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Updated: Aug 24, 2026

The Mechanics of (Poro-)Elastic Contractile Actomyosin Networks As a Model System of the Cell Cytoskeleton
Published on: March 10, 2023
Microstructural mechanics of collagen gels in confined compression: poroelasticity, viscoelasticity, and collapse
Preethi L Chandran1, Victor H Barocas
1Department of Biomedical Engineering, University of Minnesota, 312 Church St SE, Minneapolis, MN 55455, USA.
Background:
Collagen gels are important as platforms for in vitro study of cell behavior and as prototypical bioartificial tissues, but their mechanical behavior, particularly on the microscopic scale, is still poorly understood.
Method Of Approach:
Collagen gels were studied in step (10% strain in 0.05 s) and ramp (0.1%/s strain rate for 100 s) confined compression. Real-time birefringence mapping gave the local collagen concentration and orientation along with piston stress. Variations in the retardation allowed material-point tracking and qualitative determination of the strain distribution.
Results:
Ramp tests showed classical poroelastic behavior: compression near the piston and relaxation to a uniform state. Step tests, however, showed an irreversibly collapsed region near the piston.
Conclusions:
Our results suggest that interstitial flow and fibril bending at crosslinks are the dominant mechanical processes during compression, and that fibril bending is reversible before collapse.
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