<p>Outer membrane vesicles (OMVs) are non-replicating, nanoscale particles naturally released by Gram-negative bacteria, which play important roles in bacterial communication and host interactions. Due to their biocompatibility, efficient production through fermentation, and inherent lymph node targeting capability, OMVs have emerged as a promising platform for biomedical applications, including vaccine development, drug delivery, immune modulation, cancer therapy, and antimicrobial strategies. This review discusses the biogenesis and biological functions of OMVs, methods for their isolation, and recent advances in their engineering as drug delivery systems, with a focus on vaccines and immunoadjuvants. We also address key challenges in scalable production and purification, propose potential solutions, and highlight current limitations along with future research directions.</p> Graphical abstract <p>Bacterial outer membrane vesicles as a smart &amp; multifunctional platform for biomedical applications.</p> <p></p>