Littérature scientifique sur le sujet « Microfluidic processes »
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Articles de revues sur le sujet "Microfluidic processes"
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Babikian, Sarkis, Brian Soriano, G. P. Li et Mark Bachman. « Laminate Materials for Microfluidic PCBs ». International Symposium on Microelectronics 2012, no 1 (1 janvier 2012) : 000162–68. http://dx.doi.org/10.4071/isom-2012-ta54.
Texte intégralRésumé :
The printed circuit board (PCB) is a very attractive platform to produce highly integrated highly functional microfluidic devices. We have investigated laminate materials and developed novel fabrication processes to realize low cost and scalable to manufacturing integrated microfluidics on PCBs. In this paper we describe our vision to integrate functional components with microfluidic channels. We also report on the use of Ethylene Vinyl Acetate (EVA) as a laminate for microfluidics. The material was characterized for microfluidic applications and compared with our previously reported laminates: 1002F and Polyurethane.
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Bianchi, Jhonatan Rafael de Oliveira, Lucimara Gaziola de la Torre et Ana Leticia Rodrigues Costa. « Droplet-Based Microfluidics as a Platform to Design Food-Grade Delivery Systems Based on the Entrapped Compound Type ». Foods 12, no 18 (9 septembre 2023) : 3385. http://dx.doi.org/10.3390/foods12183385.
Texte intégralRésumé :
Microfluidic technology has emerged as a powerful tool for several applications, including chemistry, physics, biology, and engineering. Due to the laminar regime, droplet-based microfluidics enable the development of diverse delivery systems based on food-grade emulsions, such as multiple emulsions, microgels, microcapsules, solid lipid microparticles, and giant liposomes. Additionally, by precisely manipulating fluids on the low-energy-demand micrometer scale, it becomes possible to control the size, shape, and dispersity of generated droplets, which makes microfluidic emulsification an excellent approach for tailoring delivery system properties based on the nature of the entrapped compounds. Thus, this review points out the most current advances in droplet-based microfluidic processes, which successfully use food-grade emulsions to develop simple and complex delivery systems. In this context, we summarized the principles of droplet-based microfluidics, introducing the most common microdevice geometries, the materials used in the manufacture, and the forces involved in the different droplet-generation processes into the microchannels. Subsequently, the encapsulated compound type, classified as lipophilic or hydrophilic functional compounds, was used as a starting point to present current advances in delivery systems using food-grade emulsions and their assembly using microfluidic technologies. Finally, we discuss the limitations and perspectives of scale-up in droplet-based microfluidic approaches, including the challenges that have limited the transition of microfluidic processes from the lab-scale to the industrial-scale.
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Alexandre-Franco, María F., Rahmani Kouider, Raúl Kassir Al-Karany, Eduardo M. Cuerda-Correa et Awf Al-Kassir. « Recent Advances in Polymer Science and Fabrication Processes for Enhanced Microfluidic Applications : An Overview ». Micromachines 15, no 9 (6 septembre 2024) : 1137. http://dx.doi.org/10.3390/mi15091137.
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This review explores significant advancements in polymer science and fabrication processes that have enhanced the performance and broadened the application scope of microfluidic devices. Microfluidics, essential in biotechnology, medicine, and chemical engineering, relies on precise fluid manipulation in micrometer-sized channels. Recent innovations in polymer materials, such as flexible, biocompatible, and structurally robust polymers, have been pivotal in developing advanced microfluidic systems. Techniques like replica molding, microcontact printing, solvent-assisted molding, injection molding, and 3D printing are examined, highlighting their advantages and recent developments. Additionally, the review discusses the diverse applications of polymer-based microfluidic devices in biomedical diagnostics, drug delivery, organ-on-chip models, environmental monitoring, and industrial processes. This paper also addresses future challenges, including enhancing chemical resistance, achieving multifunctionality, ensuring biocompatibility, and scaling up production. By overcoming these challenges, the potential for widespread adoption and impactful use of polymer-based microfluidic technologies can be realized.
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Bouhid de Aguiar, Izabella, et Karin Schroën. « Microfluidics Used as a Tool to Understand and Optimize Membrane Filtration Processes ». Membranes 10, no 11 (29 octobre 2020) : 316. http://dx.doi.org/10.3390/membranes10110316.
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Membrane filtration processes are best known for their application in the water, oil, and gas sectors, but also in food production they play an eminent role. Filtration processes are known to suffer from a decrease in efficiency in time due to e.g., particle deposition, also known as fouling and pore blocking. Although these processes are not very well understood at a small scale, smart engineering approaches have been used to keep membrane processes running. Microfluidic devices have been increasingly applied to study membrane filtration processes and accommodate observation and understanding of the filtration process at different scales, from nanometer to millimeter and more. In combination with microscopes and high-speed imaging, microfluidic devices allow real time observation of filtration processes. In this review we will give a general introduction on microfluidic devices used to study membrane filtration behavior, followed by a discussion of how microfluidic devices can be used to understand current challenges. We will then discuss how increased knowledge on fundamental aspects of membrane filtration can help optimize existing processes, before wrapping up with an outlook on future prospects on the use of microfluidics within the field of membrane separation.
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Giri, Kiran, et Chia-Wen Tsao. « Recent Advances in Thermoplastic Microfluidic Bonding ». Micromachines 13, no 3 (20 mars 2022) : 486. http://dx.doi.org/10.3390/mi13030486.
Texte intégralRésumé :
Microfluidics is a multidisciplinary technology with applications in various fields, such as biomedical, energy, chemicals and environment. Thermoplastic is one of the most prominent materials for polymer microfluidics. Properties such as good mechanical rigidity, organic solvent resistivity, acid/base resistivity, and low water absorbance make thermoplastics suitable for various microfluidic applications. However, bonding of thermoplastics has always been challenging because of a wide range of bonding methods and requirements. This review paper summarizes the current bonding processes being practiced for the fabrication of thermoplastic microfluidic devices, and provides a comparison between the different bonding strategies to assist researchers in finding appropriate bonding methods for microfluidic device assembly.
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Tsur, Elishai Ezra. « Computer-Aided Design of Microfluidic Circuits ». Annual Review of Biomedical Engineering 22, no 1 (4 juin 2020) : 285–307. http://dx.doi.org/10.1146/annurev-bioeng-082219-033358.
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Microfluidic devices developed over the past decade feature greater intricacy, increased performance requirements, new materials, and innovative fabrication methods. Consequentially, new algorithmic and design approaches have been developed to introduce optimization and computer-aided design to microfluidic circuits: from conceptualization to specification, synthesis, realization, and refinement. The field includes the development of new description languages, optimization methods, benchmarks, and integrated design tools. Here, recent advancements are reviewed in the computer-aided design of flow-, droplet-, and paper-based microfluidics. A case study of the design of resistive microfluidic networks is discussed in detail. The review concludes with perspectives on the future of computer-aided microfluidics design, including the introduction of cloud computing, machine learning, new ideation processes, and hybrid optimization.
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Marzban, Mostapha, Ehsan Yazdanpanah Moghadam, Javad Dargahi et Muthukumaran Packirisamy. « Microfabrication Bonding Process Optimization for a 3D Multi-Layer PDMS Suspended Microfluidics ». Applied Sciences 12, no 9 (4 mai 2022) : 4626. http://dx.doi.org/10.3390/app12094626.
