A scallop theorem for cells moving in 3D

The famous scallop theorem proposed by Purcell in 1977 states that self-propelled objects swimming at low Reynolds number must follow a cycle of shape changes that breaks temporal symmetry. This should hold true for crawling cells as well. However a clear mechanism for this symmetry breaking is still elusive. Here we show that cells embedded in 3D matrix form at both sides of the nucleus force dipoles driven by myosin that locally and periodically pinch the matrix. Using a combination of 3D live cell imaging, traction force microscopy and a minimal model with multipolar expansion, we show that the existence of a phase shift between the two dipoles involves mainly the microtubular network and is required for directed cell motion. We confirm this mechanism by triggering local dipolar contractions with a laser, which leads to directed motion. Our study reveals that the cell controls its motility by synchronising dipolar forces distributed at front and back. This result opens new strategies to externally control cell motion.

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An Insight into Amorphous Shear Band in Magnetorheological Solid by Atomic Force Microscope

Materials ◽

10.3390/ma14164384 ◽

2021 ◽

Vol 14 (16) ◽

pp. 4384

Author(s):

Mohd Aidy Faizal Johari ◽

Asmawan Mohd Sarman ◽

Saiful Amri Mazlan ◽

Ubaidillah U ◽

Nur Azmah Nordin ◽

...

Keyword(s):

Stress Relaxation ◽

Shear Band ◽

Shear Bands ◽

Test Duration ◽

Phase Imaging ◽

Force Microscopy ◽

Atomic Force ◽

The Matrix ◽

Relaxation Stress ◽

Band Deformation

Micro mechanism consideration is critical for gaining a thorough understanding of amorphous shear band behavior in magnetorheological (MR) solids, particularly those with viscoelastic matrices. Heretofore, the characteristics of shear bands in terms of formation, physical evolution, and response to stress distribution at the localized region have gone largely unnoticed and unexplored. Notwithstanding these limitations, atomic force microscopy (AFM) has been used to explore the nature of shear band deformation in MR materials during stress relaxation. Stress relaxation at a constant low strain of 0.01% and an oscillatory shear of defined test duration played a major role in the creation of the shear band. In this analysis, the localized area of the study defined shear bands as varying in size and dominantly deformed in the matrix with no evidence of inhibition by embedded carbonyl iron particles (CIPs). The association between the shear band and the adjacent zone was further studied using in-phase imaging of AFM tapping mode and demonstrated the presence of localized affected zone around the shear band. Taken together, the results provide important insights into the proposed shear band deformation zone (SBDZ). This study sheds a contemporary light on the contentious issue of amorphous shear band deformation behavior and makes several contributions to the current literature.

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Two-dimensional TIRF-SIM–traction force microscopy (2D TIRF-SIM-TFM)

Nature Communications ◽

10.1038/s41467-021-22377-9 ◽

2021 ◽

Vol 12 (1) ◽

Cited By ~ 1

Author(s):

Liliana Barbieri ◽

Huw Colin-York ◽

Kseniya Korobchevskaya ◽

Di Li ◽

Deanna L. Wolfson ◽

...

Keyword(s):

Resolution Enhancement ◽

Traction Force ◽

Super Resolution ◽

Traction Force Microscopy ◽

Two Dimensional ◽

Structured Illumination ◽

Structured Illumination Microscopy ◽

Force Microscopy ◽

Health And Disease ◽

Spatio Temporal

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.

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Different Cell Migration Modes: Insights from Traction Force Microscopy and Modeling

Biophysical Journal ◽

10.1016/j.bpj.2020.11.905 ◽

2021 ◽

Vol 120 (3) ◽

pp. 113a

Author(s):

Wouter-Jan Rappel ◽

Elisabeth Ghabache ◽

Yuansheng Cao ◽

Yuchuan Miao ◽

Alexander Groisman ◽

...

Keyword(s):

Cell Migration ◽

Traction Force ◽

Traction Force Microscopy ◽

Force Microscopy

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Influence of Aging on Corrosion Behaviour of the 6061 Cast Aluminium Alloy

Materials ◽

10.3390/ma14081821 ◽

2021 ◽

Vol 14 (8) ◽

pp. 1821

Author(s):

Ting He ◽

Wei Shi ◽

Song Xiang ◽

Chaowen Huang ◽

Ronald G. Ballinger

Keyword(s):

Aluminium Alloy ◽

Laser Scanning ◽

Corrosion Behaviour ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Kelvin Probe ◽

Force Microscopy ◽

The Matrix ◽

6061 Aluminium Alloy

The influence of AlFeSi and Mg2Si phases on corrosion behaviour of the cast 6061 aluminium alloy was investigated. Scanning Kelvin probe force microscopy (SKPFM), electron probe microanalysis (EPMA), and in situ observations by confocal laser scanning microscopy (CLSM) were used. It was found that Mg2Si phases were anodic relative to the matrix and dissolved preferentially without significantly affecting corrosion propagation. The AlFeSi phases’ influence on 6061 aluminium alloy local corrosion was greater than that of the Mg2Si phases. The corroded region width reached five times that of the AlFeSi phase, and the accelerating effect was terminated as the AlFeSi dissolved.

