In Situ Self-Aggregation of Spirulina Skeleton Fibers Enhances the Efficacy of Anti-Tumor Thermal Immunotherapy

The lack of broad-spectrum tumor antigens, limited immunogenicity of antigens, and immunosuppressive microenvironment in tumors have impeded the development of cancer vaccines. To address this issue, a vaccine platform is developed based on Spirulina skeleton fibers loaded with gold (Au) nanoparticles (Au@E-SP). Upon subcutaneous administration, Au@E-SP self-aggregates in situ and forms a 3D vaccine scaffold owing to its elongated and helical architecture. Through the aggregation of Au@E-SP, Au nanoparticles are concentrated, which significantly enhances the local photothermal effect and releases more tumor-associated antigens. In addition, the retained E-SP serves as a natural immune adjuvant that sustainably reverses the immunosuppressive microenvironment in vivo. Combining these advantages, the vaccines induce a potent anti-tumor immune response, effectively inhibiting tumor recurrence and metastasis. This strategy utilizes microalgae as a self-adjuvant vaccine, providing a promising avenue for further research in tumor immunotherapy.