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Applying a potential across a biomembrane: electrostatic contribution to the bending rigidity and membrane
Tobias Ambjörnsson1, Michael A Lomholt, Per Lyngs Hansen
1NORDITA-Nordic Institute for Theoretical Physics, Blegdamsvej 17, Copenhagen Ø, Denmark.
Summary
An external potential alters biomembrane mechanics. In electrolytes, it reduces tension and increases bending rigidity, potentially causing stretching instability. Without salt, it can induce undulation instability.
Area of Science:
- Biophysics
- Soft Matter Physics
- Electrochemistry
Background:
- Biomembranes possess crucial mechanical properties.
- External electric fields can influence membrane behavior.
- Electrolyte presence modifies electrostatic interactions.
Purpose of the Study:
- To investigate the impact of external potentials on biomembrane mechanical properties.
- To analyze the effects in different electrolyte conditions.
- To derive quantitative relationships for electrostatic contributions.
Main Methods:
- Solving Debye-Hückel and Laplace equations for electrostatic potential.
- Utilizing stress-tensor analysis.
- Examining small screening length and dielectric limits.
Main Results:
- In the small screening length limit, applied potential decreases membrane tension and increases bending rigidity.
- Explicit expressions derived for electrostatic contributions to tension and rigidity.
- In the dielectric limit, applied potential induces effective membrane charge, leading to undulation instability.
Conclusions:
- External potentials significantly modify biomembrane mechanics.
- Instabilities like stretching and undulation can be induced by applied potentials.
- Understanding these effects is crucial for biomembrane applications.
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