Development of probiotics vesicles for antibacterial effect

Abstract

Gram-positive probiotics play a key role to modulate gastrointestinal functions and protect the gut from pathogen colonization. Recent studies suggests that gram-positive probiotic extracellular vesicles (EVs) which inherit the biological cargos of probiotics may involve in the biological events inside the host. This opens up the possibility to use gram-positive EVs as a safer alternative to viable probiotics for clinical applications. Yet, two main challenges in current EVs research include how to isolate EVs at higher yield and how to preserve EVs integrity during long-term storage. An extrusion protocol for effective production of Bacteria Derived Nanovesicles (BDNs) from a gram-positive bacteria species, Lactobacillus Rhamnosus GG (LGG) has been proposed in this document. Taking inspiration from Cell Derived Nanovesicles (CDNs) extrusion, the extrusion protocol was adopted to isolate non-viable BDNs from living bacteria. Subsequently, we performed lyophilization approach to freeze-dry the BDNs samples. Fresh and lyophilized BDNs samples were characterized to investigate the physical and biological properties of the vesicles. This project is then focused on exploring the therapeutic applications of BDNs. In vitro, both fresh and lyophilized BDNs, demonstrated antimicrobial effect to suppress the pathogen growth rate. Besides, we had reported an immunoassay to investigate the inflammatory response between colon epithelial cells with BDNs samples. These findings could suggest the potential of BDNs to replace probiotic as antibiotics inside gut. Ultimately, the research project aims to pave the way for future development of BDNs. Commercialization of probiotic BDNs for para-probiotic based therapy may become possible if scientists can easily isolate BDNs from bacteria and stabilize the BDNs by lyophilization techniques