Transmembrane pH-driven Na+ permeability of fluorinated phospholipid-based membranes.
The permeability to the H+/Na+ exchange of fluorinated phospholipid-based membranes has been evaluated by measuring the dissipation rate of a liposomal transmembrane pH gradient in the presence of Na+. The fluorinated liposomes are made from fluorocarbon/hydrocarbon or fluorocarbon/fluorocarbon double-chain ether-connected glycerophosphocholines or amido-connected phosphocholines deriving from diaminopropanol or serine. The fluorocarbon/hydrocarbon mixed-chain phospholipids, as compared to the fluorocarbon/fluorocarbon ones, form membranes that are substantially more able to maintain a transmembrane pH gradient in the presence of NA+ and display a lower Na+ permeability. However, these membranes are more permeable to the H+/Na/ exchange than conventional DSPC (1,2-distearoylphosphatidylcholine) ones. Our results indicate a detrimental impact of the membrane fluorination degree on H+/Na+ permeability: the lower the fluorination degree of the membrane, the lower its H+/Na+ permeability. Concerning structure/permeability relationships, it appears that the replacement of the ester connecting bond in their fluorinated phosphatidylcholine analogues for an ether or amide one lowers the transmembrane H+/Na+ exchange.
Clary
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Laboratoire de Chimie Bio-Organique, ESA 6001 CNRS, Université de Nice, Sophia-Antipolis, Faculté des Sciences, France.
Ravily
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Santaella
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Vierling
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D004337:Drug Carriers; D005466:Fluorocarbons / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D017136:Ion Transport; D008081:Liposomes; D008567:Membranes, Artificial; D010539:Permeability; D010713:Phosphatidylcholines / Q000737:chemistry; D010743:Phospholipids / Q000737:chemistry*; D012964:Sodium / Q000737:chemistry*; D017923:Sodium-Hydrogen Exchangers / Q000737:chemistry*; D013329:Structure-Activity Relationship
D004337:Drug Carriers; D005466:Fluorocarbons; D008081:Liposomes; D008567:Membranes, Artificial; D010713:Phosphatidylcholines; D010743:Phospholipids; D017923:Sodium-Hydrogen Exchangers; D012964:Sodium; C010942:1,2-distearoyllecithin