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