Dual-temperature and pH responsive (ethylene glycol)-based nanogels via structural design

Abstract

We report here the preparation of dual-temperature and pH responsive (ethylene glycol)-based nanogels via the reversible addition–fragmentation chain transfer (RAFT) polymerization under aqueous conditions. The core–shell structures of the nanogels were composed of 2-(2-methoxyethoxy)ethyl methacrylate (MEO₂MA), oligo(ethylene glycol) methacrylate (OEGMA), and di(ethylene glycol) dimethacrylate as a cross-linker. Both the core and shell structures of the nanogels showed a lower critical solution temperature (LCST). Interestingly, the LCST of the shell was strongly affected by the solution pH and salt concentration due to the presence of carboxyl groups at the nanogel surface. These dual temperature and pH responsive nanogels are expected to be non-toxic and therefore can be used as novel biomaterials for drug delivery applications.