Deposition of Biological Lipids on Solid Planar Substrates by Langmuir Blodgett Technique

With the goal to develop biosensors using membrane proteins as the sensing elements, we have investigated the influence of various factors on successful deposition of phospholipids by Langmuir Blodgett technique to form stable bilayers on planar supports. We use factorial experimental design to screen factors of importance for transfer of the layer separately and for its stability. These experiments were performed on hydrophilic supports (glass, platinum, chromium). The screening included factors such as temperature, pH, ionic composition of the subphase, deposition rate, pretreatment of the support and composition of the lipid mixture. The last-mentioned parameter was also separately studied with a response surface design, in which we varied the proportions of phosphatidylcholine, phosphatidylethanolamine, phosphatidic acid (all as dipalmitoyl derivatives) and cholesterol, to achieve a stable first layer on platinum.