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Service quality function deployment by the C-shaped QFD 3D matrix

Benchmarking An International Journal ◽

10.1108/bij-04-2017-0065 ◽

2018 ◽

Vol 25 (9) ◽

pp. 3386-3405 ◽

Cited By ~ 3

Author(s):

Maryam Hassani ◽

Arash Shahin ◽

Manouchehr Kheradmandnia

Keyword(s):

Quality Function Deployment ◽

Design Methodology ◽

Three Dimensional ◽

Two Dimensional ◽

Customer Requirements ◽

Content Type ◽

Process Characteristics ◽

The Matrix ◽

3D Matrix ◽

Simultaneous Comparison

Purpose The purpose of this paper is to examine the application of C-shaped QFD 3D Matrix in comparing process characteristics (PC), performance aspects (PA) and customer requirements, simultaneously and to prioritize the first two sets, respectively. Design/methodology/approach A three dimensional matrix has been developed with three sets of PC, PA and customers’ requirements and C-shaped matrix has been applied for simultaneous comparison of the dimensions and prioritization of the subsets of PC and PA. The proposed approach has been examined in a post bank. Findings Findings confirm the possibility of simultaneous comparison and prioritization of the three sets of dimensions of this study in post bank services. In addition, “growth and learning” and “bilateral relationship with suppliers” had the first priorities among PA and PC, respectively. Research limitations/implications While the proposed approach has many advantages, filling the matrixes is time-consuming. Since illustrating the 3D matrix was not possible, the matrix was separated into five two-dimensional matrixes. Originality/value Compared to the studied literature, the proposed approach is practically new in the post bank services.

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Epifluorescence-based three-dimensional traction force microscopy

Scientific Reports ◽

10.1038/s41598-020-72931-6 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Lauren Hazlett ◽

Alexander K. Landauer ◽

Mohak Patel ◽

Hadley A. Witt ◽

Jin Yang ◽

...

Keyword(s):

Spatial Frequency ◽

Open Source ◽

Single Particle ◽

Three Dimensional ◽

Traction Force ◽

High Spatial Frequency ◽

Epifluorescence Microscopy ◽

Traction Force Microscopy ◽

Force Microscopy ◽

Out Of Plane

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.

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Traction Force Microscopy Based on an Active Cable Network Model

Biophysical Journal ◽

10.1016/j.bpj.2013.11.2393 ◽

2014 ◽

Vol 106 (2) ◽

pp. 425a

Author(s):

Jerome Soine ◽

Christoph Brand ◽

Jonathan Stricker ◽

Patrick W. Oakes ◽

Margaret L. Gardel ◽

...

Keyword(s):

Network Model ◽

Traction Force ◽

Traction Force Microscopy ◽

Force Microscopy ◽

Cable Network

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Collective forces of tumor spheroids in three-dimensional biopolymer networks

eLife ◽

10.7554/elife.51912 ◽

2020 ◽

Vol 9 ◽

Cited By ~ 4

Author(s):

Christoph Mark ◽

Thomas J Grundy ◽

Pamela L Strissel ◽

David Böhringer ◽

Nadine Grummel ◽

...

Keyword(s):

Single Cells ◽

Three Dimensional ◽

Traction Force ◽

Tumor Spheroids ◽

Scale Invariant ◽

Tissue Samples ◽

Force Microscopy ◽

Surrounding Matrix ◽

Highly Nonlinear ◽

Contractile Forces

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.

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pyTFM: A tool for traction force and monolayer stress microscopy

PLoS Computational Biology ◽

10.1371/journal.pcbi.1008364 ◽

2021 ◽

Vol 17 (6) ◽

pp. e1008364

Author(s):

Andreas Bauer ◽

Magdalena Prechová ◽

Lena Fischer ◽

Ingo Thievessen ◽

Martin Gregor ◽

...

Keyword(s):

Image Annotation ◽

Traction Force ◽

Theoretical Background ◽

Ease Of Use ◽

Traction Force Microscopy ◽

Force Transmission ◽

Force Microscopy ◽

Wide Range ◽

Cell Layers ◽

Cellular Stresses

Cellular force generation and force transmission are of fundamental importance for numerous biological processes and can be studied with the methods of Traction Force Microscopy (TFM) and Monolayer Stress Microscopy. Traction Force Microscopy and Monolayer Stress Microscopy solve the inverse problem of reconstructing cell-matrix tractions and inter- and intra-cellular stresses from the measured cell force-induced deformations of an adhesive substrate with known elasticity. Although several laboratories have developed software for Traction Force Microscopy and Monolayer Stress Microscopy computations, there is currently no software package available that allows non-expert users to perform a full evaluation of such experiments. Here we present pyTFM, a tool to perform Traction Force Microscopy and Monolayer Stress Microscopy on cell patches and cell layers grown in a 2-dimensional environment. pyTFM was optimized for ease-of-use; it is open-source and well documented (hosted at https://pytfm.readthedocs.io/) including usage examples and explanations of the theoretical background. pyTFM can be used as a standalone Python package or as an add-on to the image annotation tool ClickPoints. In combination with the ClickPoints environment, pyTFM allows the user to set all necessary analysis parameters, select regions of interest, examine the input data and intermediary results, and calculate a wide range of parameters describing forces, stresses, and their distribution. In this work, we also thoroughly analyze the accuracy and performance of the Traction Force Microscopy and Monolayer Stress Microscopy algorithms of pyTFM using synthetic and experimental data from epithelial cell patches.

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