Heat-stabilized phospholipid films: film characterization and the production of protein-resistant surfaces

Phospholipid films have been shown in a number of studies to exhibit potential as nonfouling surfaces for biomaterial applications. However, the practical application of such films has been hindered by instability in aqueous solutions and significant detachment under mild shear stresses. Methods for stabilizing lipid films have been investigated, but to date require the presence of specific functional groups or chemical modification of the lipid molecule. In contrast to these methods, we present a process for heat-stabilization of lipid films. These heat-stabilized films have been shown to be able to withstand repeated rinsing without significant detachment. Phosphatidylcholine monolayers were formed on hydrophobic self-assembled monolayers using the liposome fusion method and stabilized at 80 degrees C. The films were characterized using Fourier transform infrared spectroscopy, ellipsometry, and atomic force microscopy and were shown to be defect free after repeated rinsing. Further experiments using a quartz crystal microbalance showed that the heat-stabilized lipid films were highly resistant to nonspecific protein adhesion and compared very favorably with poly(ethylene glycol)-coated surfaces under identical exposure conditions.