scholarly journals The fluid flow, containing flexible particles, in the channel of microfluidic devices

2018 ◽  
Vol 1058 ◽  
pp. 012052
Author(s):  
F.Kh. Tazyukov ◽  
E.R. Kutuzova ◽  
A.F. Tazyukova
Keyword(s):  
Fluid Flow ◽  
Microfluidic Devices

scholarly journals O23: CHARACTERISING PATIENT-DERIVED COLORECTAL CANCER TISSUE-ORIGINATED ORGANOIDAL SPHEROIDS FOR HIGH-THROUGHPUT MICROFLUIDIC APPLICATIONS

2021 ◽  
Vol 108 (Supplement_1) ◽  
Author(s):  
MI Khot ◽  
M Levenstein ◽  
R Coppo ◽  
J Kondo ◽  
M Inoue ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Fluid Flow ◽  
High Throughput ◽  
Microfluidic Devices ◽  
In Vitro Models ◽  
Fluorescent Imaging ◽  
Cancer Tissue ◽  
Cell Models

Abstract Introduction Three-dimensional (3D) cell models have gained reputation as better representations of in vivo cancers as compared to monolayered cultures. Recently, patient tumour tissue-derived organoids have advanced the scope of complex in vitro models, by allowing patient-specific tumour cultures to be generated for developing new medicines and patient-tailored treatments. Integrating 3D cell and organoid culturing into microfluidics, can streamline traditional protocols and allow complex and precise high-throughput experiments to be performed with ease. Method Patient-derived colorectal cancer tissue-originated organoidal spheroids (CTOS) cultures were acquired from Kyoto University, Japan. CTOS were cultured in Matrigel and stem-cell media. CTOS were treated with 5-fluorouracil and cytotoxicity evaluated via fluorescent imaging and ATP assay. CTOS were embedded, sectioned and subjected to H&E staining and immunofluorescence for ABCG2 and Ki67 proteins. HT29 colorectal cancer spheroids were produced on microfluidic devices using cell suspensions and subjected to 5-fluorouracil treatment via fluid flow. Cytotoxicity was evaluated through fluorescent imaging and LDH assay. Result 5-fluorouracil dose-dependent reduction in cell viability was observed in CTOS cultures (p<0.01). Colorectal CTOS cultures retained the histology, tissue architecture and protein expression of the colonic epithelial structure. Uniform 3D HT29 spheroids were generated in the microfluidic devices. 5-fluorouracil treatment of spheroids and cytotoxic analysis was achieved conveniently through fluid flow. Conclusion Patient-derived CTOS are better complex models of in vivo cancers than 3D cell models and can improve the clinical translation of novel treatments. Microfluidics can streamline high-throughput screening and reduce the practical difficulties of conventional organoid and 3D cell culturing. Take-home message Organoids are the most advanced in vitro models of clinical cancers. Microfluidics can streamline and improve traditional laboratory experiments.

THEORETICAL ANALYSES FOR LASER MACHINING MICROCHANNELS AND DEMONSTRATION OF THEIR USES IN MANUFACTURE OF A MICROFLUIDIC OPTICAL SWITCH

2006 ◽  
Vol 13 (06) ◽  
pp. 795-802 ◽  
Author(s):  
DANIEL LIM ◽  
ERNA GONDO SANTOSO ◽  
KIM MING TEH ◽  
STEPHEN WAN ◽  
H. Y. ZHENG
Keyword(s):  
Fluid Flow ◽  
Optical Switch ◽  
Low Cost ◽  
Microfluidic Devices ◽  
Cost Effective ◽  
Laser Machining ◽  
Machining Parameters ◽  
Flow Channels ◽  
Cost Effective Method ◽  
Theoretical Analyses

Silicon has been widely used to fabricate microfluidic devices due to the dominance of silicon microfabrication technologies available. In this paper, theoretical analyses are carried out to suggest suitable laser machining parameters to achieve required channel geometries. Based on the analyses, a low-power CO 2 laser was employed to create microchannels in Acrylic substrate for the use of manufacturing an optical bubble switch. The developed equations are found useful for selecting appropriate machining parameters. The ability to use a low-cost CO 2 laser to fabricate microchannels provides an alternative and cost-effective method for prototyping fluid flow channels, chambers and cavities in microfluidic lab chips.

Numerical Investigation of Heat Transfer in Rectangular Microchannels Under H2 Boundary Condition During Developing and Fully Developed Laminar Flow

2011 ◽  
Vol 134 (2) ◽  
Author(s):  
V. V. Dharaiya ◽  
S. G. Kandlikar
Keyword(s):  
Heat Transfer ◽  
Boundary Condition ◽  
Heat Flux ◽  
Fluid Flow ◽  
Microfluidic Devices ◽  
Transport Processes ◽  
Uniform Heat Flux ◽  
Data Set ◽  
Nusselt Numbers ◽  
Aspect Ratios

