Distance Tuning Floating Membranes Through pH Control

We have developed a self-assembled floating bilayer sample systems for use as a membrane biomimetic. These are comprised of fluid phase phospholipid bilayers which float adjacent to carboxyl terminated oligo-ethylene-glycol self-assembled monolayers (COOH-OEG-SAMs). We found that changing the solution salt conditions modifies the distance between the bilayer and the SAM. Simulation studies suggest cation bridging between the membrane and the SAM as the cause of this novel effect. Here we wish to use pH to modifying the membrane/SAM surface charge and measure changes in membrane-to-SAM distance as a result of this. This will provide further evidence on the cause of this novel distance tuning effect and allow us to gain a fuller understanding of this biotechnologically relivant sample system.