Abstract
Magnetic nanoparticles (MNPs) have emerged as a powerful tool in cancer theranostics due to their unique size-dependent magnetic properties, surface functionalization capabilities, and responsiveness to external magnetic fields. This review outlines different types of MNPs, including those composed of pure metals, metal oxides, and metallic alloys, and highlights their size-dependent magnetic behavior, such as superparamagnetism and dynamic magnetizations. We also explore the critical role of surface modification strategies in enhancing MNPs' biocompatibility, colloidal stability, and functional versatility for targeted biomedical applications. The applications of MNPs in cancer therapy are discussed, with a focus on magnetic hyperthermia, drug and gene delivery, and a combination of various therapies. Additionally, we examine their cancer diagnostic roles in imaging techniques such as magnetic resonance imaging (MRI) and magnetic particle imaging (MPI), and emerging magnetic biosensing technologies such as giant magnetoresistance (GMR), magnetic tunnel junction (MTJ), magnetic particle spectroscopy (MPS), and nuclear magnetic resonance (NMR)-based platforms. These advances collectively establish MNPs as key components in the future of personalized cancer diagnosis and treatment.