Related Experiment Video
Updated: Mar 6, 2026
07:26
Agarose Fluid Gels Formed by Shear Processing During Gelation for Suspended 3D Bioprinting
Published on: May 26, 2023
3.1K
Fluidization and Active Thinning by Molecular Kinetics in Active Gels
David Oriola1, Ricard Alert1, Jaume Casademunt1
1Departament de Física de la Matèria Condensada, Facultat de Física, Universitat de Barcelona, Avinguda Diagonal 647 and Universitat de Barcelona Institute of Complex Systems (UBICS), Universitat de Barcelona, 08028 Barcelona, Catalonia, Spain.
Physical Review Letters
|March 11, 2017
Summary
This study models active polar gels, revealing how molecular dynamics create viscoelasticity and active stresses. It predicts that increased activity can decrease viscosity, explaining cell cortex mechanics.
Area of Science:
- Soft Matter Physics
- Biophysics
- Rheology
Background:
- Active polar gels are complex materials with applications in cell mechanics.
- Understanding their constitutive equations is crucial for predicting material behavior.
- Existing models may not fully capture the interplay between molecular dynamics and macroscopic properties.
Purpose of the Study:
- To derive constitutive equations for active polar gels from a molecular dynamics model.
- To elucidate the origins of viscoelasticity and active stress generation.
- To provide explicit expressions for transport coefficients in terms of molecular properties.
Main Methods:
- Modeling the dynamics of elastic molecules linking polar elements.
- Analyzing molecular binding kinetics and detailed balance.
- Deriving transport coefficients and nonlinear contributions.
Main Results:
- Molecular binding kinetics induce Maxwell viscoelasticity and active stresses.
- Explicit expressions for transport coefficients are derived, including nonlinear terms.
- A decrease in viscosity with increasing activity (active thinning) is predicted due to kinetic effects.
Conclusions:
- The model bridges molecular and hydrodynamic scales for active polar gels.
- Predicted active thinning could explain experimental observations in the cell cortex.
- Results offer insights into how molecular changes affect the mechanics of cells and tissues.
