Fig. 9

Bode plots of the EIS of SLBs formed from P. aeruginosa PaO1 OMVs. EIS measured the impedance of electrolytes across a SLB built from P. aeruginosa PaO1 OMVs. SLBs treated with polymyxin B A at 280 µg/ml, 28 µg/ml and 2.8 µg/ml, showed that (from the concentrations tested) a concentration of 28 µg/ml is required to reduce the impedance of the SLB. SLBs treated with daptomycin B do not reduce impedance as the drug requires binding to teichoic acids which are specific to Gram-positive bacterial membranes. SLBs treated with the Buffer control (500 mM TrisHCl pH 8.0) C showed a slight reduction in impedance, indicating that high concentrations of TrisHCl affected membrane integrity. SLBs treated with 6xHis-Hill_BB_C10074 D demonstrated that even at the lowest concentration tested of 5 µg/mL, membranes provided no impedance to the electrolyte showing that the membrane was destroyed. This low concentration (5 µg/mL) was 1000-fold lower than the concentration used to successfully inhibit bacteria in whole-cell assays and contained just 0.5 mM Tris. All data was obtained using the Nova software. EIS data are representative of 4 independent electrodes