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Strain energy storage and dissipation rate in active cell mechanics
A Agosti1, D Ambrosi2, S Turzi1
1Dipartimento di Matematica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy.
Physical Review. E
|June 17, 2018
Summary
Cell shape, whether rounded or polarized, impacts energy dynamics. Symmetric cells store more energy at low activation, but polarized cells are more energy-efficient overall, representing lower energy states.
Area of Science:
- Cell biology
- Biophysics
- Theoretical physics
Background:
- Living cells exhibit distinct resting shapes: rounded (symmetric) or elongated (polarized).
- Active stress from molecular motors continuously deforms the cell's actin cytoskeleton, even at rest.
Purpose of the Study:
- To theoretically compare stored and dissipated energy in symmetric versus polarized cell configurations.
- To investigate how active stress influences energy dynamics in different cell geometries.
Main Methods:
- Theoretical analysis of energy storage and dissipation.
- Modeling of active stress within the actin cytoskeleton.
- Comparison of symmetric and polarized geometric configurations.
Main Results:
- Stored energy is higher in radially symmetric cells at low activation levels.
- Polarized configurations exhibit greater strain energy beyond a critical active stress threshold.
- Energy dissipation is consistently higher in symmetric cells compared to nonsymmetric (polarized) ones.
Conclusions:
- Radial symmetry represents an energetically costly metastable state.
- Polarized configurations are energetically favorable, offering access to lower energy states.
- The interplay between surface and bulk stress dictates cell shape and energy efficiency.
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