Siga este enlace para ver otros tipos de publicaciones sobre el tema: Microfluidic sorting.
Tesis sobre el tema "Microfluidic sorting"
Crea una cita precisa en los estilos APA, MLA, Chicago, Harvard y otros
Consulte los 50 mejores tesis para su investigación sobre el tema "Microfluidic sorting".
Junto a cada fuente en la lista de referencias hay un botón "Agregar a la bibliografía". Pulsa este botón, y generaremos automáticamente la referencia bibliográfica para la obra elegida en el estilo de cita que necesites: APA, MLA, Harvard, Vancouver, Chicago, etc.
También puede descargar el texto completo de la publicación académica en formato pdf y leer en línea su resumen siempre que esté disponible en los metadatos.
Explore tesis sobre una amplia variedad de disciplinas y organice su bibliografía correctamente.
1
Gao, Hua. "Microluidic Sorting of Blood Cells by Negative Selection". University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1479816171280535.
Texto completo
2
shahzad, mohd adnan faqui. "Microfluidic Chip development for acoustophoresis assisted selective cell sorting". Thesis, KTH, Skolan för kemi, bioteknologi och hälsa (CBH), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-223658.
Texto completoResumen
Analysis of blood samples is one of the major steps in diagnosing pathological conditions like cancer. The upstream sample preparation for the pathological cell analysis from complex biological fluid like blood, involves selective cell sorting. It can be achieved using fluorescently activated or magnetically activated cell sorters. Another way is to sort them using acoustophoresis which is cheaper, gives better spatial control and is also rapid apart from the fact that, it does not affect the cellular viability.6,9 In acoustophoresis, particles depending upon their density and compressibility relative to the suspended medium migrate to either pressure anti-nodes or nodes, when subjected to acoustic field. Poly vinyl alcohol-based microbubbles have a strong negative acoustic contrast factor and hence migrate to the anti-nodes in a standing ultrasonic wave. Previously, this property was utilized for cell separation by conjugating the bubbles to cells and subjecting them to ultrasonic waves in a silicon glass based microfluidic channel.55 A protocol for coating the microbubbles with avidin, so that these can readily attach to the cells has been developed in this work. However, microfluidic channel is obtained from a master mold which is developed in a clean room facility using photolithography. A cost-effective way has been developed for the production of a mold using a Computerized Numerical Control system (where the positive master for the microfluidic channel is drilled onto a PMMA sheet) for continuous separation of cancer cells. Alternate methods like a cutting plotter (which uses a double sided adhesive tape as a positive master) and a 3-D printer have been investigated, in order to be used as a mold for the microfluidic channel. As a proof, microbubbles-cell complex was focused in a PDMS based microfluidic channel, by utilizing standing Bulk acoustic waves. At flow rate of 10µl/min, efficiency greater than 80% has been achieved. This technique is low cost and can be implemented in places without a clean room facility for size independent cell sorting.
3
Seo, Duckbong. "A development of the motile sperm sorting microfluidic devices". Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/4798.
Texto completoResumen
Thesis (Ph. D.)--University of Missouri-Columbia, 2007.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on December 13, 2007) Vita. Includes bibliographical references.
4
Raafat, Mohamed Salem. "Self-sorting of deformable particles in a microfluidic circuit". Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/62536.
Texto completoResumen
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2010.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 54-57).
In this thesis, a new microfluidic device is presented for sorting of deformable particles based on the hydrodynamic resistance induced in a microchannel. Hydrodynamic resistance can be related to physical properties, including size and deformability of the particle, and can also be influenced by particle-wall interactions, hence allowing sorting based on any of these characteristics. This device could find application in cell sorting and bioseparation for therapeutics, research, and point-of-care diagnostics, as well as in sorting of droplets and emulsions for research and industrial applications (e.g., pharmaceutics, food industry, etc.). The device design is carried out using an equivalent resistance model, and numerical simulations are used to validate the design. The device is fabricated in PDMS, flow velocities are characterized using particle streak velocimetry, and sorting experiments are conducted to sort deformable gelatin particles according to size, and droplets of water and glycerol according to deformability. A sorting resolution of approximately 1 pm was obtained when sorting based on size, and droplets of water and glycerol were sorted into separate streams when sorting based on deformability. The main strength of the device over existing technology lies in its simplicity: sorting is carried out passively in the microfluidic circuit, eliminating the need for additional detection or sorting modules. Moreover, the device could be easily customized to change the sorting parameter or the sorting threshold, and multiple devices can be combined in parallel (to increase throughput) or in series (to increase resolution).
by Mohamed Salem Raafat.
S.M.
5
Haener, Edgar. "Microfluidic segregation of capsules". Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/microfluidic-segregation-of-capsules(a7e001f1-536c-475d-83d5-82aaa4098f5b).html.
Texto completoResumen
This thesis investigates the transport and sorting of capsules (elastic membranes enclosing a liquid core) using viscous flow in complex vessel geometries. Of particular interest is passive sorting by deformability using only the fluid-structure interaction between the capsule, the viscous fluid and the geometry of the vessel. Millimetric alginate-ovalbumin capsules in the regime of negligible fluid inertia are used in this work. In order to characterise the elastic properties of the capsules, a novel numerical finite element model of the compression of a thick-shelled capsule between parallel plates is implemented. The constitutive model of the capsule membranes was determined by comparison to experimental data: a Yeoh constitutive model with the ratio of constants $C_1 = 1$, $C_2 = 0$ and $C_3 = 10$ describes the capsules used. Three geometries are investigated in this work. (i) A T-Junction bifurcation. Capsule deformation in the T-Junction bifurcation is characterised by the maximal length of the capsule $L_{max}$ and depends on the ratio of viscous to elastic forces, the capillary number $Ca$. The maximal length, $L_{max}$, is especially sensitive at distinguishing soft capsules by their deformability. The sensitivity of $L_{max}$ to capsule compliance and the large deformations that can be achieved makes the T-junction a promising geometry in which to measure elastic properties of the capsules. The rate of relaxation of the capsules after the bifurcation is independent of their deformation. (ii) A half-cylinder obstacle in a channel followed by a sudden expansion. We show that the half-cylinder obstacle causes capsule trajectories to vary depending on deformability. Capsules with a factor of three difference in deformability can be separated. A practical feature of the system is its relative insensitivity to the initial lateral position of the capsules in the channel. However, while the results are reproducible across different capsules, the variations in final position amount to 10 \% at fixed parameters. As these experiments were conducted with the same capsule under identical flow conditions, this is likely to represent the best case scenario. (iii) We adapt the pinched flow fractionation (PFF) geometry to the sorting of capsules. We show that the standard PFF device cannot be used to sort capsules. However, a novel mode of operation, termed the ``T-Junction'' mode, shows great promise for the sorting of capsules. The PFF device in the T-Junction mode separates capsules with a factor of 1.5 difference in deformability. This is twice as sensitive as the half-cylinder device, although larger variability was observed in the PFF device.
6
Gerhardt, Antimony L. "Arrayed microfluidic actuation for active sorting of fluid bed particulates". Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/37198.
Texto completoResumen
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, February 2004.Includes bibliographical references (p. 227-237).
Fluidic actuation offers a facile method to move large quantities of small solids, often referred to as fluid-bed movement. Applications for fluid bed processing are integral to many fields including petrochemical, petroleum, chemical, pharmaceutical, biochemical, environmental, defense, and medical. Thermal vapor microbubbles have been shown to be a low power input with high work output fluidic actuation technique with demonstrated commercial applications in ink jet printing and optical switching. This thesis further develops microbubble actuation (BA) as an arrayed particulate actuation technology for active sorting in particulate fluid beds. Numerical and analytical models of flows, forces, and fields affecting a tBA-based system are presented. The design and fabrication of an arrayed pBA-powered device are delineated with notation of specifications that may focus future design iterations. Performance testing and characterization of CpBA technology, including over a hundred in-plane and out-of-plane nucleation site geometries, serve as the impetus for the technical guidelines that are presented, which include a detailed comparison of in-plane and out-of-plane nucleation site geometry performance.
by Antimony L. Gerhardt.
M.Eng.
7
Cartas, Ayala Marco Aurelio. "Hydrodynamic resistance and sorting of deformable particles in microfluidic circuits". Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/79312.
