Thematische Bibliographien / Closed microfluidic system

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Auswahl der wissenschaftlichen Literatur zum Thema „Closed microfluidic system“

Autor: Grafiati

Veröffentlicht am 18. Mai 2024

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Zeitschriftenartikel zum Thema "Closed microfluidic system"

Debski, Pawel, Karolina Sklodowska, Jacek Michalski, Piotr Korczyk, Miroslaw Dolata und Slawomir Jakiela. „Continuous Recirculation of Microdroplets in a Closed Loop Tailored for Screening of Bacteria Cultures“. Micromachines 9, Nr. 9 (17.09.2018): 469. http://dx.doi.org/10.3390/mi9090469.

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Emerging microfluidic technology has introduced new precision controls over reaction conditions. Owing to the small amount of reagents, microfluidics significantly lowers the cost of carrying a single reaction. Moreover, in two-phase systems, each part of a dispersed fluid can be treated as an independent chemical reactor with a volume from femtoliters to microliters, increasing the throughput. In this work, we propose a microfluidic device that provides continuous recirculation of droplets in a closed loop, maintaining low consumption of oil phase, no cross-contamination, stabilized temperature, a constant condition of gas exchange, dynamic feedback control on droplet volume, and a real-time optical characterization of bacterial growth in a droplet. The channels (tubing) and junction cubes are made of Teflon fluorinated ethylene propylene (FEP) to ensure non-wetting conditions and to prevent the formation of biofilm, which is particularly crucial for biological experiments. We show the design and operation of a novel microfluidic loop with the circular motion of microdroplet reactors monitored with optical sensors and precision temperature controls. We have employed the proposed system for long term monitoring of bacterial growth during the antibiotic chloramphenicol treatment. The proposed system can find applications in a broad field of biomedical diagnostics and therapy.

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Steege, Tobias, Mathias Busek, Stefan Grünzner, Andrés Fabían Lasagni und Frank Sonntag. „Closed-loop control system for well-defined oxygen supply in micro-physiological systems“. Current Directions in Biomedical Engineering 3, Nr. 2 (07.09.2017): 363–66. http://dx.doi.org/10.1515/cdbme-2017-0075.

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AbstractTo improve cell vitality, sufficient oxygen supply is an important factor. A deficiency in oxygen is called Hypoxia and can influence for example tumor growth or inflammatory processes. Hypoxia assays are usually performed with the help of animal or static human cell culture models. The main disadvantage of these methods is that the results are hardly transferable to the human physiology. Microfluidic 3D cell cultivation systems for perfused hypoxia assays may overcome this issue since they can mimic the in-vivo situation in the human body much better. Such a Hypoxia-on-a-Chip system was recently developed. The chip system consists of several individually laser-structured layers which are bonded using a hot press or chemical treatment. Oxygen sensing spots are integrated into the system which can be monitored continuously with an optical sensor by means of fluorescence lifetime detection.Hereby presented is the developed hard- and software requiered to control the oxygen content within this microfluidic system. This system forms a closed-loop control system which is parameterized and evaluated.

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Wang, Ningquan, Ruxiu Liu, Norh Asmare, Chia-Heng Chu, Ozgun Civelekoglu und A. Fatih Sarioglu. „Closed-loop feedback control of microfluidic cell manipulation via deep-learning integrated sensor networks“. Lab on a Chip 21, Nr. 10 (2021): 1916–28. http://dx.doi.org/10.1039/d1lc00076d.

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Loutherback, K., P. A. Bulur und A. Dietz. „Process Development and Manufacturing: CLOSED MICROFLUIDIC SYSTEM FOR MANUFACTURING DENDRITIC CELL THERAPIES“. Cytotherapy 24, Nr. 5 (Mai 2022): S171—S172. http://dx.doi.org/10.1016/s1465-3249(22)00448-0.

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Fu, Hai, Wen Zeng, Songjing Li und Shuai Yuan. „Electrical-detection droplet microfluidic closed-loop control system for precise droplet production“. Sensors and Actuators A: Physical 267 (November 2017): 142–49. http://dx.doi.org/10.1016/j.sna.2017.09.043.

