Functionalized Fluoropolymer-Compatibilized Elastomeric Bilayer Composites for Osteochondral Repair: Unraveling the Role of Substrate Stiffness and Functionalities

2021 ◽  
Author(s):  
Asish Kumar Panda ◽  
Bikramjit Basu
Keyword(s):  
Substrate Stiffness ◽  
Osteochondral Repair

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.

The development of natural polymer scaffold-based therapeutics for osteochondral repair

2020 ◽  
Vol 48 (4) ◽  
pp. 1433-1445
Author(s):  
Mark Lemoine ◽  
Sarah M. Casey ◽  
John M. O'Byrne ◽  
Daniel J. Kelly ◽  
Fergal J. O'Brien
Keyword(s):  
Synthetic Polymers ◽  
Tissue Formation ◽  
Polymer Scaffolds ◽  
Natural Polymer ◽  
Natural Polymers ◽  
Polymer Scaffold ◽  
Regenerative Capacity ◽  
Osteochondral Repair ◽  
Localized Delivery

Due to the limited regenerative capacity of cartilage, untreated joint defects can advance to more extensive degenerative conditions such as osteoarthritis. While some biomaterial-based tissue-engineered scaffolds have shown promise in treating such defects, no scaffold has been widely accepted by clinicians to date. Multi-layered natural polymer scaffolds that mimic native osteochondral tissue and facilitate the regeneration of both articular cartilage (AC) and subchondral bone (SCB) in spatially distinct regions have recently entered clinical use, while the transient localized delivery of growth factors and even therapeutic genes has also been proposed to better regulate and promote new tissue formation. Furthermore, new manufacturing methods such as 3D bioprinting have made it possible to precisely tailor scaffold micro-architectures and/or to control the spatial deposition of cells in requisite layers of an implant. In this way, natural and synthetic polymers can be combined to yield bioactive, yet mechanically robust, cell-laden scaffolds suitable for the osteochondral environment. This mini-review discusses recent advances in scaffolds for osteochondral repair, with particular focus on the role of natural polymers in providing regenerative templates for treatment of both AC and SCB in articular joint defects.

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.

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
Sign in / Sign up

Export Citation Format

Share Document