High capacity cryogel-type adsorbents for protein purification

What is it about?

Cryogel bodies were modified to obtain epoxy groups by graft-copolymerization using both chemical and gamma irradiation initiation techniques. The free epoxy adsorbents were reacted further to introduce diethylaminoethanol (DEAE) functionalities. The resulting weak anion-exchange cryogel adsorbents showed dynamic binding capacities of ca. 27 ± 3 mg/mL, which was significantly higher than previously reported for this type of adsorbent material. Gamma irradiated grafting initiation showed a 4-fold higher capacity for proteins than chemical grafting initiation procedures. The phosphate capacity for these DEAE cryogels was 119 mmol/L and also showed similar column efficiency as compared to commercial adsorbents. The large pores in the cryogel structure ensure convective transport of the molecules to active binding sites located on the polymer-grafted surface of cryogels. However, as cryogels have relatively large pores (10–100 μm), the BET area available for surface activation is low, and consequently, the capacity of the cryogels is relatively low for biomolecules, especially when compared to commercial beaded adsorbents. Nevertheless, we have shown that gamma ray mediated surface grafting of cryogel matrices greatly enhance their functional and adsorptive properties.

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Why is it important?

In this paper, we have illustrated two different ways to efficiently graft GMA onto monolithic cryogels. In the case of gamma irradiation graft-initiation, about 75% grafting was achieved. The results of this study also demonstrated that gamma irradiated DEAE monolithic cryogels exhibit a 4-fold higher binding capacity for BSA than their chemically grafted counterparts. Anion-exchange monolithic cryogel have BSA binding capacity of 27 mg/mL. Since the hydrodynamic properties were preserved, grafted cryogels may become a resin of choice for the downstream processing of various biomolecules.

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