Magnetic nanoparticle with size, shape and composition tunable properties have been demonstrated the great potential for various biomedical applications such as protein/cell separation, biosensor, drug delivery, magnetic resonance imaging (MRI) and magnetic hyperthermia treatment.In particular, iron oxide nanoparticles have been considered as a promising contrast/hyperthermia agent for early diagnostics and therapy of cancer.However, the application of these nanoparticles for cancer diagnostics and therapy has been largely hindered by low MR detection sensitivity and low magnetic thermal conversion efficiency.