scholarly journals Design of a Well-Defined Poly(Dimethylsiloxane)-Based Microbial Nanoculture System

2020 ◽  
Author(s):  
Huda Usman ◽  
Shanna-Leigh Davidson ◽  
Nithil H. Manimaran ◽  
Jenna T. Nguyen ◽  
Aïssatou Bah ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Drug Delivery ◽  
Shear Stress ◽  
Culture System ◽  
Microbial Culture ◽  
High Shear ◽  
Biological Applications ◽  
High Shear Stress ◽  
Microbial Dynamics ◽  
Semipermeable Membranes

<p>Organosilanes contain hydrocarbon-like backbones, allowing them to react with silicone-based agents in the presence of a catalyst and polymerize into membranes with tunable transport and mechanical properties. Owing to their high hydrophobicity, Poly(dimethylsiloxane) (PDMS) membranes, and more particularly, Sylgard® 184, have been used for applications including drug delivery, gas separation, and microfluidics fabrication. However, the undefined composition of the material and its ability to leach out uncured oligomers make its functionalization and usage challenging for many biological applications. This article presents the design of a novel culture system generated using PDMS-based membranes to study microbial dynamics. The microbial culture system that is referred to as “nanoculture” serves to encapsulate and grow microbes in semipermeable membranes. The mechanical properties of the membranes are reinforced through osmotic annealing, which enable the nanocultures to withstand high shear stress similar to environmental conditions while maintaining transport properties essential to microbial communication and growth. The present study lays the foundation for a novel microbial culture system that would enable the cultivation of microorganisms in environments other than laboratory conditions.</p>

scholarly journals Design of a Well-Defined Poly(Dimethylsiloxane)-Based Microbial Nanoculture System

2020 ◽  
Author(s):  
Huda Usman ◽  
Shanna-Leigh Davidson ◽  
Nithil H. Manimaran ◽  
Jenna T. Nguyen ◽  
Aïssatou Bah ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Drug Delivery ◽  
Shear Stress ◽  
Culture System ◽  
Microbial Culture ◽  
High Shear ◽  
Biological Applications ◽  
High Shear Stress ◽  
Microbial Dynamics ◽  
Semipermeable Membranes

<p>Organosilanes contain hydrocarbon-like backbones, allowing them to react with silicone-based agents in the presence of a catalyst and polymerize into membranes with tunable transport and mechanical properties. Owing to their high hydrophobicity, Poly(dimethylsiloxane) (PDMS) membranes, and more particularly, Sylgard® 184, have been used for applications including drug delivery, gas separation, and microfluidics fabrication. However, the undefined composition of the material and its ability to leach out uncured oligomers make its functionalization and usage challenging for many biological applications. This article presents the design of a novel culture system generated using PDMS-based membranes to study microbial dynamics. The microbial culture system that is referred to as “nanoculture” serves to encapsulate and grow microbes in semipermeable membranes. The mechanical properties of the membranes are reinforced through osmotic annealing, which enable the nanocultures to withstand high shear stress similar to environmental conditions while maintaining transport properties essential to microbial communication and growth. The present study lays the foundation for a novel microbial culture system that would enable the cultivation of microorganisms in environments other than laboratory conditions.</p>

scholarly journals High shear stress suppresses proliferation and migration but promotes apoptosis of endothelial cells co-cultured with vascular smooth muscle cells via down-regulating MAPK pathway

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Qiang Ji ◽  
Yu Lin Wang ◽  
Li Min Xia ◽  
Ye Yang ◽  
Chun Sheng Wang ◽  
...  
Keyword(s):  
Shear Stress ◽  
Culture System ◽  
Stress Condition ◽  
Mapk Pathway ◽  
High Shear ◽  
High Shear Stress ◽  
Cellular Processes ◽  
Mapk Pathways ◽  
And Migration ◽  
Proliferation And Migration

Abstract Background Early neointimal hyperplasia of vein graft may be ameliorated via enhancing intravenous surface shear stress. Cellular processes including proliferation, apoptosis and migration of endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) may play very important roles in the process of neointimal hyperplasia of vein graft; and mitogen-activated protein kinase (MAPK) pathways including extracellular signal-regulated kinase (ERK1/2) and p38 pathways play vital roles in regulating a large variety of cellular processes. This study evaluated the impacts of shear stress and MAPK pathways on cellular processes of ECs in a co-culture system with VSMCs, and aimed to test the hypothesis that high shear stress suppresses proliferation and migration but promotes apoptosis of ECs co-cultured with VSMCs via down-regulating MAPK pathway. Methods Primary ECs and VSMCs derived from porcine great saphenous vein were collected, respectively. 4–7 generation of cells were used as work cells. ECs and VSMCs were co-cultured and synchronized under high and low shear stress using Parallel-Plate Flow Chamber system. And then, ECs co-cultured with VSMCs were incubated with U0126 (ERK1/2 inhibitor) or PD98059 (p38 inhibitor) under different shear stress. Proliferation, apoptosis and migration of ECs in a co-culture system with VSMCs were detected by 4,5-dimethyl-2-thiazolyl (MTT) assay and bromodeoxyuridine (BrdU) assay, fluorescent-activated cell sorting (FACS) technique, and Transwell assay separately. Each test repeated 3 times. Additionally, protein expressions of ERK1/2 and p38 MAPK were detected by using Western blot, respectively. Results Under higher level of shear stress condition, proliferation and migration of ECs co-cultured with VSMCs were suppressed, while cell apoptosis was promoted. And blocking ERK1/2 pathway by U0126 or blocking p38 pathway by PD98059, proliferation and migration of ECs co-cultured with VSMCs were further suppressed, while cell apoptosis was further promoted. Additionally, protein expressions of phosphorylation of ERK1/2 and p38MAPK were decreased under higher level of shear stress condition, and were further reduced by blocking ERK1/2 or p38 pathway under shear stress condition. Conclusions High shear stress may suppress proliferation and apoptosis of ECs in a co-culture system with VSMCs but promote cell migration via down-regulating ERK1/2 and p38 MAPK pathways.

