Today's Medical Engineering Interdisciplinary Topic Design: Tumor Melting Mineralization Bacteria as Effective Local Immunotherapeutic Agents

Oncolytic bacteria can trigger innate immune activity. However, the anti-tumor effect of inactivated bacteria is poor, while attenuated live bacteria pose significant safety risks. We hereby demonstrate that injecting manganese dioxide coated polyformaldehyde immobilized bacteria into tumors can effectively activate innate immune activity, regulate the immunosuppressive tumor microenvironment, and trigger tumor specific immune responses and distant anti-tumor responses. Single intratumoral injection of mineralized Salmonella typhimurium can inhibit the growth of various types of subcutaneous and in situ tumors in mice, rabbits, and tree shrews, and protect cured animals from tumor re attack. We also demonstrate that mineralized bacteria can be administered through arterial embolization to treat in situ liver cancer in rabbits. Our research findings support further translational testing of oncolytic mineralizing bacteria as an effective and safe anti-tumor immunotherapy.