Embracing cancer immunotherapy with manganese particles

A substance integral to the sustenance and functionality of virtually all forms of life is manganese (Mn), classified as an essential trace metal. Its significance lies in its pivotal role in facilitating metabolic processes crucial for survival. Additionally, Mn exerts influence over various biological functions including bone formation and maintenance, as well as regulation within systems governing immunity, nervous signaling, and digestion. Manganese nanoparticles (Mn-NP) stand out as a beacon of promise within the realm of immunotherapy, their focus honed on intricate mechanisms such as triggering immune pathways, igniting inflammasomes, inducing immunogenic cell death (ICD), and sculpting the nuances of the tumor microenvironment. These minuscule marvels have dazzled researchers with their potential in reshaping the landscape of cancer immunotherapy - serving as potent vaccine enhancers, efficient drug couriers, and formidable allies when paired with immune checkpoint inhibitors (ICIs) or cutting-edge photodynamic/photothermal therapies. Herein, we aim to provide a comprehensive review of recent advances in the application of Mn and Mn-NP in the immunotherapy of cancer. We hope that this review will display an insightful view of Mn-NPs and provide guidance for design and application of them in immune-based cancer therapies.