European Biophysics Journal

, Volume 40, Issue 3, pp 329–338 | Cite as

Direct imaging of salt effects on lipid bilayer ordering at sub-molecular resolution

  • Urs M. Ferber
  • Gillian Kaggwa
  • Suzanne P. JarvisEmail author
Original Paper


The interactions of salts with lipid bilayers are known to alter the properties of membranes and therefore influence their structure and dynamics. Sodium and calcium cations penetrate deeply into the headgroup region and bind to the lipids, whereas potassium ions only loosely associate with lipid molecules and mostly remain outside of the headgroup region. We investigated a dipalmitoylphosphatidylcholine (DPPC) bilayer in the gel phase in the presence of all three cations with a concentration of Ca2+ ions an order of magnitude smaller than the Na+ and K+ ions. Our findings indicate that the area per unit cell does not significantly change in these three salt solutions. However the lipid molecules do re-order non-isotropically under the influence of the three different cations. We attribute this reordering to a change in the highly directional intermolecular interactions caused by a variation in the dipole-dipole bonding arising from a tilt of the headgroup out of the membrane plane. Measurements in different NaCl concentrations also show a non-isotropic re-ordering of the lipid molecules.


Lipid model membranes Membrane-ion interactions Sodium cations Calcium cations Potassium cations 



The authors thank Siu-Hong Loh and Dr. Khizar Sheikh for help in using the AFM and Dr. Jason Kilpatrick for the assistance using digtal FM. This work was supported by Science Foundation Ireland (grant no. 07/IN1/B031).