Texto completoResumen
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2013.Cataloged from PDF version of thesis.
Includes bibliographical references.
Sorting of microparticles has numerous applications in science and technology, from cell analysis to sample purification for biomaterials, photonics, and drug delivery. Methods used for particle separation relied only on procedures that involved sedimentation, filtration through porous material or other physical procedures that could be performed macroscopically and in bulk; only recently has miniaturization of fluid systems enabled individual particle separation at the macroscopic level. In the 1980's, as new fabrication techniques originally used to miniaturize circuits became available, they were used to miniaturize structures used for filtration, creating new membranes for filtration with sub millimeter thickness and new fluidic devices that enabled completely new functionalities. Hydrodynamic resistance, the extra resistance induced by a particle as it flows through a microfluidic channel, has been recently proposed as a viable property for particle characterization. Particle-induced hydrodynamic resistance can be linked to relevant biological properties, e.g. deformability, which is an important parameter in diseases like sickle cell anemia, malaria, sepsis and some kinds of cancers. In this work we propose the concept of 'hydrodynamic resistance sorting', which adds to the repertoire of current sorting technologies. We propose a microfluidic circuit capable of sorting particles according to the hydrodynamic resistance they induce in micro channel as they flow through. The circuit has two flow modes: rejection and sorting modes. The microfluidic circuit switches from rejection to sorting mode automatically when a particle induces an increment in hydrodynamic resistance larger than a designed threshold value. The circuit uses the concept of microfluidic logic, in which a microfluidic system has multiple discrete output modes, (sorting and rejecting particle modes), which are activated by an input variable, in this case the hydrodynamic resistance. As opposed to previous logic microfluidic circuits based on droplets, the sorting circuit uses particle self-interactions and does not require particle synchronization to enable microfluidic logic; hence the circuit is asynchronous. Further, we showed the circuit's ability to work with cells by sorting red blood cells and tested the circuit's capacity to sort particles based on mechanical properties by sorting cured and uncured droplets made of a UV-curable solution. Finally, in addition to development of circuits to sort particles based on hydrodynamic resistance, we investigated the link between hydrodynamic resistance and the change in mechanical properties experienced by cells. From first principles it is unclear exactly how and to what extent cell mechanical properties affect cell passage through constrained channels. The force opposing cell passage could be proportional to the cell velocity, as it occurs during lubrication of rigid objects, or proportional to normal forces, as it occurs in the case of many macroscopic objects sliding on surfaces. We used a microfluidic differential manometer, particle image velocimetry, high-speed imaging, confocal microscopy and non-dimensional analysis to investigate the relationship between cell mechanical properties, friction forces and hydrodynamic resistance. The results revealed that the transport of cells through constrained channels is a soft lubrication flow, where the driving force depends primarily on viscous dissipation and secondarily on the compressive forces acting on the cell. This work advances our understanding of the flow of deformable particles through constrained channels and provides a method to sort single particles based on their hydrodynamic resistance. The devices developed here have potential applications in biomechanical analysis of cells, bioseparation, point-of-care diagnostics, as well as in two-phase microfluidics.
by Marco Aurelio Cartas Ayala.
Ph.D.
8
Aubrecht, Donald Michael. "Droplet Microfluidics: Tools for Screening and Sorting Applications". Thesis, Harvard University, 2013. http://dissertations.umi.com/gsas.harvard:11069.
Texto completoResumen
Microfluidic droplets are a powerful tool for screening large populations of cells, molecules, and biochemical reactions. Droplet systems are able to encapsulate, incubate, screen, and sort millions of samples, providing access to large number statistics that make searching for rare events feasible. Initial development of the microfluidic devices and methods has attracted applications in biology, biochemistry, and material science, but the set of tools remains incomplete. Efforts are required to develop micro-scale droplet analogs for all bulk-scale bench top procedures and instruments. The droplet analogs must be versatile, robust, and process samples rapidly.Engineering and Applied Sciences
9
Riordon, Jason A. "Developing Microfluidic Volume Sensors for Cell Sorting and Cell Growth Monitoring". Thèse, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/30955.
Texto completoResumen
Microfluidics has seen an explosion in growth in the past few years, providing researchers with new and exciting lab-on-chip platforms with which to perform a wide variety of biological and biochemical experiments. In this work, a volume quantification tool is developed, demonstrating the ability to measure the volume of individual cells at high resolution and while enabling microfluidic sample manipulations. Care is taken to maximise measurement sensitivity, range and accuracy, though novel use of buoyancy and dynamically tunable microchannels. This first demonstration of a microfluidic tunable volume sensor meant volume sensing over a much wider range, enabling the detection of ̴ 1 µm3 E.coli that would otherwise go undetected. Software was written that enables pressure-driven flow control on the scale of individual cells, which is used to great success in (a) sorting cells based on size measurement and (b) monitoring the growth of cells. While there are a number of macroscopic techniques capable of sorting cells, microscopic lab-on-chip equivalents have only recently started to emerge. In this work, a label-free, volume sensor operating at high resolution is used in conjunction with pressure-driven flow control to actively extract particle/cell subpopulations. Next, a microfluidic growth monitoring device is demonstrated, whereby a cell is flowed back and forth through a volume sensor. The integration of sieve valves allows cell media to be quickly exchanged. The combination of dynamic trapping and rapid media exchange is an important technological contribution to the field, one that opens the door to studies focusing on cell volumetric response to drugs and environmental stimuli. This technology was designed and fabricated in-house using soft lithography techniques readily available in most biotechnology labs. The main thesis body contains four scientific articles that detail this work (Chapters 2-5), all published in peer-reviewed scientific journals. These are preceded by an introductory chapter which provides an overview to the theory underlying this work, in particular the non-intuitive physics at the microscale and the Coulter principle.
10
Xavier, Miguel. "Label-free, microfluidic characterisation and sorting of human skeletal stem cells". Thesis, University of Southampton, 2018. https://eprints.soton.ac.uk/424494/.
Texto completoResumen
Skeletal stem cells (SSCs) are a sub-population of bone marrow (BM) stromal cells with multipotent differentiation potential. SSCs are responsible for the unique regeneration capacity inherent to bone and offer unlimited potential for application in bone regenerative therapies. A current unmet challenge hampering their clinical translation remains the isolation of homogeneous SSC populations with consistent regeneration and differentiation capacities. Factors limiting the efficiency of existing sorting approaches include the scarcity of SSCs in BM, estimated at fewer than 1 in 10,000 nucleated cells, the complexity of BM tissue and, most significantly, the absence of a specific marker that is unique to the SSC. Microfluidics offers the potential to characterise and sort cells marker-free, based on intrinsic biophysical properties. These include, but are not limited to, cell size, shape, stiffness, and dielectric properties. The work presented herein aimed to provide a comprehensive characterisation of the biophysical fingerprint of SSCs and to build on this new understanding to develop new tools to isolate SSCs, label-free, with significant physiological and therapeutic implications. In real-time deformability cytometry (RT-DC), cells are deformed by shear and normal stresses as they flow through a narrow constriction at high speed, providing the capability to screen cell mechanical properties at high-throughput. Here, RT -DC was used to relate the mechano-phenotype of expanded SSCs with other cells in BM. Critically, SSCs were found to be significantly stiffer than white blood cells, which are abundant in human BM. Microfluidic impedance cytometry was coupled to fluorescence optical detection to provide accurate characterisation of the dielectric properties and cell size of SSCs within heterogeneous primary human BM samples. The membrane capacitance of SSCs was found to be indistinct from other cells in BM. Conversely, their average size in suspension, at 9 micrometres, was within the largest BM cell fraction. Centred on these findings, label-free sorting devices were designed based on the principle of deterministic lateral displacement (DLD). DLD uses arrays of micropillars in a channel to sort cells based on their diameter, at throughputs of thousands per second. Cell deformation, induced by shear and contact with the pillars, can change the effective cell size and affect sorting efficiency. This was demonstrated using two human cells lines of different size and stiffness, and by size fractionation of expanded SSCs. Crucially, SSCs sorted by DLD remained viable and retained their capacity to form clonogenic cultures. Overall, this work provided a detailed characterisation of relevant biophysical properties of SSCs and paved the way towards the design of a novel label-free sorting approach, potentially based on DLD, to provide purified SSC populations from BM with impactful use in fundamental stem cell research and the clinic.