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Hansen, J. S., J. T. Ottesen und A. Lemarchand. „Molecular dynamics simulations of valveless pumping in a closed microfluidic tube-system“. Molecular Simulation 31, Nr. 14-15 (Dezember 2005): 963–69. http://dx.doi.org/10.1080/08927020500419297.

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Yafia, Mohamed, Amir M. Foudeh, Maryam Tabrizian und Homayoun Najjaran. „Low-Cost Graphene-Based Digital Microfluidic System“. Micromachines 11, Nr. 9 (22.09.2020): 880. http://dx.doi.org/10.3390/mi11090880.

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In this work, the laser-scribing technique was used as a low-cost, rapid and facile method for fabricating digital microfluidic (DMF) systems. Laser-scribed graphene (LSG) electrodes are directly synthesized on flexible substrates to pattern the DMF electrode arrays. This facilitates the DMF electrodes’ fabrication process by eliminating many microfabrication steps. An electrowetting test was performed to investigate the effectiveness of the LSG DMF electrodes in changing the contact angles of droplets. Different DMF operations were successfully performed using the proposed LSG DMF chips in both open and closed DMF systems. The quality and output resolution were examined to assess the performance of such patterned electrodes in the DMF systems. To verify the efficacy of the LSG DMF chips, a one-step direct assay for the detection of Legionellapneumophila deoxyribonucleic acid (DNA) was performed on the chip without the need for any washing step. The high specificity in distinguishing a single-nucleotide mismatch was achieved by detecting target DNA concentrations as low as 1 nM. Our findings suggest that the proposed rapid and easy fabrication method for LSG DMF electrodes offers a great platform for low-cost and easily accessible point-of-care diagnostic devices.

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Lim, Hyunjung, Jae Young Kim, Seunghee Choo, Changseok Lee, Byoung Joe Han, Chae Seung Lim und Jeonghun Nam. „Separation and Washing of Candida Cells from White Blood Cells Using Viscoelastic Microfluidics“. Micromachines 14, Nr. 4 (23.03.2023): 712. http://dx.doi.org/10.3390/mi14040712.

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An early and accurate diagnosis of Candida albicans is critical for the rapid antifungal treatment of candidemia, a mortal bloodstream infection. This study demonstrates viscoelastic microfluidic techniques for continuous separation, concentration, and subsequent washing of Candida cells in the blood. The total sample preparation system contains two-step microfluidic devices: a closed-loop separation and concentration device and a co-flow cell-washing device. To determine the flow conditions of the closed-loop device, such as the flow rate factor, a mixture of 4 and 13 μm particles was used. Candida cells were successfully separated from the white blood cells (WBCs) and concentrated by 74.6-fold in the sample reservoir of the closed-loop system at 800 μL/min with a flow rate factor of 3.3. In addition, the collected Candida cells were washed with washing buffer (deionized water) in the microchannels with an aspect ratio of 2 at a total flow rate of 100 μL/min. Finally, Candida cells at extremely low concentrations (Ct > 35) became detectable after the removal of WBCs, the additional buffer solution in the closed-loop system (Ct = 30.3 ± 1.3), and further removal of blood lysate and washing (Ct = 23.3 ± 1.6).

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Jang, Kihoon, Yan Xu, Yo Tanaka, Kae Sato, Kazuma Mawatari, Tomohiro Konno, Kazuhiko Ishihara und Takehiko Kitamori. „Single-cell attachment and culture method using a photochemical reaction in a closed microfluidic system“. Biomicrofluidics 4, Nr. 3 (September 2010): 032208. http://dx.doi.org/10.1063/1.3494287.

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Dissertationen zum Thema "Closed microfluidic system"

Watel, Quentin. „Conception et réalisation de structures textiles microfluidiques pour application médicale de criblage d’organoïdes à haut débit“. Electronic Thesis or Diss., Centrale Lille Institut, 2023. http://www.theses.fr/2023CLIL0035.