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Microfluidic systems have received increased attention due to their wide variety of applications, from chemical sensing to biological detection to medical analysis. Microfluidics used to be fabricated by using etching techniques that required cleanroom and aggressive chemicals. However, another microfluidic fabrication technique, namely, soft lithography, is less expensive and safer compared to former techniques. Polydimethylsiloxane (PDMS) has been widely employed as a fabrication material in microfluidics by using soft lithography as it is transparent, soft, bio-compatible, and inexpensive. In this study, a 3D multi-layer PDMS suspended microfluidics fabrication process using soft lithography is presented, along with its manufacturing issues that may deteriorate or compromise the microsystem’s test results. The main issues considered here are bonding strength and trapped air-bubbles, specifically in multi-layer PDMS microfluidics. In this paper, these two issues have been considered and resolved by optimizing curing temperature and air-vent channel integration to a microfluidic platform. Finally, the suspended microfluidic system has been tested in various experiments to prove its sensitivity to different fluids and flow rates.
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Naderi, Arman, Nirveek Bhattacharjee et Albert Folch. « Digital Manufacturing for Microfluidics ». Annual Review of Biomedical Engineering 21, no 1 (4 juin 2019) : 325–64. http://dx.doi.org/10.1146/annurev-bioeng-092618-020341.
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The microfluidics field is at a critical crossroads. The vast majority of microfluidic devices are presently manufactured using micromolding processes that work very well for a reduced set of biocompatible materials, but the time, cost, and design constraints of micromolding hinder the commercialization of many devices. As a result, the dissemination of microfluidic technology—and its impact on society—is in jeopardy. Digital manufacturing (DM) refers to a family of computer-centered processes that integrate digital three-dimensional (3D) designs, automated (additive or subtractive) fabrication, and device testing in order to increase fabrication efficiency. Importantly, DM enables the inexpensive realization of 3D designs that are impossible or very difficult to mold. The adoption of DM by microfluidic engineers has been slow, likely due to concerns over the resolution of the printers and the biocompatibility of the resins. In this article, we review and discuss the various printer types, resolution, biocompatibility issues, DM microfluidic designs, and the bright future ahead for this promising, fertile field.
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Cha, Haotian, Hedieh Fallahi, Yuchen Dai, Dan Yuan, Hongjie An, Nam-Trung Nguyen et Jun Zhang. « Multiphysics microfluidics for cell manipulation and separation : a review ». Lab on a Chip 22, no 3 (2022) : 423–44. http://dx.doi.org/10.1039/d1lc00869b.
Texte intégralRésumé :
We reviewed the state-of-the-art field of multiphysics microfluidics, in which multiple functional physical processes are combined in a microfluidic platform, examining the different formats of cascaded connections and physical coupling.
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Kurniawan, Yehezkiel Steven, Arif Cahyo Imawan, Sathuluri Ramachandra Rao, Keisuke Ohto, Wataru Iwasaki, Masaya Miyazaki et Jumina. « Microfluidics Era in Chemistry Field : A Review ». Journal of the Indonesian Chemical Society 2, no 1 (31 août 2019) : 7. http://dx.doi.org/10.34311/jics.2019.02.1.7.
Texte intégralRésumé :
By miniaturizing the reactor dimension, microfluidic devices are attracting world attention and starting the microfluidic era, especially in the chemistry field because they offer great advantages such as rapid processes, small amount of the required reagents, low risk, ease and accurate control, portable and possibility of online monitoring. Because of that, microfluidic devices have been massively investigated and applied for the real application of human life. This review summarizes the up-to-date microfluidic research works including continuous-flow, droplet-based, open-system, paper-based and digital microfluidic devices. The brief fabrication technique of those microfluidic devices, as well as their potential application for particles separation, solvent extraction, nanoparticle fabrication, qualitative and quantitative analysis, environmental monitoring, drug delivery, biochemical assay and so on, are discussed. Recent perspectives of the microfluidics as a lab-on-chip or micro total analysis system device and organ-on-chip are also introduced.
Thèses sur le sujet "Microfluidic processes"
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Haswell, Stephen John. « The development of microfluidic based processes ». Thesis, University of Plymouth, 2015. http://hdl.handle.net/10026.1/4189.
Texte intégral
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Kim, Jae Jung Ph D. Massachusetts Institute of Technology. « Microfluidic processes to create structured microparticle arrangements and their applications ». Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/115018.
Texte intégralRésumé :
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Chemical Engineering, 2017.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 136-145).
Multifunctional polymeric microparticles have shown the great potentials in a variety of fields. While the advance in particle synthesis allows for fine tuning of their physical properties and chemical functionality, particle manipulation is still appealing, but challenging issue in colloidal science. In order to expand the utility of microparticles, many particle manipulation techniques have been developed to arrange large-scale of particles at precise locations. However, current approaches cannot simultaneously fulfill desired capabilities of arrangement: scalability, precision, specificity, and versatility. This thesis explores the ability to synthesize particles with a controllability of characteristics, and development of a new microfluidic platform, porous microwell arrays, to create structured large-scale microparticle arrays using a scaling theory, which is a function of particles' characteristics. Lastly, we demonstrate the potential of generated particle arrays in various bioengineering application and material sciences. First, we synthesize anisotropic, cell-adhesive microparticles using stop flow lithography (SFL) and carbodimide coupling. Synthesized microparticles are functionalized with collagen or poly-L-lysine using streptavidin-biotin interaction, resulting in cell-adhesiveness. After functionalization, target cells are spread on the particles and spatially patterned only on the functionalized region. Thus, cells are not exposed to potentially harmful components of particle synthesis processes, photoinitiators and ultraviolet light, ensuring no physiological changes. Second, we synthesize multi-striped, upconverting nanocrystal (UCN)-laden microparticles using SFL. Distinct upconversion emission colors are combined with the ability to spatial pattern them, providing superior encoding capacities. We can fine-tune upconversion emission by controlling the dopant composition in nanocrystal, and synthesize microparticles in a highly reproducible manner by SFL, allowing for the development of predictable decoding system. Two types of particles are synthesized with this appealing encoding strategy for two distinct applications: thermally stable particles for anti-counterfeiting application; and porous hydrogels for multiplexed microRNA detection. Third, we develop a microfluidic platform, porous microwell arrays, to manipulate microparticles while fulfilling all four desired capabilities (i.e. scalability, precision, specificity, and versatility). Microwells are fabricated on top of porous membrane by a vacuum-assisted molding method. Particles are guided and assembled into wells by hydrodynamic force associated with fluid flow through pores in microwell. Iteration of assembly and washing steps ensures high-throughput, large-scale particle arrangement with high yields on filling and capturing. Scaling theory allows for the rational design of platform to specifically position microparticles depending on their physical characteristics (i.e. size, shape, and modulus), enabling to generate complex patterns. We utilize this platform in three practical applications: high-throughput, large-scale single-cell arrays; microenvironment fabrication for neutrophil chemotaxis; and UCN-laden covert 2D tags for anti-counterfeiting. Lastly, we modified the porous microwell platform to a closed system, microfluidic channels, to park and isolate particles in monodisperse droplets surrounded by fluorinated oil. Rational modification retains the platform's desired capabilities, resulting in a single particle in a droplet with high yields on both parking and isolation. Particle-in-droplet arrays enables the observation of reaction in confined volume over the time. Such arrays can be utilized to accumulate the desired product from enzymatic reaction, amplifying the signal and improving the sensitivity of bioassays. We demonstrate the highly sensitive, multiplexed miRNA detections with these particle-in-droplet arrays.
by Jae Jung Kim.
