scholarly journals Integer topological defects of cell monolayers: Mechanics and flows

2021 ◽  
Vol 103 (1) ◽  
Author(s):  
Carles Blanch-Mercader ◽  
Pau Guillamat ◽  
Aurélien Roux ◽  
Karsten Kruse
Keyword(s):  
Topological Defects ◽  
Cell Monolayers

Unifying polar and nematic active matter: Emergence and co-existence of half-integer and full-integer topological defects

2022 ◽  
Author(s):  
Aboutaleb Amiri ◽  
Romain Mueller ◽  
Amin Doostmohammadi
Keyword(s):  
Continuum Model ◽  
Topological Defect ◽  
Topological Defects ◽  
Active Matter ◽  
Defect States ◽  
Cell Monolayers ◽  
Half Integer ◽  
Generic Framework ◽  
Active Turbulence ◽  
The Continuum

Abstract The presence and significance of active topological defects is increasingly realised in diverse biological and biomimetic systems. We introduce a continuum model of polar active matter, based on conservation laws and symmetry arguments, that recapitulates both polar and apolar (nematic) features of topological defects in active turbulence. Using numerical simulations of the continuum model, we demonstrate the emergence of both half- and full-integer topological defects in polar active matter. Interestingly, we find that crossover from active turbulence with half- to full-integer defects can emerge with the coexistence region characterized by both defect types. These results put forward a minimal, generic framework for studying topological defect patterns in active matter which is capable of explaining the emergence of half-integer defects in polar systems such as bacteria and cell monolayers, as well as predicting the emergence of coexisting defect states in active matter.

scholarly journals Quantifying Material Properties of Cell Monolayers by Analyzing Integer Topological Defects

2021 ◽  
Vol 126 (2) ◽  
Author(s):  
Carles Blanch-Mercader ◽  
Pau Guillamat ◽  
Aurélien Roux ◽  
Karsten Kruse
Keyword(s):  
Material Properties ◽  
Topological Defects ◽  
Cell Monolayers

scholarly journals Topological defects of integer charge in cell monolayers

Soft Matter ◽  
2021 ◽  
Author(s):  
Kirsten D. Endresen ◽  
MinSu Kim ◽  
Matthew Pittman ◽  
Yun Chen ◽  
Francesca Serra
Keyword(s):  
Epithelial Cells ◽  
Topological Charge ◽  
Topological Defects ◽  
Cell Type ◽  
Cell Monolayers

Using microscale topographic patterns to guide fibroblasts and epithelial cells to form topological defects in monolayers, we examine behaviors dependent on cell type as well as topological charge.

scholarly journals Active forces in confluent cell monolayers

2021 ◽  
Author(s):  
Guanming Zhang ◽  
Julia Mary Yeomans
Keyword(s):  
Field Model ◽  
Collective Motion ◽  
Cell Monolayer ◽  
Phase Field Model ◽  
Topological Defects ◽  
Cellular Interactions ◽  
Cell Monolayers ◽  
Nematic Ordering ◽  
Active Turbulence ◽  
Confluent Cell

We use a computational phase-field model together with analytical analysis to study how inter-cellular active forces can mediate individual cell morphology and collective motion in a confluent cell monolayer. Contractile inter-cellular interactions lead to cell elongation, nematic ordering and active turbulence, characterised by motile topological defects. Extensile interactions result in frustration, and perpendicular cell orientations become more prevalent. Furthermore, we show that contractile behaviour can change to extensile behaviour if anisotropic fluctuations in cell shape are considered.

scholarly journals Chiral stresses in nematic cell monolayers

Soft Matter ◽  
2020 ◽  
Vol 16 (3) ◽  
pp. 764-774 ◽  
Author(s):  
Ludwig A. Hoffmann ◽  
Koen Schakenraad ◽  
Roeland M. H. Merks ◽  
Luca Giomi
Keyword(s):  
Collective Motion ◽  
Topological Defects ◽  
Cell Monolayers ◽  
Microscopic Origin

We discuss the microscopic origin of chiral stresses in nematic cell monolayers and investigate how chirality affects the motion of topological defects, as well as the collective motion in stripe-shaped domains.

