Multicomponent magnetic nanoparticle engineering: the role of structure-property relationship in advanced applications

Combining magnetic nanomaterials with materials of other classes can produce multicomponent nanoparticles with an entire ensemble of new structures and unique, enhanced, synergetic, and/or complementary functionalities. Here we discuss the most recent developments in the synthesis of multicomponent magnetic nanoparticles, describe the resulting structures and their novel properties, and explore their application in a variety of fields, including multimodal imaging, nanomedicine, sensing, surface-enhanced Raman scattering, and heterogeneous catalysis. The current synthetic methods (usu-ally bottom-up approaches) of multicomponent nanoparticles can produce a number of tailored mor-phologies (core@shell, yolk-shell, core-satellite, Janus, nanochains, anisotropic, etc.), making them invaluable for applications in biology, medicine, chemistry, physics, and engineering. But like any new technology, their synthesis methods need to be optimized to be simple, scalable, and as environmentally friendly as possible before they can be widely adopted. In particular, the use of life cycle assessment (LCA) to guide future works toward environmental sustainability is highlighted. Overall, this review not only presents a critical and timely summary of the state-of-the-art of this burgeoning field in both fundamental and applied nanotechnology, but also addresses the challenges associated with under-standing the particular structure-property relationships of multicomponent magnetic nanoparticles.