Engineering strategies of bacterial outer membrane vesicles for enhancing tumor immunotherapy

Outer membrane vesicles (OMVs) have emerged as highly promising bio-derived nanoplatforms in tumor immunotherapy due to their inherent immunogenicity, structural diversity, and molecular customization capabilities. Recent studies have introduced various engineering strategies to enhance their therapeutic efficacy, yet these approaches are often presented as isolated modifications lacking a unified functional theoretical framework. This paper categorizes OMVs engineering techniques into pre-isolation and post-isolation strategies, analyzing how they regulate antigen presentation, immune activation, biodistribution, and therapeutic integration within the tumor immune cycle. By comparing the advantages, limitations, and applicable scenarios of genetic, metabolic, chemical, and physical modifications, we propose a function-oriented design framework. Simultaneously, we address critical challenges including safety control, production consistency, and mechanism standardization, charting future pathways for translating engineered OMVs into clinically viable cancer immunotherapies.