Design of Smart Oligo(ethylene glycol)-Based Biocompatible Hybrid Microgels Loaded with Magnetic Nanoparticles

This article reports a rational strategy for preparing smart oligo(ethylene glycol)‐based hybrid microgels loaded with high content of homogeneously distributed preformed magnetic nanoparticles (NPs) (up to 33 wt%). The strategy is based on the synthesis of biocompatible multiresponsive microgels by precipitation copolymerization of di(ethylene glycol) methyl ether methacrylate, oligo(ethylene glycol) methyl ether methacrylate, methacrylic acid, and oligo(ethylene glycol)diac­rylate. An aqueous dispersion of preformed magnetic NPs is straightforwardly loaded into the microgels. Robust monodisperse thermoresponsive magnetic microgels are produced, exhibiting a constant value of the volume phase transition temperature whatever the NPs content. The homogeneous microstructure of the initial stimuli‐responsive biocompatible microgels plays a crucial role for the design of unique well‐defined ethylene glycol‐based thermoresponsive hybrid microgels. Smart biocompatible oligo(ethylene glycol)‐based hybrid microgels loaded with a high content of homogeneously distributed preformed magnetic nanoparticles are synthesized by a simple two‐step method. The monodisperse thermoresponsive magnetic microgels exhibit a constant value of the volume phase transition temperature up to high nanoparticle (NP) content (33 wt%) thanks to the homogeneous microstructure of the initial biocompatible microgels.