Study of Long Term Viability of Endothelial Cells on Biochip for Rapid and Reliable Water Toxicity Measurements

2013 ◽  
Author(s):  
Fei Liu ◽  
Tingting Chen ◽  
Xudong Zhang ◽  
Fang Li ◽  
Ioana Voiculescu
Keyword(s):  
Shear Stress ◽  
Microfluidic Device ◽  
Cell Attachment ◽  
Good Health ◽  
Low Flow ◽  
Live Cells ◽  
Toxicity Tests ◽  
Bovine Aortic Endothelial Cell ◽  
Microfluidic Channels ◽  
Water Toxicity

Measuring water toxicity is a lengthy process, and rapid analytical methods are limited. A complementary approach is to measure water toxicity on live cells via electric cell-substrate impedance sensing (ECIS) using a field portable device. This paper presents a study of the longevity of bovine aortic endothelial cell (BAECs VEC Technologies, Rensselaer, NY) by integrating a microfluidic device onto the ECIS sensors. This microfluidic chamber with a network of tree-like perfusion microfluidic channels for cell media delivery to the culturing chamber was fabricated from a biocompatible polymer and tested for longevity studies. This perfusion microchannels were designed as a symmetric arbor with binary splitting to provide equal flow in all the perfusion channels. The microdimensions of the perfusion channels provide high flow resistance, thus carrying low flow rates for a given head pressure and generating low shear stress to the cells during the long-time cell attachment and proliferation period. With such a microfluidic device, cell media can be automatically and evenly perfused into the culturing chamber and no significant shear stress produced by media perfusion was observed. During the longevity study, the BAECs were able to survive in good health for longer than one month. Toxicity tests to study the BAECs responsiveness to health-threatening concentrations of ammonia using the microfluidic ECIS sensor will be also presented. Using impedance spectroscopy technique we demonstrated the BAECs can rapidly respond to ammonia concentrations between the military exposure guideline of 2mM and human lethal concentration of 55mM. The BAECs monolayer represent the most important component of a biosensor for testing water toxicity in the field. This research concluded that the BAECs could resist at least 34 days on the microfluidic chip and demonstrate high values of cell membrane impedance during long period of time.

A Sensitive Multiparametric Biosensor With Capabilities of Rapid Toxicity Detection of Drinking Water

2013 ◽  
Author(s):  
Fei Liu ◽  
Anis N. Nordin ◽  
Fang Li ◽  
Ioana Voiculescu
Keyword(s):  
Mammalian Cells ◽  
False Positive Rate ◽  
Impedance Measurement ◽  
Toxicity Tests ◽  
Microfluidic Channels ◽  
Impedance Sensing ◽  
Aortic Endothelial Cells ◽  
Water Toxicity ◽  
Sensing Platform ◽  
Positive Rate

Recently, there has been interest to develop biosensors based on live mammalian cells to monitor the toxicity of water. The cell viability after exposure to toxic water can be monitored by electric cell-substrate impedance sensing (ECIS) of the cell membrane. However, these impedance based toxicity sensors can only provide one single sensing endpoint (impedance measurement), and many toxicants cannot be detected at the concentration between Military Exposure Guideline levels and estimated Human Lethal Concentrations. The goal of this paper is to provide a rapid and sensitive sensing platform for long-term water toxicity detection. In this paper a novel multiparametric biosensor with integrated microfluidic channels for water toxicity detection is presented. Toxicity tests to study bovine aortic endothelial cells (BAECs) responsiveness to health-threatening concentrations of ammonia in de-ionized (DI) water will be presented. We demonstrated the BAECs can rapidly respond to ammonia concentrations between the military exposure guideline of 2mM and human lethal concentration of 55mM. The successful testing of water toxicity by simultaneous gravimetric and impedimetric measurements indicates that the multiparametric biosensor platform is able to perform rapid and sensitive detection of water toxicity and minimize the false-positive rate.