11
Lake, Melinda Ann. "Electrostatic curved electrode actuator for particle sorting at a microfluidic bifurcation". The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1560441199033201.
Texto completo
12
Dhingra, Karan. "Manipulation and Sorting of Cell-Laden Hydrogel Microcapsules Within Microfluidic Environment". Thesis, Université d'Ottawa / University of Ottawa, 2019. http://hdl.handle.net/10393/39858.
Texto completoResumen
Encapsulating cells within semi-permeable hydrogel material has been shown to boost the therapeutic effectiveness of stem cell therapy in certain applications. Cell encapsulation promotes high retention and engraftment rates, and protects against attack from the immune system of the host, as these are challenges often seen in utilizing stem cells in suspension alone. Leveraging droplet-based microfluidics has yielded a platform capable of producing monodispersed microcapsules embedded with cells at high throughput, typically achieved by mixing an aqueous hydrogel solution that contains cells with an immiscible liquid (oil) in a flow focusing geometry. However, encapsulation using microfluidics results in randomized generation of empty and cell-laden microcapsules, following Poisson statistics, raising the need to institute a successful sorting mechanism, thereby increasing occupancy and ultimately purifying the desired sample. In this thesis we propose a sorting strategy by combining two conceptual mechanisms of electrophoresis (EP) and deterministic lateral displacement (DLD). Different varieties of microcapsules were characterized for EP and DLD respectively. Leveraging these differences was used in a device combining both of the concepts towards sorting of empty and cell-laden microcapsules.
13
Wang, Gonghao. "Microfluidic cell separation based on cell stiffness". Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/54285.
Texto completoResumen
Cell biophysical properties are a new class of biomarkers that can characterize cells into subgroups that indicate differences in phenotypes that may correlate with disease and cell state. Microfluidic biophysical cell sorters are platforms that utilize these newly developed biomarkers to expand biomedical capabilities for improvements in cell state detection and characterization. Cell biophysical properties are important indicators for cell state and function because they point to differences in cell structures, such as cytoskeletal arrangement and nuclear content. In particular, some diseases, such as cancer and malaria, can cause significant changes in cell biophysical properties. Therefore, cell biophysical properties have the potential to be used for disease diagnostics. Microfluidic systems which can interrogate these biophysical properties and exploit changes in biophysical properties to separate cells into subpopulations will provide important biomedical capabilities.
In this combined theoretical and experimental investigation, we explore a new type of cell sorter which utilizes differences in biophysical properties of cells. These biophysical properties that can be utilized to sort cells include size, elasticity and viscosity. We invented a microfluidic system for continuous, label-free cell separation that utilizes variations in cell biophysical properties. A microfluidic channel is decorated by periodic diagonal ridges that are designed to compress flowing cells in rapid succession. The physical compression, in combination with hydrodynamic secondary flows induced by the ridged microfluidic channel, translates each cell perpendicular to the channel axis in proportion to its biophysical properties. Through careful experimental and computational studies, we found that the cell trajectories in the microfluidic cell sorter correlated to these biophysical properties. Furthermore, we examine the effect of channel design parameters under various experimental conditions to derive cell separation models that can be used to qualitatively predict cell sorting outcome. A variety of biophysical measurement tools, including atomic force microscopy and high-speed optical microscopy are used to directly characterize the heterogeneous population of cells before and after separation. Taken together, we describe the physical principles that our microfluidic approach can be effectively used to separate a variety of cell types.
The major contribution is the creation and characterization of a novel microfluidic cell- sorting platform that utilizes cell biophysical properties to enrich cells into phenotypic subtypes. This innovative approach opens new ways for conducting rapid and low-cost cell analysis and disease diagnostics through biophysical markers.
14
Peca, Marco. "High-throughput skeletal stem cell separation using magnetic labelling and microfluidic sorting". Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/382975/.
Texto completo
15
Wang, Xiao. "Inertial microfluidic vortex cell sorter". University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1458643998.
Texto completo
16
Vesperini, Doriane. "Biomechanical study of cells in microfluidic flow : application to sorting and platelet production". Thesis, Compiègne, 2018. http://www.theses.fr/2018COMP2437/document.
Texto completoResumen
Les mégacaryocytes sont des cellules de la moelle osseuse, à l’origine de la production des plaquettes sanguines. Quand elles arrivent à maturité, elles grossissent et émettent des prolongements de cytoplasme à travers la paroi des vaisseaux irriguant la moelle. Dans la circulation sanguine, ces prolongements, soumis aux forces de l’écoulement, s’allongent et se rompent pour former des plaquettes. Des techniques microfluidiques capables de produire des plaquettes in vitro existent et sont une alternative prometteuse au don. Mais le rendement reste à améliorer. Pour cela, il est nécessaire de mieux comprendre la fragmentation des mégacaryocytes en plaquettes. Ce travail de doctorat s’inscrit dans ce contexte et sera développé en deux axes principaux dans ce manuscrit. Dans une première partie nous développons une méthode pour trier des cellules en fonction de leur déformabilité, afin de savoir si les propriétés mécaniques d’un mégacaryocyte sont liées à leur stade de maturité. La méthode a d’abord été mise au point avec des microcapsules. Leurs propriétés mécaniques sont déterminées par analyse inverse à partir de la mesure de leur forme en écoulement dans des constrictions droites. Puis le dispositif utilisé a été miniaturisé pour s’adapter à la taille des cellules. Pour la caractérisation de leurs propriétés mécaniques, deux outils ont été utilisés: l’analyse inverse et la microscopie à force atomique sans pointe. Une deuxième partie porte sur l’étude de l’élongation et de la rupture de mégacaryocytes soumis écoulement. Nous avons quantifié les variations spatiotemporelles du taux d’élongation et développé un protocole d’ablation laser pour étudier les mécanismes de rupture de cellules en élongationWhen they mature in the bone marrow, the precursors of platelets, called megakaryocytes, grow and extend protrusions able to join blood circulation. There these protrusions elongate and break into platelets. Microfluidic techniques for in vitro platelet production represent a promising alternative to donation. In order to enhance platelet production and match the needs of clinical applications such as transfusion, we need to better understand the fragmentation of megakaryocytes into platelets. Our contribution will be described in this manuscript in two main axes. First, in order to know if mechanical properties of megakaryocytes can indicate their maturity stage, we develop a cell sorting method based on deformability. The method is first validated with microcapsules. Their mechanical properties are determined by inverse analysis from their shape under flow in straight microchannels. Then the device is downscaled. The characterization of cell mechanical properties are performed using inverse analysis and tipless atomic force microscopy. Second, we study megakaryocyte elongation and rupture in a microfluidic device. We quantify the spatial and temporal variations of the elongation rate and develop a laser ablation protocol to trigger and study the rupture of elongating cells
17
Du, Mingming. "Mechanical characterization of therapeutic cells and physical property-based sorting in microfluidic systems". Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7510/.
Texto completoResumen
Bone marrow-derived mesenchymal and hematopoietic stem cells (MSCs and HSCs) have rapidly become the leading cells for consideration to aid tissue regeneration following injury. However, potential HSCs and MSCs migration to the injured tissue after infusion is impeded by cell trap within the upstream vessels, where physical and mechanical properties of cells play an important role. Microfluidic system has a potential to sort cells/particles based on their mechanical properties. It is hypothesized that such sorting system could be utilized to separate smaller and more deformable SCs from a cell population, infusion of which might be able to enhance the recruitment of the cells. The mechanical properties of murine HSCs were determined using micromanipulation and atomic force microscopy (AFM). Microfluidic devices were fabricated to separate sub-set of HSCs, followed by the infusion of the isolated cells into ischemia-reperfusion injured animals. HSCs as a whole became weaker and more deformable after pre-treatment with SDF-la and H 2 02, but HSC surface stiffened after the same pre-treating, accompanied by the expansion and polymerization ofF-actin interacting with the plasma membrane. A spiral microfluidic system with channel width 300m and height 40m was found to effectively isolate smaller and more deformable HSCs from a cell population, resulting in a significant increase of free flowing cells in vivo. This study comprehensively characterized cell mechanics at different levels using micromanipulation and AFM, determining mechanical markers of therapeutic cells. Most importantly, a simple cell sorting system was successfully developed to isolate target cells without introducing any chemical modification, and the possible underlying mechanism was discussed, which can be valuable to cellular therapy.