Ph. D.
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Tarn, Mark Duncan. « Continuous flow processes on single magnetic and diamagnetic particles in microfluidic devices ». Thesis, University of Hull, 2011. http://hydra.hull.ac.uk/resources/hull:4915.
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Magnetic microparticles have seen increasing interest in (bio)chemical processes in recent years due to their various surface functionalities, high surface-to-volume ratio, small sizes, and ease of manipulation via magnetic fields. However, conventional reactions and assays that use magnetic particles as solid supports are typically performed in multi-step procedures that require consecutive reaction and washing steps. While offering high capture efficiencies, these are batch processes that, due to the consecutive steps required, are typically time-consuming and laborious. Their incorporation into microfluidic devices has brought about benefits including finer control over the movement of particles and reagent/sample solutions, as well as the ability to place a magnet closer to the area of interest. However, most instances of on-chip magnetic particle based procedures rely on trap-and-release methodology, essentially requiring the same stepwise routine as with conventional systems. A method of reducing these inefficiencies is to perform the reaction or separation in continuous flow, thereby allowing continuous sample introduction and analysis of the process in rapid times, and with minimal reagent consumption and waste production.Two methods of performing continuous flow procedures on single particles in microfluidic devices via the application of magnetic forces were investigated: 1) the use of magnetic microparticles as mobile solid supports for performing rapid separations, reactions, and immunoassays via magnetic attraction, and 2) the use of diamagnetic repulsion forces for performing similar procedures on non-magnetic particles, with a view to the label-free processing of diamagnetic species such as polymer particles and biological cells, based on their intrinsic properties.For the magnetic attraction experiments, a study into the effect of temperature on magnetic particle deflection behaviour and separations was performed, whereupon it was found that an increased temperature of the system yielded increased deflection distances and separation resolution due to the reduced viscous drag. This was followed by several investigations into the deflection of particles through laminar flow streams containing alternating reagents and washing buffers for performing multistep reactions and assays. The setup was used to demonstrate amide bond formation and polyelectrolyte deposition in continuous flow, before being used to detect clinically relevant levels (5 and 10�g mL-1) of the inflammatory biomarker, C-reactive protein. Thus, these findings show great potential for rapid, continuous processing of particles for a number of chemical and biological applications, as well as in clinical diagnostics.For the diamagnetic repulsion studies, diamagnetic polystyrene particles were suspended in paramagnetic media and deflected away from a magnetic field in continuous flow. The effect of particle size and the magnetic susceptibility of the paramagnetic media on particle deflection were investigated using high magnetic fields, where it was found that larger particles in a medium with higher susceptibility yielded the greatest deflection. This work was extended via a proof-of-principle setup in which polystyrene particles were repelled out of a reagent stream and into a buffer stream using permanent magnets, with a view to performing continuous flow reactions through laminar flow reagent and washing buffer streams, akin to those achieved via magnetic attraction. Finally, flow focussing of polystyrene particles and label-free cells was achieved via diamagnetic repulsion forces applied by permanent magnets, demonstrating the ability to manipulate cells in continuous flow by magnetic forces based on their intrinsic properties. This work could be applied to the label-free processing of particles and cells for separations, reactions, and assays.
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Sendekie, Zenamarkos Bantie. « Clogging dynamics of particles and bacteria in microfluidic systems mimicking microfiltration processes ». Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30355/document.
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L'objectif de cette thèse est de progresser dans la compréhension du colmatage lors de la filtration de la matière molle (particules colloïdales et bactéries) et d'étudier l'efficacité et la faisabilité de séparateurs microfluidiques. Ces recherches sont réalisées avec des puces microfluidiques constituées de canaux dont la taille est du même ordre de grandeur que les objets filtrés. Ces puces, conçues pour représenter les processus ayant lieu en microfiltration frontale et tangentielles, permettent d'observer in-situ sous microscope les mécanismes de colmatage. Le système est instrumenté avec des capteurs de débit et de pression et permet ainsi une analyse croisée entre les observations et les variations de perméabilité. Les expériences ont été réalisées pour différentes conditions hydrodynamiques (débit, mode de filtration) et conditions d'interactions colloïdales (en changeant la force ionique). Les résultats mettent en évidence l'importance de la dynamique du blocage de pore par des agrégats de particules et du réentrainement de ces agrégats lorsqu'ils sont fragilisés par l'écoulement. La dynamique de ces évènements provoque des fluctuations de perméabilité. Les interactions particule-particule ou particule-paroi jouent également un rôle important sur la dynamique du colmatage. Trois scenarios sont discutés par analogie anthropomorphique : un scenario panique (0.01 mM) où les répulsions entre les particules induit un phénomène de poussée entre particules qui engendre la formation d'arches à l'entrée des canaux ; un scenario instinct de troupeau (10 mM) où l'attraction entre particules (dans un minimum DLVO secondaire) facilite le transport dans le canal et retarde le colmatage ; un scenario sacrificiel (100 mM) où l'efficacité de capture des particules par les parois est élevée mais les agrégats formés sont très fragiles et fréquemment réentraînés par l'écoulement. Cette analyse illustre l'importance des phénomènes collectifs lors du colmatage par des particules inter-agissantes. Le mécanisme de colmatage par des particules biologiques (bactéries) et notamment la création de panaches bactériens en aval des canaux sont ensuite analysés. Ces phénomènes sont étudiés pour différentes conditions de culture (ratio carbone-azote dans le substrat) afin d'examiner l'effet de la production de substances polymériques extracellulaires (EPS) sur le colmatage. Les résultats montrent que les EPS (et donc les conditions de cultures) jouent un rôle crucial sur le développement de panaches bactériens lors d'écoulement dans des constrictions. Il est montré également que la filtration d'un mélange entre des bactéries produisant peu d'EPS et des bactéries produisant d'EPS favorise la formation des panaches bactériens. Des filtrations de mélange de bactéries et de particules montrent que la présence de bactérie modifie la dynamique du blocage des canaux ; de façon surprenante l'ajout de bactérie permet de retarder le colmatage et de former des dépôts de particules plus fragiles. Des systèmes microfluidiques avec un design spécifique ont également été développés pour réaliser un fractionnement par taille de dispersions sous un écoulement tangentiel. Des résultats préliminaires ont permis d'optimiser leur fonctionnement en trouvant des conditions permettant de filtrer en évitant le blocage des canaux ; leur utilisation pour réaliser des fractionnements continus dans des puces microfluidiques peut être envisagéeThe aim of the PhD is to progress in the understanding of the fouling phenomena during filtration of soft matter (colloidal particles and bacteria) and to examine the efficiency and feasibility of microfluidic separators. These studies are realized with microfluidic devices constituted of micrometric channels having the same size range as the materials being filtered. These devices, which mimic membrane dead-end and cross-flow microfiltration processes, allow in-situ and direct microscopic observations of the fouling mechanisms. The microfluidic system is equipped with flow rate and pressure measurement devices allowing a dynamic cross analysis of the observations with the variations of permeability. Experiments have been realized for different hydrodynamic conditions (flow rate, filtration mode) and for different colloidal interactions (by varying the ionic strength) in order to analyse their interplay in the clogging mechanism by soft matter (interacting particles). The results evidenced the importance of clogs formation, fragility and sweeping out dynamics during the fouling process. These dynamic events at bottlenecks induce important permeability fluctuations. The particle-particle and particle-wall interactions also play important roles on the clogging dynamics. Three different scenarios are discussed by analogy to crowd swarming: panic scenario (0.01 mM) where repulsion between particles induce pushing effects leading to the creation of robust arches at pore entrances; herding instinct scenario (10 mM) where the attraction (in secondary minima) between particles enhances the transport in pores and delays clogging; sacrifice scenario (100 mM) where the capture efficiency is high but the aggregates formed at the wall are fragile. These analyses illustrate the importance of collective behaviour exhibited by interacting particles during fouling. The fouling phenomena by biological particles (bacteria) are analysed in terms of the streamer formation conditions and mechanisms. The streamer formation phenomena are in turn analysed by playing with the cultivation conditions (the carbon to nitrogen ratio in the substrate) in order to study the effect of extracellular polymeric substances (EPS) on the process. The results show that EPS (and hence the bacterial cultivation conditions) play crucial role in streamer formation by microorganisms under flow in constrictions. Furthermore, the presence of non-EPS producing bacterial species along with EPS producing species in a mixed culture enhances the streamer formation. On the other hand, filtration of mixed particles and bacteria suspensions show that the presence of bacteria substantially modifies the clogging dynamics. Microfluidic devices with specific configurations have also been developed for fractionation in order to maximize performances of these processes. The preliminary results with these chips in cross-flow conditions show that it is possible to limit the clogging impact by working below a critical flux; their use for continuous microparticles fractionation could be then considered
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Xu, Jin (Jin C. ). « Fabrication and function of microfluidic devices for monitoring of in-vitro fertilization processes ». Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/40930.