High-Sensitivity MEMS Resonant Biosensor for Monitoring Water Toxicity

2017 ◽  
Author(s):  
Kun-Lin Lee ◽  
Simon Ng ◽  
Fang Li ◽  
Ioana Voiculescu
Keyword(s):  
Resonant Frequency ◽  
Quartz Crystal ◽  
High Sensitivity ◽  
Live Cells ◽  
Toxicity Tests ◽  
Piezoelectric Resonator ◽  
Sensitivity Testing ◽  
Water Toxicity ◽  
Water Based ◽  
Trout Gill

This paper presents the use of a piezoelectric resonator, which can be applied to investigate live cells activity in water-based toxic solution. We perform toxicity tests using commercial quartz crystal microbalance (QCM). The QCM used in this research has the resonant frequency of 10 MHz and consists in an AT-cut crystal with gold electrodes on both sides. This QCM was transformed into a functional biosensor by integrating with polydimethylsiloxane (PDMS) culturing chambers. Rainbow trout gill epithelial cells (RTgill-W1) were cultured on the resonators as sensorial layer. The fluctuation of the resonant frequency, due to the change of cell morphology and adhesion, is an indicator of water toxicity. The shift of resonant frequency will provide information about the cells viability after exposure to toxicants. Experiment setup, fabrication process, and sensor sensitivity testing are addressed. The toxicity result shows distinct responses for different ammonia concentrations.

P–171 Automated oocyte and zygote denudation using a novel microfluidic device supervised by a computer vision algorithm

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
J Guerrer. Sánchez ◽  
Y Cabello ◽  
G Fernánde. Blanco ◽  
J Fidalgo ◽  
I Hernánde. Montilla ◽  
...  
Keyword(s):  
Computer Vision ◽  
Shear Stress ◽  
Microfluidic Device ◽  
False Negative ◽  
Fluid Motion ◽  
Cumulus Cells ◽  
Automated System ◽  
Microfluidic Channels ◽  
Dna Contamination ◽  
Metabolomics Analysis

Abstract Study question Is it possible to remove cumulus cells using a 16-well microfluidic device with automated flows to facilitate vitrification, ICSI, NI-PGT or non-invasive metabolomics analysis? Summary answer The designed automated system and protocol efficiently denude 16 samples simultaneously with a x10 lower shear stress than the manual process and without human intervention. What is known already Most processes involved in IVF such as insemination, washing, denudation, embryo culture and selection are still manually performed, labor-intensive and require highly skilled professionals. This leads to a significant variability in the clinical outcomes achieved by different embryologists and labs. The automation of these processes is a promising approach to reduce costs and improve the accessibility to assisted reproductive therapies. Although a simple procedure, standardization of cumulus oocyte complex (COCs) and zygotes denudation is key to facilitate ICSI, vitrification and to avoid DNA contamination for NI-embryo testing (PGT or metabolomics), while avoiding damage to the oocyte by excessive shear stress. Study design, size, duration A total of 160 cow COCs were used due to their size similarity with human COCs. Half were denuded 16–20 hours post-insemination and half pre-insemination for 5–10 minutes. COCs were classified as partially denuded if fertilization assessment, ICSI or vitrification was possible, and completely denuded if no cumulus cells remained. COCs controls were manually denuded (Stripper® capillary 145μm ID) to compare shear stress between procedures. This study was conducted during 2020 – 2021. Participants/materials, setting, methods We developed a customized microfluidic biochip that exerts a particular fluid motion while avoiding egg entrapment within microfluidic channels. The denudation efficacy was established by subjectively scoring images of bovine oocytes after generating a continuous “Push & Pull” fluid motion inside the biochip wells. A Computer Vision model was developed in parallel in order to optically assess denudation completion. The model used was a Pytorch implementation of Faster-RCNN with ImageNet pretrained weights Main results and the role of chance 96 bovine COCs were microfuidically handled post insemination achieving complete (56/96) or partial (40/96) removal of the cumulus cells on day 1, while for day 3 double denudation group, 89/96 (92.7%) were completely denuded while the rest remained partially denuded. In comparison, 80/80 (100%) of manually denuded cow COCs, achieved complete denudation (50% post-insemination group and 50% pre-insemination group). In addition, 48/64 (75%) cow COCs treated pre-insemination were partially denuded, enough to carry out ICSI after 5–10 min of treatment. The results here obtained indicate that media needs to flow through the device at a rate that can generate enough shear to strip off the cumulus-corona cells while avoiding emptying of the reservoirs containing the fertilization or culture medium. The shear stress of our design was calculated to be smaller than 4.4 Pa, about ten times lower than the one applied by the manual process (∼44Pa). The deep learning algorithm was tested on 20 unseen human oocytes on day 1, with 10 true positives 9 true negatives, and 1 false negative (95% accuracy). Limitations, reasons for caution The success of the denudation procedure was dependent on the design of the biochip wells and the microfluidic protocol used. The accuracy of our findings is still limited because of the difficulty in manufacturing prototype biochips. Wider implications of the findings: Complete denudation is key to avoid DNA contamination for NI-PGT or metabolomics analysis, while avoiding damage to the oocyte by excessive shear stress. Our device, which has the potential of scaling up and treat each oocyte individually, can improve automation and increase efficiency of current ART procedures Trial registration number NA