  1. Altenbach C, Seelig J (1984) Calcium binding to phosphatidylcholine bilayers as studied by deuterium magnetic resonance. Evidence for the formation of a calcium complex with two phospholipid bilayers. Biochemistry 23:3913–3920PubMedCrossRefGoogle Scholar
  2. Asakawa H, Fukuma T (2009) The molecular-scale arrangement and mechanical strength of phospholipid/cholesterol mixed bilayers investigated by frequency modulation atomic orce microscopy in liquid. Nanotechnology 20:264008–264015PubMedCrossRefGoogle Scholar
  3. Berkowitz ML, Bostick DL, Pandit S (2006) Aqueous solutions next to phospholipid membrane surfaces: insights from simulations. Chem Rev 106:1527–1539PubMedCrossRefGoogle Scholar
  4. Böckmann RA, Hac A, Heimburg T, Grubmüller H (2003) Effect of sodium chloride on a lipid bilayer. Biophys J 85:1647–1655PubMedCrossRefGoogle Scholar
  5. Cordomí A, Edholm O, Perez JJ (2008) Effect of ions on a dipalmitoyl phosphatidylcholine bilayer. A molecular dynamics simulation study. J Phys Chem B 112:1397–1408PubMedCrossRefGoogle Scholar
  6. Cordomí A, Edholm O, Perez JJ (2009) Effect of force field parameters on sodium and potassium ion binding to dipalmitoyl phosphatidylcholine bilayers. J Chem Theory Comput 5:2125–2134CrossRefGoogle Scholar
  7. Edidin M (2003) Lipids on the frontier: a century of cell-membrane bilayers. Nat Rev Mol Cell Biol 4:414–418PubMedCrossRefGoogle Scholar
  8. Filippov A, Orädd G, Lindblom G (2009) Effect of NaCl and CaCl2 on the lateral diffusion of zwitterionic and anionic lipids in bilayers. Chem Phys Lipids 159:81–87PubMedCrossRefGoogle Scholar
  9. Fukuma T, Jarvis SP (2006) Development of liquid-environment frequency modulation atomic force microscope with low noise detection sensor for cantilevers of various imensions. Rev Sci Instrum 77:043701–043709CrossRefGoogle Scholar
  10. Fukuma T, Higgins MJ, Jarvis SP (2007a) Direct imaging of individual intrinsic hydration layers on lipid bilayers at Angstrom resolution. Biophys J 92:3603–3609PubMedCrossRefGoogle Scholar
  11. Fukuma T, Higgins MJ, Jarvis SP (2007b) Direct imaging of lipid-ion network ormation under physiological conditions by frequency modulation atomic force microscopy. Phys Rev Lett 98:106101–106105PubMedCrossRefGoogle Scholar
  12. Garcia-Celma JJ, Hatahet L, Kunz W, Fendler K (2007) Specific anion and cation binding to lipid membranes investigated on a solid supported membrane. Langmuir 23:10074–10080PubMedCrossRefGoogle Scholar
  13. Garcia-Manyes S, Oncins G, Sanz F (2005a) Effect of ion-binding and chemical phospholipid structure on the nanomechanics of lipid bilayers studied by force spectroscopy. Biophys J 89:1812–1826PubMedCrossRefGoogle Scholar
  14. Garcia-Manyes S, Oncins G, Sanz F (2005b) Effect of temperature on the nano-mechanics of lipid bilayers studied by force spectroscopy. Biophys J 89:4261–4274PubMedCrossRefGoogle Scholar
  15. Giessibl FJ, Bielefeldt H, Hembacher S, Mannhart J (1999) Calculation of the optimal imaging parameters for frequency modulation atomic force microscopy. Appl Surf Sci 140:352–357CrossRefGoogle Scholar
  16. Gurtovenko AA (2005) Asymmetry of lipid bilayers induced by monovalent salt: atomistic molecular-dynamics study. J Chem Phys 122:244902–244912PubMedCrossRefGoogle Scholar
  17. Gurtovenko AA, Vattulainen I (2008) Effect of NaCl and KCl on phosphatidylcholine and phosphatidylethanolamine lipid membranes: insight from atomic-scale simulations for understanding salt-induced effects in the plasma membrane. J Phys Chem B 112:1953–1962PubMedCrossRefGoogle Scholar
  18. Johnson SJ, Bayerl TM, McDermott DC, Adam GW, Rennie AR, Thomas RK, Sackmann E (1991) Structure of an adsorbed dimyristoylphosphatidylcholine bilayer measured with specular reflection of neutrons. Biophys J 59:289–294PubMedCrossRefGoogle Scholar
  19. Kilpatrick JI, Gannepalli A, Cleveland JP, Jarvis SP (2009) Frequency modulation atomic force microscopy in ambient environments utilizing robust feedback tuning. Rev Sci Instrum 80:023701–023707PubMedCrossRefGoogle Scholar
  20. Kotulska M, Kubica K (2005) Structural and energetic model of the mechanisms for reduced self-diffusion in a lipid bilayer with increasing ionic strength. Phys Rev E 72:061903–061909CrossRefGoogle Scholar
  21. Koynova R, Caffrey M (1998) Phases and phase transitions of the phosphatidyl-cholines. Biochim Biophys Acta 1376:91–145PubMedGoogle Scholar
  22. Lee S-J, Song Y, Baker NA (2008) Molecular dynamics simulations of asymmetric NaCl and KCl solutions separated by phosphatidylcholine bilayers: potential drops and structural changes induced by strong Na+-lipid interactions and finite size effects. Biophys J 94:3565–3576PubMedCrossRefGoogle Scholar
