An electrochemical impedance study of the effect of pathogenic bacterial toxins on tethered bilayer lipid membrane

Pathogenic bacteria secrete various virulence factors that can directly interact with the outer lipid bilayer membrane of eukaryotic cells, inducing cell death by apoptosis or necrosis. Such virulence factors account for much of the toxic action associated with bacterial infection; therefore the detection of such proteins could provide a methodology for sensing/detection of pathogenic bacteria in, for example, food or human tissue. Detection and identification of pathogenic bacteria by conventional methods such as plating and counting in laboratory is expensive and time consuming. With growing concerns over emergence and re-emergence of pathogenic bacteria with high resistant to current antibiotics, there is a potential need for effective detection of pathogenic toxins in-vitro. This paper presents the application of tethered bilayer lipid membrane (TBLM) as a sensing platform for the detection of the clinically relevant pathogenic bacterial, Staphylococcus aureus MSSA 476 and Pseudomonas aeruginosa PAO1 via their secreted virulence factors, using electrochemical impedance spectroscopy (EIS). A non-pathogenic strain of bacteria, E. coli DH5 alpha was used as a control. A clear difference in the impedance of the TBLM for the pathogenic vs. non-pathogenic species was observed.