Characterization of the interface of binary mixed DOPC:DOPS liposomes in water: The impact of charge condensation.
Solutions of liposomes composed of binary mixtures of anionic dioleoylphosphatidylserine (DOPS) and zwitterionic dioleoylphosphatidylcholine (DOPC) are investigated with label-free angle-resolved (AR) second harmonic scattering (SHS) and electrophoretic mobility measurements. The membrane surface potential is extracted from the AR-SHS response. The surface potential changes from -10 to -145 mV with varying DOPS content ( from 0% to 100%) and levels off already at ∼ 10 % DOPS content. The ζ-potential shows the same trend but with a drastically lower saturation value (-44 mV). This difference is explained by the formation of a condensed layer of Na+counterions around the outer leaflet of the liposome as predicted by charge condensation theories for polyelectrolyte systems.
Laboratory for fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI), and Institute of Materials Science (IMX), School of Engineering (STI), and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
Cornelis
C
Lütgebaucks
Laboratory for fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI), and Institute of Materials Science (IMX), School of Engineering (STI), and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
Carlos
C
Macias-Romero
Laboratory for fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI), and Institute of Materials Science (IMX), School of Engineering (STI), and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
Sylvie
S
Roke
D000838:Anions / Q000737:chemistry; D002414:Cations, Monovalent / Q000737:chemistry; D008051:Lipid Bilayers / Q000737:chemistry; D008081:Liposomes / Q000737:chemistry*; D010713:Phosphatidylcholines / Q000737:chemistry*; D010718:Phosphatidylserines / Q000737:chemistry*; D012964:Sodium / Q000737:chemistry; D055672:Static Electricity; D014867:Water / Q000737:chemistry
D000838:Anions; D002414:Cations, Monovalent; D008051:Lipid Bilayers; D008081:Liposomes; D010713:Phosphatidylcholines; D010718:Phosphatidylserines; D014867:Water; C042511:1,2-dioleoylphosphatidylserine; D012964:Sodium; C017251:1,2-oleoylphosphatidylcholine