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Ions modulate stress-induced nano-texture in supported fluid lipid bilayers

Piantanida, L.; Bolt, H.; Rozatian, N.; Cobb, S.; Voïtchovsky, K.

Ions modulate stress-induced nano-texture in supported fluid lipid bilayers Thumbnail


L. Piantanida

H. Bolt

N. Rozatian

S. Cobb


Most plasma membranes comprise a large number of different molecules including lipids and proteins. In the standard fluid mosaic model, the membrane function is effected by proteins whereas lipids are largely passive and serve solely in the membrane cohesion. Here we show, using supported 1,2-dioleoyl-sn-glycero-3-phosphocholine lipid bilayers in different saline solutions, that ions can locally induce ordering of the lipid molecules within the otherwise fluid bilayer when the latter is supported. This nanoordering exhibits a characteristic length scale of ∼20 nm, and manifests itself clearly when mechanical stress is applied to the membrane. Atomic force microscopy (AFM) measurements in aqueous solutions containing NaCl, KCl, CaCl2, and Tris buffer show that the magnitude of the effect is strongly ion-specific, with Ca2+ and Tris, respectively, promoting and reducing stress-induced nanotexturing of the membrane. The AFM results are complemented by fluorescence recovery after photobleaching experiments, which reveal an inverse correlation between the tendency for molecular nanoordering and the diffusion coefficient within the bilayer. Control AFM experiments on other lipids and at different temperatures support the hypothesis that the nanotexturing is induced by reversible, localized gel-like solidification of the membrane. These results suggest that supported fluid phospholipid bilayers are not homogenous at the nanoscale, but specific ions are able to locally alter molecular organization and mobility, and spatially modulate the membrane’s properties on a length scale of ∼20 nm. To illustrate this point, AFM was used to follow the adsorption of the membrane-penetrating antimicrobial peptide Temporin L in different solutions. The results confirm that the peptides do not absorb randomly, but follow the ion-induced spatial modulation of the membrane. Our results suggest that ionic effects have a significant impact for passively modulating the local properties of biological membranes, when in contact with a support such as the cytoskeleton.


Piantanida, L., Bolt, H., Rozatian, N., Cobb, S., & Voïtchovsky, K. (2017). Ions modulate stress-induced nano-texture in supported fluid lipid bilayers. Biophysical Journal, 113(2), 426-439.

Journal Article Type Article
Acceptance Date May 30, 2017
Online Publication Date Jul 25, 2017
Publication Date Jul 25, 2017
Deposit Date Jun 8, 2017
Publicly Available Date Jun 8, 2017
Journal Biophysical Journal
Print ISSN 0006-3495
Publisher Biophysical Society
Peer Reviewed Peer Reviewed
Volume 113
Issue 2
Pages 426-439


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