Sugar-installed thermoresponsive micellar aggregates self-assembled from “coil-comb-coil” triblock glycopolymers: preparation and recognition with Concanavalin A

Abstract

The combination of reversible addition-fragmentation chain transfer (RAFT) radical polymerization and ring-opening polymerization was employed to synthesize the coil-comb-coil triblock copolymer poly(3-O-methacryloyl-1,2:5,6-di-O-isopropylidiene-D-glucofuranose)-block-poly(2-hydroxyethyl methacrylate-graft-poly(ε-caprolactone))-block-poly(N-isopropylacrylamide) (PMAIpGlc-b-P(HEMA-g-PCL)-b-PNIPAM). The deprotection of MAIpGlc units in 80% formic acid solution produced biodegradable and thermoresponsive “coil-comb-coil” triblock glycopolymer with pendant glucose residues. The formation of glucose-installed micellar aggregates self-assembled from triblock glycopolymers was investigated by fluorescence spectroscopy, transmission electron microscopy (TEM) and dynamic light scattering (DLS). The results demonstrated that the “coil-comb-coil” triblock glycopolymers self-assembled to spherical compound micelles with P(HEMA-g-PCL) blocks as hydrophobic cores and PMAGlc and PNIPAM blocks as hydrophilic shells in aqueous solution, and the micellar size was dependent on temperature. The interaction of triblock glycopolymers with FITC-labeled Concanavalin A (Con A) was studied by means of fluorescence spectroscopy and the binding constant K_a of glucose residues with Con A was calculated using the Scatchard equation. The biomolecular recognition, thermoresponsive and biodegradable characteristics make these “coil-comb-coil” triblock glycopolymers potential multifunctional platforms for targeted delivery, biomimetics and bioassays.