With the development of nanomedicine, magnetic nanomaterials have great potential for use as a combined therapeutic and diagnostic tool in medical applications, especially in cancer treatment.1–3 In diagnostic applications, magnetic nanomaterials can be detected by magnetic resonance imaging (MRI)4,5 and X-ray computed tomography (CT).5 In therapeutic applications, metallic nanomaterials can not only serve as drug carriers,6 but they can also be applied as thermotherapeutic probes under radial high-frequency fields.7 Among those current magnetic nanomaterials, iron oxide-based nanoparticles have a key advantage with high biocompatibility.3,8,9 Indeed, iron oxide-based nanoparticles used as MRI contrast agents were among the first approved clinical nanomaterials.1