Role of substrate stiffness in ultrasonic consolidation

2011 ◽  
Vol 2 (3) ◽  
pp. 162 ◽  
Author(s):  
Chris J. Robinson ◽  
G.D. Janaki Ram ◽  
Brent E. Stucker
Keyword(s):  
Substrate Stiffness ◽  
Ultrasonic Consolidation

scholarly journals Role of Substrate Stiffness in Tissue Spreading: Wetting Transition and Tissue Durotaxis

Langmuir ◽  
2018 ◽  
Vol 35 (23) ◽  
pp. 7571-7577 ◽  
Author(s):  
Ricard Alert ◽  
Jaume Casademunt
Keyword(s):  
Substrate Stiffness ◽  
Wetting Transition

scholarly journals The role of nonlinear substrate elasticity in the wrinkling of thin films

2013 ◽  
Vol 371 (1993) ◽  
pp. 20120422 ◽  
Author(s):  
John W. Hutchinson
Keyword(s):  
Thin Films ◽  
Substrate Stiffness ◽  
Modulus Ratio ◽  
Compliant Substrates ◽  
Wide Range ◽  
The Stability ◽  
Film Substrate ◽  
Film Stiffness ◽  
Substrate Elasticity

The role of substrate nonlinearity in the stability of wrinkling of thin films bonded to compliant substrates is investigated within the initial post-bifurcation range when wrinkling first emerges. A fully nonlinear neo-Hookean bilayer composed of a thin film on a deep substrate is analysed for a wide range of the film–substrate stiffness ratio, from films that are very stiff compared with the substrate to those only slightly stiffer. Substrate pre-stretch prior to film attachment is shown to have a significant effect on the nonlinearity relevant to wrinkling. Two dimensionless parameters are identified that control the stability and mode shape evolution of the bilayer: one specifying arbitrary uniform substrate pre-stretch and the other a stretch-modified modulus ratio. For systems with film stiffness greater than about five times that of the substrate the wrinkling bifurcation is stable, whereas for systems with smaller relative film stiffness bifurcation can be unstable, especially if substrate pre-stretch is not tensile.

scholarly journals Neutrophil transendothelial migration hotspots – mechanisms and implications

2021 ◽  
Vol 134 (7) ◽  
pp. jcs255653
Author(s):  
Max L. B. Grönloh ◽  
Janine J. G. Arts ◽  
Jaap D. van Buul
Keyword(s):  
Transendothelial Migration ◽  
Blood Stream ◽  
Substrate Stiffness ◽  
Physical Factors ◽  
Membrane Composition ◽  
Leukocyte Transendothelial Migration ◽  
Membrane Protrusions ◽  
Endothelial Junction ◽  
Current Paradigm

ABSTRACTDuring inflammation, leukocytes circulating in the blood stream exit the vasculature in a process called leukocyte transendothelial migration (TEM). The current paradigm of this process comprises several well-established steps, including rolling, adhesion, crawling, diapedesis and sub-endothelial crawling. Nowadays, the role of the endothelium in transmigration is increasingly appreciated. It has been established that leukocyte exit sites on the endothelium and in the pericyte layer are in fact not random but instead may be specifically recognized by migrating leukocytes. Here, we review the concept of transmigration hotspots, specific sites in the endothelial and pericyte layer where most transmigration events take place. Chemokine cues, adhesion molecules and membrane protrusions as well as physical factors, such as endothelial junction stability, substrate stiffness, the presence of pericytes and basement membrane composition, may all contribute to local hotspot formation to facilitate leukocytes exiting the vasculature. In this Review, we discuss the biological relevance of such hotspots and put forward multiple mechanisms and factors that determine a functional TEM hotspot.

Substrate Stiffness as a Regulator in Catalyzing Integrin-Mediated Cell Adhesion Nucleation: A Mechanochemical Model

2013 ◽  
Vol 459 ◽  
pp. 555-559
Author(s):  
Xiao Ling Peng
Keyword(s):  
Cell Adhesion ◽  
Energy Input ◽  
Experimental Studies ◽  
Substrate Stiffness ◽  
Dependent Manner ◽  
Integrin Activation ◽  
A Value ◽  
Integrin Clustering ◽  
Mechanochemical Model

We provide here a simplified mechanochemical model to describe the role of substrate stiffness in mediating the chemical reactions between integrins on cell membrane and ligands immobilized on the substrate. By taking into account the energy input for integrin activation on a compliant substrate, Our simulation shows that integrin activation and the downstream integrin clustering can be regulated by substrate stiffness in a value-dependent manner, which is consistent with previous experimental studies.

scholarly journals Plastic multicellular development ofMyxococcus xanthus: genotype–environment interactions in a physical gradient

2019 ◽  
Vol 6 (3) ◽  
pp. 181730 ◽  
Author(s):  
Natsuko Rivera-Yoshida ◽  
Alejandro V. Arzola ◽  
Juan A. Arias Del Angel ◽  
Alessio Franci ◽  
Michael Travisano ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Physical Environment ◽  
Myxococcus Xanthus ◽  
Substrate Stiffness ◽  
Multicellular Development ◽  
Physical Context ◽  
The Individual