Study of fluid flow characteristics at microscale is gaining importance with shrinking device sizes. Better understanding of fluid flow and heat transfer in microchannels will have important implications in electronic chip cooling, heat exchangers, MEMS, and microfluidic devices. Due to short lengths employed in microchannels, entrance header effects can be significant and need to be investigated. In this work, three dimensional model of microchannels, with aspect ratios (α = a/b) ranging from 0.1 to 10, are numerically simulated using CFD software tool fluent. Heat transfer effects in the entrance region of microchannel are presented by plotting average Nusselt number as a function of nondimensional axial length x*. The numerical simulations with both circumferential and axial uniform heat flux (H2) boundary conditions are validated for existing data set for four wall heat flux case. Large numerical data sets are generated in this work for rectangular cross-sectional microchannels with heating on three walls, two opposing walls, one wall, and two adjacent walls under H2 boundary condition. This information can provide better understanding and insight into the transport processes in the microchannels. Although the results are seen as relevant in microscale applications, they are applicable to any sized channels. Based on the numerical results obtained for the whole range, generalized correlations for Nusselt numbers as a function of channel aspect ratio are presented for all the cases. The predicted correlations for Nusselt numbers can be very useful resource for the design and optimization of microchannel heat sinks and other microfluidic devices.

Flow Physics in Microchannels

2005 ◽  
Author(s):  
S. B. Pidugu ◽  
T. Bayraktar
Keyword(s):  
Fluid Flow ◽  
Pressure Drop ◽  
Microfluidic Devices ◽  
Control Methods ◽  
Flow Physics ◽  
Macro Scale ◽  
Inkjet Printers ◽  
Friction Measurements ◽  
Electrokinetic Flows

Even though microfluidic devices are slowly becoming commercial reality (e.g. Inkjet printers), the challenges in the design of microfluidic devices remain since not all aspects of fluid flow in microchannels have been fully understood yet. This paper presents an extensive review of studies on flow physics for both pressure-driven and electrokinetic flows in microchannels. The primary goal of the present paper is to provide a wide overview of findings on underlying principles of microflow physics. The issues discussed include the effect of pressure drop and friction measurements; mixing and flow control methods for microfluidic systems; and joule heating and viscous dissipation effects in microchannel flows. No agreement has been found among studies focusing on the characterization of friction factor/pressure drop for microflow systems. Further investigation requires understanding how entrance effects differ in the case of microflows when compared to macro scale flow. There is a clear need to investigate characteristics of non-Newtonian fluid flow in microchannels.

Vision-Based Real-Time Microflow-Rate Control System for Cell Analysis

2016 ◽  
Vol 28 (6) ◽  
pp. 854-861 ◽  
Author(s):  
Tadayoshi Aoyama ◽  
◽  
Amalka De Zoysa ◽  
Qingyi Gu ◽  
Takeshi Takaki ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Control System ◽  
Real Time ◽  
Flow Rate ◽  
Rate Control ◽  
Microfluidic Devices ◽  
Cell Analysis ◽  
Time Flow ◽  
On Chip ◽  
Flow Rate Control

[abstFig src='/00280006/09.jpg' width='300' text='Snapshots of particle sorting experiment using our system' ] On-chip cell analysis is an important issue for microtechnology research, and microfluidic devices are frequently used in on-chip cell analysis systems. One approach to controlling the fluid flow in microfluidic devices for cell analysis is to use a suitable pumps. However, it is difficult to control the actual flow-rate in a microfluidic device because of the difficulty in placing flow-rate sensors in the device. In this study, we developed a real-time flow-rate control system that uses syringe pumps and high-speed vision to measure the actual fluid flow in microfluidic devices. The developed flow-rate control system was verified through experiments on microparticle velocity control and microparticle sorting.

Optimal Architecture of Shack Hartmann Wave-Front Sensor for Microfluidic Applications

2006 ◽  
Author(s):  
M. J. Cyca ◽  
S. A. Spiewak
Keyword(s):  
Fluid Flow ◽  
Wave Front ◽  
Measurement Technique ◽  
Microelectromechanical Systems ◽  
Microfluidic Devices ◽  
Mapping Technique ◽  
Biomedical Devices ◽  
Temperature Mapping ◽  
Flow Monitoring ◽  
Heated Element

Means of measuring temperature and fluid flow in microelectromechanical systems (MEMS) continue to show limitations. This paper discusses the development of a noninvasive optical based temperature mapping technique for use in microsystems. The technique employs the Shack-Hartmann wave-front sensor (SHWFS), with documented accuracy in macroscale applications of ±0.7°C [1]. Microscale models indicate the potential to collect data with the same accuracy. With continued development, fluid flow monitoring by thermally seeding an element of fluid and using the SHWFS to detect the location of this heated element will be possible. This measurement technique can be applied to a variety of microfluidic devices, including biomedical devices, since the temperature "seed" can be small enough to prevent damage to sensitive biological systems.