Naturally Produced Extracellular Matrix Is an Excellent Substrate for Canine Endothelial Cell Proliferation and Resistance to Shear Stress on PTFE Vascular Grafts

1997 ◽  
Vol 78 (05) ◽  
pp. 1392-1398 ◽  
Author(s):  
A Schneider ◽  
M Chandra ◽  
G Lazarovici ◽  
I Vlodavsky ◽  
G Merin ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Endothelial Cells ◽  
Shear Stress ◽  
Endothelial Cell ◽  
Cell Attachment ◽  
Thrombus Formation ◽  
Endothelial Cell Proliferation ◽  
Ptfe Graft ◽  
Vascular Prostheses ◽  
Endothelial Cell Attachment

SummaryPurpose: Successful development of a vascular prosthesis lined with endothelial cells (EC) may depend on the ability of the attached cells to resist shear forces after implantation. The present study was designed to investigate EC detachment from extracellular matrix (ECM) precoated vascular prostheses, caused by shear stress in vitro and to test the performance of these grafts in vivo. Methods: Bovine aortic endothelial cells were seeded inside untreated polytetrafluoro-ethylene (PTFE) vascular graft (10 X 0.6 cm), PTFE graft precoated with fibronectin (FN), or PTFE precoated with FN and a naturally produced ECM (106 cells/graft). Sixteen hours after seeding the medium was replaced and unattached cells counted. The strength of endothelial cell attachment was evaluated by subjecting the grafts to a physiologic shear stress of 15 dynes/cm2 for 1 h. The detached cells were collected and quantitated. PTFE or EC preseeded ECM coated grafts were implanted in the common carotid arteries of dogs. Results: While little or no differences were found in the extent of endothelial cell attachment to the various grafts (79%, 87% and 94% of the cells attached to PTFE, FN precoated PTFE, or FN+ECM precoated PTFE, respectively), the number of cells retained after a shear stress was significanly increased on ECM coated PTFE (20%, 54% and 85% on PTFE, FN coated PTFE, and FN+ECM coated PTFE, respectively, p <0.01). Implantation experiments in dogs revealed a significant increase in EC coverage and a reduced incidence of thrombus formation on ECM coated grafts that were seeded with autologous saphenous vein endothelial cells prior to implantation. Conclusion: ECM coating significantly increased the strength of endothelial cell attachment to vascular prostheses subjected to shear stress. The presence of adhesive macromolecules and potent endothelial cell growth promoting factors may render the ECM a promising substrate for vascular prostheses.

scholarly journals Studying dynamic stress effects on the behaviour of THP-1 cells by microfluidic channels

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Semra Zuhal Birol ◽  
Rana Fucucuoglu ◽  
Sertac Cadirci ◽  
Ayca Sayi-Yazgan ◽  
Levent Trabzon
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Vascular System ◽  
Circulatory System ◽  
Disease Process ◽  
Microfluidic Channels ◽  
Shear Stresses ◽  
Stress Effects ◽  
Adhesion Behavior ◽  
Cycling System

AbstractAtherosclerosis is a long-term disease process of the vascular system that is characterized by the formation of atherosclerotic plaques, which are inflammatory regions on medium and large-sized arteries. There are many factors contributing to plaque formation, such as changes in shear stress levels, rupture of endothelial cells, accumulation of lipids, and recruitment of leukocytes. Shear stress is one of the main factors that regulates the homeostasis of the circulatory system; therefore, sudden and chronic changes in shear stress may cause severe pathological conditions. In this study, microfluidic channels with cavitations were designed to mimic the shape of the atherosclerotic blood vessel, where the shear stress and pressure difference depend on design of the microchannels. Changes in the inflammatory-related molecules ICAM-1 and IL-8 were investigated in THP-1 cells in response to applied shear stresses in an continuous cycling system through microfluidic channels with periodic cavitations. ICAM-1 mRNA expression and IL-8 release were analyzed by qRT-PCR and ELISA, respectively. Additionally, the adhesion behavior of sheared THP-1 cells to endothelial cells was examined by fluorescence microscopy. The results showed that 15 Pa shear stress significantly increases expression of ICAM-1 gene and IL-8 release in THP-1 cells, whereas it decreases the adhesion between THP-1 cells and endothelial cells.