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Pour réduire les coûts liés à la médecine de précision, le projet ANR DROMOS vise à développer une plateforme d’analyse pour réaliser des tests sur des cellules en grand nombre en s’appuyant sur les avantages de la microfluidique et des technologies textiles. Cette nouvelle plateforme est réalisée à l’aide d’une structure tissée et imprégnée dans une matrice transparente. Différents fils composent cette structure tissée, tels que des fils de renfort et des monofilaments dont l’extraction permet la création de canaux microfluidiques.Les limites de la mise en œuvre de cette structure composite sont étudiées pour une matrice non-renforcée selon la nature, le diamètre et la longueur d’enchâssement du monofilament sacrificiel. Avec cette méthode, des canaux de 500 μm de diamètre et de 200 mm de long peuvent être produits dans une matrice PDMS. Ensuite, différentes structures tissées intégrant le monofilament sacrificiel sont conçues et produites avant d’être imprégnées dans une matrice élastomère pour former un matériau composite. Après le retrait mécanique du matériau sacrificiel, la puce textile microfluidique obtenue est étanche. Il apparait que le nombre de fils qui lient le monofilament sacrificiel au tissu est un paramètre fondamental dans la conception de systèmes microfluidiques textiles, qui influence à la fois la visibilité du canal microfluidique et le retrait du matériau sacrificiel de la matrice renforcée. Enfin, pour améliorer la visibilité du canal microfluidique dans les structures tissées, un fil élastomère àbase de PDMS est développé et inséré dans un renfort tissé pour réaliser le liage du monofilament sacrificiel. Pour produire ce fil élastomère, un procédé de mise en forme par filage innovant a été mis en place, qui permet une production continue sur plusieurs dizaines de mètres. Les propriétés morphologiques et mécaniques du filament élastomère sont étudiées selon différents paramètres de production. La puce textile microfluidique obtenue avec ce renfort tissé est ainsi un matériau composite complètement transparent au niveau du canal microfluidique
To reduce the costs associated with precision medicine, the ANR DROMOS project aims to develop an analysis platform for carrying out tests on large numbers of cells, drawing on the advantages of microfluidics and textile technologies. This new platform is based on a woven structure impregnated in a transparent matrix. This woven structure is made up of various yarns, such as reinforcing yarns and monofilaments, which can be extracted to create microfluidic channels. The implementation limits of this composite structure are studied for an unreinforced matrix, depending on the nature, diameter and embedding length of the sacrificial monofilament. Using this method, channels with a diameter of 500 μm and a length of 200 mm can be produced in a PDMS matrix. Different woven structures embedding the sacrificial monofilament are then designed and produced before being impregnated in an elastomer matrix to form a composite material. Once the sacrificial material has been mechanically removed, the resulting microfluidic textile chip is watertight. It appears that the number of threads that bind the sacrificial monofilament to the fabric is a fundamental parameter in the design of textile microfluidic systems, influencing both the visibility of the microfluidic channel and the removal of the sacrificial material from the reinforced matrix. Finally, to improve the visibility of the microfluidic channel in woven structures, an elastomeric PDMS filament is developed and inserted into a woven reinforcement to bond the sacrificial monofilament. To produce this elastomeric filament, an innovative spinning process has been used. It enables continuous production over several tens of metres. The morphological and mechanical properties of the elastomeric filament are being studied according to different production parameters. The microfluidic textile chip obtained with this woven reinforcement is a composite material that is completely transparent in the microfluidic channel

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Lai, Chiu-Chi, und 賴秋吉. „Development of a Closed Loop High-Throughput Microfluidic PCR Chip and System“. Thesis, 2006. http://ndltd.ncl.edu.tw/handle/13412075722599016560.

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碩士
國立臺灣大學
生物產業機電工程學研究所
95
This research has developed a novel disposable closed-loop PCR chip which allows non-restricted number of thermal cycles on a small footprint. The fluid in the microchannel of the PCR chip is driven by mechanically compressing the microchannel using wheels pressing on the channel in only one direction to precisely control the flow to loop through three temperature zones. An automatic driving mechanism is also developed to achieve high throughput by driving multiple chips at the same time on a single thermal platform. The PCR chip is made by bonding a PDMS top layer to a glass substrate. The PDMS top layer is casted on a PMMA mold. The channel pattern on the mold is machined on a CNC machine then furbished by hand. The PDMS cover is then treated by O2 plasma and bond to the glass substrate. The microchannel is 300 μm wide, 100 μm high, with a total loop length of 282.24 mm to contain about 13.1 μl of fluid when full. Fluid to be processed is simply dropped onto a well of the I/O port and then taken into the channel loop automatically by the driving mechanism. When the PCR process completes, the fluid is again released through the same port. Simultaneous PCR amplification results have been successfully demonstrated on two chips. The reported PCR chip is the first flow-type PCR chip that could fully prevent cross contamination within the microchannel.

