Selective Isotopic Labeling Resolves the Gel-to-Fluid Phase Transitions of the Individual Leaflets of a Planar-Supported Phospholipid Bilayer

in: Langmuir (2019)
Richard-Lacroix, Marie; Umuhire, Kayiganwa Natyvella; Lister, Eugénie; Pellerin, Christian; Badia, Antonella
Knowledge of the thermotropic phase behavior of solid-supported bilayer lipid assemblies is essential to mimick the molecular organization and lateral fluidity of cell membranes. The gel-to-fluid phase transitions in a homologous series of single phospholipid bilayers supported on planar silicon substrates were investigated by temperature-controlled atomic force microscopy and attenuated total reflection infrared spectroscopy to obtain complementary information at the mesoscopic and molecular scales. Symmetric bilayers of dipalmitoylphosphatidylcholine (DPPC) and vertically asymmetric bilayers composed of a leaflet of DPPC and another of acyl-chain-deuterated DPPC (DPPC-d62) were prepared by the Langmuir−Blodgett technique. The selective deuteration of one of the bilayer leaflets enabled the simultaneous monitoring by IR spectroscopy of the acyl chain melting in each leaflet via the spectrally isolated CH2 and CD2 stretching vibrations. Two gel-to-fluid transitions were discerned for both the symmetric and asymmetric bilayers in ultrapure water. The deuterium isotope effect observed in free-standing membranes was maintained for the supported bilayers. IR spectroscopy revealed that the melting of one leaflet promotes the disordering of the acyl chains in the adjacent one. The findings suggest that the two leaflet phase transitions do not evolve in isolation. This work sheds insight into the nature of leaflet−leaflet interactions and the thermodynamic properties of surface-confined phospholipid bilayers.

Cookies & Skripte von Drittanbietern

Diese Website verwendet Cookies. Für eine optimale Performance, eine reibungslose Verwendung sozialer Medien und aus Werbezwecken empfiehlt es sich, der Verwendung von Cookies & Skripten durch Drittanbieter zuzustimmen. Dafür werden möglicherweise Informationen zu Ihrer Verwendung der Website von Drittanbietern für soziale Medien, Werbung und Analysen weitergegeben.
Weitere Informationen finden Sie unter Datenschutz und im Impressum.
Welchen Cookies & Skripten und der damit verbundenen Verarbeitung Ihrer persönlichen Daten stimmen Sie zu?

Sie können Ihre Einstellungen jederzeit unter Datenschutz ändern.