Antimicrobial and antibiofilm potential of bacteriocin loaded nano-vesicles functionalized with rhamnolipids against foodborne pathogens

Abstract Synthetic lipid membranes are considered as promising food-grade nano vesicles (NVs), but their functionalization is required to empower them as active-nano vesicle systems. In this study, rhamnosomes (RS) were developed by engineering the membrane of nano-liposomes with antimicrobial surfactant i.e. rhamnolipids (RL). Intrinsically active rhamnosome nano-vesicles (RSNVs) were loaded with bacteriocin (nisin Z) to acquire broad-spectrum antimicrobial activity. Addition of rhamnolipids into the lipid bilayer exhibited an increase in the encapsulation efficiency of nisin from 47 ± 4% to 88 ± 7%. Scanning electron microscope (SEM) and Zeta-sizer revealed that the surface functionalization with RL increased the size of vesicles from 145 ± 2 nm to 209 ± 4 nm. Whereas, the zeta potential of nisin-loaded RSNVs was −20 ± 0.25 mV as compared to −3.47 ± 0.13 mV for loaded nano-liposomes, indicating higher physical stability of RSNVs. RSNVs not only demonstrated higher antimicrobial activity than liposomes but also enhanced the activity of nisin against Gram-positive and Gram-negative resistant foodborne pathogens including L. monocytogenes, S. aureus, E. coli and P. aeruginosa. Almost 80% reduction in biofilm biomass was observed when treated with nisin-loaded RSNVs due to its improved binding with bacterial surface. Thus, surface-active nanoliposomes (intrinsically active) with higher stability can provide an innovative strategy to control the biofilm-forming food associated pathogens.