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Buchteile zum Thema "Closed microfluidic system"

Bruus, Henrik. „Complex Flow Patterns“. In Theoretical Microfluidics, 231–54. Oxford University PressOxford, 1997. http://dx.doi.org/10.1093/oso/9780199235087.003.0014.

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Abstract Viscous forces dominate in microfluidics and tend to favor laminar flow at the expense of turbulence. Most laminar flow patterns are simple, and in the case of creeping flow they even closely follow the geometry of the enclosing channel. Nevertheless, it is possible by careful design to create complex flow patterns in microfluidic lab-on-a-chip systems. In this chapter we will study two examples of such an increasing level of complexity in microflows.

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Deng, Kaiwen, Chunyu Chang, Jiansheng Ding, Zhiqiang Jia, Dongping Wang, Shurong Wang und Hanbin Ma. „A Digital Microfluidics System with Closed-Loop Feedback Droplet Sensing“. In Advances in Transdisciplinary Engineering. IOS Press, 2024. http://dx.doi.org/10.3233/atde231140.

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In this paper, we present a digital microfluidics (DMF) system with closed-loop feedback droplet sensing. The system is capable of controlling the movement of droplets and detecting their positions in real time, and is compatible with different numbers of DMF electrodes. The detection of the droplet position is realized by impedance sensing. When an electrode failure occurs, the system automatically performs path planning to move the droplet successfully. Besides, we designed a voltage control unit (5V DC/AC to 80V DC/AC) to realize the voltage control for different droplets. The experimental results show that the droplet position detection time is about 2 ms, and the detection accuracy reaches 100% at 100 times. With the help of the droplet sensing system, even there’s an ineffective electrode in the origin path, the droplet was able to move to the target electrode by the replanned path. The system is expected to play an important role in many biochemical experiments due to its automation and reliability.

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Buranda, Tione, und Larry A. Sklar. „Flow Cytometry, Beads, and Microchannels“. In Flow Cytometry for Biotechnology. Oxford University Press, 2005. http://dx.doi.org/10.1093/oso/9780195183146.003.0010.

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Microfluidic devices generally consume microliter to submicroliter volumes of sample and are thus well suited for use when the required reagents are scarce or expensive. Because microfluidic devices operate in a regime in which small Reynolds numbers govern the delivery of fluid samples, reagent mixing and subsequent reactivity has been a severe limiting factor in their applicability. The inclusion of packed beads in the microfluidic device repertoire has several advantages: molecular assemblies for the assay are created outside the channel on beads and characterized with flow cytometry, uniform populations of beads may be assured through rapid cytometric sorting, beads present a larger surface area for the display of receptors than flat surfaces, rapid mixing in the microcolumn is achieved because the distance that must be covered by diffusion is limited to the (≤1-μm) interstitial space between the closely packed receptorbearing beads, and analytes are captured in a flow-through format and, as such, each bead can act as a local concentrator of analytes. Progress in the combined use of beads and microfluidic devices has been limited by the ability to pack beads at specific sections of microfluidic devices. A subsequent challenge associated with the packed microcolumns of beads is the substantial pressure drop that affects the fluid flow velocity. However, some of these challenges have been overcome in the design of simple model systems that have potential applications in DNA analysis, chromatography, and immunoassays. It is the intent of this chapter to examine the recent emergence of small-volume heterogeneous immunoassays, using beads trapped in microchannels, while excluding other closely related applications such as capillary electrophoresis and flow injection–based approaches. Of necessity, the authors’ interests and availability of information pertinent to the specific discussions presented below impose additional restrictions. To date, there are only a handful of applications that combine packed beads and microfluidic devices, and even fewer that make the overt connection between flow cytometry–based assays and beads. Harrison and coworkers have provided one of the earliest conceptual demonstrations of the capability to incorporate packed beads in microfluidic devices for analytical purposes.

