Antigen-Inorganic Hybrid Flowers-Based Vaccines with Enhanced Room Temperature Stability and Effective Anticancer Immunity

Particle-based antigen carriers as adjuvants play an important role in vaccine development. Herein, an antigen-inorganic hybrid flower-like particle is developed as a novel vaccine carrier. Model antigen ovalbumin (OVA)-copper (II) sulfate hybrid vaccines (OVA-Cu-HVs) are mildly and facilely constructed through a biomimetic mineralization process. OVA-Cu-HVs facilitate cellular uptake in antigen-presenting cells and the internalization of OVA-Cu-HVs involves macropinocytosis-mediated endocytosis. OVA-Cu-HVs can release OVA in a pH-responsive behavior and promote cytosolic release of antigen to enhance antigen cross-presentation. Immunization with OVA-Cu-HVs promotes the maturation of dendritic cells in draining lymph nodes, induces robust antigen-specific T lymphocyte response, and inhibits tumor growth in vivo. In addition, OVA-Cu-HVs are efficacious after being stored for 4 weeks at room temperature and are expected to simplify vaccine storage and lower the cost of cold storage for transportation. Looking forward, OVA-Cu-HVs may hold strong potential to be as an effective vaccine delivery platform, which will facilitate the application of organic-inorganic hybrid flowers in biomedical areas.