Self-assembled Floating Lipid Bilayers: What Forces Are Causing the Bilayer to Surface Distance Control?

Recently (RB19100102) we have discovered that floating bilayers composed of fluid phase lipids can be produced by deposited vesicles onto charge modified oligo(ethylene glycol)coated gold surfaces. Changing the solution NaCl concentration was found to cause the membrane to surface distance to increase. This effect is likely related to one or a combination of two phenomena. Either secondary hydration forces arising from the binding of hydrated cations to the charged SAM surface or a change in membrane surface charge due to head group ion interactions. We plan to compare the change in bilayer to surface distance using four differing Salt solutions (NaCl, LiCl, NaBr and LiBr) to determine which mechanism is controlling the changes in membrane to surface distance in these new functional membrane mimetics.