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Bose, Goutam Kumar, Pritam Ghosh und Debashis Pal. „Analytical and Numerical Modelling of Liquid Penetration in a Closed Capillary“. In Process Analysis, Design, and Intensification in Microfluidics and Chemical Engineering, 114–35. IGI Global, 2019. http://dx.doi.org/10.4018/978-1-5225-7138-4.ch004.

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The chapter explores the dynamics of liquid penetration in a closed end vertical capillary. This model is very important for impedance spectroscopy methodology where oxidized porous silicon provides an in vitro medium, and one important criteria of this methodology is the liquid penetration depth inside the silicon pores as the impedance is greatly affected by this penetration depth. This problem is also important in order to understand how the presence of entrapped air inside a micro pore can influence the dynamics of capillary flow. For this purpose, the model is studied both analytically and numerically. In this study, different pore size (500 nm and 2 µm diameter) with equal pore depth (~10 µm) have been used. Finally, the analytical solution is compared with the numerical results. In addition, the linearization of the system is also investigated and found the critical viscosity of which demarcates the over-damped and under-damped regimes. Further, this study is extended by incorporating the dynamic contact angle effects on the meniscus dynamics.

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Konferenzberichte zum Thema "Closed microfluidic system"

Edwards, Maegan, und Rodward L. Hewlin. „A Computational Model for Analyisis of Field Force and Particle Dynamics in a Ferro-Magnetic Microfluidic System“. In ASME 2022 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/imece2022-95690.

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Abstract This paper presents the development of a computational model for analyzing the magnetic field, particle dynamics, and capture efficiency of magnetic and non-magnetic microparticles in a ferro-magnetic microfluidic system. This computational model demonstrates a proof-of-concept of a method for greatly enhancing magnetic bio-separation in microfluidic systems using an array of conductive elements arranged in quadrature. In contrast to previous works, our approach theoretically uses a microfluidic device with an electronic chip platform consisting of integrated copper electrodes that carry currents to generate programmable magnetic field gradients locally. In practice, alternating currents would be applied to the electrodes in quadrature to create a periodic magnetic field pattern that travels along the length of the microchannel. This work is a phase 1 study that analyzes particle dynamics in a static magnetic field. The model, which is described in more detail in the methods section, combines a Eulerian-Lagrangian and two-way particle-fluid coupling CFD analysis with closed-form magnetic field analysis that be used to predict magnetic separation considering dominant magnetic and hydrodynamic forces similar to our previous work in magnetic drug targeting. The result of this analysis show that the proposed magnetic capture configuration provides substantially enhanced particle capture efficiency relative to conventional systems.

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Martin, Heather, Miguel Murran, Rachael L’Orsa und Homayoun Najjaran. „Experimental Technique for Sensing Droplet Position in Digital Microfluidic Systems Using Capacitance Measurement“. In ASME 2010 International Mechanical Engineering Congress and Exposition. ASMEDC, 2010. http://dx.doi.org/10.1115/imece2010-39278.

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Capacitance measurement has been identified as an effective technique for droplet position sensing in digital microfluidic systems mainly due to its non-intrusive nature. In essence, this technique relies on the correlation between the capacitance of two top-bottom electrodes with the amount of droplet overlap on the electrode. This paper describes an experimental setup used to gather capacitance data from a set of electrodes with varying droplet overlap to determine the droplet position. A prototype closed digital microfluidic (DMF) system consisting of an array of electrodes in the form of a 2 × 2 matrix was fabricated. A circular droplet was positioned on the DMF system, and capacitance measurements for each of the four electrodes were taken using a fast data acquisition device. A sufficiently accurate approximation of the droplet position was made using the four capacitance measurements. The paper presents the experimental results and also discusses the sources of error, viability of the experimental setup and manufacturing procedure for use in the development of capacitance measurement droplet position sensing techniques.

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Zeng, Wen, Hai Fu und Songjing Li. „Closed-Loop Pressure Feedback Control of a Pressure-Driven Microdroplet Generator“. In 9th FPNI Ph.D. Symposium on Fluid Power. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/fpni2016-1524.

