Related Experiment Video
Updated: May 9, 2026
09:29
Obtention of Giant Unilamellar Hybrid Vesicles by Electroformation and Measurement of their Mechanical Properties by Micropipette Aspiration
Published on: January 19, 2020
Membrane viscosity determined from shear-driven flow in giant vesicles
Aurelia R Honerkamp-Smith1, Francis G Woodhouse, Vasily Kantsler
1Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA, United Kingdom.
Physical Review Letters
|August 6, 2013
Summary
Measuring lipid bilayer membrane viscosity is challenging. This study introduces a novel microfluidic method using vesicle flow patterns to accurately determine membrane viscosity, crucial for protein dynamics.
Area of Science:
- Biophysics
- Fluid Dynamics
- Materials Science
Background:
- Lipid bilayer membrane viscosity is critical for protein diffusion and membrane deformation dynamics.
- Accurate measurement of membrane viscosity has been a long-standing challenge in biophysics.
Purpose of the Study:
- To develop and validate a new method for directly measuring lipid bilayer membrane viscosity.
- To investigate the relationship between membrane mechanics and fluid flow dynamics.
Main Methods:
- Utilized a microfluidic device to apply simple shear flow to adhered vesicles.
- Employed particle image velocimetry with spinning disk confocal imaging to track tracer particles.
- Analyzed large-scale circulation patterns within and around the vesicles.
- Tracked phase-separated membrane domains to reconstruct 3D flow patterns.
Main Results:
- Successfully reconstructed the full three-dimensional flow patterns induced by shear flow.
- Demonstrated excellent agreement between experimental measurements and theoretical predictions.
- Enabled direct and accurate determination of membrane viscosity.
Conclusions:
- The developed microfluidic method provides a robust approach for measuring lipid bilayer membrane viscosity.
- This technique offers new insights into membrane dynamics and the behavior of embedded proteins.
- The findings validate recent theoretical models of membrane mechanics in flow.
Related Concept Videos
01:23Membrane Fluidity
Cell membranes are composed of phospholipids, proteins, and carbohydrates loosely attached to one another through chemical interactions. Molecules are generally able to move about in the plane of the membrane, giving the membrane its flexible nature called fluidity. Two other features of the membrane contribute to membrane fluidity: the chemical structure of the phospholipids and the presence of cholesterol in the membrane.
01:26Membrane Fluidity
Membrane fluidity is explained by the fluid mosaic model of the cell membrane, which describes the plasma membrane structure as a mosaic of components—including phospholipids, cholesterol, proteins, and carbohydrates—that gives the membrane a fluid character.
Mosaic nature of the membrane
The mosaic characteristic of the membrane helps the plasma membrane remain fluid. The integral proteins and lipids exist as separate but loosely-attached molecules in the membrane. The membrane is a relatively...
Mosaic nature of the membrane
The mosaic characteristic of the membrane helps the plasma membrane remain fluid. The integral proteins and lipids exist as separate but loosely-attached molecules in the membrane. The membrane is a relatively...
02:57Surface Tension, Capillary Action, and Viscosity
Surface Tension
The various IMFs between identical molecules of a substance are examples of cohesive forces. The molecules within a liquid are surrounded by other molecules and are attracted equally in all directions by the cohesive forces within the liquid. However, the molecules on the surface of a liquid are attracted only by about one-half as many molecules. Because of the unbalanced molecular attractions on the surface molecules, liquids contract to form a shape that minimizes the number...
The various IMFs between identical molecules of a substance are examples of cohesive forces. The molecules within a liquid are surrounded by other molecules and are attracted equally in all directions by the cohesive forces within the liquid. However, the molecules on the surface of a liquid are attracted only by about one-half as many molecules. Because of the unbalanced molecular attractions on the surface molecules, liquids contract to form a shape that minimizes the number...
01:17Viscosity
When water is poured into a glass, it falls freely and quickly, whereas if honey or maple syrup is poured over a pancake, it flows slowly and sticks to the surface of the container. This difference in the flow of different kinds of liquids arises due to the fluid friction between the liquid layers and the liquid and the surrounding material. This property of fluids is called fluid viscosity. In this example, water has a lower viscosity than honey and maple syrup.
The SI unit of viscosity is...
The SI unit of viscosity is...
01:27Viscosity
Viscosity is a property of fluids that measures their resistance to flow. It is influenced by factors such as the surface area of contact, the gradient of flow speed, and the fluid's viscosity constant, called the coefficient of viscosity. The coefficient of viscosity, also known as dynamic viscosity, is denoted by the symbol η. It determines the proportionality between the viscous force and the gradient of flow speed.Newton's law of viscosity states that the viscous force on a faster-moving...
01:19Viscosity of Fluid
Viscosity measures the resistance a fluid offers to flow and deformation. It results from internal friction between layers of fluid moving relative to one another. Dynamic viscosity, denoted by the Greek letter mu (μ), quantifies the force needed to move one fluid layer over another. For Newtonian fluids like water and air, the relationship between the shearing stress and the rate of shearing strain is linear, meaning their viscosity remains constant regardless of the applied stress.