Synthesis and micellization of thermoresponsive galactose-based diblock copolymers

Thermoresponsive double hydrophilic diblock copolymers poly(2-(2′-methoxyethoxy)ethyl methacrylate-co-oligo(ethylene glycol) methacrylate)-b-poly(6-O-methacryloyl-D-galactopyranose) (P(MEO2MA-co-OEGMA)-b-PMAGP) with various compositions and molecular weights were obtained by deprotection of amphiphilic diblock copolymers P(MEO2MA-co-OEGMA)-b-poly(6-O-methacryloyl-1,2:3,4-di-O-isopropylidene-D-galactopyranose) (P(MEO2MA-co-OEGMA)-b-PMAlpGP), which were prepared via reversible addition-fragmentation chain transfer (RAFT) polymerization using P(MEO2MA-co-OEGMA) as macro-RAFT agent. Dynamic light scattering and UV–vis studies showed that the micelles self-assembled from P(MEO2MA-co-OEGMA)-b-PMAlpGP were thermoresponsive. A hydrophobic dye Nile Red could be encapsulated by block copolymers P(MEO2MA-co-OEGMA)-b-PMAGP upon micellization and released upon dissociation of the formed micelles under different temperatures. The galactose functional groups in the PMAGP block have specific interaction with HepG2 cells, and P(MEO2MA-co-OEGMA)-b-PMAGP has potential applications in hepatoma-targeting drug delivery and biodetection. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011