Enhanced adsorption capacity of cryogel bed by incorporating polymeric resin particles

Novel composite cryogel monoliths were fabricated by incorporating polymeric resin particles and grafting anion-exchange groups on the pore wall surfaces. The embedded resin particles in different size distributions were prepared by grinding poly(glycidyl methacrylate-ethylene glycol dimethacrylate) monoliths. Observations by scanning electron microscopy clearly indicated that the composite cryogel had interconnected large pores (10-100 μm in width), similar to normal (pure) cryogel. However, the composite material had very rough pore walls, which provided larger surface area for protein adsorption. As a result, the dynamic binding capacity of bovine serum albumin (BSA) on the composite cryogel bed reached 6 mg/mL bed (flow velocity, 5 cm/min), which was 2.8 times higher than a cryogel bed without embedding the ground resin particles. The capacity value was also much higher than the BSA capacities of cryogel beds reported in literature (1-4 mg/mL). Though the capacity decreased by about 1mg/mL with the increase of flow rate from 0.5 to 5 cm/min, it then kept almost unchanged till a flow rate up to 15 cm/min. The height equivalent to a theoretical plate of the composite bed was in the range of 1.1-1.4mm, and kept nearly constant in a flow rate range of 5-20 cm/min. The results indicated that the composite cryogel bed offered a large improvement in protein adsorption capacity and was suitable for high-speed protein chromatography.