Magnetic iron oxide nanoparticles: Recent trends in design and synthesis of magnetoresponsive nanosystems

•Synthesis procedures of iron oxide nanoparticle systems are comparatively analyzed.•The properties of single core and multicore iron oxide nanoparticles are reviewed.•Biocompatible functional coatings are thoroughly discussed.

Recent developments in nanotechnology and application of magnetic nanoparticles, in particular in magnetic iron oxide nanosystems, offer exciting possibilities for nanomedicine. Facile and precise synthesis procedures, high magnetic response, tunable morphologies and multiple bio-functionalities of single- and multi-core magnetic particles designed for nanomedicine applications are thoroughly appraised. This review focuses on the structural and magnetic characterization of the cores, the synthesis of single- and multicore iron oxide NPs, especially the design of the latter, as well as their protection, stabilization and functionalization by desired coating in order to protect against the corrosion of core, to prevent non-specific protein adsorption and particle aggregation in biological media, and to provide binding sites for targeting and therapeutic agents.