Texte intégralRésumé :
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.Includes bibliographical references (leaf 36).
The process of assistive reproduction is often a headache and heartache for those who choose to go through it. The field currently relies heavily on morphological characteristics to determine embryo health and development success, a highly unreliable method. While they appear healthy at implantation, many embryos, in reality, have poor development potential and fail to survive within the womb. Therefore, to offset the high chances of miscarriage, multiple eggs are implanted in the uterus. This has occasionally lead to multi-fetal pregnancies, which have a higher maternal mortality risk, and, in general, is more physically demanding. This thesis researches a microfluidic device that aids in the crucial stages of in vitro- fertilization. The device allows for a fertilized egg to be cultured within, and provides the ability to carefully monitor its health through a series of metabolic assays, a better indication of embryo health. This microfluidic embryo health monitoring device is comprised of two layers of channel networks. It works through passing fluids along flow channels that are driven by control channels. The control layer, when pressurized with gas, operates as valves and peristaltic pumps along the flow layer to pump and transport fluids through the flow channels. As embryonic fluids are passed through the channels, the status of the fertilized egg can be monitored with metabolic assays taken of the embryo at various detection sites.
by Jin Xu.
S.B.
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Abdelhady, Ahmed Mohammed Said lutfi. « Developing novel processes in chemistry for several types of nanoparticles ». Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/developing-novel-processes-in-chemistry-for-several-types-of-nanoparticles(0712d3c6-e2d5-415a-b787-c9ce457e1355).html.
Texte intégralRésumé :
The work presented in this thesis reports the use of a series of novel thiobiuret metal complexes [M(SON(CNiPr2)2)n] (M = Cu, Ni, Fe, Zn, Cd or In; n = 2 or 3) for the first time as single source precursors for the colloidal synthesis of metal sulfide nanoparticles. Other single source precursor(s) were also used for the synthesis of CdSe, CdS, CdSe/CdS core/shell, CdSeS alloys and Cu2-xS nanoparticles in microfluidic reactors. Thermolysis experiments of [Cu(SON(CNiPr2)2)2] using only oleylamine produced Cu7S4 nanoparticles as a mixture of monoclinic and orthorhombic phases. Pure orthorhombic Cu7S4 nanoparticles were obtained when a solution of precursor in octadecene was injected into hot oleylamine whereas, Cu1.94S nanoparticles were obtained when a solution of the precursor in oleylamine was injected into hot dodecanethiol. The thermolysis of [Ni(SON(CNiPr2)2)2] gave Ni3S4 in all cases except when precursor solution in oleylamine was injected into hot octadecene which produced NiS nanoparticles. The thermolysis of [Fe(SON(CNiPr2)2)3] in oleylamine/oleylamine produced Fe7S8 nanoparticles but other combinations, in most cases, gave amorphous material. Thermolysis of [Zn(SON(CNiPr2)2)2] in oleylamine produced spherical ZnS nanoparticles. Particles with size smaller than 4.3 nm had a cubic phase, whereas the particles with size larger than 4.3 nm had a hexagonal crystal structure as suggested by the selected area electron diffraction. Powder X-Ray diffraction showed that the CdS nanoparticles obtained from the thermolysis of [Cd(SON(CNiPr2)2)2] in oleylamine were cubic under all reaction conditions except when dodecanethiol was used as an injection solvent which produced hexagonal CdS. β-In2S3 were synthesized from the thermolysis of [In(SON(CNiPr2)2)3]. Transmission electron microscopy showed that the copper, nickel and iron sulfide nanoparticles had various morphologies such as spherical, hexagonal disks, trigonal disks, rods or wires; depending on the reaction temperature, concentration of the precursor, the growth time and the solvent/capping agent combination. The zinc and cadmium sulfide nanoparticles were mostly spherical whereas the indium sulfide nanoparticles were produced in the form of ultra-thin (< 1.0 nm) nanorods or nanowires. ZnxCd1-xS and CuInS2 nanoparticles were synthesised from the 1,1,5,5-tetra-iso-propyl-4-thiobiureto complexes of Zn, Cd and Cu, In, respectively. Powder X-Ray diffraction showed that the obtained ZnxCd1-xS nanoparticles are cubic under all reaction conditions. The ZnxCd1-xS nanoparticles had an average diameter between 3.5 to 6.4 nm as shown by transmission electron microscopy. The optical properties of the ZnxCd1-xS nanoparticles were highly dependent on the ZnS to CdS precursor ratio and the solvents/capping agents. Chalcopyrite (tetragonal), wurtzite (hexagonal) or a mixture of both CuInS2 nanoparticles were obtained depending on the reaction conditions. TEM showed that the CuInS2 nanoparticles could be synthesised with different morphologies (spherical, hexagonal, trigonal or cone). Luminescent CuInS2 nanoparticles were obtained only in the absence of oleylamine. [Cd(S2CNMenHex)2], [Cd(Se2P(iPr)2)2] and [Cu(SON(CNiPr2)2)2] were used as single source precursor(s) for the synthesis of CdS, CdSe, CdSe/CdS core/shell, CdSeS alloys and Cu2-xS in microfludic reactor. The CdS nanoparticles were in size range of 5.0 to 8.0 nm whereas the CdSe nanoparticles were ultra small (ca. 2 nm) with blue luminescence. The CdSe/CdS core/shell and the CdSeS alloys were bluish green or green luminescent depending on their size. The copper sulfide nanoparticles were found to be monoclinic Cu7S4 or monoclinic Cu7S4 with minor impurities of rhombohedral Cu9S5 depending on the reaction conditions.
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Haben, Patrick. « Controlling the Synthesis of Bunte Salt Stabilized Gold Nanoparticles Using a Microreactor Platform in Concert with Small Angle X-ray Scattering Analysis ». Thesis, University of Oregon, 2013. http://hdl.handle.net/1794/13429.