Shear stress induces eNOS mRNA expression and improves endothelium-dependent dilation in senescent soleus muscle feed arteries

2005 ◽  
Vol 98 (3) ◽  
pp. 940-946 ◽  
Author(s):  
Christopher R. Woodman ◽  
Elmer M. Price ◽  
M. Harold Laughlin
Keyword(s):  
Shear Stress ◽  
Mrna Expression ◽  
Soleus Muscle ◽  
Low Flow ◽  
No Production ◽  
Fischer 344 ◽  
Enos Mrna ◽  
Series Of Experiments ◽  
Endothelial Nitric Oxide ◽  
Feed Arteries

We tested the hypothesis that increased intraluminal shear stress induces endothelial nitric oxide (NO) synthase (eNOS) mRNA expression and improves endothelium-dependent dilation in senescent soleus muscle feed arteries (SFA) by increasing NO production. SFA were isolated from young (4 mo) and old (24 mo) male Fischer 344 rats and cannulated with two resistance-matched glass micropipettes. SFA were exposed to no flow (NF), low flow (LF), intermediate flow (IF), or high flow (HF) for 4 h. Mean intraluminal shear stress ranged from 0 to 82 dyn/cm2. At the end of the 4-h treatment period, eNOS mRNA expression was assessed in each SFA. eNOS mRNA expression was significantly lower in old NF SFA than in young NF SFA. In old SFA, eNOS mRNA expression was induced by IF (+154%) and HF (+136%), resulting in a level of expression that was not different from that of young SFA. In a separate series of experiments, SFA were pretreated with NF or HF for 4 h, and endothelial function was assessed by examining vasodilator responses to ACh. ACh-induced dilation was less in old NF SFA than young NF SFA. Pretreatment with HF improved ACh-induced dilation in old SFA such that the response was similar to that of young SFA. In the presence of Nω-nitro-l-arginine to inhibit NOS, ACh-induced dilation was inhibited in old HF SFA such that the response was no longer greater than that of old NF SFA. These results indicate that increased intraluminal shear stress induces eNOS mRNA expression and improves endothelium-dependent dilation in senescent SFA by increasing NO production.

Vasomotor responses in chronically hyperperfused and hypoperfused rat mesenteric arteries

1998 ◽  
Vol 274 (4) ◽  
pp. H1301-H1307 ◽  
Author(s):  
Fabrice Pourageaud ◽  
Jo G. R. De Mey
Keyword(s):  
Blood Flow ◽  
Shear Stress ◽  
Sodium Nitroprusside ◽  
Arginine Vasopressin ◽  
Side Branch ◽  
Mesenteric Arteries ◽  
Low Flow ◽  
Basal Diameter ◽  
Lower Shear ◽  
Altered Blood

We evaluated the reactivity of small arteries after remodeling induced by elevated or reduced blood flow. In 6-wk-old rats, every other first-order side branch of the superior mesenteric artery was ligated near the bifurcation of second-order branches. Four weeks after surgery, vessels that had been exposed to high flow (HF) or low flow (LF) were isolated and mounted in a pressure myograph at 100 mmHg and were compared with vessels from sham-operated rats (Sham). In HF: 1) basal lumen diameter was increased; 2) sensitivity to norepinephrine, arginine vasopressin, and perivascular nerve stimulation was not modified; 3) maximal constrictor responses (Δ diameter) to these stimuli and 125 mM K+ were increased; and 4) sensitivity and maximal dilator responses to sodium nitroprusside, acetylcholine, and flow were not modified. In LF: 1) basal diameter was reduced; 2) sensitivity to constrictor stimuli was not altered; 3) maximal responses to all vasoconstrictors except arginine vasopressin were reduced; and 4) sensitivity but not maximal dilator responses to sodium nitroprusside and acetylcholine was reduced. During acute flow-induced dilatations, lower shear stress was maintained in HF (48 ± 7 dyn/cm2) than in Sham (63 ± 10 dyn/cm2), but no shear stress regulation was observed in LF. These observations indicate that arterial structural responses to altered blood flow are accompanied by modified reactivity of the arterial smooth muscle, which entails changes in responsiveness to neurogenic and endothelium-dependent stimuli.

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