Magnetic Nanoparticles with Aspects of their Use in Cancer Therapy

Cancers remain the leading cause of death worldwide, despite significant advances in their diagnosis and treatment. The inadequacy and ineffectiveness of standard treatments (chemotherapy, radiotherapy, and surgery), their severe side effects, and the resistance of tumor cells to chemotherapeutics have forced researchers to investigate alternative therapeutic strategies. Magnetic nanoparticles (MNPs) have been evaluated as one of the promising strategies in treating cancers, a major public health problem. Due to their intrinsic magnetic properties, MNPs are tools that can be designed to be multifunctional in medicine, including cancer therapy. Multifunctionality can be achieved with various drug/agent loadings, such as chemotherapeutic drugs, radionuclides, nucleic acids, and antibodies. This provides a multimodal theranostics platform for cancer diagnosis, monitoring, and therapy. These substances can then be delivered to the tumor tissue using an external magnetic field (EMF). Magnetic or photothermal applications kill cancer cells at the tumor site by inducing local hyperthermia, whereas photodynamic therapy kills them by producing reactive oxygen species. MNP applications also prevent drug resistance. In addition, alone or with different combination options, MNP applications provide synergistic effects and reduce side effects. Functionalized MNPs can be used to remove unwanted cells from blood, including circulating tumor cells (CTCs), which are key factors in the metastatic process and leukemia cells. Despite numerous successful studies, there are some unpredictable obstacles to be discovered in routine usage. This review focuses mainly on the application of MNPs in cancer treatment, covering future perspectives and challenges.