  23. López Cascales JJ, Otero TF, Smith BD, González C, Márquez M (2006) Model of an asymmetric DPPC/DPPS membrane: effect of asymmetry on the lipid properties. A molecular dynamics simulation study. J Phys Chem B 110:2358–2363PubMedCrossRefGoogle Scholar
  24. Miettinen MS, Gurtovenko AA, Vattulainen I, Karttunen M (2009) Ion dynamics in cationic lipid bilayer systems in saline solutions. J Phys Chem B 113:9226–9234PubMedCrossRefGoogle Scholar
  25. Nagle JF, Tristram-Nagle S (2000) Structure of lipid bilayers. Biochim Biophys Acta 1469:159–195PubMedGoogle Scholar
  26. Pabst G, Hodzic A, Strancar J, Danner S, Rappolt M, Laggner P (2007) Rigidification of neutral lipid bilayers in the presence of salts. Biophys J 93:2688–2696PubMedCrossRefGoogle Scholar
  27. Pandit SA, Bostick D, Berkowitz ML (2003) Molecular dynamics simulation of a dipalmitoylphosphatidylcholine bilayer with NaCl. Biophys J 84:3743–3750PubMedCrossRefGoogle Scholar
  28. Pasenkiewicz-Gierula M, Takaoka Y, Miyagawa H, Kitamura K, Kusumi A (1997) Hydrogen bonding of water to phosphatidylcholine in the membrane as studied by a molecular dynamics simulation: location, geometry, and lipid-lipid bridging via hydrogen-bonded water. J Phys Chem A 101:3677–3691CrossRefGoogle Scholar
  29. Pasenkiewicz-Gierula M, Takaoka Y, Miyagawa H, Kitamura K, Kusumi A (1999) Charge pairing of headgroups in phosphatidylcholine membranes: a molecular dynamics simulation study. Biophys J 76:1228–1240PubMedCrossRefGoogle Scholar
  30. Pedersen UR, Leidy C, Westh P, Peters GH (2006) The effect of calcium on the properties of charged phospholipid bilayers. Biochim Biophys Acta 1758:573–582PubMedCrossRefGoogle Scholar
  31. Petrache HI, Tristram-Nagle S, Harries D, Kucerka N, Nagle JF, Parsegian VA (2006a) Swelling of phospholipids by monovalent salt. J Lipid Res 47:302–309PubMedCrossRefGoogle Scholar
  32. Petrache HI, Zemb T, Belloni L, Parsegian VA (2006b) Salt screening and specifc ion adsorption determine neutral-lipid membrane interactions. Proc Natl Acad Sci USA 103:7982–7987PubMedCrossRefGoogle Scholar
  33. Sachs JN, Nanda H, Petrache HI, Woolf TB (2004) Changes in phosphatidylcholine headgroup tilt and water order induced by monovalent salts: molecular dynamics simulations. Biophys J 86:3772–3782PubMedCrossRefGoogle Scholar
  34. Saiz L, Klein ML (2002) Electrostatic interactions in a neutral model phospholipid bilayer by molecular dynamics simulations. J Chem Phys 116:3052–3058CrossRefGoogle Scholar
  35. Seelig J, MacDonald PM, Scherer PG (1987) Phospholipid head groups as sensors of electric charge in membranes. Biochemistry 26:7535–7541PubMedCrossRefGoogle Scholar
  36. Sun W-J, Suter RM, Knewtson MA, Worthington CR, Tristram-Nagle S, Zhang R, Nagle JF (1994) Order and disorder in fully hydrated unoriented bilayers of gel-phase dipalmitoylphosphatidylcholine. Phys Rev E 49:4665–4676CrossRefGoogle Scholar
  37. Tardieu A, Luzzati Vittorio, Reman FC (1973) Structure and polymorphism of the hydrocarbon chains of lipids: a study of lecithin-water phases. J Mol Biol 75:711–718PubMedCrossRefGoogle Scholar
  38. Tatulian SA (1987) Binding of alkaline-earth metal cations and some anions to phosphatidylcholine liposomes. Eur J Biochem 170:413–420PubMedCrossRefGoogle Scholar
  39. Tu K, Tobias D, Blasie J, Klein M (1996) Molecular dynamics investigation of the structure of a fully hydrated gel-phase dipalmitoylphosphatidylcholine bilayer. Biophys J 70:595–608PubMedCrossRefGoogle Scholar
  40. Uhríková D, Kucerka N, Teixeira J, Gordeliy V, Balgavy P (2008) Structural changes in dipalmitoylphosphatidylcholine bilayer promoted by Ca2+ ions: a small angle neutron scattering study. Chem Phys Lipids 155:80–89PubMedCrossRefGoogle Scholar
  41. Vácha R, Siu SWI, Petrov M, Böckmann RA, Barucha-Krasewska J, Jurkiewicz P, Hof M, Berkowitz ML, Jungwirth P (2009) Effects of alkali cations and halide anions on DOPC lipid membrane. J Phys Chem A 113:7235–7243PubMedCrossRefGoogle Scholar
  42. Vácha R, Jurkiewicz P, Petrov M, Berkowitz ML, Böckmann RA, Barucha-Krasewska J, Hof M, Jungwirth P (2010) Mechanism of interaction of monovalent ions with the phosphatidylcholine lipid membranes. J Phys Chem B 114:9504–9509PubMedCrossRefGoogle Scholar
  43. Wohlert J, Edholm O (2004) The range and shielding of dipole–dipole interactions in phospholipid bilayers. Biophys J 87:2433–2445PubMedCrossRefGoogle Scholar
  44. Zhang L, Spurlin TA, Gewirth AA, Granick S (2006) Electrostatic stitching in gel-phase supported phospholipid bilayers. Phys Chem B 110:33–35CrossRefGoogle Scholar

Copyright information

© European Biophysical Societies' Association 2010

Authors and Affiliations

  • Urs M. Ferber
    • 1
  • Gillian Kaggwa
    • 1
  • Suzanne P. Jarvis
    • 1
    Email author
  1. 1.Conway Institute of Biomolecular and Biomedical ResearchUniversity College DublinDublin 4Ireland

Personalised recommendations