Progress Of Magnetic Hyperthermia Based On Magnetic Nanomaterials

One of the important research fields in tumor nanomedicine is the novel tumor physical therapy strategy called magnetic induction hyperthermia. It was developed through the following views: Tumor cells have worse thermal tolerance than normal cells, and magnetic iron oxide nanoparticles can generate heat under the action of an alternating magnetic field (AMF). According to its principle, magnetic nanoparticles serve as a thermal medium under AMF for locating tumors and absorb the energy of the external magnetic field to generate heat through several factors, including hysteresis loss and relaxation loss; consequently, the tumor tissue locally heats up rapidly, causing tumor cell apoptosis. Compared with the traditional tumor hyperthermia therapy, magnetic induction hyperthermia has no limitation on penetration depth, has no drug resistance in physical therapy, causes minimal side effects of iron oxide nanoparticles, and is applicable in clinical tumor treatment. However, the application of tumor magnetic hyperthermia still have several bottlenecks, including the following: (1) The biological effects and mechanisms of magnetic induction heating remain poorly understood; (2) the current iron oxide hyperthermia agent has low magnetothermal conversion efficiency; (3) nano-targeted delivery efficiency is low and cannot achieve precise targeted magnetic hyperthermia; (4) the equipment generating a magnetic field is limited. Nonetheless, with the rapid advancement of nanomaterial synthesis technology and the in-depth understanding of the biological effects of magnetic nanomaterials, research on magnetic nanomaterials, especially iron oxide, has greatly improved the application of tumor magnetic hyperthermia as a new and smart strategy. Its application can mediate external fields. For instance, optimizing the size, morphology, composition, and surface modification of magnetic nanoparticles is necessary to improve magnetic hyperthermia performance. This study aimed to improve the curative effect of magnetothermal activity on tumors, further understand the heat generation mechanism of magnetic nanomaterials, optimize the conversion efficiency of thermotherapy agents, and enhance the tumor-targeting of magnetic nanoagents and magnetic field generating equipment. Herein, we review the latest research progress of magnetic nanomaterials in tumor magnetic hyperthermia and discuss the prospects for tumor magnetic hyperthermia research. The nanosized magnetic iron oxide served as a heat source. Although the nanoparticle concentration at the tumor cells does not produce macroscopic heating, magnetic nanoparticles can induce tumor cell apoptosis under AMF. The local heat shows steep exponential decays with an increasing distance from the nanoparticle surface. Thus, nanoscale magnetic heating may exert biological effects on tumor cells by regulating the interaction network of biological macromolecules (such as proteins, nucleic acids, and polysaccharides) and enzyme catalytic activity or changing the tumor microenvironment. Further investigation is required to explore the biological effects and mechanisms of nanoscale magnetic induction heating, design safe and efficient smart nanopreparations, develop new-generation magnetic hyperthermia equipment, and comprehensively apply nanotechnology methods and nanoscience principles to tumor magnetic hyperthermia.To elucidate the mechanism of nanoscale magnetothermal effect on life activities, we need to establish a new, accurate, safe, and efficient magnetic nanoparticle hyperthermia, which will build a solid foundation for the diagnosis and treatment of diseases using magnetic nanomaterials in the future.