Nanoparticle-supported polymer brushes for temperature-regulated glycoprotein separation: investigation of structure-function relationship.

In this work, we synthesized a series of nanoparticle-supported boronic acid polymer brushes for affinity separation of glycoproteins. Polymer brushes were prepared by surface-initiated atom transfer radical polymerization of glycidyl methacrylate and N-isopropylacrylamide, followed by stepwise modification of the pendant as well as the end functional groups to introduce boronic acid moieties through a Cu(i)-catalyzed alkyne-azide cycloaddition reaction. We investigated the impact of the polymer structure on glycoprotein binding under different pH and temperature conditions, and established new methods that allow glycoproteins to be more easily isolated and recovered with minimal alteration in solvent composition. Our experimental results suggest that for the separation of glycoproteins, terminal boronic acids located at the end of polymer chains play the most important role. The thermo-responsibility of the new affinity adsorbents, in addition to the high capacity for glycoprotein binding (120 mg ovalbumin per g adsorbent), provides a convenient means to realize simplified bioseparation not only for glycoproteins, but also for other carbohydrate-containing biological molecules.