Texte intégralRésumé :
Gold nanoparticles (AuNPs) have garnered considerable attention for their interesting size-dependent properties. These properties have fueled applications that span a continuum ranging from simple to sophisticated. Applications for these materials have grown more complex as syntheses for these materials have improved. For simple applications, current synthetic processes are sufficient. However, development of syntheses that generate well-defined particle sizes with specifically tailored surface functionalities is an on-going challenge for chemists. The aim of this dissertation is to improve upon current AuNP syntheses to produce sophisticated materials needed to discover new material properties, and provide efficient access to materials to develop new advanced applications.
The research described in this dissertation improves upon current methods for AuNP production by using a microreactor to provide enhanced mixing and synthetic control, and small angle X-ray scattering (SAXS) as a precise, rapid, solution-based method for size distribution determination. Using four ligand-stabilized AuNP samples as reference materials, SAXS analysis was compared to traditional microscopic size determination. SAXS analysis provided similar average diameters while avoiding deposition artifacts, probing a larger number of particles, and reducing analysis time. Next, the limits of SAXS size analysis was evaluated, focusing on identifying multiple distributions in solution. Utilizing binary and ternary mixtures of well-defined AuNP reference samples, SAXS analysis was shown to be effective at identifying multiple distributions. While microscopy has limited ability to differentiate these modes, SAXS analysis is more rapid and introduces less researcher bias.
Because AuNP size and ligand functionality are interdependent, accessing desired core sizes with varied functionality is challenging. To address this, a new microfluidic synthetic method was developed to produce thiolate-passivated AuNPs with targeted core sizes from 1.5 - 12 nm with tailored functionality. This ability to control size while independently varying surface functionality is unprecedented.
Lastly, AuNP core formation was probed by simultaneous in situ SAXS and UV/visible spectroscopy. A coalescence mechanism for AuNP growth was observed when using Bunte salt ligands. This finding compares well to observed coalescence in other systems using weakly-passivating ligands, and supports the hypothesis that Bunte salts passivate ionically during particle growth while resulting in covalent linkages.2015-10-10
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Janakiraman, Vijayakumar. « DESIGN, FABRICATION AND CHARACTERIZATION OF BIFURCATING MICROFLUIDIC NETWORKS FOR TISSUE-ENGINEERED PRODUCTS WITH BUILT-IN MICROVASCULATURE ». Case Western Reserve University School of Graduate Studies / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=case1196457966.
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Schianti, Juliana de Novais. « Sistemas de microcanais em vidro para aplicações em microfluidica ». Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/3/3140/tde-19082008-083259/.
Texte intégralRésumé :
Neste trabalho são apresentados resultados relativos ao desenvolvimento de um processo de fabricação para a produção de sistemas de microcanais em vidro tipo borosilicato, 7059 Corning Glass. O objetivo do trabalho é implementar um processo básico, mas completo, de fabricação de sistemas microfluídicos em vidro, que possam futuramente ser aprimorados com a introdução de dispositivos ópticos e eletrônicos e de elementos microfluídicos ativos, como válvulas e microbombas, para sensoreamento e controle de fluxo. O processo de fabricação foi dividido em três grandes etapas, sendo a primeira delas, a produção dos microcanais, envolvendo processos como litografia e corrosão úmida. Nos estudos de corrosão procurou-se uma solução que permitisse a obtenção de canais com superfície uniforme e lisa, sem a produção de resíduos durante a corrosão do vidro. Os melhores resultados foram obtidos com a solução HF + HCl + H2O (1:2:3), com a possibilidade de produzir canais com até 150 µm de profundidade. A segunda etapa do processo de produção dos sistemas microfluídicos envolveu o encapsulamento dos microcanais, o que foi feito através de um processo de soldagem direta (vidro com vidro) à temperatura ambiente, com aplicação de pressão entre 0,1 a 1,0 MPa. Os melhores resultados nesta etapa envolveram pressões acima de 0,5 MPa, podendo-se obter cerca de 95 - 100% da área das lâminas soldadas. A terceira etapa do processo de fabricação engloba a interconexão com o meio externo, envolvendo a produção dos furos no vidro para entrada e saída de líquidos e a introdução dos tubos de acesso para o meio externo. Para a produção dos furos foi desenvolvido um sistema posicionador computarizado que movimenta o substrato de vidro nas direções x, y e z com precisão de alguns micrometros, garantindo o alinhamento necessário entre as duas lâminas de vidro que devem ser soldadas para encapsular os microcanais. Os furos foram feitos com broca diamantada de uso odontológico fixa em uma furadeira comum. Cateteres e scalps de uso médico foram empregados como tubos de acesso, sendo selados com resina epóxi. Os sistemas microfluídicos fabricados foram testados monitorando o fluxo de soluções aquosas de anilina, o qual foi mantido através de bomba peristáltica. Os resultados se mostraram reprodutíveis, tendo se obtido microcanais lisos e sem resíduos, sem apresentar vazamentos e exibindo regime de fluxo tipicamente laminar. Em conjunto, estes resultados mostraram-se muito promissores para desenvolvimento futuro de aplicações em áreas como Biotecnologia e Análises Químicas.In this work, a process for the fabrication of microchannels over borlosilicate 7059 Corning Glass is presented. The main objective is to develop a simple and complete process for the fabrication of microfluidic systems over glass, that can be further improved in the future, with the integration of optical, electronic and active microfluidic devices such as valves and micropumps, for sensing and flow control. The fabrication process has three main parts. The first part is the microchannel production, which is achieved through contact-lithography and wet etching. In the etching studies, a solution that led to the fabrication of channels with uniform and smooth surfaces, without residue formation was sought. The best results were attained with a HF + HCl + H2O (1:2:3), which allow for the production of channels with depths of up to 150 µm. The second part of the fabrication process is the microchannels encapsulation, which is achieved through direct (glass-glass) bonding at room temperature, with applied pressure ranging from 0.1 to 1.0 MPa. The best results were obtained with pressure values above 0.5 MPa, which allowed for the bonding of up to 95 -100% of the glass sufaces. The third part of the fabrication process concerns the interconnection with the outside environment, which involves hole production and the introduction of tubes, to allow external access of liquids. For the hole production, a computer controlled positioning system was developed, for accurate positioning of the glass substrate in the x, y and z directions, with a precision of a few micrometers. This system guaranteed the necessary alignment of the upper and lower glass substrates, which were bonded for the encapsulation of the microchannels. The holes were made with diamond burs with a common drill. Medical catheters and scalps were used as access tubes, with epoxy resin. The characterization of the fabricated microfluidic systems was achieved by monitoring the flow of aniline aqueous solutions, which was maintained through a peristaltic pump. Reproducible results were obtained, with the production smooth and residue free microchannels, which did not present leakage and exhibited a laminar flow behavior. These results are very promising for the future application of this process in the fabrication of devices for areas such as biotechnology and chemical analysis, among others.
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Kirschbaum, Michael. « A microfluidic approach for the initiation and investigation of surface-mediated signal transduction processes on a single-cell level ». Phd thesis, Universität Potsdam, 2009. http://opus.kobv.de/ubp/volltexte/2009/3957/.
Texte intégralRésumé :
For the elucidation of the dynamics of signal transduction processes that are induced by cellular interactions, defined events along the signal transduction cascade and subsequent activation steps have to be analyzed and then also correlated with each other. This cannot be achieved by ensemble measurements because averaging biological data ignores the variability in timing and response patterns of individual cells and leads to highly blurred results. Instead, only a multi-parameter analysis at a single-cell level is able to exploit the information that is crucially needed for deducing the signaling pathways involved.
