MnOx Nanospikes as Nanoadjuvants and Immunogenic Cell Death Drugs with Enhanced Antitumor Immunity and Antimetastatic Effect

Abstract Despite the widespread applications of manganese oxide nanomaterials (MONs) in biomedicine, the intrinsic immunogenicity of MONs is still unclear. MnO x nanospikes (NSs) as tumor microenvironment (TME)‐responsive nanoadjuvants and immunogenic cell death (ICD) drugs are proposed for cancer nanovaccine‐based immunotherapy. MnO x NSs with large mesoporous structures show ultrahigh loading efficiencies for ovalbumin and tumor cell fragment. The combination of ICD via chemodynamic therapy and ferroptosis inductions, as well as antigen stimulations, presents a better synergistic immunopotentiation action. Furthermore, the obtained nanovaccines achieve TME‐responsive magnetic resonance/photoacoustic dual‐mode imaging contrasts, while effectively inhibiting primary/distal tumor growth and tumor metastasis.