New insights into lung surfactant monolayers using vibrational sum frequency generation spectroscopy.
At the air-water interface, interfacial molecular structure, intermolecular interactions, film relaxation and film respreading of model lung surfactant monolayers were studied using vibrational sum frequency generation (VSFG) spectroscopy combined with a Langmuir film balance. Chain-perdeuterated dipalmitoylphosphatidylcholine (DPPC-d62), palmitoyloleoyl-phosphatidylglycerol (POPG), palmitic acid (PA) and tripalmitin were investigated. In the DPPC-d62-PA binary monolayer, PA showed a condensing effect on the DPPC chains. On the contrary, in the DPPC-d62-POPG binary monolayer, POPG showed a fluidizing effect on the DPPC chains. In the ternary monolayer system of DPPC-d62-POPG-PA, the balance between the fluidizing and the condensing effect was also observed. In addition, the film relaxation behavior of DPPC-d62 and the enhanced film stability of DPPC-d62 caused by the addition of tripalmitin were observed. Real-time VSFG was also employed to study the respreading properties of a complex lung surfactant mixture containing DPPC-d62, POPG, PA and KL4 (a mimic of SP-B) peptide, which revealed DPPC enrichment after film compression.
Ma
Gang
G
Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH, USA.
Allen
Heather C
HC
D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry; D003903:Deuterium; D036341:Intercellular Signaling Peptides and Proteins; D008958:Models, Molecular; D010455:Peptides / Q000737:chemistry; D010715:Phosphatidylglycerols; D011663:Pulmonary Surfactants / Q000737:chemistry*; D013055:Spectrophotometry, Infrared
D036341:Intercellular Signaling Peptides and Proteins; C097558:KL4 surfactant; D010455:Peptides; D010715:Phosphatidylglycerols; D011663:Pulmonary Surfactants; D015060:1,2-Dipalmitoylphosphatidylcholine; C060037:1-palmitoyl-2-oleoylglycero-3-phosphoglycerol; D003903:Deuterium