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(MEO 2 MA‐ co ‐OEGMA)‐ b ‐PMAGP) with various compositions and molecular weights were obtained by deprotection of amphiphilic diblock copolymers P(MEO 2 MA‐ co ‐OEGMA)‐ b ‐poly(6‐ O ‐methacryloyl‐1,2:3,4‐di‐ O ‐isopropylidene‐ D ‐galactopyranose) (P(MEO 2 MA‐ co ‐OEGMA)‐ b ‐PMAlpGP), which were prepared via reversible addition‐fragmentation chain transfer (RAFT) polymerization using P(MEO 2 MA‐ co ‐OEGMA) as macro‐RAFT agent. Dynamic light scattering and UV–vis studies showed that the micelles self‐assembled from P(MEO 2 MA‐ co ‐OEGMA)‐ b ‐PMAlpGP were thermoresponsive. A hydrophobic dye Nile Red could be encapsulated by block copolymers P(MEO 2 MA‐ 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(MEO 2 MA‐ co ‐OEGMA)‐ b ‐PMAGP has potential applications in hepatoma‐targeting drug delivery and biodetection.