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.

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.

Development of Infrared Microscopy for Measuring Asperity Contact Temperatures

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
Julian Le Rouzic ◽  
Tom Reddyhoff
Keyword(s):  
Spatial Resolution ◽  
Heat Dissipation ◽  
Background Radiation ◽  
Rough Surfaces ◽  
Super Resolution ◽  
Research Area ◽  
Mapping Technique ◽  
Asperity Contact ◽  
Temperature Mapping ◽  
Current Limit

Surface temperature measurements within sliding contacts are useful since interfacial heat dissipation is closely linked to tribological behavior. One of the most powerful techniques for such measurements is in-contact temperature mapping whereby a sliding contact is located beneath an infrared microscope. In this approach, one of the specimens must be transparent to infrared and coated such that radiation components can be distinguished and isolated from background values. Despite its effectiveness, a number of practical constraints prevent this technique from being applied to rough surfaces—a research area where temperature maps could provide much needed two-dimension input data to inform mixed and boundary friction models. The research described in this paper is aimed at improving the infrared temperature mapping technique in terms of validity, robustness, and spatial resolution, so that measurements of rough surfaces contacts can be made. First, Planck's law is applied in order to validate the use of surface coating as a means of removing background radiation. Second, a refined method of calibration is put forward and tested, which negates the need for a soft aluminum coating and hence enables rough surfaces to be measured. Finally, the use of super-resolution algorithms is assessed in order extend spatial resolution beyond the current limit of 6 μm.

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.

FLUID-FLOW MONITORING BY A 4-D GEOELECTRICAL TECHNIQUES

2006 ◽  
Author(s):  
H. Mizunaga ◽  
T. Tanaka. K. Ushijima ◽  
N. Ikeda
Keyword(s):  
Fluid Flow ◽  
Flow Monitoring

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

Fluid flow monitoring of EOR process by electrical prospecting

1997 ◽  
Author(s):  
Keisuke Ushijima ◽  
Hideki Mizunaga ◽  
Toshiaki Tanaka ◽  
Kazuo Masuda
Keyword(s):  
Fluid Flow ◽  
Flow Monitoring ◽  
Electrical Prospecting

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.

Investigation of flow through P[NIPAM/MMA] copolymer coated glass capillary tubes, and glass copolymer adhesion improvements with hydrofluoric acid etching

2010 ◽  
Vol 3 (1) ◽  
Author(s):  
R. Wiegmann ◽  
Y. Zhang ◽  
A. Yarin
Keyword(s):  
Fluid Flow ◽  
Hydrofluoric Acid ◽  
Microelectromechanical Systems ◽  
Capillary Tube ◽  
Acid Etching ◽  
Glass Capillary ◽  
Polymer Adhesion ◽  
Flow Through ◽  
Copolymer Poly ◽  
The Stability

This study aims to display the retention of the thermo-responsive properties of the copolymer poly(N-isopropyl acrylamide-methyl methacrylate) [P(NIPAM/MMA)] when coated on the inner diameter of a glass capillary tube, and to prove the stability of the copolymer coating when subjected to pressure driven fluid flow. The study shows that the fluid flow through such a capillary tube follows Hagen-Poiseuille flow. Furthermore, this study examines methods of improving polymer adhesion to glass by hydrofluoric acid etching. Such a coated tube system is applicable in drug delivery, self cleaning tubes, and microelectromechanical systems (MEMS).

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