Emerging trends and future outlook towards magnetic nanoparticles as frontiers in cancer immunotherapy

Magnetic nanoparticles (MNPs) are becoming significant assets in cancer immunotherapy. Their unique magnetic and surface-functional properties allow them to serve as multifunctional platforms capable of modulating immune responses at multiple levels. MNPs have the potential to enhance immune cell activation and targeting inside the tumor microenvironment. MNPs assist in transporting immune-stimulating agents and tumor antigens directly to antigen-presenting cells. This increases T cell activity and improves anti-tumor reactions. MNPs are additionally utilized to enhance checkpoint blockade and to overcome the immunosuppressive milieu that often hinders the therapeutic efficacy of immunotherapies. In certain preclinical models, MNPs facilitate local hyperthermia to stimulate local immune activation at tumor sites. The magnetic guidance of these nanoparticles also facilitates the delivery of cytotoxic lymphocytes such as CD8 T cells and natural killer (NK) cells to solid tumors, addressing the challenge of poor infiltration of immune effector cells into the tumor. Numerous designs currently integrate therapy with imaging for accurate monitoring of biodistribution. Although MNPs hold potential, challenges remain in terms of biodegradability, long-term biosafety, immune compatibility and clinical applications. This review covers recent advances in MNP-based cancer immunotherapy, including their mechanisms of immune modulation, innovative design strategies, and integration with existing therapies. It also discusses the current limitations and future perspectives that will guide the next generation of magnetically assisted immunotherapeutic platforms toward clinical success.