Interaction of a partially fluorinated alcohol (F8H11OH) with biomembrane constituents in two-component monolayers

The interaction of (perfluorooctyl)undecanol (F8H11OH) with dipalmitoylphosphatidylcholine (DPPC), dipalmitoylphosphatidylglycerol (DPPG), and cholesterol (Ch) has been investigated in two-component monolayers at the air–water interface. The thermodynamic properties and phase behavior of the monolayers have been systematically elucidated employing isotherm measurements and several methods at the mesoscopic and microscopic scales. Addition of F8H11OH induces strong condensation in DPPC and DPPG monolayers. The magnitude for the Gibbs free energy and the interaction parameter between the two components for the DPPC/F8H11OH and DPPG/F8H11OH systems are twice as large as those for the Ch/F8H11OH system. Judging from the evidence that disordered/ordered transition pressures and collapse pressures for the binary monolayers change with molar fraction of F8H11OH, F8H11OH was (partially) miscible with all the compounds investigated. The miscibility of the two components in the monolayer is also supported by the in situ (Brewster angle and fluorescence microscopies) and ex situ (atomic force microscopy after transfer on a mica plate) morphological aspects. The present study reports firstly on the interaction between Ch and the fluorinated amphiphile by simply employing the monolayer technique. The molecular function of Ch in pulmonary surfactants and lipid rafts is now extensively investigated. To our knowledge, Ch does not interact strongly with lipid components in biomembranes. However, this study indicates that the partially fluorinated amphiphile has some affinity for Ch. This study provides a fundamental insight into the molecular function of biomembrane components and support for biomedical use of fluorinated materials.