How to best estimate the viscosity of lipid bilayers.

The viscosity of lipid bilayers is a property relevant to biological function, as it affects the diffusion of membrane macromolecules. To determine its value, and hence portray the membrane, various literature-reported techniques lead to significantly different results. Herein we compare the results issuing from two widely used techniques to determine the viscosity of membranes: the Fluorescence Lifetime Imaging Microscopy (FLIM), and Fluorescence Recovery After Photobleaching (FRAP). FLIM relates the time of rotation of a molecular rotor inserted into the membrane to the macroscopic viscosity of a fluid. Whereas FRAP measures molecular diffusion coefficients. This approach is based on a hydrodynamic model connecting the mobility of a membrane inclusion to the viscosity of the membrane. We show that: This article emphasizes the pitfalls to be avoided and the rules to be observed in order to obtain a value of the bilayer viscosity that characterizes the bilayer instead of interactions between the bilayer and the embedded probe. Copyright © 2021 Elsevier B.V. All rights reserved.

Citation

Vladimir Adrien, Gamal Rayan, Ksenia Astafyeva, Isabelle Broutin, Martin Picard, Patrick Fuchs, Wladimir Urbach, Nicolas Taulier. How to best estimate the viscosity of lipid bilayers. Biophysical chemistry. 2022 Feb;281:106732

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PMID: 34844029

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