Raman spectroscopy of model membrane monolayers of dipalmitoylphosphatidic acid at the air-water interface using surface enhancement from buoyant thin silver films

• Published in: BIOPOLYM Vol. 57; no. 2; pp. 103 - 116
• Main Authors: Pemberton, Jeanne E., Chamberlain, James R.
• Format: Journal Article
• Language: English
• Published: New York John Wiley & Sons, Inc 2000
• Subjects: Air; air-water interface; Buoyancy; Colloids - chemistry; dipalmitoylphosphatidic acid; Electrochemistry; Langmuir Blodgett films; Membrane Lipids - chemistry; Membrane Lipids - metabolism; Membranes, Artificial; Metallic films; model membrane monolayers; Monolayers; Phase interfaces; Phosphatidic Acids - chemistry; Phosphatidic Acids - metabolism; Pressure; Raman scattering; Raman spectroscopy; Silver; Silver - metabolism; Spectrum Analysis, Raman; Surface Properties; Surface-Active Agents - metabolism; Thin films; thin silver films; Water - metabolism
• ISSN: 0006-3525; 1097-0282
• DOI: 10.1002/(SICI)1097-0282(2000)57:2<103::AID-BIP7>3.0.CO;2-T

A novel method for the acquisition of surface enhanced Raman (SER) spectra of model membranes of dipalmitoylphosphatidic acid (DPPA) in Langmuir layers at the air–water interface is reported. The approach is based on the electrochemical formation of a buoyant thin layer of coalesced silver colloids in the vicinity of the phosphatidic acid head groups at the interface. This Ag layer is an excellent platform for SER scattering, which shows the spectral features from all parts of the molecule and water between the Ag surface and the DPPA layer. The observation of the spectral response from the phosphatidic acid head groups is of particular significance, allowing insight into their chemical state and orientation at the air–water interface. © 2000 John Wiley & Sons, Inc. Biopolymers (Biospectroscopy) 57: 103–116, 2000