Calcium-mediated binding of DNA to 1,2-distearoyl-sn-glycero-3-phosphocholine-containing mixed lipid monolayers

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The calcium-mediated interaction of DNA with monolayers of the non-toxic, zwitterionic phospholipid, 1,2-distearoyl-sn-glycero-3-phosphocholine when mixed with 50 mol% of a second lipid, either the zwitteronic 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine or neutral cholesterol was investigated using a combination of surface pressure-area isotherms, Brewster angle microscopy, external reflectance Fourier transform infrared spectroscopy and specular neutron reflectivity in combination with contrast variation. When calcium and DNA were both present in the aqueous subphase, changes were observed in the compression isotherms as well as the surface morphologies of the mixed lipid monolayers. In the presence of calcium and DNA, specular neutron reflectivity showed that directly underneath the head groups of the lipids comprising the monolayers, DNA occupied a layer comprises approximately 13 and 18 %v/v DNA for the 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine and cholesterol-containing monolayers, respectively. The volume of the corresponding layer for 1,2-distearoyl-sn-glycero-3-phosphocholine only containing monolayers was ~ 15 %v/v DNA. Furthermore regardless of the presence and nature of the second lipid and the surface pressure of the monolayer, the specular neutron reflectivity experiments showed that the DNA-containing layer was 20-27 Å thick, suggesting the presence of a well-hydrated layer of double-stranded DNA. External reflectance Fourier transform infrared studies confirmed the presence of double stranded DNA, and indicated that the strands are in the B-form conformation. The results shed light on the interaction between lipids and nucleic material cargo as well as the role of a second lipid in lipid-based carriers for drug delivery.


  • Aleksandra Dabkowska
  • David J. Barlow
  • Luke A. Clifton
  • Arwel V. Hughes
  • John Webster
  • Rebecca Green
  • Peter Quinn
  • M. Jayne Lawrence
External organisations
  • External Organization - Unknown
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Physical Chemistry
  • Nano Technology
Original languageEnglish
JournalSoft Matter
Early online date2014 Jan 7
Publication statusPublished - 2014
Publication categoryResearch
Externally publishedYes