scholarly journals Finite Element Analysis of Traction Force Microscopy: Influence of Cell Mechanics, Adhesion, and Morphology

2013 ◽  
Vol 135 (7) ◽  
Author(s):  
Rachel Zielinski ◽  
Cosmin Mihai ◽  
Douglas Kniss ◽  
Samir N. Ghadiali

The interactions between adherent cells and their extracellular matrix (ECM) have been shown to play an important role in many biological processes, such as wound healing, morphogenesis, differentiation, and cell migration. Cells attach to the ECM at focal adhesion sites and transmit contractile forces to the substrate via cytoskeletal actin stress fibers. This contraction results in traction stresses within the substrate/ECM. Traction force microscopy (TFM) is an experimental technique used to quantify the contractile forces generated by adherent cells. In TFM, cells are seeded on a flexible substrate and displacements of the substrate caused by cell contraction are tracked and converted to a traction stress field. The magnitude of these traction stresses are normally used as a surrogate measure of internal cell contractile force or contractility. We hypothesize that in addition to contractile force, other biomechanical properties including cell stiffness, adhesion energy density, and cell morphology may affect the traction stresses measured by TFM. In this study, we developed finite element models of the 2D and 3D TFM techniques to investigate how changes in several biomechanical properties alter the traction stresses measured by TFM. We independently varied cell stiffness, cell-ECM adhesion energy density, cell aspect ratio, and contractility and performed a sensitivity analysis to determine which parameters significantly contribute to the measured maximum traction stress and net contractile moment. Results suggest that changes in cell stiffness and adhesion energy density can significantly alter measured tractions, independent of contractility. Based on a sensitivity analysis, we developed a correction factor to account for changes in cell stiffness and adhesion and successfully applied this correction factor algorithm to experimental TFM measurements in invasive and noninvasive cancer cells. Therefore, application of these types of corrections to TFM measurements can yield more accurate estimates of cell contractility.

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Christoph Mark ◽  
Thomas J Grundy ◽  
Pamela L Strissel ◽  
David Böhringer ◽  
Nadine Grummel ◽  
...  

We describe a method for quantifying the contractile forces that tumor spheroids collectively exert on highly nonlinear three-dimensional collagen networks. While three-dimensional traction force microscopy for single cells in a nonlinear matrix is computationally complex due to the variable cell shape, here we exploit the spherical symmetry of tumor spheroids to derive a scale-invariant relationship between spheroid contractility and the surrounding matrix deformations. This relationship allows us to directly translate the magnitude of matrix deformations to the total contractility of arbitrarily sized spheroids. We show that our method is accurate up to strains of 50% and remains valid even for irregularly shaped tissue samples when considering only the deformations in the far field. Finally, we demonstrate that collective forces of tumor spheroids reflect the contractility of individual cells for up to 1 hr after seeding, while collective forces on longer timescales are guided by mechanical feedback from the extracellular matrix.


2011 ◽  
Vol 04 (02) ◽  
pp. 143-150
Author(s):  
LINHONG DENG ◽  
XUEMEI JIANG ◽  
CHENG CHEN ◽  
AIJING SONG ◽  
FENG LIN

Optical magnetic twisting cytometry and traction force microscopy are two advanced cell mechanics research tools that employ optical methods to track the motion of microbeads that are either bound to the surface or embedded in the substrate underneath the cell. The former measures rheological properties of the cell such as cell stiffness, and the latter measures cell traction force dynamics. Here we describe the principles of these two cell mechanics research tools and an example of using them to study physical behaviors of the living cell in response to transient stretch or compression. We demonstrate that, when subjected to a stretch–unstretch manipulation, both the stiffness and traction force of adherent cells promptly reduced, and then gradually recover up to the level prior to the stretch. Immunofluorescent staining and Western blotting results indicate that the actin cytoskeleton of the cells underwent a corresponding disruption and reassembly process almost in step with the changes of cell mechanics. Interestingly, when subjected to compression, the cells did not show such particular behaviors. Taken together, we conclude that adherent cells are very sensitive to the transient stretch but not transient compression, and the stretch-induced cell response is due to the dynamics of actin polymerization.


2019 ◽  
Author(s):  
Christoph Mark ◽  
Thomas J. Grundy ◽  
David Böhringer ◽  
Julian Steinwachs ◽  
Geraldine M. O’Neill ◽  
...  

ABSTRACTWe describe a method for quantifying the contractile forces that tumor spheroids collectively exert on highly nonlinear three-dimensional collagen networks. While three-dimensional traction force microscopy for single cells in a nonlinear matrix is computationally complex due to the variable cell shape, here we exploit the spherical symmetry of tumor spheroids to derive a scale-invariant relationship between spheroid contractility and the surrounding matrix deformations. This relationship allows us to directly translate the magnitude of matrix deformations to the total contractility of arbitrarily sized spheroids. We show that collective forces of tumor spheroids reflect the contractility of individual cells for up to 1h after seeding, while collective forces on longer time-scales are guided by mechanical feedback from the extracellular matrix.


2021 ◽  
Author(s):  
Małgorzata Grabowska ◽  
Konrad Kuczyński ◽  
Monika Piwecka ◽  
Alicja Rabiasz ◽  
Joanna Zemła ◽  
...  