The aim of this work was to develop a process line that allows the initiation of cell-cell or cell-particle interactions while at the same time the induced cellular reactions can be analyzed at various stages along the signal transduction cascade and correlated with each other. As this approach requires the gentle management of individually addressable cells, a dielectrophoresis (DEP)-based microfluidic system was employed that provides the manipulation of microscale objects with very high spatiotemporal precision and without the need of contacting the cell membrane. The system offers a high potential for automation and parallelization. This is essential for achieving a high level of robustness and reproducibility, which are key requirements in order to qualify this approach for a biomedical application.
As an example process for intercellular communication, T cell activation has been chosen. The activation of the single T cells was triggered by contacting them individually with microbeads that were coated with antibodies directed against specific cell surface proteins, like the T cell receptor-associated kinase CD3 and the costimulatory molecule CD28 (CD; cluster of differentiation). The stimulation of the cells with the functionalized beads led to a rapid rise of their cytosolic Ca2+ concentration which was analyzed by a dual-wavelength ratiometric fluorescence measurement of the Ca2+-sensitive dye Fura-2. After Ca2+ imaging, the cells were isolated individually from the microfluidic system and cultivated further. Cell division and expression of the marker molecule CD69 as a late activation event of great significance were analyzed the following day and correlated with the previously recorded Ca2+ traces for each individual cell.
It turned out such that the temporal profile of the Ca2+ traces between both activated and non-activated cells as well as dividing and non-dividing cells differed significantly. This shows that the pattern of Ca2+ signals in T cells can provide early information about a later reaction of the cell.
As isolated cells are highly delicate objects, a precondition for these experiments was the successful adaptation of the system to maintain the vitality of single cells during and after manipulation. In this context, the influences of the microfluidic environment as well as the applied electric fields on the vitality of the cells and the cytosolic Ca2+ concentration as crucially important physiological parameters were thoroughly investigated. While a short-term DEP manipulation did not affect the vitality of the cells, they showed irregular Ca2+ transients upon exposure to the DEP field only. The rate and the strength of these Ca2+ signals depended on exposure time, electric field strength and field frequency. By minimizing their occurrence rate, experimental conditions were identified that caused the least interference with the physiology of the cell.
The possibility to precisely control the exact time point of stimulus application, to simultaneously analyze short-term reactions and to correlate them with later events of the signal transduction cascade on the level of individual cells makes this approach unique among previously described applications and offers new possibilities to unravel the mechanisms underlying intercellular communication.Zelluläre Interaktionen sind wirkungsvolle Mechanismen zur Kontrolle zellulärer Zustände in vivo. Für die Entschlüsselung der dabei beteiligten Signaltransduktionsprozesse müssen definierte Ereignisse entlang der zellulären Signalkaskade erfasst und ihre wechselseitige Beziehung zueinander aufgeklärt werden. Dies kann von Ensemble-Messungen nicht geleistet werden, da die Mittelung biologischer Daten die Variabilität des Antwortverhaltens individueller Zellen missachtet und verschwommene Resultate liefert. Nur eine Multiparameteranalyse auf Einzelzellebene kann die entscheidenden Informationen liefern, die für ein detailliertes Verständnis zellulärer Signalwege unabdingbar sind. Ziel der vorliegenden Arbeit war die Entwicklung einer Methode, welche die gezielte Kontaktierung einzelner Zellen mit anderen Zellen oder Partikeln ermöglicht und mit der die dadurch ausgelösten zellulären Reaktionen auf unterschiedlichen zeitlichen Ebenen analysiert und miteinander korreliert werden können. Da dies die schonende Handhabung einzeln adressierbarer Zellen erfordert, wurde ein auf Dielektrophorese (DEP) basierendes mikrofluidisches System eingesetzt, welches die berührungslose Manipulation mikroskaliger Objekte mit hoher zeitlicher und örtlicher Präzision erlaubt. Das System besitzt ein hohes Potential zur Automatisierung und Parallelisierung, was für eine robuste und reproduzierbare Analyse lebender Zellen essentiell, und daher eine wichtige Voraussetzung für eine Anwendung in der Biomedizin ist. Als Modellsystem für interzelluläre Kommunikation wurde die T-Zell-Aktivierung gewählt. Die Aktivierung der einzelnen T-Zellen wurde durch ihre gezielte Kontaktierung mit Mikropartikeln („beads“) induziert, welche mit Antikörpern gegen spezielle Oberflächenproteine, wie die dem T-Zell-Rezeptor assoziierte Kinase CD3 oder das kostimulatorische Protein CD28, beschichtet waren. Die Stimulation der Zellen mit den funktionalisierten beads führte zu einem raschen Anstieg der intrazellulären Ca2+-Konzentration, welche über eine ratiometrische Detektion des Ca2+-sensitiven Fluoreszenzfarbstoffs Fura-2 gemessen wurde. Anschließend wurden die einzelnen Zellen aus dem mikrofluidischen System isoliert und weiterkultiviert. Am nächsten Tag wurden Zellteilung und die CD69-Expression – ein wichtiger Marker für aktivierte T-Zellen – analysiert und auf Ebene der individuellen Zelle mit dem zuvor gemessenen Ca2+-Signal korreliert. Es stellte sich heraus, dass der zeitliche Verlauf des intrazellulären Ca2+-Signals zwischen aktivierten und nicht aktivierten, sowie zwischen geteilten und nicht geteilten Zellen signifikant verschieden war. Dies zeigt, dass Ca2+-Signale in stimulierten T-Zellen wichtige Informationen über eine spätere Reaktion der Zelle liefern können. Da Einzelzellen äußerst empfindlich auf ihre Umgebungsbedingungen reagieren, war die Anpassung der experimentellen Vorgehensweise im Hinblick auf die Zellverträglichkeit von großer Bedeutung. Vor diesem Hintergrund wurde der Einfluss sowohl der mikrofluidischen Umgebung, als auch der elektrischen Felder auf die Überlebensrate und die intrazelluläre Ca2+-Konzentration der Zellen untersucht. Während eine kurzzeitige DEP-Manipulation im mikrofluidischen System die Vitalität der Zellen nicht beeinträchtigte, zeigten diese unregelmäßige Fluktuationen ihrer intrazellulären Ca2+-Konzentration selbst bei geringer elektrischer Feldexposition. Die Ausprägung dieser Fluktuationen war abhängig von der Expositionszeit, der elektrischen Feldstärke und der Feldfrequenz. Über die Minimierung ihres Auftretens konnten experimentelle Bedingungen mit dem geringsten Einfluss auf die Physiologie der Zellen identifiziert werden. Die Möglichkeit, einzelne Zellen zeitlich definiert und präzise mit anderen Zellen oder Oberflächen zu kontaktieren, die unmittelbare Reaktion der Zellen zu messen und diese mit späteren Ereignissen der Zellantwort zu korrelieren, macht die hier vorgestellte Methode einzigartig im Vergleich mit anderen Ansätzen und eröffnet neue Wege, die der interzellulären Kommunikation zugrunde liegenden Mechanismen aufzuklären.
Livres sur le sujet "Microfluidic processes"
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Chakraborty, Suman. Microfluidics and Microfabrication. Boston, MA : Springer Science+Business Media, LLC, 2010.
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1938-, Casas-Vázquez J. (José), et Lebon G. (Georgy), dir. Extended irreversible thermodynamics. 4e éd. New York : Springer, 2010.
