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Thermoelasticity of large lecithin bilayer vesicles
Biophysical Journal
|September 1, 1981
Summary
Large lecithin bilayer vesicles can exist without tension. Temperature changes affect their surface area and internal pressure, influencing stability and potentially causing fragmentation. This study quanties these thermal and elastic properties.
Area of Science:
- Biophysics
- Materials Science
- Physical Chemistry
Background:
- Bilayer vesicles are fundamental structures in biological systems and biomaterials.
- Understanding their mechanical properties under varying conditions is crucial for applications.
- Previous studies have explored vesicle stability, but comprehensive micromechanical data as a function of temperature were limited.
Purpose of the Study:
- To investigate the micromechanical properties of large lecithin bilayer vesicles.
- To determine the tension-free state and critical temperatures of vesicles.
- To quantify thermal and elastic parameters, including area expansivity and compressibility.
Main Methods:
- Micromechanical experiments using pipet aspiration and compression against a flat surface.
- Vesicles were subjected to controlled temperature changes and mechanical stress.
- Measurements included surface area, internal pressure, and membrane tension.
Main Results:
- Bilayer vesicles can exist in a tension-free state (< 10(-2) dyn/cm).
- A critical temperature was identified where vesicles become tension-free spheres.
- Thermal area expansivity was measured at 2.4 X 10(-3)/°C.
- Elastic area compressibility modulus was determined to be 140 dyn/cm.
- Lysis tension limit was observed at 3-4 dyn/cm.
Conclusions:
- Vesicle behavior is strongly dependent on temperature due to thermoelastic effects.
- Vesicles exhibit limited surface rigidity, leading to fragmentation at higher temperatures without support.
- The study provides quantitative data on the thermoelastic properties of lecithin bilayers, essential for understanding their behavior in various environments.