Surface enhanced Raman scattering of a lipid Langmuir monolayer at the air-water interface.
Surface enhanced Raman spectra were recorded from a phospholipid monolayer directly at the air-water interface. We used an organized monolayer of negatively charged tetramyristoyl cardiolipins as a template for the electrochemical generation of silver deposits. This two-dimensional electrodeposition of silver under potentiostatic control was the substrate for enhancement of Raman spectra. We report the optimized conditions for the Raman enhancement, the microscopic observations of the deposits, and their characterization by atomic force microscopy. Laser excitation at 514.5 nm leads to intense and reproducible surface enhanced Raman scattering spectra recorded in situ from one monolayer of cardiolipin, using 0.5 mol % of 10N nonyl acridine orange or 5 mol % of acridine in the film, and demonstrates the possibility of estimating the pH at the metal/phospholipidic film interface.
Mangeney
C
C
Interface, Traitement, Organisation et Dynamique des Systèmes, UMR CNRS 7086, Université Denis Diderot-Paris 7, 1 rue Guy de la Brosse, 75 005 Paris, France.
Dupres
V
V
Roche
Y
Y
Felidj
N
N
Levi
G
G
Aubard
J
J
Bernard
S
S
D000165:Acridine Orange / Q000494:pharmacology; D000388:Air; D002308:Cardiolipins / Q000737:chemistry*; D004396:Coloring Agents / Q000494:pharmacology; D004563:Electrochemistry; D006863:Hydrogen-Ion Concentration; D007834:Lasers; D008055:Lipids / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D010743:Phospholipids / Q000737:chemistry; D012834:Silver; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013696:Temperature; D014867:Water / Q000737:chemistry*; D014961:X-Ray Diffraction
D002308:Cardiolipins; D004396:Coloring Agents; D008055:Lipids; D010743:Phospholipids; D014867:Water; D012834:Silver; D000165:Acridine Orange