Bacteria-based bioactive materials for tumor immunotherapy

As one of the most abundant biological populations endowed with unique properties such as specific targeting and genetic engineering vectors, bacteria with immunogenic potential have garnered significant attention for their ability to elicit immune activation against tumors. This approach has achieved substantial breakthroughs as a modality for cancer treatment and is known as bacterial immunotherapy. However, the immunosuppressive tumor microenvironment (TME) can inhibit the immune response induced by bacteria and promote tumor growth and metastasis. To overcome this challenge, recent advancements in bacteria-based bioactive materials, which are biological substances synthesized by bacteria, have not only harnessed the inherent properties of bacteria but also specifically targeted the modulation of the TME, providing a more favorable environment for immune activation and significantly enhancing the efficacy of immunotherapy for cancer treatment. This review introduces the key mechanisms of bacteria-based biomaterials as anticancer agents and reviews the latest research progress, along with their clinical applications in cancer treatment. Finally, the potential and challenges of bacteria-based biomaterials for tumor therapy are explored, aiming to provide insights into the functions of bacteria-based bioactive materials and their role in advancing cancer immunotherapy while offering recommendations for the development of new bacteria-based biomaterials. • The relevance of bacteria and immune cells is explored, which helps to understand the mechanisms of bacterial immunotherapy. • The design of bacteria-based bioactive materials is summarized to improve the efficiency of bacteria for immune activation. • The synergistic mechanism of nanomaterial-assisted bacterial immunotherapy offers a theoretical basis for biomaterial design.