Thermoresponsive Polymer Brushes on Organic Microspheres for Biomolecular Separation and Immobilization

A new method is developed to synthesize organic microsphere-supported polymer brushes for affinity separation of saccharides and glycoproteins. In the first step, crosslinked polymer microspheres are synthesized using atom transfer radical polymerization (ATRP). The terminal ATRP initiators on the microspheres are used to graft polymer brushes from propargyl acrylate and N-isopropyl acrylamide. The microsphere-supported polymer brushes are conjugated with an azide-tagged phenylboronic acid to complete the material synthesis. The microsphere-supported, boronic acid-containing polymer brushes are able to bind not only low molecular weight cis-diol compounds but also glycoproteins. The synthetic procedure developed in this work provides a convenient means for preparing all-organic microsphere-supported polymer brushes that have high alkaline stability. Using the surface-attached polymer brushes to immobilize a catalytic glycoprotein (horseradish peroxidase), it is possible to retain on-particle enzyme activity due to the open structure of the polymer brushes and the oriented immobilization. (Figure presented.).