scholarly journals 5065Platelet desialylation induced by high shear-stress mechanical circulatory support

2018 ◽  
Vol 39 (suppl_1) ◽  
Author(s):  
H Spillemaeker ◽  
A Dupont ◽  
A Kauskot ◽  
A Rauch ◽  
F Vincent ◽  
...  
Keyword(s):  
Shear Stress ◽  
Mechanical Circulatory Support ◽  
Circulatory Support ◽  
High Shear ◽  
High Shear Stress

scholarly journals Nitric Oxide–Dependent and Nitric Oxide–Independent Transcriptional Responses to High Shear Stress in Endothelial Cells

Hypertension ◽  
2005 ◽  
Vol 45 (4) ◽  
pp. 672-680 ◽  
Author(s):  
Branko Braam ◽  
Remmert de Roos ◽  
Hans Bluyssen ◽  
Patrick Kemmeren ◽  
Frank Holstege ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Shear Stress ◽  
High Shear ◽  
High Shear Stress ◽  
Transcriptional Responses

DIFFUSION LIMITED AGGREGATION FROM SHEAR STRESS AS A SIMPLE MODEL OF VASCULOGENESIS

Fractals ◽  
1999 ◽  
Vol 07 (01) ◽  
pp. 33-39 ◽  
Author(s):  
VINCENT FLEURY ◽  
LAURENT SCHWARTZ
Keyword(s):  
Shear Stress ◽  
Dendritic Growth ◽  
High Shear ◽  
Vascular Pattern ◽  
Laplacian Growth ◽  
High Shear Stress ◽  
Diffusion Limited Aggregation ◽  
Diffusion Limited ◽  
Capillary Bed ◽  
Arteries And Veins

A model is proposed by which the formation of the vascular network in animals proceeds via progressive penetration of the vessel ramification into a capillary mesh, by means of a laplacian growth mechanism of hydrodynamical origin. In this model, the growth of both arteries and veins follows the directions of high shear stress provoked by the blood flow on the endothelial wall of a pre-existing capillary mesh. This process is shown to be identical to the phenomenon of dendritic growth, which is responsible for the formation of such well-known patterns as dendritic crystals, lightning sparks or branching aggregates of bacteria. A number of straightforward consequences of potentially important medical and physiological interests are deduced. These include the natural and spontaneous organization of the arterial and venal trees, the spontaneous and unavoidable tropism of arteries towards veins and vice-versa, the hierarchical character of the vessels and the possibility of computerized prediction of the vascular pattern from the shape of the capillary bed.

scholarly journals Antithrombotic Effects of Paeoniflorin from Paeonia suffruticosa by Selective Inhibition on Shear Stress-Induced Platelet Aggregation

2019 ◽  
Vol 20 (20) ◽  
pp. 5040 ◽  
Author(s):  
Thien Ngo ◽  
Keunyoung Kim ◽  
Yiying Bian ◽  
Hakjun Noh ◽  
Kyung-Min Lim ◽  
...  
Keyword(s):  
Shear Stress ◽  
Platelet Aggregation ◽  
Ex Vivo ◽  
Antiplatelet Agents ◽  
Human Platelets ◽  
Platelet Glycoprotein ◽  
High Shear ◽  
High Shear Stress ◽  
Paeonia Suffruticosa ◽  
Induced Aggregation

Antiplatelet agents are important in the pharmacotherapeutic regime for many cardiovascular diseases, including thrombotic disorders. However, bleeding, the most serious adverse effect associated with current antiplatelet therapy, has led to many efforts to discover novel anti-platelet drugs without bleeding issues. Of note, shear stress-induced platelet aggregation (SIPA) is a promising target to overcome bleeding since SIPA happens only in pathological conditions. Accordingly, this study was carried out to discover antiplatelet agents selectively targeting SIPA. By screening various herbal extracts, Paeonia suffruticosa and its major bioactive constituent, paeoniflorin, were identified to have significant inhibitory effects against shear-induced aggregation in human platelets. The effects of paeoniflorin on intraplatelet calcium levels, platelet degranulation, and integrin activation in high shear stress conditions were evaluated by a range of in vitro experiments using human platelets. The inhibitory effect of paeoniflorin was determined to be highly selective against SIPA, through modulating von Willebrand Factor (vWF)-platelet glycoprotein Ib (GP Ib) interaction. The effects of paeoniflorin on platelet functions under high shear stress were confirmed in the ex vivo SIPA models in rats, showing the good accordance with the anti-SIPA effects on human platelets. Treatment with paeoniflorin significantly prevented arterial thrombosis in vivo from the dose of 10 mg/kg without prolonging bleeding time or blood clotting time in rats. Collectively, our results demonstrated that paeoniflorin can be a novel anti-platelet agent selectively targeting SIPA with an improved safety profile.

scholarly journals Biomarkers related to hemodynamic abnormalities with high shear stress

2016 ◽  
Vol 67 (2) ◽  
pp. 213 ◽  
Author(s):  
Toru Kubo ◽  
Hiroaki Kitaoka
Keyword(s):  
Shear Stress ◽  
High Shear ◽  
High Shear Stress
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