18
Cao, Zhenning. "Microfluidic Engineering for Ultrasensitive Molecular Analysis of cells". Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/76721.
Texto completoResumen
The main focus of this research was the development of microfluidic technology for ultrasensitive and fast molecular analysis of cells.
Chromatin immunoprecipitation (ChIP) assay followed by next generation sequencing serves as the primary technique to characterize the genomic locations associated with histone modifications. However, conventional ChIP-seq assay requires large numbers of cells. We demonstrate a novel microfluidics-based ChIP-seq assay which dramatically reduced the required cell number. Coupled with next generation sequencing, the assay permitted the analysis of histone modifications at the whole genome from as few as ~100 cells. Using the same device, we demonstrated that MeDIP-seq with tiny amount of DNA (<5ng) generated high quality genome-wide profiles of DNA methylation.
Off-chip sonication often leads to sample loss due to multiple tube transferring. In addition, conventional sonicators are not able to manipulate samples with small volume. We developed a novel microfluidic sonicator, which is able to achieve on-chip DNA/chromatin shearing into ideal fragment size (100~600bp) for both chromatin immunoprecipitation (ChIP) and methylated DNA immunoprecipitation (MeDIP). The integrated on-chip sonication followed by immunoprecipitation (IP) reaction can significantly reduce sample loss and contamination.
Simple and accessible detection methods that can rapidly screen a large cell population with single cell resolution have been seriously lacking. We demonstrate a simple protocol for detecting translocation of native proteins using a common flow cytometer which detects fluorescence intensity without imaging. Using our approach, we successfully detected the translocation of native NF-kappa B (an important transcription factor) at its native expression level and examine the temporal dynamics in the process.
Droplets with encapsulated beads and cells have been increasingly used for studying molecular and cellular biology. However, a mixed population of droplets with an uneven number or type of encapsulated particles is resulted and used for screening. We developed a fluorescence-activated microfluidic droplet sorter that integrated a simple deflection mechanism. By passing droplets through a narrow interrogation channel, the encapsulated particles were detected individually. The microcontroller conducted the computation to determine the number and type of encapsulated particles in each droplet and made the sorting decision. Our results showed high efficiency and accuracy for sorting and enrichment.Ph. D.
19
Guo, Quan. "Deformability based sorting of red blood cells and white blood cells using microfluidic ratchets". Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/59592.
Texto completoResumen
There are many situations in medicine and biology where it is desirable to sort cells in a heterogeneous sample based on their mechanical deformability, which can potentially serve as a proxy for morphology or pathology. This biophysical characteristic is particularly relevant for cells in the circulatory system, such as red blood cells and white blood cells, because deformability determines the capacity for these cells to transit through the microvasculature. Since deformability is such a fundamental characteristics of blood cells, deviations in normal cell deformability can contribute to a range of pathological conditions, such as microvascular occlusion, tissue necrosis and organ failure, observed in diseases such as malaria caused by Plasmodium falciparum. A commonly employed approach for deformability-based cell sorting is microfiltration. However, this method suffers from cell clogging at the filter microstructures, leading to reduced selectivity and device malfunction.
This dissertation presents an improved microfiltration strategy performed using the microfluidic ratchet mechanism, which relies on the deformation of individual cells through micrometer-scale tapered constrictions. Deforming single cells through such constrictions requires directionally asymmetrical forces, which enables oscillatory flow to create a ratcheting transport that depends on cell size and deformability. Simultaneously, oscillatory flow continuously agitates the cells to limit the contact time with the filter microstructure to prevent clogging and adsorption.
This work demonstrates the utility of the ratchet mechanism for cell sorting by developing a microfluidic device to sort red blood cells based on deformability. The device is used to separate Plasmodium falciparum infected red blood cells from uninfected cells. The method was shown to dramatically improve the sensitivity of malaria diagnosis performed using both microscopy and rapid diagnostic tests by converting samples with difficult-to-detect parasitemia (<0.01%) into samples with easily detectable parasitemia (>0.1%). This work further demonstrates the utility of the microfluidic ratchet mechanism by developing a microfluidic device to isolate and sort leukocytes directly from whole blood. The method is capable of separating leukocytes from whole blood with 100% purity (i.e. no contaminant erythrocytes) and <2% leukocytes loss. Furthermore, the approach demonstrates the potential to phenotypically sort leukocytes to enrich for granulocytes and lymphocytes subpopulations.Applied Science, Faculty of
Mechanical Engineering, Department of
Graduate
20
Schor, Alisha R. (Alisha Robin). "A dielectrophoretic, microfluidic device for sorting lipid-producing organisms used as bio-oil sources". Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/104222.
Texto completoResumen
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 173-182).
In this thesis, we present a microfluidic screening device for selecting high-lipid-content cells from a heterogeneous population. The device utilizes dielectrophoresis (DEP) to simultaneously sense and sort individual cells based on their internal lipid content. Microorganisms such as yeast, algae, and bacteria produce high fractions of neutral lipids as part of normal metabolism, and are being explored as a hydrocarbon source for products such as biodiesel, nutraceuticals, and more. Thus, there is a global effort to select or genetically engineer microorganisms that produce higher proportions of lipids. Currently, screening is a laborious process and one of the primary bottlenecks to commercialization. Our cell sorter consists of an array of 105, 25-pim-wide gold microposts that span the height of a 15-[mu]m channel. The electrodes were constructed by a low current electroplating process, allowing for extremely rapid metal deposition. At 100 [mu]A, electroplating proceeds at 3.38 0.63 [mu]m/min, creating our structures in fewer than 15 minutes. This is an order of magnitude improvement over previous related methods. We are able separate high and low lipid phenotypes of the oleaginous yeast Yarrowia lipolytica using a 250 MHz, 2.6 Vp) signal in our device. Purity of the low lipid streams and high lipid streams are 98% and 71%, respectively. The high lipid stream purity can be improved by adjusting the spacing of the array. This work provides a method for label-free detection and sorting of cells based on their internal lipid content. This unique protocol for the rapid fabrication of 3D microstructures has enabled the creation of a non-invasive sorting tool for genetically engineered, lipid producing organisms. The ability to screen organisms based on lipid content will alleviate one of the major bottlenecks in conunercialization of microbial biofuels and other bio-oil products. Thesis Supervisor
by Alisha R. Schor.
Ph. D.
21
Kilimnik, Alexander. "Cross stream migration of compliant capsules in microfluidic channels". Thesis, Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/43669.
Texto completoResumen
An understanding of the motion of soft capsules in microchannels is useful for a number applications. This knowledge can be used to develop devices to sort biological cells based on their size and stiffness. For example, cancer cells have a different stiffness from healthy cells and thus can be readily identified. Additionally, devices can be developed to detect flaws in synthetic particles. Using a 3D hybrid lattice Boltzmann and lattice spring method, the motion of rigid and soft capsules in a pressure-driven microfluidic flow was probed. The effect of inertial drift is evaluated in channels different Reynolds numbers. Other system parameters such as capsule elasticity and channel size are also varied to determine their effect. The equilibrium position of capsules in the channel is also obtained. The equilibrium position of rigid and soft capsules depends on the relative particle size. If the capsule is small, the equilibrium position is found to be closer to the channel wall. Conversely, for larger capsules, the equilibrium position is closer to the channel centerline. The capsule stiffness affects the magnitude of the cross-stream drift velocity. For a given Reynolds number, the equilibrium position of softer capsules is closer to the channel centerline. However, It is found that the equilibrium position of soft capsules is insensitive to the magnitude of the Reynolds number.
22
Bhandarkar, Sheela. "Multiple Bio-Particle Separation Using a Two-Stage Microfluidic Dielectrophoretic Sorter". University of Akron / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=akron1218821450.
Texto completo
23
Balaji, Varun Venkatesh [Verfasser]. "Sorting, missorting and spreading of Tau in neurons studied in microfluidic chambers / Varun Venkatesh Balaji". Bonn : Universitäts- und Landesbibliothek Bonn, 2017. http://d-nb.info/1166754804/34.
