/g polymer. Different amounts of Zn(II) ions (0.4-32.4 mg/g polymer were incorporated on the microbeads by changing the initial concentration of Zn(II) ions and medium pH. Bovine serum albumin (BSA) adsorption onto unmodified, Cibacron Blue F3GA-attached and Cibacron Blue F3GA-Zn(II)-derivatized microbeads was investigated. The non-specific adsorption of BSA was very low (0.051 mg/g polymer). Cibacron Blue F3GA attachment significantly increased the BSA adsorption (60.5 mg/g polymer). The maximum BSA adsorption (122 mg/g polymer) was observed at pH 6.0 when Cibacron Blue F3GA-Zn(II)-derivatized microbeads were used. Desorption of BSA was achieved by using 25 mM EDTA (pH 4.9). High desorption ratios (up to 95% of the adsorbed BSA) were observed. It was possible to reuse Cibacron Blue F3GA-Zn(II)-derivatized microbeads without significant losses in the adsorption capacities.