Shear rheology of lipid monolayers and insights on membrane fluidity

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 108; no. 15; pp. 6008 - 6013
• Main Authors: Espinosa, Gabriel, López-Montero, Iván, Monroy, Francisco, Langevin, Dominique
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 12.04.2011; National Acad Sciences
• Subjects: Biological Sciences; Cell Membrane - chemistry; Cell membranes; Cholesterols; deformation; Fluid shear; Fluids; lipid bilayers; Lipid Bilayers - chemistry; Lipids; mechanical properties; Membrane Fluidity; Membrane Microdomains - chemistry; Membranes; modulus of elasticity; P branes; Physical Sciences; Proteins; Rheology; shear stress; Solids; Viscosity
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.1018572108

The concept of membrane fluidity usually refers to a high molecular mobility inside the lipid bilayer which enables lateral diffusion of embedded proteins. Fluids have the ability to flow under an applied shear stress whereas solids resist shear deformations. Biological membranes require both properties for their function: high lateral fluidity and structural rigidity. Consequently, an adequate account must include, in addition to viscosity, the possibility for a nonzero shear modulus. This knowledge is still lacking as measurements of membrane shear properties have remained incomplete so far. In the present contribution we report a surface shear rheology study of different lipid monolayers that model distinct biologically relevant situations. The results evidence a large variety of mechanical behavior under lateral shear flow.