Texto completo
24
Morgan, Alex John Lewis. "Microfluidic devices to facilitate in-flow medium exchange, and tuneable size-based sorting, of microspheres". Thesis, Cardiff University, 2014. http://orca.cf.ac.uk/69902/.
Texto completoResumen
This thesis is focused on the manipulation of solid spheres and droplets with a particular focus on medium exchange and size based sorting. Two novel microfluidic devices are demonstrated. Firstly, a medium exchanger capable of transferring spheres and droplets between two miscible liquids was developed. The primary phase was extracted via a series of narrow perpendicular channels using a pressure differential created by mismatched input flow rates. Complete exchange of mineral oil phases has been demonstrated along with the use of the device to create a buffer region for chemical sphere curing of alginate droplets for use in stem cell encapsulation. This device offers simple passive exchange at greater throughput than previously demonstrated. The second device is a tuneable sphere focusing device that focuses spheres via inertial lift forces. Through the compression of the device the channel width is reduced such that the spheres are moved from an unfocused state into two focused streams. Focusing of 12μm spheres into two streams is achieved through channel dimension deformation. The device is shown to be capable of up to 88% ±1.1% focusing when compressed whilst the uncompressed device only focuses 51.4% ±2.1% of the spheres. The deformation of the device offers the potential for a greater range of tuning than previously possible with inertial lift based sorting.
25
Kaplinsky, Joseph John. "Single cell analysis and cell sorting using microfluidic devices with application to circulating tumour cells". Thesis, Imperial College London, 2012. http://hdl.handle.net/10044/1/9474.
Texto completoResumen
This thesis describes the development of integrated microfluidic technology for single cell proteomic analysis, focusing on circulating tumour cells (CTCs). While single cell proteomic analysis has wide applicability across biology and medicine, CTCs form an ideal first application. Circulating tumour cells are intimately involved in metastasis, the step in cancer overwhelmingly responsible for death, yet have proved hard to study. Single cell microfluidic technology is ideal first because the quantity of material available is inherently at the level of a few cells and second because cell to cell variation is of great interest. Chapter 1 is an introduction to the field. In chapter 2 a microfluidic sandwich assay for quantification of protein at the single cell level is described. In chapter 3 the isolation of CTCs in a microfluidic device is described. This relies on taking the output of the CellSearch® system and inputing it to a microfluidic device. While CTCs were identified, the result showed that a more systematic approach is required for counting and integration with the single cell assay previously described. Chapters 4 and 5 describe development of technology suitable for counting and isolation of CTCs integrated into a microfluidic device with single cell proteomic analysis, although the work done here makes use of fluorescently labelled beads and model cell lines rather than CTCs from patient samples. Chapter 4 describes microfluidic cytometry that can be used to count and identify a labelled population of cells, such as stained CTCs. Chapter 5 describes the prelimary development of a sorting system suitable for isolation of CTCs integrated with the cytometer.
26
Caën, Ouriel. "Droplet microfluidics for cancer cell evolution Parallelized ultra-high throughput microfluidic emulsifier for multiplex kinetic assays Counting single cells in droplets Multiplexed droplet sorting". Thesis, Sorbonne Paris Cité, 2016. https://wo.app.u-paris.fr/cgi-bin/WebObjects/TheseWeb.woa/wa/show?t=1888&f=11697.
Texto completoResumen
Cette thèse porte sur une problématique moderne: la prise en charge de patients cancéreux par thérapie ciblée. De tels traitements sont efficaces et représentent une récente avancée thérapeutique majeure pour des patients multi-traités en cas d'échec thérapeutique. Cependant, les réponses des patients sont souvent transitoires puisqu'ils rechutent plusieurs mois après le traitement. Il a été récemment démontré que pour les cancers du poumon, ces rechutes sont associées à l'émergence de nouvelles altérations génétiques au sein des tumeurs. Il est donc important de discriminer avant traitement le processus de résistance qui pourrait se produire et proposer ainsi la combinaison de traitements qui empêcheraient l'apparition d'une résistance. Une telle évaluation précoce pourrait être facilitée grâce à l'utilisation de la microfluidique de goutte qui permet un criblage à haut débit à l’échelle de la cellule unique. Cette technologie pourrait ainsi devenir un outil générique pour identifier la résistance à un traitement à un stade précoce de son développement. Dans le cadre de cette thèse, nous avons utilisé comme modèle in vitro des lignées cellulaires NSCLC (Non-Small Cell Lung Cancer) respectivement sensibles et résistantes au traitement. Nous avons développé de nouveaux outils de microfluidique de goutte qui ont permis de discriminer entre le phénotype et le génotype de cellules uniques sensibles au traitement et résistantes au traitement. Une telle preuve de principe constitue une première étape vers la compréhension de l'hétérogénéité de populations de cellules tumorales, dont il a été montré qu’elle est corrélée avec la résistance aux thérapiesThis thesis deals with a modern problematic: the management of cancer patients using targeted therapy. Such treatments are efficient and represent a recent major therapeutic advance for multi-treated patients in therapeutic failure. However patients responses are often transitory as they relapse several months following the treatment. It has been recently demonstrated that for lung cancers these escapes are associated with the emergence of new genetic alterations within tumors. It is thus important to discriminate before treatment the resistance process that could occur and thus propose the therapeutic combination of treatments that would prevent the appearing of a resistance. Such early assessment could be eased-up thanks to the use of droplet microfluidics which allows high-throughput screening at a single-cell level resolution. This technology could hence become a generic tool to identify resistance to a treatment in an early stage of its development. In the framework of this thesis we used as an in vitro model treatment-sensitive and treatment-resistant NSCLC (Non-Small Cell Lung Cancer) cell lines. We developed novel droplet microfluidics tools which allowed to discriminate between the phenotype and genotype of single treatment-sensitive and treatment-resistant single cells. Such a proof of principle constitutes a first step towards the understanding of tumor cell population heterogeneity, which has been shown to be correlated with resistance to therapies
27
Adeyemi, Adefemi Habib. "Microfluidic Devices for the Characterization and Manipulation of Encapsulated Cells in Agarose Microcapsules Using Dielectrophoresis and Electrophoresis". Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/37102.
Texto completoResumen
Cell encapsulation is a promising concept in regenerative medicine and stem cell treatment of diseases. Cells encapsulated in hydrogels have shown to yield better therapeutic outcome over cells in suspension. Microfluidic platforms have facilitated the process of cell encapsulation through the controlled mixing of aqueous cell solution and hydrogel with an immiscible liquid to yield a monodispersed population of microcapsules at a high throughput. However, given that the microfluidic process of placing cells in microcapsules is completely random, yielded samples are often riddled with empty microcapsules, raising the need for a post-encapsulation purification step to sort empty microcapsules from cell-laden ones. Sorting of microcapsules can be achieved through several techniques, most desirable of which are electrokinetic such as dielectrophoresis (DEP) and electrophoresis (EP). The advantages of DEP and EP techniques are that they support label-free sorting and yield a high throughput. However to achieve true effective DEP or EP sorting, there is a need to understand how empty microcapsules react to these electrokinetic forces versus occupied microcapsules. This study developed microfluidic devices for characterising the electrokinetic effects on microcapsules using DEP and EP. Results of both characterization techniques showed notable differences in the response of empty microcapsules versus cell-laden ones, reinforcing their potentials for sorting. Furthermore, this study proposed designs for microcapsules sorting devices that leverage EP and DEP.
28
Marchington, Robert F. "Applications of microfluidic chips in optical manipulation & photoporation". Thesis, University of St Andrews, 2010. http://hdl.handle.net/10023/1633.
