The relationship between cell and tissue strain in three-dimensional bio-artificial tissues
J Pablo Marquez1, Guy M Genin, George I Zahalak
1Department of Mechanical Engineering, and Department of Biochemistry and Molecular Biophysics, Washington University, St. Louis, Missouri 63130, USA.
Biophysical Journal
|December 15, 2004
Summary
This study refines a model for bio-artificial tissues, revealing that cell stiffness in tissue constructs may be higher than previously estimated, impacting tissue engineering. The updated model accounts for complex cell orientations.
Area of Science:
- Biomaterials Science
- Tissue Engineering
- Computational Mechanics
Background:
- Accurate mechanical modeling of bio-artificial tissues is crucial for replicating native tissue function.
- Existing models like the Zahalak model have been adapted for inhomogeneous strain fields in thin tissues.
- Previous modifications suggested higher continuum stiffness for fibroblasts.
Purpose of the Study:
- To further modify the Zahalak model to include inhomogeneous strain fields in constructs with out-of-plane cell orientations.
- To re-evaluate continuum cell stiffness estimates based on the improved model.
- To investigate the impact of various cell orientation distributions on mechanical response.
Main Methods:
- Developed a modified Zahalak model incorporating out-of-plane cell orientations.
- Introduced a 'strain factor' to update average cell strain based on elastic response.
- Validated the model against analytical solutions for dilute concentrations and 3D finite element analyses for high concentrations.
Main Results:
- The new model indicates that continuum cell stiffness estimates may need upward revision.
- Three distinct cell orientation distributions were analyzed.
- An approximate scaling model for the strain factor was derived and validated.
Conclusions:
- The refined Zahalak model provides a more accurate prediction of mechanical behavior in bio-artificial tissues with complex cell structures.
- This work highlights the importance of considering cell orientation in mechanical modeling for tissue engineering applications.
- Revised stiffness values are essential for designing functional tissue replacements.