A pre-embedding, protein a-gold immunolabelling technique for cytocentrifuged cell monolayers for lm and tem

1986 ◽  
Vol 44 ◽  
pp. 220-221
Author(s):  
K. Chien ◽  
I.P. Shintaku ◽  
A.F. Sassoon ◽  
R.L. Van de Velde ◽  
R. Heusser
Keyword(s):  
Cell Surface ◽  
Staining Method ◽  
Protein A ◽  
Surface Antigens ◽  
Cell Suspensions ◽  
Cellular Morphology ◽  
Cellular Phenotype ◽  
Cell Surface Antigens ◽  
Cell Monolayers ◽  
Diagnostic Histopathology

Identification of cellular phenotype by cell surface antigens in conjunction with ultrastructural analysis of cellular morphology can be a useful tool in the study of biologic processes as well as in diagnostic histopathology. In this abstract, we describe a simple pre-embedding, protein A-gold staining method which is designed for cell suspensions combining the handling convenience of slide-mounted cell monolayers and the ability to evaluate specimen staining specificity prior to EM embedding.

Processing Immunoperoxidase Labeled Cell Monolayers and Cryostat Sesctions For Electron Microscopy

1985 ◽  
Vol 43 ◽  
pp. 714-715
Author(s):  
K. Chien ◽  
R. Van de Velde ◽  
I.P. Shintaku ◽  
A.F. Sassoon
Keyword(s):  
Cell Monolayer ◽  
Cell Types ◽  
Surface Antigens ◽  
Immunoperoxidase Method ◽  
Reaction Step ◽  
Hot Plate ◽  
Air Drying ◽  
New Approach ◽  
Cell Monolayers ◽  
Glass Slides

Immunoelectron microscopy of neoplastic lymphoma cells is valuable for precise localization of surface antigens and identification of cell types. We have developed a new approach in which the immunohistochemical staining can be evaluated prior to embedding for EM and desired area subsequently selected for ultrathin sectioning.A freshly prepared lymphoma cell suspension is spun onto polylysine hydrobromide- coated glass slides by cytocentrifugation and immediately fixed without air drying in polylysine paraformaldehyde (PLP) fixative. After rinsing in PBS, slides are stained by a 3-step immunoperoxidase method. Cell monolayer is then fixed in buffered 3% glutaraldehyde prior to DAB reaction. After the DAB reaction step, wet monolayers can be examined under LM for presence of brown reaction product and selected monolayers then processed by routine methods for EM and embedded with the Chien Re-embedding Mold. After the polymerization, the epoxy blocks are easily separated from the glass slides by heatingon a 100°C hot plate for 20 seconds.

Transport in Caco-2 cell monolayers of cucurbitane triterpenoids from Momordica charantia

Planta Medica ◽  
2012 ◽  
Vol 78 (11) ◽  
Author(s):  
SB Wu ◽  
GGL Yue ◽  
AC Keller ◽  
MH To ◽  
CBS Lau ◽  
...  
Keyword(s):  
Momordica Charantia ◽  
Cell Monolayers

A Pseudo Five-Fold Symmetrical Ligand Drives Geometric Frustration in Porous Metal-Organic and Hydrogen Bonded Frameworks

2020 ◽  
Author(s):  
Frederik Haase ◽  
Gavin Craig ◽  
Mickaele Bonneau ◽  
kunihisa sugimoto ◽  
Shuhei Furukawa
Keyword(s):  
Topological Defects ◽  
Porous Metal ◽  
Building Blocks ◽  
Structural Features ◽  
Equilibrium Structure ◽  
Sorption Behavior ◽  
Building Unit ◽  
Geometric Frustration ◽  
Secondary Building Units ◽  
Hydrogen Bonded

Reticular framework materials thrive on designability, but unexpected reaction outcomes are crucial in exploring new structures and functionalities. By combining “incompatible” building blocks, we employed geometric frustration in reticular materials leading to emergent structural features. The combination of a pseudo C<sub>5</sub> symmetrical organic building unit based on a pyrrole core, with a C<sub>4</sub> symmetrical copper paddlewheel synthon led to three distinct frameworks by tuning the synthetic conditions. The frameworks show structural features typical for geometric frustration: self-limiting assembly, internally stressed equilibrium structures and topological defects in the equilibrium structure, which manifested in the formation of a hydrogen bonded framework, distorted and broken secondary building units and dangling functional groups, respectively. The influence of geometric frustration on the CO<sub>2</sub> sorption behavior and the discovery of a new secondary building unit shows geometric frustration can serve as a strategy to obtain highly complex porous frameworks.

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