Texto completoResumen
Integration and miniaturisation in electronics has undoubtedly revolutionised the modern world. In biotechnology, emerging lab-on-a-chip (LOC) methodologies promise all-integrated laboratory processes, to perform complete biochemical or medical synthesis and analysis encapsulated on small microchips. The integration of electrical, optical and physical sensors, and control devices, with fluid handling, is creating a new class of functional chip-based systems. Scaled down onto a chip, reagent and sample consumption is reduced, point-of-care or in-the-field usage is enabled through portability, costs are reduced, automation increases the ease of use, and favourable scaling laws can be exploited, such as improved fluid control. The capacity to manipulate single cells on-chip has applications across the life sciences, in biotechnology, pharmacology, medical diagnostics and drug discovery. This thesis explores multiple applications of optical manipulation within microfluidic chips. Used in combination with microfluidic systems, optics adds powerful functionalities to emerging LOC technologies. These include particle management such as immobilising, sorting, concentrating, and transportation of cell-sized objects, along with sensing, spectroscopic interrogation, and cell treatment. The work in this thesis brings several key applications of optical techniques for manipulating and porating cell-sized microscopic particles to within microfluidic chips. The fields of optical trapping, optical tweezers and optical sorting are reviewed in the context of lab-on-a-chip application, and the physics of the laminar fluid flow exhibited at this size scale is detailed. Microfluidic chip fabrication methods are presented, including a robust method for the introduction of optical fibres for laser beam delivery, which is demonstrated in a dual-beam optical trap chip and in optical chromatography using photonic crystal fibre. The use of a total internal reflection microscope objective lens is utilised in a novel demonstration of propelling particles within fluid flow. The size and refractive index dependency is modelled and experimentally characterised, before presenting continuous passive optical sorting of microparticles based on these intrinsic optical properties, in a microfluidic chip. Finally, a microfluidic system is utilised in the delivery of mammalian cells to a focused femtosecond laser beam for continuous, high throughput photoporation. The optical injection efficiency of inserting a fluorescent dye is determined and the cell viability is evaluated. This could form the basis for ultra-high throughput, efficient transfection of cells, with the advantages of single cell treatment and unrivalled viability using this optical technique.
29
Ashok, Praveen Cheriyan. "Integration methods for enhanced trapping and spectroscopy in optofluidics". Thesis, University of St Andrews, 2011. http://hdl.handle.net/10023/2546.
Texto completoResumen
“Lab on a Chip” technologies have revolutionized the field of bio-chemical analytics. The crucial role of optical techniques in this revolution resulted in the emergence of a field by itself, which is popularly termed as “optofluidics”. The miniaturization and integration of the optical parts in the majority of optofluidic devices however still remains a technical challenge. The works described in this thesis focuses on developing integration methods to combine various optical techniques with microfluidics in an alignment-free geometry, which could lead to the development of portable analytical devices, suitable for field applications. The integration approach was applied to implement an alignment-free optofluidic chip for optical chromatography; a passive optical fractionation technique fractionation for cells or colloids. This system was realized by embedding large mode area photonic crystal fiber into a microfluidic chip to achieve on-chip laser beam delivery. Another study on passive sorting envisages an optofluidic device for passive sorting of cells using an optical potential energy landscape, generated using an acousto-optic deflector based optical trapping system. On the analytical side, an optofluidic chip with fiber based microfluidic Raman spectroscopy was realized for bio-chemical analysis. A completely alignment-free optofluidic device was realized for rapid bio-chemical analysis in the first generation by embedding a novel split Raman probe into a microfluidic chip. The second generation development of this approach enabled further miniaturization into true microfluidic dimensions through a technique, termed Waveguide Confined Raman Spectroscopy (WCRS). The abilities of WCRS for online process monitoring in a microreactor and for probing microdroplets were explored. Further enhanced detection sensitivity of WCRS with the implementation of wavelength modulation based fluorescent suppression technique was demonstrated. WCRS based microfluidic devices can be an optofluidic analogue to fiber Raman probes when it comes to bio-chemical analysis. This allows faster chemical analysis with reduced required sample volume, without any special sample preparation stage which was demonstrated by analyzing and classifying various brands of Scotch whiskies using this device. The results from this study also show that, along with Raman spectroscopic information, WCRS picks up the fluorescence information as well, which might enhance the classification efficiency. A novel microfabrication method for fabricating polymer microlensed fibers is also discussed. The microlensed fiber, fabricated with this technique, was combined with a microfluidic gene delivery system to achieve an integrated system for optical transfection with localized gene delivery.
30
Manczak, Rémi. "Dispositif microfluidique pour la quantification de sous-populations de cellules". Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30165/document.
Texto completoResumen
La détection quantitative de cellule est généralement réalisée par cytométrie en flux en raison de sa haute sensibilité, cependant cette technique est difficile à mettre en oeuvre pour des analyses de routine ou des analyses au chevet du patient. Les méthodes électrochimiques et en particulier la spectroscopie d'impédance électrochimique ont gagné en popularité en raison de la possibilité de réaliser des analyses sans marquage et de miniaturiser les systèmes d'analyse pour une intégration sur puce. De plus, les avancées récentes dans le domaine des technologies de microfabrication ont permis de développer des électrodes micrométriques ayant de nombreux avantages tels que des hautes impédances dues à des courants très faibles ainsi que la possibilité de les intégrer dans des systèmes microfluidiques. L'objectif de ce travail de thèse se concentre sur la réalisation et l'optimisation de dispositifs microfluidiques contenant les systèmes d'électrodes pour le piégeage immunologique et le comptage impédimétrique de monocytes pro-inflammatoires, marqueurs d'une infection. Compte tenu de l'influence du taux de recouvrement de la surface sur la sensibilité, plusieurs géométries d'électrodes ont été testées. Les meilleures sensibilités et reproductibilités ont été obtenues dans le cas de microélectrodes interdigitées ayant de faibles espaces inter-électrodes (50 µm). D'autre part les études ont également permis de montrer dans ce cas, que la gamme de concentration cellulaire pour laquelle la sensibilité était maximale dépendait de la surface de l'électrode. Les électrodes de plus petites surfaces ont permis d'atteindre une limite de détection inférieure à 10 cellules/mL. De plus, compte tenu de la grande sensibilité des dispositifs ainsi réalisés, ces systèmes ont également été testés pour la caractérisation d'interaction récepteurs-ligands à partir de cellules entières. Ces études ont permis de mettre en évidence l'interaction de cellules CHO exprimant le récepteur A2a à des ligands c-di-AMP pour de très faibles concentrations cellulairesThe quantitative detection of specific cells is usually carried out by flow cytometry due to its high sensitivity and reliability, however, this technique is not suited for routine screening and point-of-care diagnostics. Electrochemical methods, as electrochemical impedance spectroscopy have gained interest mainly due to a label-free detection and their miniaturization capability required for integration on chip. Furthermore, recent advances in microfabrication based technologies have allowed to develop micron-sized electrodes whose main advantages over conventional electrodes are higher impedances due to smaller currents and the possibility of being integrated inside microfluidic channels. The aim of the present work was the realization and the optimization of microfluidic devices with improved sensitivity targeting the immuno-trapping and counting of pro-inflammatory monocytes as infection markers. Taking into account the influence of the surface coverage on the sensitivity, different geometries were tested. The best sensitivities and reproducibility were recorded in the case of interdigitated micro-electrodes with weak inter-electrodes gap (50 µm). Moreover, experiments carried out with different surfaces demonstrated that there was a threshold beyond which a surface is exploitable for a given slice of concentration. Such microfluidic devices allowed to reach a detection limit around 10 cells/mL. Furthermore, due to the high sensitivity recorded, the devices were also tested to detect ligand binding by cell receptors. These studies have allowed to demonstrate the interaction of CHO-A2a with c-di-AMP for low cell concentrations
31
Nivedita, Nivedita. "Fluid Dynamics and Inertial Focusing in Spiral Microchannels for Cell Sorting". University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1460731135.
Texto completo
32
Chung, Kwanghun. "Automated and integrated microsystems for highthroughput and high-resolution imaging, sorting, and laser ablation of C. elegans". Diss., Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/37163.
Texto completoResumen
The objective of this research is to develop automated and integrated microsystems for high-resolution imaging and high-throughput phenotyping / laser ablation of C. elegans. These microsystems take advantage of microfluidic technology for precisely handling animals and computer-aid automation for high-throughput processing. We demonstrated automated and high-throughput imaging / sorting and laser ablation of C. elegans. This thesis work is divided into four parts: development of a microsystem for imaging and sorting, development of a microsystem for laser cell ablation, development of a novel temperature measurement method, and development of pressure measurement method in microchannels.
First, a microsystem was developed for high-throughput microscopy at high resolution and sorting. The microfluidic chip integrates novel microfluidic components to trap, position, immobilize, and sort/release animals. To characterize device operation and aid design of the device numerical models were developed. The experimental results demonstrate that the device operates robustly in a completely automatable manner. Additionally, a sophisticated control algorithm developed by Matthew Crane (Dr. Hang Lu¡¯s lab) automates the entire process of image acquisition, analysis, and sorting, which allows the system to operate without human intervention. This microsystem sorted worms based on their fluorescent expression pattern with over 95% accuracy per round at a rate of several hundred worms per hour.
