Well-defined pH-sensitive block glycopolymers via reversible addition-fragmentation chain transfer radical polymerization: Synthesis, characterization, and recognition with lectin

Abstract

pH-Sensitive block glycopolymers of poly(2-(diethylamino)ethyl methacrylate) (PDEAEMA) and poly(3-O-methacryloy-α,β-D-glucopyranose) (PMAGlc) were synthesized via reversible addition–fragmentation chain transfer (RAFT) radical polymerization based on protected glycomonomer 3-O-methacryloyl-1,2:5,6-di-O-isopropylidene-D-glucofuranose (MAIpGlc). It was found that RAFT homopolymerization of MAIpGlc proceeded in a controlled fashion with 4-cyanopentanoic acid dithiobenzoate as chain transfer agent. Using the dithioester-capped PDEAEMA as macro-RAFT agent, block copolymerization of MAIpGlc was in good control as indicated by the linear pseudo first-order kinetic plot, the linear increment of number-average molecular weights as well as narrow and symmetrical gel permeation chromatography peaks, and low polydispersities. Well-defined diblock copolymers of DEAEMA and MAIpGlc were prepared successfully through the chain extension of PDEAEMA. The deprotection of MAIpGlc units in trifluoroacetic acid/H2O solution afforded PDEAEMA-b-PMAGlc block glycopolymer. The self-assembly behavior of PDEAEMA-b-PMAGlc in aqueous solution was investigated by using 1H NMR, UV-vis spectroscopy, dynamic light scattering, and transmission electron microscopy. The results demonstrated that spherical micelles with PDEAEMA as the hydrophobic cores and PMAGlc as the hydrophilic shells were formed in alkaline aqueous solution. These glucose-installed micelles had specific recognition with Concanavalin A. The combination of pH-sensitivity of PDEAEMA and biomolecular recognition of PMAGlc in one micellar system may create a multifunctional platform for targeted delivery, biomimetics, and biodection. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3350–3361, 2010