The phospholipid mono-layer was compressed from 2 sides with a total speed of 10 mm/min (5 mm/min from opposite sides, Figure 2A ) using a Kibron pTroughXS equipped with a Teflon ribbon (polytetrafluoroethylene, hydrophobic barrier). The temperature was maintained at 25 °C using an external water bath. The surface tension of the subphase during each compression was monitored using a wire probe as a Wilhemy plate. The surface pressure was calculated from the surface tension using equation 1 where π is the surface pressure, y0 is the surface tension of water (72.8 mN/m), and γ is the surface tension at a given area per phospholipid after the film has been applied.
Each compression isotherm experiment consisted of at least 3 replicates and the averages with standard deviations of the area per phospholipid at every 5 mN/m was calculated using Microsoft Excel. The worked-up data were transferred to OriginPro Version 9.1 to be graphed. From the averages of the compression isotherms, the percent difference from the control of each sample at 5mN/m, 30 mN/m, and 35 mN/m were calculated. The compression moduli were calculated using OriginPro Version 9.1 from the compression isotherm average results using equation 2, where Cs1 is the compression modulus, A is the surface area, and π is the surface pressure.
Each compression isotherm experiment consisted of at least 3 replicates and the averages with standard deviations of the area per phospholipid at every 5 mN/m was calculated using Microsoft Excel. The worked-up data were transferred to OriginPro Version 9.1 to be graphed. From the averages of the compression isotherms, the percent difference from the control of each sample at 5mN/m, 30 mN/m, and 35 mN/m were calculated. The compression moduli were calculated using OriginPro Version 9.1 from the compression isotherm average results using equation 2, where Cs1 is the compression modulus, A is the surface area, and π is the surface pressure.