The rapid progress of nanoscience a

The rapid progress of nanoscience and nanotechnology hasenabled researchers to material engineers on the molecular- andnanoscale to a great extent.1 A large number of novel nanomaterialsand nanostructures that exhibit fantastic physical,chemical, and biological properties have been created anddemonstrated high potentials for biomedicine, catalysis, sensor,energy conversion, and so on.2-6 Composite nanomaterials withwell-defined structures have been extensively explored to realizethe combination of respective properties of each component orachieve cooperatively enhanced performances.7-14 Core-shellstructured nanocomposites have become a rapidly growingresearch field in material community. In general, the core-shellnanostructures can be easily obtained through two pathways.One is the self-assembly of surfactants with different compositionsor the supramolecular assembly based on molecularrecognition,10 and another is surface reaction or precipitation(deposition) on a preformed nanoobject through electrostaticassembly, covalently grafting, or affinity coating.11–14 As animportant family of advanced nanomaterials, magnetic microsphereswith magnetically responsive core and functional shellhave gained much attention due to their unique separable featurewhich makes it possible to realize selective capture of interesttarget objects from the complex samples,15 magnetically controllableon-off reactions16 and convenient recycling of magneticcarriers. So far, to improve their performance in practicalapplications, much work has been done to enhance magneticresponsiveness and surface areas, and addition of new functionalitiesby combining with other functional nanomaterials.A variety of microspheres with inorganic magnetic particlesembedded in different matrixes have been reported for applicationsin information storage, bioseparation, bioimaging, enzymeimmobilization, and catalysis.12–2