Immunomodulatory effects of metal nanoparticles: current trends and future prospects

The advent of nanotechnology has steered into a new era of medical advancements, with metal nanoparticles (MNPs) emerging as potent agents for precise regulation of the immune system. This review provides a comprehensive overview of the immunomodulatory roles of MNPs, including gold, silver, and metal oxide nanoparticles, in regulating innate and adaptive immunity. Additionally, we discuss the immunological effects of metal ions and metal complexes, offering a comparative analysis with nanoparticulate systems. We analyse cutting-edge strategies utilising MNPs to optimise vaccine efficacy, achieve targeted delivery to immune cells, and orchestrate inflammatory responses. Additionally, we discuss the therapeutic potential of MNPs in combating autoimmune diseases, cancers, and infectious agents, which is evaluated within the framework of precision medicine. Furthermore, we critically assess challenges such as biocompatibility, potential toxicity, and regulatory hurdles. Finally, we propose future directions for integrating MNPs with advanced delivery systems and other nanomaterials to propel the frontiers of immunotherapy. This review aims to provide a foundational understanding of MNP-mediated immunomodulation, inspiring further research and development in this burgeoning field.