Limits...
Monolayer stress microscopy: limitations, artifacts, and accuracy of recovered intercellular stresses.

Tambe DT, Croutelle U, Trepat X, Park CY, Kim JH, Millet E, Butler JP, Fredberg JJ - PLoS ONE (2013)

Bottom Line: To assess the validity of these assumptions and to quantify associated errors, here we report new analytical, numerical, and experimental investigations.For several commonly used experimental monolayer systems, the simplifying assumptions used previously lead to errors that are shown to be quite small.Out-of-plane components of displacement and traction fields can be safely neglected, and characteristic features of intercellular stresses that underlie plithotaxis remain largely unaffected.

View Article: PubMed Central - PubMed

Affiliation: Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, USA. dhananjay@alumni.brown.edu

ABSTRACT
In wound healing, tissue growth, and certain cancers, the epithelial or the endothelial monolayer sheet expands. Within the expanding monolayer sheet, migration of the individual cell is strongly guided by physical forces imposed by adjacent cells. This process is called plithotaxis and was discovered using Monolayer Stress Microscopy (MSM). MSM rests upon certain simplifying assumptions, however, concerning boundary conditions, cell material properties and system dimensionality. To assess the validity of these assumptions and to quantify associated errors, here we report new analytical, numerical, and experimental investigations. For several commonly used experimental monolayer systems, the simplifying assumptions used previously lead to errors that are shown to be quite small. Out-of-plane components of displacement and traction fields can be safely neglected, and characteristic features of intercellular stresses that underlie plithotaxis remain largely unaffected. Taken together, these findings validate Monolayer Stress Microscopy within broad but well-defined limits of applicability.

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Accuracy of in-plane tractions as a function of Poisson's ratio when out-of-plane components of displacements are neglected. denotes the angle of the displacement vector relative to the  plane. (a) Ratio of recovered in-plane traction to true in-plane traction. (b) Error in the phase of the recovered in-plane traction (degrees).
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pone-0055172-g002: Accuracy of in-plane tractions as a function of Poisson's ratio when out-of-plane components of displacements are neglected. denotes the angle of the displacement vector relative to the plane. (a) Ratio of recovered in-plane traction to true in-plane traction. (b) Error in the phase of the recovered in-plane traction (degrees).

Mentions: We now consider a unit displacement that has three-dimensional components , the first two being in-plane and last out-of-plane. The tractions are given by,The true in-plane traction is . The recovered in-plane traction (neglecting the out-of-plane displacement) is . The departures from unity of the ratio quantifies the error in magnitude, while quantifies the error in phase. These quantities are plotted in Fig. 2.


Monolayer stress microscopy: limitations, artifacts, and accuracy of recovered intercellular stresses.

Tambe DT, Croutelle U, Trepat X, Park CY, Kim JH, Millet E, Butler JP, Fredberg JJ - PLoS ONE (2013)

Accuracy of in-plane tractions as a function of Poisson's ratio when out-of-plane components of displacements are neglected. denotes the angle of the displacement vector relative to the  plane. (a) Ratio of recovered in-plane traction to true in-plane traction. (b) Error in the phase of the recovered in-plane traction (degrees).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3585344&req=5

pone-0055172-g002: Accuracy of in-plane tractions as a function of Poisson's ratio when out-of-plane components of displacements are neglected. denotes the angle of the displacement vector relative to the plane. (a) Ratio of recovered in-plane traction to true in-plane traction. (b) Error in the phase of the recovered in-plane traction (degrees).
Mentions: We now consider a unit displacement that has three-dimensional components , the first two being in-plane and last out-of-plane. The tractions are given by,The true in-plane traction is . The recovered in-plane traction (neglecting the out-of-plane displacement) is . The departures from unity of the ratio quantifies the error in magnitude, while quantifies the error in phase. These quantities are plotted in Fig. 2.

Bottom Line: To assess the validity of these assumptions and to quantify associated errors, here we report new analytical, numerical, and experimental investigations.For several commonly used experimental monolayer systems, the simplifying assumptions used previously lead to errors that are shown to be quite small.Out-of-plane components of displacement and traction fields can be safely neglected, and characteristic features of intercellular stresses that underlie plithotaxis remain largely unaffected.

View Article: PubMed Central - PubMed

Affiliation: Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, USA. dhananjay@alumni.brown.edu

ABSTRACT
In wound healing, tissue growth, and certain cancers, the epithelial or the endothelial monolayer sheet expands. Within the expanding monolayer sheet, migration of the individual cell is strongly guided by physical forces imposed by adjacent cells. This process is called plithotaxis and was discovered using Monolayer Stress Microscopy (MSM). MSM rests upon certain simplifying assumptions, however, concerning boundary conditions, cell material properties and system dimensionality. To assess the validity of these assumptions and to quantify associated errors, here we report new analytical, numerical, and experimental investigations. For several commonly used experimental monolayer systems, the simplifying assumptions used previously lead to errors that are shown to be quite small. Out-of-plane components of displacement and traction fields can be safely neglected, and characteristic features of intercellular stresses that underlie plithotaxis remain largely unaffected. Taken together, these findings validate Monolayer Stress Microscopy within broad but well-defined limits of applicability.

Show MeSH
Related in: MedlinePlus