Synthesis and Characterization of α,ω-End Orthogonally Functionalizable Glycopolymers from Native Glycans

Glycopolymers have been employed as biomimetic glycoconjugates in both biological and biomedical research and applications. Among them, chain-end functionalized glycopolymers are very often explored for protein modification, microarray, biosensor, bioprobe and other applications. Herein, we report a straightforward synthesis of α,ω-end orthogonally functionalizable glycopolymers. Specifically, glycopolymers with an alkyne or azide group at one end and an O-cyanate on the other end were synthesized via cyanoxyl-mediated free-radical polymerization from native glycans without protection and deprotection. The alkyne chain-end can react with azide-containing molecules via click chemistry. The azide chain-end can react with alkyne-containing molecules via click chemistry or copper free click chemistry. On the other hand, O-cyanate can react with an amine group via isourea bond, affording a site-specific bioconjugation as well. Furthermore, chain-end heterofunctionalizations of the glycopolymers were demonstrated via sequential or one-pot click chemistry and isourea bond formation, respectively. Finally, end-to-end dimerization of the glycopolymers was demonstrated via chain-end click chemistry. These α,ω-end orthogonally functionalizable glycopolymers will be useful in many biological and biomedical research applications.