Using a variety of vibrational spectroscopic techniques, we have investigated the role of phospholipid, principally dipalmitoylphosphatidylcholine (DPPC), in human lung surfactant as an enhancer of alveolar stability during respiration. Because of the high fluorescence associated with pulmonary surfactant, we must use Fourier transform (FT) Raman spectroscopic approaches coupled with near- infrared laser excitation in order to obtain useful spectra of native material. Although we have characterized the gel to liquid crystalline phase transition properties of DPPC and related systems from FT-Raman spectra, we have not yet discerned the dominant lipid/protein interactions present in lung surfactant. We have demonstrated, however, that FT-Raman techniques can provide an important new biophysical tool.
