S Aeffner

Publications (4)7.78 Total impact

• Article: Influence of cholesterol on the collective dynamics of the phospholipid acyl chains in model membranes

  B. Brüning, M. C. Rheinstädter, A. Hiess, B. Weinhausen, T. Reusch, S. Aeffner, T. Salditt
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  ABSTRACT: We have studied the packing and collective dynamics of the phospholipid acyl chains in a model membrane composed of 1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine (DMPC) and cholesterol in varied phase state. After a structural characterization of this two-component model bilayer using X-ray reflectivity, we have carried out coherent inelastic neutron scattering to investigate the chain dynamics. Both DMPC/cholesterol membranes exhibited much sharper and more pronounced low-energy inelastic excitations than a pure DMPC membrane. In the high-energy regime above 10meV, the insertion of cholesterol into the membrane was found to shift the position of the inelastic excitation towards values otherwise found in the pure lipids gel phase. Thus, the dissipative collective short-range dynamics of the acyl chains is strongly influenced by the presence of cholesterol.
  The European Physical Journal E 04/2012; 31(4):419-428. · 1.94 Impact Factor
• Article: Influence of cholesterol on the collective dynamics of the phospholipid acyl chains in model membranes.

  B Brüning, M C Rheinstädter, A Hiess, B Weinhausen, T Reusch, S Aeffner, T Salditt
  [show abstract] [hide abstract]
  ABSTRACT: We have studied the packing and collective dynamics of the phospholipid acyl chains in a model membrane composed of 1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine (DMPC) and cholesterol in varied phase state. After a structural characterization of this two-component model bilayer using X-ray reflectivity, we have carried out coherent inelastic neutron scattering to investigate the chain dynamics. Both DMPC/cholesterol membranes exhibited much sharper and more pronounced low-energy inelastic excitations than a pure DMPC membrane. In the high-energy regime above 10 meV, the insertion of cholesterol into the membrane was found to shift the position of the inelastic excitation towards values otherwise found in the pure lipids gel phase. Thus, the dissipative collective short-range dynamics of the acyl chains is strongly influenced by the presence of cholesterol.
  The European Physical Journal E 04/2010; 31(4):419-28. · 1.94 Impact Factor
• Article: Influence of cholesterol on the collective dynamics of the phospholipid acyl chains in model membranes

  B. Brüning, M. C. Rheinstädter, A. Hiess, B. Weinhausen, T. Reusch, S. Aeffner, T. Salditt
  [show abstract] [hide abstract]
  ABSTRACT: We have studied the packing and collective dynamics of the phospholipid acyl chains in a model membrane composed of 1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine (DMPC) and cholesterol in varied phase state. After a structural characterization of this two-component model bilayer using X-ray reflectivity, we have carried out coherent inelastic neutron scattering to investigate the chain dynamics. Both DMPC/cholesterol membranes exhibited much sharper and more pronounced low-energy inelastic excitations than a pure DMPC membrane. In the high-energy regime above 10meV, the insertion of cholesterol into the membrane was found to shift the position of the inelastic excitation towards values otherwise found in the pure lipids gel phase. Thus, the dissipative collective short-range dynamics of the acyl chains is strongly influenced by the presence of cholesterol.
  The European Physical Journal E 03/2010; · 1.94 Impact Factor
• Article: Membrane fusion intermediates and the effect of cholesterol: an in-house X-ray scattering study.

  S Aeffner, T Reusch, B Weinhausen, T Salditt
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  ABSTRACT: We have developed an X-ray scattering setup which allows to study membrane fusion intermediates or other nonlamellar lipid mesophases by laboratory-scale X-ray sources alone, thus taking advantage of unrestricted beamtime compared to synchrotron sources. We report results of a study of pure lipid bilayers and phospholipid/cholesterol binary mixtures. Stalks, putative intermediate structures occurring during the membrane fusion process, can clearly be identified from reconstructed electron density maps. Phase diagrams of the lyotropic phase behavior of DOPC/cholesterol and DPhPC/cholesterol samples are presented. If cholesterol is present in moderate concentrations, it can substantially promote the formation of stalks at higher degree of hydration. In addition, a possibly new phase in DOPC/cholesterol is found at high cholesterol content in the low humidity range.
  The European Physical Journal E 07/2009; 30(2):205-14. · 1.94 Impact Factor