Investigation of Automated Cell Manipulation in Optical Tweezers-Assisted Microfluidic Chamber Using Simulations

2011 ◽  
Author(s):  
Sagar Chowdhury ◽  
Petr Svec ◽  
Chenlu Wang ◽  
Kevin T. Seale ◽  
John P. Wikswo ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Optical Tweezers ◽  
High Precision ◽  
High Throughput ◽  
Microfluidic Devices ◽  
Cell Manipulation ◽  
Precise Control ◽  
Biological Objects ◽  
Microfluidic Chamber ◽  
Manipulation Process

Microfluidic devices are well suited for the study of biological objects because of their indirect nature of manipulation and high throughput. However, the cell manipulation process solely depends on the fluid flow and hence precise control is difficult to attain inside a microfluidic chamber. Utilizing optical tweezers as a complementary tool provides precise manipulation control. We have presented an automated cell manipulation approach using optical tweezers operating inside a microfluidic chamber. To test and demonstrate the effectiveness of the approach we have developed a physics-based simulator that is completely automated and allows high precision of manipulation.

scholarly journals Numerical Simulation of Separation of Circulating Tumor Cells from Blood Stream in Deterministic Lateral Displacement (DLD) Microfluidic Channel

2015 ◽  
Vol 32 (4) ◽  
pp. 463-471 ◽  
Author(s):  
F. Khodaee ◽  
S. Movahed ◽  
N. Fatouraee ◽  
F. Daneshmand
Keyword(s):  
Fluid Flow ◽  
Tumor Cells ◽  
Circulating Tumor Cells ◽  
Microfluidic Device ◽  
Flow Condition ◽  
Lateral Displacement ◽  
Microfluidic Devices ◽  
Blood Stream ◽  
Deterministic Lateral Displacement ◽  
Effective Design

AbstractDeterministic Lateral Displacement (DLD) microfluidic devices provide a reliable label-free separation method for detection of circulating tumor cells (CTCs) in blood samples based on their biophysical properties. In this paper, we proposed an effective design of the DLD microfluidic device for the CTC separation in the blood stream. A typical DLD array is designed and numerical simulations are performed to separate the CTC and leukocyte (white blood cells) in different fluid flow conditions. Fluid-Solid Interaction method is used to investigate the behaviour of these deformable cells in fluid flow. In this study, the effects of critical parameters affecting cell separation in the DLD microfluidic devices (e.g.flow condition, cell deformability, and stress) have been investigated. The obtained results show that unlike leukocytes, the CTC’s motion is independent of the flow condition and is laterally displaced even in higher Reynolds number. Larger cells (CTCs) cannot intercept the low-velocity fluid near the wall of the posts; thus, they move faster and become separated from leukocytes. To reduce the cellular stress during separation process, which causes increase of cell viability and more effective design of microfluidic device, the results obtained here may be used as a significant design parameter for the DLD fabrication.

scholarly journals Self-assembled artificial cilia

2009 ◽  
Vol 107 (5) ◽  
pp. 1844-1847 ◽  
Author(s):  
Mojca Vilfan ◽  
Anton Potočnik ◽  
Blaž Kavčič ◽  
Natan Osterman ◽  
Igor Poberaj ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Numerical Simulation ◽  
Reynolds Number ◽  
Fluid Flow ◽  
External Magnetic Field ◽  
Low Reynolds Number ◽  
Microfluidic Devices ◽  
Superparamagnetic Particles ◽  
Artificial Cilia ◽  
Biomimetic Cilia

Due to their small dimensions, microfluidic devices operate in the low Reynolds number regime. In this case, the hydrodynamics is governed by the viscosity rather than inertia and special elements have to be introduced into the system for mixing and pumping of fluids. Here we report on the realization of an effective pumping device that mimics a ciliated surface and imitates its motion to generate fluid flow. The artificial biomimetic cilia are constructed as long chains of spherical superparamagnetic particles, which self-assemble in an external magnetic field. Magnetic field is also used to actuate the cilia in a simple nonreciprocal manner, resulting in a fluid flow. We prove the concept by measuring the velocity of a cilia-pumped fluid as a function of height above the ciliated surface and investigate the influence of the beating asymmetry on the pumping performance. A numerical simulation was carried out that successfully reproduced the experimentally obtained data.

Dripping, Jetting, Drops, and Wetting: The Magic of Microfluidics

MRS Bulletin ◽  
2007 ◽  
Vol 32 (9) ◽  
pp. 702-708 ◽  
Author(s):  
A. S. Utada ◽  
L.-Y. Chu ◽  
A. Fernandez-Nieves ◽  
D. R. Link ◽  
C. Holtze ◽  
...  
Keyword(s):  
Fluid Flow ◽  
San Francisco ◽  
Food Additives ◽  
Microfluidic Devices ◽  
Research Society ◽  
Harvard University ◽  
New Materials ◽  
Double Emulsions ◽  
Materials Research ◽  
Control Fluid

The following article is based on the Symposium X presentation given by David A. Weitz (Harvard University) on April 11, 2007, at the Materials Research Society Spring Meeting in San Francisco. The article describes how simple microfluidic devices can be used to control fluid flow and produce a variety of new materials. Based on the concepts of coaxial flow and hydrodynamically focused flow, used alone or in various combinations, the devices can produce precisely controlled double emulsions (droplets within droplets) and even triple emulsions (double emulsions suspended in a third droplet). These structures, which can be created in a single microfluidic device, have various applications such as encapsulants for drugs, cosmetics, or food additives.

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