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To predict the size of droplets formed by pressure-driven flows, the droplet size as a nonlinear function of the pressure ratio is measured experimentally. The mathematical model of the pressure-driven microfluidic device is established, and by varying the volume of a container, comparative and quantitative measurements of the response speed and control accuracy of pressure-driven flows are presented. In particular, a closed-loop control system with feedback of the driven pressure is demonstrated, and the deviation between the measured and the predicted value of the driven pressure can be eliminated by using a PI controller. As a result, by accurately controlling the driven pressure of pressure-driven flows, monodisperse droplets with a desired size can be formed for pressure-driven microdroplet generators.

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Marschner, Uwe, Anthony Beck, Philipp Mehner, Georgi Paschew, Andreas Voigt und Andreas Richter. „Analogies Between Stimuli-Responsive (Smart) Hydrogel-Based Microfluidic Valves and Electronic Transistors“. In ASME 2022 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/smasis2022-91225.

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Abstract Stimuli-sensitive or responsive (smart) hydrogels, or chemofluidic transistors, are the base of the key control elements of smart chemomechanical valves. These valves have an outstanding potential for miniaturized, integrated sensor and actuator systems in many application areas and especially for lab-on-chip technology. Due to the multifaceted design parameters the design and realization of hydrogel-based systems are exceptionally complex and demanding. In this work we compare two types of stimuli-sensitive hydrogel-based valves with two types of electronic transistors and analyze analogies. As a result, the membrane isolated chemical volume phase transition Transistors (MIS-CVPT’s) exhibit a behavior with various analogies to electrical Field Effect Transistors (FET’s). The FET device embodies a voltage-controlled channel resistor, which is related to the chemically controlled fluidic channel of the MIS-CVPT. Chemical volume phase transition transistors (CVPT’s) on the other hand show in part similarities both to the bipolar transistor (BJT) and the MOSFET. The analogies allow a closed description of a microfluidic system by equivalent circuits and an efficient behavioral simulation by sophisticated circuit simulators. Several chemofluidic circuits, as a microfluidic oscillator, a NAND gate and an Analog/Digital Converter (ADC) and their behavioral simulation will be presented. The applied lab-on-a-chip (LoC) predictive simulation-based design concept is very helpful as it saves many practical experiments and leads to optimized components.

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Peysepar, Mahyar, Mohammad Behshad Shafii, Ramin Rasoulian, Hosein Jamalifar und Mohammad Reza Fazeli. „Use of the Freely-Swimming, Serratia Marcescens Bacteria to Enhance Mixing in Microfluidic Systems“. In ASME 2009 International Mechanical Engineering Congress and Exposition. ASMEDC, 2009. http://dx.doi.org/10.1115/imece2009-11469.

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Mixing has become a challenge in micro-fluidic systems because of the low Reynolds number in micro-channels. The method which is implemented in this paper is to use freely-swimming bacteria to enhance the mixing process. Accordingly, the Serratia marcescens bacteria were used for this matter. The mixing performance of the system is quantified by measuring the diffusion rate of Rhodamine B in a particular section of a channel connected to a chamber with varying Rhodamine B concentration. The concentration of Rhodamine B was measured using the Laser Induced Fluorescence (LIF) technique. The channel is in the form of a pipe and is closed on the extending side. In this paper, it is demonstrated that the corresponding diffusion coefficient can be augmented by bacterial participation and that this augmentation can be continued for several hours, depending on the environmental conditions. Additionally, it is shown that the mixing process reacts in response to modifications to the chemical environment of the system, which in turn affect the metabolic activity of the bacteria. Also, a 30 mM glucose buffer was used to show the impact of food on the performance of the bacterial system. It is thus shown that the existence of glucose increases the mixing ability of bacteria.

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Zhou, Xiaoming, Xin Liang, Zhiquan Shu, Pingan Du und Dayong Gao. „Numerical Investigation of a Novel Microfluidic System and its Application in Achieving Ultra-Fast Cooling/Warming Rates for Cell Vitrification Cryopreservation“. In ASME 2013 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/sbc2013-14077.

