Changes in Interfacial Tension of a Lipid Membrane Formed at the Water/Chloroform Interface upon DNA Complex Formation

Anal Sci. 2015;31(10):979-86. doi: 10.2116/analsci.31.979.


Changes in the interfacial tension of a lipid monolayer membrane formed at the water/chloroform interface upon DNA addition were measured using the quasi-elastic laser scattering (QELS) method. A cationic lipid, N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium chloride (DOTAP), as well as zwitterionic lipids, 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) and 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), were used to form lipid monolayer membranes at different calcium ion concentrations. A rapid decrease of the interfacial tension resulting from electrostatic interactions between DOTAP and DNA was observed within 10 s. However, such rapid decreases were not observed for DOPE or DOPC. A decrease in the interfacial tension was exhibited by DOPE after 1000 s from the addition of DNA, which may be due to an overall structural change in the DOPE membrane. A DOTAP/DOPE complex system showed behaviors attributable to both DOTAP and DOPE, whereas the behavior of the DOTAP/DOPC system resembled that of DOPC alone. The current results provide a model for the so-called lipoplex carriers used in gene therapy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Calcium Chloride / chemistry
  • Cell Membrane / chemistry*
  • Chloroform / chemistry*
  • DNA / chemistry*
  • Fatty Acids, Monounsaturated / chemistry
  • Phosphatidylcholines / chemistry
  • Phosphatidylethanolamines / chemistry
  • Quaternary Ammonium Compounds / chemistry
  • Surface Tension
  • Water / chemistry*


  • 1,2-dioleoyl-glycero-3-phosphatidyl ethanolamine
  • Fatty Acids, Monounsaturated
  • Phosphatidylcholines
  • Phosphatidylethanolamines
  • Quaternary Ammonium Compounds
  • Water
  • Chloroform
  • DNA
  • 1,2-oleoylphosphatidylcholine
  • Calcium Chloride
  • 1,2-dioleoyloxy-3-(trimethylammonium)propane