In-situ and ex-situ structural analysis of phospholipid-supported planar bilayers using infrared spectroscopy and atomic force microscopy

Academic Article

Abstract

  • We report here both the in-situ and ex-situ study of phospholipids incorporated into supported planar bilayers using spectroscopic and imaging techniques. We have demonstrated the feasibility of using attenuated total reflectance infrared (ATR-IR) spectroscopy for the in-situ study of Langmuir monolayers at the air-water interface. This method results in a higher signal-to-noise ratio and more easily measured molecular orientation when compared with the external reflection infrared method previously developed. For ex-situ studies, we have demonstrated that a combination of IR spectroscopy and atomic force microscopy (AFM) provides detailed information concerning the conformation and distribution of the bilayer components. Our AFM images of the phospholipid 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) show molecularly-resolved phospholipid headgroups existing in a well-ordered, hexagonal-type lattice with unit cell areas obtained from these images corresponding to molecular areas commensurate with those obtained by X-ray diffraction from analogous phospholipid single crystals. Our results demonstrate that the combination of IR and AFM is a powerful tool for structural investigation of supported planar bilayers.
  • Authors

    Published In

  • Thin Solid Films  Journal
  • Digital Object Identifier (doi)

    Author List

  • Stephens SM; Dluhy RA
  • Start Page

  • 381
  • End Page

  • 386
  • Volume

  • 284-285