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Background: During conventional cryopreservation, cells are often damaged by ice formation. An alternative approach is to use ultra-rapid cooling rates to achieve vitrification of cell suspension. A variety of systems and methods have been developed, e.g. open pulled straws (OPS), closed pulled straws (CPS), cryo-loop and micro-droplets, by which cooling/warming rates up to 104∼105 °C/min can be achieved[1]. Although these methods have been well used in some areas, they are still far from perfect because (1) the cooling/warming rates are still not fast enough and thus high-concentration cryoprotectants should be used; (2) the sample size is often seriously limited.

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Yan, Deguang, Chun Yang, Nam-Trung Nguyen und Xiaoyang Huang. „Measurement of Transient Electrokinetic Flow in Microchannels Using Micro-PIV Technique“. In ASME 4th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2006. http://dx.doi.org/10.1115/icnmm2006-96071.

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Measurement of the steady-state electroosmotic velocity distributions in microchannels has been reported in the literature. Characterizing time-dependent electrokinetic flows is of importance to the development of microfluidic devices such as rapid capillary electrophoretic separation systems, AC pumps, novel micromixers etc. In this paper, we report a novel technique for studying and quantifying the transient electrokinetic flow phenomena in microchannels using the micro-PIV system with an ordinary PIV CCD camera. This is achieved by synchronizing different trigger signals for the laser, CCD camera, and custom high-voltage switch. Using the transient micro-PIV technique, we further propose a method to determine the electrophoretic component in the particle velocity and the zeta potential of the channel wall. Then the time evolution of the full-field, electroosmotic velocity distributions in both open- and closed-end rectangular microchannels is obtained from the micro-PIV measurement data. Using the slip velocity approach and the measured channel zeta potential, the theoretical predictions of the transient electroosmotic flow in the open- and closed-end microchannels are obtained, and they are found in good agreement with the experimental results.

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Li, Kebin, Keith Morton, Matthew Shiu, Karine Turcotte, Luke Lukic, Gaetan Veilleux, Lucas Poncelet und Teodor Veres. „Normally Closed Microfluidic Valves with Microstructured Valve Seats: A Strategy for Industrial Manufacturing of Thermoplastic Microfluidics with Microvalves“. In 2020 IEEE 33rd International Conference on Micro Electro Mechanical Systems (MEMS). IEEE, 2020. http://dx.doi.org/10.1109/mems46641.2020.9056136.

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Alsharhan, Abdullah T., Anthony J. Stair, Ryan R. Utz, Andrew C. Lamont, Michael A. Restaino, Ruben Acevedo und Ryan D. Sochol. „A 3D Nanoprinted Normally Closed Microfluidic Transistor“. In 2020 IEEE 33rd International Conference on Micro Electro Mechanical Systems (MEMS). IEEE, 2020. http://dx.doi.org/10.1109/mems46641.2020.9056155.

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Gómez, Juan R., und Juan P. Escandón. „Combined Magnetohydrodynamic/Pressure Driven Flow of Multi-Layer Pseudoplastic Fluids Through a Parallel Flat Plates Microchannel“. In ASME 2018 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/imece2018-86676.

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With the advance of microfluidic platforms and due to the need to solve different implications that still exist on the transport of electrically conducting fluids, the analysis on strategies in micropumps that involve a simplicity in its structure, absence of mechanical moving parts, flow reversibility and low power requirement is current. Therefore, the present investigation contributes with the analysis of the combined magnetohydrodynamic/pressure driven flow of multilayer immiscible fluids in a microchannel formed by two parallel flat plates. The mathematical model is based in a steady fully developed flow and the pumped fluids follow the power law model to describe the pseudoplastic fluids rheology, while magnetic effects on the flow are given from the Lorentz forces. The velocity profiles and flow rate are obtained in the limit of small Hartmann numbers by solving analytically a closed system of ordinary differential equations, together to the corresponding boundary conditions at the solid-liquid interfaces in the channel walls and at the liquid-liquid interfaces between the fluid layers. The results show that the flow field is controlled by the dimensionless parameters that arise from the mathematical modeling being a parameter that indicates the competition between pressure to the magnetic forces, magnetic parameters related to Hartmann numbers, viscosities ratios between the fluids, flow behavior indexes and the dimensionless position of the liquid-liquid interfaces.

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