Multiparametric sensing of outer membrane vesicle-derived supported lipid bilayers demonstrates the specificity of bacteriophage interactions

The use of bacteriophage, viruses that specifically infect bacteria, as antibiotics has become an area of great interest in recent years as the effectiveness of conventional antibiotics recedes. The detection of phage interactions with specific bacteria in a rapid and quantitative way is key for identifying phage of interest for novel antimicrobials. Outer membrane vesicles (OMVs) derived from gram-negative bacteria can be used to make supported lipid bilayers (SLBs) and therefore in vitro membrane models that contain naturally occurring components of the bacterial outer membrane. In this study, we used Escherichia coli OMV derived SLBs and use both fluorescent imaging and surface sensitive techniques to show their interactions with T4 phage. We also integrate these bilayers with microelectrode arrays (MEAs) functionalised with the conducting polymer PEDOT:PSS and show that the pore forming interactions of the phage with the SLBs can be monitored using electrical impedance spectroscopy. To highlight our ability to detect specific phage interactions, we also generate SLBs using OMVs derived from Citrobacter rodentium, which is resistant to T4 phage infection, and identify their lack of interaction with phage. The work presented here shows how interactions occurring between phage and these complex SLB systems can be monitored using a range of experimental techniques. We believe this approach can be used to identify phage against bacterial strains of interest, as well as more generally to monitor any pore forming structure (such as defensins) interacting with bacterial outer membranes, and thus aid in the development of next generation antimicrobials.