Formation of Air-Stable Supported Lipid Monolayers and Bilayers

Abstract

We have devised a means of depositing planar, air-stable supported lipid adlayers on modified Au substrates. Using the phospholipid 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), we form planar supported adlayer structures by vesicle fusion. Lipid bilayer formation proceeds on a hydroxythiol-terminated Au surface. Phospholipid monolayers form on hydroxythiol-terminated gold surfaces that have been treated with POCl3 and ZrOCl2(aq) prior to lipid deposition, providing an interface that interacts strongly with the DMPC phosphocholine headgroup. We use FTIR, cyclic voltammetry, optical ellipsometry, and water contact angle measurements to confirm the presence of lipid bilayers or monolayers on the modified Au substrates. For the zirconated surface, we observe the conversion of an initial partial lipid bilayer to a lipid monolayer, over a ca. 20 min time period, on the basis on ellipsometric thickness and contact angle data. 31P NMR measurements show the complexation of the phospholipid headgroup to a Zr-phosphate surface.