Affinity adsorption of recombinant human interferon‐α on monosize dye‐affinity beads

Monosize, nonporous poly(glycidyl methacrylate) [poly(GMA)] beads were prepared by dispersion polymerization. Cibacron Blue F3GA was covalently attached onto the poly(GMA) beads for adsorption of recombinant interferon-α (rHuIFN-α). Monosize poly(GMA) beads were characterized by scanning electron microscopy. Dye-carrying beads (1.73 mmol/g) were used in the adsorption–elution studies. The effect of initial concentration of rHuIFN-α, pH, ionic strength, and temperature on the adsorption efficiency was studied in a batch system. Nonspecific adsorption of rHuIFN-α on the beads was 0.78 mg/g. Dye attachment significantly increased the rHuIFN-α adsorption up to 181.7 mg/g. Equilibrium adsorption of rHuIFN-α onto the dye-carrying beads increased with increasing temperature. Negative change in free energy (ΔG0 < 0) indicated that the adsorption was a thermodynamically favorable process. ΔS and ΔH values were 146.1 J/mol K and −37.39 kJ/mol, respectively. Significant amount of the adsorbed rHuIFN-α (up to 97.2%) was eluted in the elution medium containing 1.0M NaCl in 1 h. To determine the effects of adsorption conditions on possible conformational changes of rHuIFN-α structure, fluorescence spectrophotometry was employed. We concluded that dye-affinity beads can be applied for rHuIFN-α adsorption without causing any significant conformational changes. Repeated adsorption–elution processes showed that these beads are suitable for rHuIFN-α adsorption. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 975–981, 2007