title: Temperature and pH Dual-Responsive Core-Brush Nanocomposite for Enrichment of Glycoproteins.
abstract: In this report, we present a novel modular approach to the immobilization of a high density of boronic acid ligands on thermoresponsive block copolymer brushes for effective enrichment of glycoproteins via their synergistic multiple covalent binding with the immobilized boronic acids. Specifically, a two-step, consecutive surface-initiated atom transfer radical polymerization (SI-ATRP) was employed to graft a flexible block copolymer brush, pNIPAm-b-pGMA, from an initiator-functionalized nanosilica surface, followed by postpolymerization modification of the pGMA moiety with sodium azide. Subsequently, an alkyne-tagged boronic acid (PCAPBA) was conjugated to the polymer brush via a Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) click reaction, leading to a silica-supported polymeric hybrid material, Si@pNIPAm-b-pBA, with a potent glycol binding affinity. The obtained core-brush nanocomposite was systematically characterized with regard to particle size, morphology, organic content, brush density, and number of immobilized boronic acids. We also studied the characteristics of glycoprotein binding of the nanocomposite under different conditions. The nanocomposite showed high binding capacities for ovalbumin (OVA) (98.0 mg g-1) and horseradish peroxidase (HRP) (26.8 mg g-1) in a basic buffer (pH 9.0) at 20 °C. More importantly, by adjusting the pH and temperature, the binding capacities of the nanocomposite can be tuned, which is meaningful for the separation of biological molecules. In general, the synthetic approach developed for the fabrication of block copolymer brushes in the nanocomposite opened new opportunities for the design of more functional hybrid materials that will be useful in bioseparation and biomedical applications.
authors.affiliation: Division of Pure and Applied Biochemistry, Department of Chemistry, Lund University , Box 124, 221 00 Lund, Sweden.
authors.forename: Lingdong
authors.initials: L
authors.lastname: Jiang
authors.affiliation: Division of Solid State Physics and NanoLund, Department of Physics, Lund University , Box 118, 221 00 Lund, Sweden.
authors.forename: Maria E
authors.initials: ME
authors.lastname: Messing
authors.affiliation: Division of Pure and Applied Biochemistry, Department of Chemistry, Lund University , Box 124, 221 00 Lund, Sweden.
authors.forename: Lei
authors.identifier: http://orcid.org/0000-0002-3646-4072
authors.initials: L
authors.lastname: Ye
mesh_terms: D006023:Glycoproteins; D006863:Hydrogen-Ion Concentration; D053761:Nanocomposites; D058105:Polymerization; D011108:Polymers; D013499:Surface Properties; D013696:Temperature
chemical_list: D006023:Glycoproteins; D011108:Polymers
keywords: atom transfer radical polymerization; bioseparation; block copolymer brush; boronic acid; glycoprotein; nanocomposite