Secondly, the technologies developed for the imaging/sorting system were adapted and further improved to develop a microsystem for high-throughput cell laser ablation of C. elegans. The multiplex ablation module combined with the embryo trap module enables robust manipulation of embryos/L1-stage C. elegans. In addition, software for image processing and automation was developed to allow high-throughput cell ablations. This system performed ablation of a large number of animals and demonstrated accurate ablation by showing behavioral defects of the ablated worms in a chemotaxis avoidance assay.
Thirdly, to aid future development of the microdevices, a novel in situ method for three-dimensionally resolved temperature measurement in microchannels was developed. This method uses video-microscopy in combination with image analysis software (developed by Jaekyu Cho in Dr. Victor Breedveld¡¯s group) to measure Brownian diffusion of nanoparticles that is correlated to temperature. This method offers superior reproducibility and reduced systematic errors. In addition, we demonstrated that this method can be used to measure spatial temperature variations in three dimensions in situ.
Lastly, a method for pressure measurement in microdevices was also developed through collaboration with Hyewon Lee (Dr. Hang Lu¡¯s lab) to aid further device optimization. These micro pressure-sensors are composed of two flow layers with a polydimethylsiloxane (PDMS) membrane in between. The membrane deforms as a function of pressure and its deformation is quantified by a simple image-based method. These sensors offer high-precision pressure measurement in broad sensing ranges. In addition, a pressure transduction scheme combined with imaging-based method enables multiplex pressure measurement for simultaneously detecting pressures in multiple locations in a microsystem.
Overall, the technologies developed in this thesis will establish a solid basis for continuous improvement of the microsystems for multi-cellular model organisms. This high-throughput technology will facilitate a broad range of biological and medical research.
33
Perronno, Paul. "Development of a biosensor for in situ pathogen detection on hands". Electronic Thesis or Diss., Strasbourg, 2024. http://www.theses.fr/2024STRAD049.
Texto completoResumen
Les infections sont un problème grandissant aujourd’hui, notamment due à l’augmentation de pathogènes résistant aux antibiotiques, L’hygiène des mains et les gestes barrières sont les premiers outils de prévention d’infections. Cependant, il y a un besoin de systèmes d’alertes rapides pour une meilleure prévention et éviter des épidémies ou pandémies. Il existe de nombreuses techniques de détection d‘infections tel que la réaction en chaine par polymérase. Ces dernières années, de nouveaux systèmes miniatures ont émergé basé sur diverses technologies comme l’optique ou l’impédance. Ces méthodes sont souvent spécifiques, longues ou couteuses. Une prévention efficace repose sur la possibilité de tester rapidement un grand nombre d’infections, ce qui n’est pas possible actuellement. Cette thèse développe un système de détection d’infections intégrable, rapide et abordable scindé en trois parties : un tri microfluidique, une détection par spectroscopie d’impédance et une détection optiqueInfections are a big issue in today’s health world, partly due to the rising number of multi-resistant pathogens. Hand hygiene and barrier gestures are the first tools for infections prevention. However, early alert systems are also required for a better prevention and to avoid future epidemics or pandemics. Numerous techniques exist for infection detection such as culture or polymerase chain reaction. In recent years, miniaturized systems emerged based on various technologies such as optics, mechanics, nuclear magnetic resonance or impedance. Unfortunately, all these methods are usually specific, time-consuming or expensive. An effective prevention relies on the performance of a large number of rapid tests on a large scale, which is not currently achievable. This thesis develops an integrable, fast and affordable infection detection system combining three parts based on three technologies: a microfluidic sorting, an impedance spectroscopy detection and an optical detection
34
Estes, Matthew D. "On-chip Cell Separator using Magnetic Bead-based Enrichment and Depletion of Various Cell Surface Markers". University of Cincinnati / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1242661265.
Texto completo
35
Fouet, Marc. "Microfluidique 3D et actionneurs magnétiques : de leur intégration à la préparation d'échantillons biologiques". Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30036/document.
Texto completoResumen
Les puces microfluidiques sont des éléments clés pour la manipulation et l'analyse de solutions et d'échantillons biologiques. Elles facilitent les études aux échelles microscopiques et sont le fondement du concept de laboratoire sur puce, à la pointe des diagnostics médicaux. L'objectif de ces travaux de thèse a été d'explorer les possibilités fonctionnelles offertes par les architectures microfluidiques 3D, dans le cadre du développement d'outils diagnostiques reposant sur le tri, le marquage et la manipulation de cellules. Ces fonctions ont été validées sur des sous-populations de monocytes, qui sont des marqueurs de maladies inflammatoires. Afin de couvrir une chaîne cohérente d'étapes nécessaires au prétraitement des échantillons biologiques complexes, trois fonctions complémentaires ont été étudiées : le tri par taille par filtration hydrodynamique, le tri immunologique par séparation magnétique et le marquage sur puce par microparticules magnétiques. En vue d'effectuer des réactions de marquage (sondes fluorescentes ou microbilles magnétiques), un micro-mélangeur reposant sur la séparation et recombinaison de flux (transformation du boulanger) a été fabriqué et caractérisé. Des expériences de test des dispositifs pour les mélanges fluorescéine/eau et cellules/microbilles sont proposées, ainsi que les modèles analytiques et numériques associés. De nouvelles approches de tri par taille par filtration hydrodynamique ont été étudiées, en réalisant des structures 3D en "bypass", qui rendent possible une stratégie de mélange adaptée aux cellules et particules. Un modèle analytique des écoulements et de l'efficacité de tri et de mélange est proposé, ainsi qu'une caractérisation des dispositifs. Il a été de plus démontré que cette approche permettait également de réaliser la séparation d'espèces sub-micrométriques comme les microparticules sanguines. Tous les systèmes microfluidiques 3D ont été obtenus par une technique originale d'empilement (laminage) de films secs photosensibles, réduisant nettement le temps de micro-fabrication et compatibles avec les procédés standards. Cette technique de fabrication permet également l'intégration de micro-sources magnétiques dans les laboratoires sur puce par la réalisation de micro-bobines planaires sous des canaux microfluidiques. En couplant les effets des micro-bobines intégrées aux champs générés par des aimants extérieurs, nous apportons la preuve de concept de systèmes pour la séparation, la déviation et le piégeage de microbilles magnétiques. Les modèles (champs et force magnétiques) et la caractérisation des dispositifs seront présentés. Nous aborderons également la réalisation d'instrumentation spécifique (source de courant) pour l'actionnement des bobines, permettant le contrôle (temporel et en intensité) des champs magnétiques appliquésMicrofluidic chips are key elements for solutions and biological samples handling and analysis. They are enablers for micro-scale studies and are the cornerstone of lab on chips, at the cutting edge of medical diagnostics. The aim of this thesis work was to explore functional possibilities offered by 3D microfluidic architectures for the development of diagnostic tools relying on cell sorting, tagging and handling. These functions were investigated on monocytes sub-populations, which are markers for many inflammatory diseases. In order to cover a consistent series of necessary steps for complex biological samples pretreatment, three additional functions were studied: size sorting with hydrodynamic filtration, immuno-isolation by magnetic separation, and on-chip tagging with magnetic microparticles. To perform tagging reactions, a micromixer based on diffusion and flow split and recombination (baker's transform) was fabricated and characterized. Analytical (diffusion) and numerical (diffusion-advection) models are showed, together with test experiments on the devices for mixing reactions of fluorescein/water and cells/microbeads. New approaches of hydrodynamic filtration based size sorting were investigated by devising 3D bypass structures, that allow developing a mixing strategy (tagging reactions) suited to cells and particles. An analytical model for flows and sorting efficiency is introduced and compared to the devices characterization. Furthermore, it was shown that this approach also enables sorting of sub-micron particles (like blood microparticles). All 3D microfluidic systems were obtained thanks to an original dry film photoresist stacking (lamination) technique, dramatically reducing micro-fabrication time, even though compatible with standard process. This fabrication technique also enables magnetic micro-sources integration in lab on chips by realizing planar micro-coils underneath microfluidic channels. By coupling the effects of integrated micro-coils to the fields generated by external magnets, we brought the proof of concept of systems dedicated to trapping, focusing and separating (in flow) magnetic microbeads. Models (magnetic fields and forces) are described along with devices characterization. Conception of specific instrumentation (current source) for micro-coils actuation is also shown, as it allows time and intensity control over applied magnetic fields
36
Valette, Marion. "Laboratoire sur puce pour la détection d'événements cellulaires rares". Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30292.