In order to investigate the contribution of the physical environment to variation in multicellular development ofMyxococcus xanthus, phenotypes developed by different genotypes in a gradient of substrate stiffness conditions were quantitatively characterized. Statistical analysis showed that plastic phenotypes result from the genotype, the substrate conditions and the interaction between them. Also, phenotypes were expressed in two distinguishable scales, the individual and the population levels, and the interaction with the environment showed scale and trait specificity. Overall, our results highlight the constructive role of the physical context in the development of microbial multicellularity, with both ecological and evolutionary implications.

Substrate Stiffness Modulates the Crosstalk Between Mesenchymal Stem Cells and Macrophages

2020 ◽  
Vol 143 (3) ◽  
Author(s):  
Rukmani Sridharan ◽  
Daniel J. Kelly ◽  
Fergal J. O'Brien
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Inflammatory Responses ◽  
Macrophage Polarization ◽  
Cell Types ◽  
Substrate Stiffness ◽  
Positive Interactions ◽  
Inflammatory Stimulus ◽  
Underlying Substrate

Abstract Upon implantation of a biomaterial, mesenchymal stem cells (MSCs) and macrophages contribute to the wound healing response and the regeneration cascade. Although biomaterial properties are known to direct MSC differentiation and macrophage polarization, the role of biomaterial cues, specifically stiffness, in directing the crosstalk between the two cell types is still poorly understood. This study aimed to elucidate the role of substrate stiffness in modulating the immunomodulatory properties of MSCs and to shed light on their complex interactions with macrophages when presented with diverse biomaterial stiffness cues, a situation analogous to the implant environment where multiple cell types interact with an implanted biomaterial to determine regenerative outcomes. We show that MSCs do not play an immunomodulatory role in the absence of an inflammatory stimulus. Using collagen-coated polyacrylamide gels of varying stiffness values, we demonstrate that the immunomodulatory capability of MSCs in the presence of an inflammatory stimulus is not dependent on the stiffness of the underlying substrate. Moreover, using paracrine and direct contact culture models, we show that a bidirectional crosstalk between MSCs and macrophages is necessary for promoting anti-inflammatory responses and positive immunomodulation, which is dependent on the stiffness of the underlying substrate. We finally show that direct cell–cell contact is not essential for this effect, with paracrine interactions promoting immunomodulatory interactions between MSCs and macrophages. Together, these results demonstrate that biophysical cues such as stiffness that are presented by biomaterials can be tuned to promote positive interactions between MSCs and macrophages which can in turn direct the downstream regenerative response.

scholarly journals THE ROLE OF SUBSTRATE STIFFNESS IN MAINTAINING PLURIPOTENCY OF EMBRYONIC STEM CELLS IN VITRO CULTURE

2021 ◽  
Vol 67 (3) ◽  
pp. 27-34
Author(s):  
D.I. Bilko ◽  
◽  
Y.B. Chaikovsky ◽  
Keyword(s):  
Stem Cells ◽  
Alkaline Phosphatase ◽  
Embryonic Stem Cells ◽  
In Vitro Culture ◽  
Embryonic Stem ◽  
Embryoid Bodies ◽  
Polyacrylamide Gel ◽  
Substrate Stiffness

Murine embryonic stem cells (ESCm) cultured in vitro in the presence of LIF (leukemia inhibitory factor) maintain pluripotency. However, when LIF is removed from the media, an active differentiation into various specialized somatic cells is observed. The aim of the study was to determine the role of substrate stiffness in maintaining of pluripotency of embryonic stem cells in vitro culture. To this aim, we used the method of culturing pluripotent stem cells in vitro, the method of “hanging drop”, the determination of the Young’s modulus for polyacrylamide gel of different hardness, the immunocytochemical alkaline phosphatase (AP) streptavidin-biotin method, microscopy. By culturing ESCm on a soft, medium and hard density polyacrylamide gel as a substrate (0.8, 4.0, 8.0 кPа), we found that on a soft gel ESCm differentiation does not occur even in the absence of LIF. ESCm cultured on a soft substrate continue to show signs of pluripotency, namely, create round compact colonies with high alkaline phosphatase activity and form embryoid bodies (EB), the efficiency of which (87.5 ± 3.2 per 100 cells seeded) did not decrease even after LIF withdrawal. In the absence of LIF, ESCs cultured on a hard base showed a low level of EB formation (23.5 ± 2.24). The results of our observations demonstrate that the process of EB formation may be influenced not only by a composition of nutrient medium, but also by complex interaction between the physical forces of the matrix and the mechanical properties of 3D cell aggregates. The model is considered as a tool to study early events in embryogenesis in the search of conditions for effective culture of progenitor cells and differentiated cells for transplantation.

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