CuInP₂S₆ Captures Virus for Viral Inhibition and Vaccine Adjuvanticity

The development of broad-spectrum antiviral agents and effective vaccine adjuvants remains a critical challenge. Herein, we report biodegradable CuInP₂S₆ (CIPS) nanosheets as a dual-functional material that enables direct viral interception and potent immunoenhancement. Its action stems from a functional paradigm we term CIPS-dependent cellular phagocytosis, wherein CIPS binds viral particles and leverages intrinsic phagocytic clearance to promote macrophage-mediated viral uptake and degradation. This process not only directly neutralizes viruses but also enhances antigen presentation and facilitates dendritic cell activation, thereby establishing the foundation for its adjuvant function. Consequently, in a murine immunization model, the CIPS-adjuvanted formulation elicited a significantly stronger humoral immune response, including elevated antigen-specific IgG titers and robust neutralizing antibody induction, even with a monomeric receptor-binding domain antigen. This work elucidates how the antiviral mechanism of CIPS translates into potent immunoenhancement, offering a novel strategy for applying functional nanomaterials in vaccine development.