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Chakraborty, Suman. Microfluidics and Microscale Transport Processes. Taylor & Francis Group, 2012.
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Chakraborty, Suman. Microfluidics and Microscale Transport Processes. Taylor & Francis Group, 2012.
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Chakraborty, Suman. Microfluidics and Microscale Transport Processes. Taylor & Francis Group, 2012.
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Microfluidics and Microscale Transport Processes. Taylor & Francis Group, 2012.
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Delamarche, Emmanuel, et Govind V. Kaigala. Open-Space Microfluidics : Concepts, Implementations, Applications. Wiley & Sons, Incorporated, John, 2018.
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Delamarche, Emmanuel, et Govind V. Kaigala. Open-Space Microfluidics : Concepts, Implementations, Applications. Wiley & Sons, Limited, John, 2018.
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Delamarche, Emmanuel, et Govind V. Kaigala. Open-Space Microfluidics : Concepts, Implementations, Applications. Wiley & Sons, Limited, John, 2018.
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Delamarche, Emmanuel, et Govind V. Kaigala. Open-Space Microfluidics : Concepts, Implementations, Applications. Wiley & Sons, Incorporated, John, 2018.
Trouver le texte intégralChapitres de livres sur le sujet "Microfluidic processes"
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Matson, Dean W., Peter M. Martin, Wendy D. Bennett, Dean E. Kurath, Yuehe Lin et Donald J. Hammerstrom. « Fabrication Processes for Polymer-Based Microfluidic Analytical Devices ». Dans Micro Total Analysis Systems ’98, 371–74. Dordrecht : Springer Netherlands, 1998. http://dx.doi.org/10.1007/978-94-011-5286-0_88.
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Gaa, Ramona, Hannah Melina Mayer, Daniela Noack et Achim Doerner. « Efficient Microfluidic Downstream Processes for Rapid Antibody Hit Confirmation ». Dans Methods in Molecular Biology, 327–41. New York, NY : Springer US, 2023. http://dx.doi.org/10.1007/978-1-0716-3279-6_18.
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Przekwas, A., V. Makhijani, M. Athavale, A. Klein et P. Bartsch. « Computational Simulation of Bio-Microfluidic Processes in Integrated DNA Biochips ». Dans Micro Total Analysis Systems 2000, 561–64. Dordrecht : Springer Netherlands, 2000. http://dx.doi.org/10.1007/978-94-017-2264-3_132.
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Kockmann, Norbert. « Microfluidic Networks ». Dans Micro Process Engineering, 41–59. Weinheim, Germany : Wiley-VCH Verlag GmbH & Co. KGaA, 2013. http://dx.doi.org/10.1002/9783527631445.ch2.
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Barthel, Lars, Philipp Kunz, Rudibert King et Vera Meyer. « Harnessing Genetic and Microfluidic Approaches to Model Shear Stress Response in Cell Wall Mutants of the Filamentous Cell Factory Aspergillus niger ». Dans Dispersity, Structure and Phase Changes of Proteins and Bio Agglomerates in Biotechnological Processes, 467–90. Cham : Springer Nature Switzerland, 2024. http://dx.doi.org/10.1007/978-3-031-63164-1_15.
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Rabhi, F., G. Cheng et T. Barriere. « Modeling of Viscoelasticity of Thermoplastic Polymers Employed in the Hot Embossing Process ». Dans Lecture Notes in Mechanical Engineering, 251–60. Cham : Springer International Publishing, 2024. http://dx.doi.org/10.1007/978-3-031-58006-2_19.
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AbstractThe manufacturing of micro-scale components requires mastery of shaping processes ranging from micromechanics to electronic microfabrication. The hot embossing (HE) process is widely developed in various fields, since it allows to emboss complex structures at the micro/nanoscale such as optical sensors, diffractive lenses, microfluidic channels, and so on. The development of micro-structured parts via this process requires an in-depth analysis of the surface quality obtained and the mold filling rate. It is essential to analyze the influence of polymer properties to optimize the final mold filling to reduce cycle time and obtain defect-free replicated components. In this research, compression tests were carried out with poly(methyl methacrylate) (PMMA) and polycarbonate (PC), at different forming temperatures to determine their behavior law properties. Numerical simulation of the polymer forming processing was carried out by using Abaqus finite element software, taking into account the mechanical properties of both polymers and the characteristics of microchannels. The aim was to analyze the effect of the elastic–viscoplastic properties of the materials on the mold filling rate at different temperatures. Numerical simulation of the HE process with PMMA shows that the mold cavity is completely filled with elastic-viscoplastic behaviors, and the filling rate increases as a function of mold displacement. On the other hand, for PC, the embossed temperature has an influence on the filling ratio of the mold.
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Fletcher, David F., Brian S. Haynes, Joëlle Aubin et Catherine Xuereb. « Modeling of Microfluidic Devices ». Dans Micro Process Engineering, 117–44. Weinheim, Germany : Wiley-VCH Verlag GmbH & Co. KGaA, 2013. http://dx.doi.org/10.1002/9783527631445.ch5.
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Buchberger, Gerda, Martina Muck, Cristina Plamadeala et Johannes Heitz. « Laser Structuring for Biomedical Applications ». Dans Springer Series in Optical Sciences, 1105–65. Cham : Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-14752-4_31.
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AbstractLaser structuring enables modification of sample topography, surface chemistry, and/or physical properties of materials. Examples of these processes are ripple, nap or wall formation, surface oxidation, induction of polymerization reactions, or changes in crystallinity or contact angle. These – most of the time – interrelated modifications are exploited widely for biomedical applications. They range from cell-repellent surfaces for easy-to-replace cardiac pacemakers, control of cell proliferation required in regenerative medicine, to increased cell adhesion for cell arrays. Furthermore, ns-laser-induced nanoripples were used for formation of gold nanowires for future surface plasmon resonance sensors directly integrated into biotechnological devices. Additive nano- and microscale manufacturing by two-photon polymerization allows for considerable progress in cell scaffold formation, paving the path for in vitro–grown organs, bones, and cartilages. The very same fs-laser-based technique was also used for biomimetic microneedles with enhanced liquid spreading on their surface. Microneedles are promising candidates for low-cost, high-throughput drug delivery and vaccination applicable even by nonmedically trained personnel. Microfluidic systems fabricated by fs-lasers have enabled progress in 3D microscopy of single cells and in studies on thrombocyte activation with the help of nanoanchors. Explicating the abovementioned and further biomedical applications, the authors put special focus on the achieved limits pointing out what scientists have accomplished so far in their pursuit of extreme scales.
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DasGupta, Sunando. « Microscale Transport Processes and Interfacial Force Field Characterization in Micro-cooling Devices ». Dans Microfluidics and Microfabrication, 113–30. Boston, MA : Springer US, 2009. http://dx.doi.org/10.1007/978-1-4419-1543-6_3.
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Kashid, Madhvanand, Albert Renken et Lioubov Kiwi-Minsker. « Effects of Microfluidics on Preparative Chemistry Processes ». Dans Microreactors in Preparative Chemistry, 13–54. Weinheim, Germany : Wiley-VCH Verlag GmbH & Co. KGaA, 2013. http://dx.doi.org/10.1002/9783527652891.ch02.
Texte intégralActes de conférences sur le sujet "Microfluidic processes"
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Sun, Jianren, Christopher Bock et Quanfang Chen. « Mechanical Properties of PDMS and Influences by Micromachining Processes ». Dans ASME 2008 International Manufacturing Science and Engineering Conference collocated with the 3rd JSME/ASME International Conference on Materials and Processing. ASMEDC, 2008. http://dx.doi.org/10.1115/msec_icmp2008-72296.
