Fabrication of biocompatible and stimuli-responsive hybrid microgels with magnetic properties via aqueous precipitation polymerization

• Poly(NVCL-co-IA) microgels containing iron oxide were prepared.
• NVCL and IA were polymerized from functionalized iron oxide nanoparticles surfaces.
• Hybrid microgels with between 166.9 and 193.3 nm in size were obtained.
• The hydrid microgels showed temperature-, pH- and magnetic responsive behavior.
• TEM revealed a core of magnetic nanoparticles surrounded by the polymeric shell.

This article reports the fabrication of poly(N-vinylcaprolactam-co-itaconic acid)- (poly(NVCL-co-IA))-based microgels containing magnetic nanoparticles. Preformed iron oxide nanoparticles that were functionalized with oleic acid and the reactive surfactant dodecan-1-ene-1-sodium sulfonate were used for such a purpose. NVCL and IA were polymerized in situ from the functionalized iron oxide nanoparticle surfaces. The process resulted in hybrid microgels with size between 166.9 and 193.3 nm. The polydispersity index was low, which indicated that the microgels' magnetic dispersion is stable and homogeneous. The hydrid poly(NVCL-co-IA)-based microgels showed both temperature- and pH-sensitive behavior. The addition of iron oxide to the microgels was confirmed qualitatively by FTIR, X-ray diffraction and magnetization. The transmission electron microscopy (TEM) images confirmed the spherical morphology of the hybrid microgel which had a core that consisted of magnetic nanoparticles surrounded by a polymeric shell. Finally, the biocompatibility of (poly(NVCL-co-IA)) microgel containing magnetic nanoparticles was confirmed in vitro. All together, these results indicate the feasibility of the hybrid microgel to be used as a new drug delivery system.