Review on bacterial outer membrane vesicles: structure, vesicle formation, separation and biotechnological applications

Abstract

Outer membrane vesicles (OMVs), shed by Gram-negative bacteria, are spherical nanostructures that play a pivotal role in bacterial communication and host-pathogen interactions. Comprising an outer membrane envelope and encapsulating a variety of bioactive molecules from their progenitor bacteria, OMVs facilitate material and informational exchange. This review delves into the recent advancements in OMV research, providing a comprehensive overview of their structure, biogenesis, and mechanisms of vesicle formation. It also explores their role in pathogenicity and the techniques for their enrichment and isolation. Furthermore, the review highlights the burgeoning applications of OMVs in the field of biomedicine, emphasizing their potential as diagnostic tools, vaccine candidates, and drug delivery vectors.

Keywords: Biotechnological applications; Extracellular vesicles; Gram-negative bacteria; Outer membrane vesicles.

Fig. 1

(A) The inverse relationship between the production of OMVs and the level of covalently crosslinked Lpp. (B) Significant holes observed in the cell wall through quick-freeze deep-etch electron microscopy represent key structural features for periplasmic accumulation and the formation of OMVs. (C) When PagL is expressed in Salmonella Typhimurium, deacylated LPS is selectively enriched in OMVs, revealing a direct link between LPS remodeling and the formation of OMVs

Fig. 2

(A) Effect of OMVs on bacterial survival: At different concentrations of colistin, OMVs protected P. syringae Lz4W bacteria from inhibition by adsorption of antibiotics, as indicated by the increase in NPN fluorescence intensity. (B) Thin-layer chromatography (TLC) analysis revealed how Pseudomonas aeruginosa packages the signaling molecule PQS into OM vesicles (OMVs) for effective cellular communication and coordination of population behavior among bacteria. (C) Co-culture of pretreated AGS cells with DiO-labeled Hp OMVs showed that OMVs enter the cells through multiple endocytosis pathways that may trigger inflammation and pathogenesis