Abstract BackgroundGlioblastoma (GBM) is the most common malignant brain tumour. GBM cells have ability to infiltrate into the surrounding brain tissue, which results in a significant decrease in the patient’s survival rate. Infiltration is a consequence of the low adhesion and high migration of the tumour cells, two features being associated with the highly remodelled extracellular matrix (ECM). MethodsThe expression profile of miRNAs and mRNAs was analysed by qPCR on 19 GBM tissue samples. Than luciferase assay was performed to confirm interaction between miR-218 and target sequences. Next we checked how supplementation of glioma cell line (U118-MG) with microRNA 218 will change expression pattern of TN-C and SDC both on transcript level and on protein level. Analysis of protein level were made with western-blot technique. Last step in expression profiling of genes connected to cellular motility and adhesion was done with use of qPCR analysis after supplementation with miR-218. To assess the abilities of cells to migrate and proliferate real-time cell culture analysis with use of Incelligence system were utilized. Also this results were backed by classic wound-healing assay. To conclude we used atomic force microscopy (AFM) to measure physical properties such as adhesion and stiffness of cells. This study was supported by microscopy analysis of cytoskeleton changes after supplementation of miR-218.ResultsIn this study, we report that ECM composition is partially regulated at the posttranscriptional level by miRNA. Particularly, we show that miR-218, a well-known miRNA suppressor, is involved in direct regulation of ECM components, tenascin-C (TN-C) and syndecan-2 (SDC-2). We demonstrated that the overexpression of miR-218 reduces the mRNA and protein expression levels of TN-C and SDC-2, and subsequently influences biomechanical properties of GBM cells. Atomic force microscopy (AFM) and real-time migration analysis revealed that miR-218 overexpression impairs the migration potential and enhances the adhesive properties of cells. AFM analysis followed by F-actin staining demonstrated that expression level of miR-218 has an impact on cell stiffness and cytoskeletal reorganization. Global gene expression analysis showed deregulation of a number of genes involved in tumour cell motility and adhesion or ECM remodelling upon miR-218 treatment, suggesting further indirect interactions between the cells and ECM. Conclusion The results demonstrated a direct impact of miR-218 reduction in GBM tumours on the qualitative ECM content, leading to changes in the rigidity of the ECM and GBM cells being conducive to increased invasiveness of GBM.


Life ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 515
Author(s):  
Andrea Cugno ◽  
Alex Marki ◽  
Klaus Ley

Leukocytes, including neutrophils, which are propelled by blood flow, can roll on inflamed endothelium using transient bonds between selectins and their ligands, and integrins and their ligands. When such receptor–ligand bonds last long enough, the leukocyte microvilli become extended and eventually form thin, 20 m long tethers. Tether formation can be observed in blood vessels in vivo and in microfluidic flow chambers. Tethers can also be extracted using micropipette aspiration, biomembrane force probe, optical trap, or atomic force microscopy approaches. Here, we review the biomechanical properties of leukocyte tethers as gleaned from such measurements and discuss the advantages and disadvantages of each approach. We also review and discuss viscoelastic models that describe the dependence of tether formation on time, force, rate of loading, and cell activation. We close by emphasizing the need to combine experimental observations with quantitative models and computer simulations to understand how tether formation is affected by membrane tension, membrane reservoir, and interactions of the membrane with the cytoskeleton.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Liliana Barbieri ◽  
Huw Colin-York ◽  
Kseniya Korobchevskaya ◽  
Di Li ◽  
Deanna L. Wolfson ◽  
...  

AbstractQuantifying small, rapidly evolving forces generated by cells is a major challenge for the understanding of biomechanics and mechanobiology in health and disease. Traction force microscopy remains one of the most broadly applied force probing technologies but typically restricts itself to slow events over seconds and micron-scale displacements. Here, we improve >2-fold spatially and >10-fold temporally the resolution of planar cellular force probing compared to its related conventional modalities by combining fast two-dimensional total internal reflection fluorescence super-resolution structured illumination microscopy and traction force microscopy. This live-cell 2D TIRF-SIM-TFM methodology offers a combination of spatio-temporal resolution enhancement relevant to forces on the nano- and sub-second scales, opening up new aspects of mechanobiology to analysis.


2021 ◽  
Vol 120 (3) ◽  
pp. 113a
Author(s):  
Wouter-Jan Rappel ◽  
Elisabeth Ghabache ◽  
Yuansheng Cao ◽  
Yuchuan Miao ◽  
Alexander Groisman ◽  
...  

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Lauren Hazlett ◽  
Alexander K. Landauer ◽  
Mohak Patel ◽  
Hadley A. Witt ◽  
Jin Yang ◽  
...  

Abstract We introduce a novel method to compute three-dimensional (3D) displacements and both in-plane and out-of-plane tractions on nominally planar transparent materials using standard epifluorescence microscopy. Despite the importance of out-of-plane components to fully understanding cell behavior, epifluorescence images are generally not used for 3D traction force microscopy (TFM) experiments due to limitations in spatial resolution and measuring out-of-plane motion. To extend an epifluorescence-based technique to 3D, we employ a topology-based single particle tracking algorithm to reconstruct high spatial-frequency 3D motion fields from densely seeded single-particle layer images. Using an open-source finite element (FE) based solver, we then compute the 3D full-field stress and strain and surface traction fields. We demonstrate this technique by measuring tractions generated by both single human neutrophils and multicellular monolayers of Madin–Darby canine kidney cells, highlighting its acuity in reconstructing both individual and collective cellular tractions. In summary, this represents a new, easily accessible method for calculating fully three-dimensional displacement and 3D surface tractions at high spatial frequency from epifluorescence images. We released and support the complete technique as a free and open-source code package.


2014 ◽  
Vol 106 (2) ◽  
pp. 425a
Author(s):  
Jerome Soine ◽  
Christoph Brand ◽  
Jonathan Stricker ◽  
Patrick W. Oakes ◽  
Margaret L. Gardel ◽  
...  

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