A phospholipid bilayer supported under a polymerized Langmuir film.

Phospholipid single bilayers supported on a hydrophilic solid substrate are extensively used in the study of the interaction between model membranes and proteins or polypeptides. In this article, the formation of a single dimyristoylphosphatidylcholine (DMPC) bilayer under an octadecyltrimethoxysilane (OTMS) polymerized Langmuir monolayer at the air-water interface is followed by Brewster angle microscopy (BAM) and polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS). The formation of the bilayer is initiated by injection of dimyristoylphosphatidylcholine small unilamellar vesicles into the aqueous subphase. Brewster angle microscopy allows visualization of the kinetics of formation and the homogeneity of the bilayer. Spectral simulations of the polarization-modulated infrared reflection absorption spectroscopy spectra reveal that the bilayer thickness is 39 +/- 5 A. This system constitutes the first example of a phospholipid bilayer on a "nanoscopic" support and opens the way to studies involving supported bilayers using powerful experimental techniques such as x-ray reflectivity, vibrational spectroscopies, or Brewster angle microscopy.