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Microfluidics is both a science and a technology that offers great and perhaps even revolutionary capabilities to impact the society in the future. Polydimethylsiloxane (PDMS) has been widely used in fabricating microfluidic systems but few efforts were made in the past on mechanical properties of PDMS. Very importantly there is no report on influences of microfabrication processes which normally involve chemical reaction processes. A comprehensive investigation was made by authors to study fundamental issues regarding chemical emersion and their effects on mechanical properties of PDMS. Results shown in this work can be used to guide future developments of microfluidics in utilizing PDMS especially those devices involve actuation of PDMS membranes.
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Laura Jáuregui, Ana, Héctor R. Siller, Ciro A. Rodriguez, Alex Elías-Zúñiga et Vicente Jesus Segui. « Evaluation of Manufacturing Processes for Microfluidic Devices ». Dans THIRD MANUFACTURING ENGINEERING SOCIETY INTERNATIONAL CONFERENCE : MESIC-09. AIP, 2009. http://dx.doi.org/10.1063/1.3273635.
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Galambos, Paul, et Conrad James. « Surface Micromachined Microfluidics : Example Microsystems, Challenges and Opportunities ». Dans ASME 2005 Pacific Rim Technical Conference and Exhibition on Integration and Packaging of MEMS, NEMS, and Electronic Systems collocated with the ASME 2005 Heat Transfer Summer Conference. ASMEDC, 2005. http://dx.doi.org/10.1115/ipack2005-73491.
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A variety of fabrication techniques have been used to make microfluidic microsystems: bulk etching in silicon and glass, plastic molding and machining, and PDMS (silicone) casting. Surprisingly the most widely used method of integrated circuit (IC) fabrication (surface micromachining — SMM) has not been extensively utilized in microfluidics despite its wide use in MEMS. There are economic reasons that SMM is not often used in microfluidics; high infrastructure and start-up costs and relatively long fabrication times: and there are technical reasons; packaging difficulties, dominance of surface forces, and fluid volume scaling issues. However, there are also important technical and economic advantages for SMM microfluidics relating to large-scale batch, no-assembly fabrication, and intimate integration of mechanical, electrical, microfluidic, and nano-scale sub-systems on one chip. In our work at Sandia National Laboratories MDL (Microelectronics Development Lab) we have built on the existing MEMS SMM infrastructure to produce a variety of microfluidic microsystems. These example microsystems illustrate the challenges and opportunities associated with SMM microfluidics. In this paper we briefly discuss two SMM microfluidic microsystems (made in the SUMMiT™ and SwIFT™ processes — www.mdl.sandia.gov/micromachine) in terms of technical challenges and unique SMM microfluidics opportunities. The two example microsystems are a DEP (dielectrophoretic) trap, and a drop ejector patterning system.
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Li, Dongqing. « Electrokinetic Microfluidics and Biomedical Lab-on-a-Chip Devices ». Dans ASME 2011 9th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2011. http://dx.doi.org/10.1115/icnmm2011-58305.
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Lab-on-a-chip devices are miniaturized bio-medical laboratories on a small glass/plastic plate. These lab chips can duplicate the specialized functions of their room-sized counterparts such as clinical diagnoses and tests. The key microfluidic functions required in various lab-on-a-chip devices include pumping and mixing liquids, controlling bio-reactions, dispensing samples and reagents, and separating molecules and cells/particles. Using electrokinetic microfluidics to realize these functions can make the devices fully automatic, independent of external support (e.g., tubing, valves and pump), and truly portable. Understanding, modeling and controlling of various electrokinetic microfluidic phenomena and the electrokinetic microfluidic processes are essential to systematic design and operation control of the lab-on-a-chip systems. This presentation will explain the principles of these electrokinetic microfluidic processes and how they are used in lab-on-a-chip devices. Some lab-on-a-chip devices such as real-time PCR chip, immunoassay chip and flow cytometer chip developed in Dr. Li’s lab will be introduced.
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Li, Dongqing. « Electrokinetic-Based Microfluidic Processes in Lab-on-a-Chip Devices ». Dans ASME 2004 2nd International Conference on Microchannels and Minichannels. ASMEDC, 2004. http://dx.doi.org/10.1115/icmm2004-2322.
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Most microfluidic processes in lab-on-a-chip devices are electrokinetic processes. Fundamental understanding of the electrokinetic based microfluidic processes is key to the design and process control of lab-on-a-chip devices. This paper will review basics of the electrical double layer field, and three key on-chip microfluidic processes: electroosmotic flow, sample mixing and sample dispensing.
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Del Giudice, F., G. D’Avino, M. M. Villone, F. Greco et P. L. Maffettone. « Particle manipulation through polymer solutions in microfluidic processes ». Dans THE SECOND ICRANET CÉSAR LATTES MEETING : Supernovae, Neutron Stars and Black Holes. AIP Publishing LLC, 2015. http://dx.doi.org/10.1063/1.4937289.
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Gonçalves, Inês, Miguel Madureira, Inês Miranda, Helmut Schütte, Ana Moita, Graça Minas, Stefan Gassmann et Rui Lima. « Separation Microfluidic Devices Fabricated by Different Milling Processes ». Dans 15th International Conference on Biomedical Electronics and Devices. SCITEPRESS - Science and Technology Publications, 2022. http://dx.doi.org/10.5220/0010906500003123.
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Cairone, F., et M. Bucolo. « Design of control systems for two-phase microfluidic processes ». Dans 2016 24th Mediterranean Conference on Control and Automation (MED). IEEE, 2016. http://dx.doi.org/10.1109/med.2016.7535866.
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Chen, Jyh Jian, Guan Wei Duan, Jyun Cian Jheng, Jhen Yu Wu, Muw Shing Liu et Jenn Der Lin. « Filling Processes of Microfluidic Flows with Dynamic Contact Angles ». Dans 38th Fluid Dynamics Conference and Exhibit. Reston, Virigina : American Institute of Aeronautics and Astronautics, 2008. http://dx.doi.org/10.2514/6.2008-4280.
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Liu, Miao, Jianren Sun, Ying Sun et Quanfang Chen. « Mechanical Properties of PDMS Membrane and Influences of Commonly Used Chemicals in Microfabrication ». Dans 2008 Second International Conference on Integration and Commercialization of Micro and Nanosystems. ASMEDC, 2008. http://dx.doi.org/10.1115/micronano2008-70343.
Texte intégralRésumé :
Microfluidics is both a science and a technology that offers great and perhaps even revolutionary capabilities to impact the society in the future. Polydimethylsiloxane (PDMS) has been widely used in fabricating microfluidic systems but few attentions were paid in the past to mechanical properties of PDMS. Very importantly there is no report on influences of microfabrication processes which normally involve chemical reaction processes. A comprehensive investigation was made by authors to study fundamental issues regarding chemical emersion and their effects on mechanical properties of PDMS. Results shown in this work can be used to guide future developments of microfluidics in utilizing PDMS especially those devices involve actuation of PDMS membranes.
Rapports d'organisations sur le sujet "Microfluidic processes"
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Rose, K. A Programmable MicroFluidic Processor : Integrated and Hybrid Solutions. Office of Scientific and Technical Information (OSTI), mai 2002. http://dx.doi.org/10.2172/15006001.
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