Texto completoResumen
Le tissu adipeux est une source riche en cellules souches multipotentes : les Cellules Souches Adipeuses (ASCs pour Adipose Stem Cells). Ces cellules, qui possèdent la capacité de se différencier en différents types cellulaires, ouvrent de nombreuses perspectives dans le domaine de la médecine régénératrice et dans des applications telles que le diagnostic du diabète de type 2. Connues pour migrer et circuler dans la lymphe, l'hypothèse de leur présence dans le sang n'est pas exclue mais aucune méthode n'existe afin de le prouver. L'objectif de ces travaux de thèse est alors de développer un laboratoire sur puce capable d'isoler les ASCs à partir d'échantillons biologiques complexes en mettant en application des méthodes microfluidiques de tri passives et sans marquage. Ce sont ainsi les propriétés intrinsèques des cellules qui sont exploitées. Or, les ASCs ne présentent aucune caractéristique physique spécifique. En effet, nous avons tout d'abord montré que leur diamètre est compris entre 10 et 25 µm, ce qui ne leur permet pas de se distinguer de la plupart des cellules sanguines. De même, ces cellules ne possèdent pas d'antigène spécifique sur leur membrane. Nous proposons alors un dispositif combinant deux étapes complémentaires afin d'isoler complètement les ASCs des autres types cellulaires. La première étape a pour objectif de prétraiter l'échantillon en retirant, par filtration hydrodynamique, toutes les cellules de diamètre inférieur à 10 µm. Ce dispositif doit ainsi permettre de retirer du milieu les globules rouges qui représentent plus de 99 % des cellules constituant le sang ainsi que les plaquettes et quelques globules blancs. Ces travaux de thèse ont démontré que le dispositif développé est capable de prétraiter efficacement un échantillon sanguin pur (humain ou murin) en éliminant plus de 99,9 % des globules rouges. De plus, il a été démontré que la filtration n'engendre pas de lyse cellulaire, ce qui est encourageant pour des questions de viabilité cellulaire et l'exploitation des cellules après filtration. L'échantillon alors obtenu contient les cellules d'intérêt ainsi que quelques cellules hématopoïétiques restantes. La deuxième étape a pour but de parfaire l'isolement des ASCs en les séparant des cellules hématopoïétiques restantes. Pour ce faire, la méthode employée, l'exclusion immunologique par cell rolling, se base sur la spécificité de la réaction antigène-anticorps. Les ASCs ne possédant pas d'antigène spécifique, ce sont les antigènes spécifiques des leucocytes qui ont été ciblés. L'objectif est ainsi de dépléter l'échantillon des leucocytes restants. Ces travaux ont mené à l'élaboration d'un protocole de fonctionnalisation de surface optimal. De plus, de premiers résultats encourageants sur le cell rolling sur une surface fonctionnalisée avec des anticorps anti-CD45 ont été obtenusAdipose tissue is a rich source of multipotent stem cells: Adipose Stem Cells (or ASCs). Due to their differentiation capabilities, ASCs became cells of considerable interest for regenerative medicine and are of high interest for type II diabetes diagnosis. Known to migrate and circulate in lymph, the hypothesis of their presence in blood is not excluded but no method exists to prove it. The aim of this study is to develop a lab-on-chip able to isolate ASCs from complex biological samples by using passive and label-free microfluidic sorting methods. These methods involve intrinsic properties of fluids and objects. Yet, ASCs do not have specific physical characteristic. We have demonstrated that their diameter is comprised between 10 and 25 µm: they cannot be distinguished from most of other blood cells. In addition, they do not present specific antigen on their membrane. In order to completely isolate ASCs from other cell types, we propose an original approach combining two complementary steps. The first step aims at pre-treating the sample by removing, via hydrodynamic filtration, all the cells with a diameter below 10 µm. With this device, red blood cells, which represent more than 99% of blood cells, platelets and some leukocytes, have to be removed. This study has demonstrated that the device is able to effectively pre-treat pure blood sample (either from human or from mouse) as it removes more than 99.9% of red blood cells. It has also been demonstrated that filtration does not lead to cell lysis, which is a promising result for cell viability and the reuse of cells after filtration. The obtained sample contains cells of interest and some remaining hematopoietic cells. The second step aims at refining ASCs isolation by separating them from remaining hematopoietic cells. The method used, called immunological exclusion by cell rolling, is based on antigen-antibody specific reaction. As ASCs do not have specific antigen, leukocytes antigens have been involved. The objective is so to deplete the sample of the remaining leukocytes. This study led to the elaboration of an optimised surface functionalization protocol. Moreover, promising results on cell rolling realised on a surface functionalized with anti-CD45 antibodies were obtained
37
Ehrenhofer, Adrian, Manfred Hahn, Martin Hofmann y Thomas Wallmersperger. "Mechanical behavior and pore integration density optimization of switchable hydrogel composite membranes". Sage, 2019. https://tud.qucosa.de/id/qucosa%3A74211.
Texto completoResumen
Switchable hydrogel-layered composite membranes can be used for the analysis of particle size distributions. This functionality is provided by pores with controllable diameter. In order to obtain a device that can be used to measure the cell size distribution in native biological samples, lots of switchable pores are required. In the current work, we model and simulate the mechanical behavior of active composite membranes with switchable pores. This is done in order to find the maximum number of pores that can be integrated into a membrane without cross-influencing effects on the actuation of the pores. Therefore, we investigate (1) the interaction of active pores inside the multifunctional composite and (2) the membrane bending under microfluidic pressure load. We show that through miniaturization, sufficient pores can be added to a permeation control membrane for processing native blood samples. The envisioned device allows a parallelized measurement of cell sizes in a simple lab-on-a-chip setup.
38
Lin, Gungun. "Multifunctional Droplet-based Micro-magnetofluidic Devices". Doctoral thesis, Universitätsbibliothek Chemnitz, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-208797.
Texto completoResumen
Confronted with the global demographic changes and the increasing pressure on modern healthcare system, there has been a surge of developing new technology platforms in the past decades. Droplet microfluidics is a prominent example of such technology platforms, which offers an efficient format for massively parallelized screening of a large number of samples and holds great promise to boost the throughput and reduce the costs of modern biomedical activities. Despite recent achievements, the realization of a compact and generic screening system which is suited for resource-limited settings and point-of-care applications remains elusive.
To address the above challenges, the dissertation focuses on the development of a compact multifunctional droplet micro-magnetofluidic system by exploring the advantages of magnetic in-flow detection principles. The methodologies behind a novel technique for biomedical applications, namely, magnetic in-flow cytometry have been put forth, which encompass magnetic indexing schemes, quantitative multiparametric analytics and magnetically-activated sorting. A magnetic indexing scheme is introduced and intrinsic to the magnetofluidic system. Two parameters characteristic of the magnetic signal when detecting magnetically functionalized objects, i.e. signal amplitude and peak width, providing information which is necessary to perform quantitative analysis in the spirit of optical cytometry has been proposed and realized. Magnetically-activated sorting is demonstrated to actively select individual droplets or to purify a population of droplets of interest. Together with the magnetic indexing scheme and multiparametric analytic technique, this functionality synergistically enables controlled synthesis, quality administration and screening of encoded magnetic microcarriers, which is crucial for the practical realization of magnetic suspension arrays technologies. Furthermore, to satisfy the needs of cost-efficient fabrication and high-volume delivery, an approach to fabricate magnetofluidic devices on flexible foils is demonstrated. The resultant device retains high performance of its rigid counterpart and exhibits excellent mechanical properties, which promises long-term stability in practical applications.
39
White, William Neil. "Microfluidic cell sorting techniques to study disease processes /". 2009. http://digital.library.louisville.edu/cgi-bin/showfile.exe?CISOROOT=/etd&CISOPTR=909&filename=910.pdf.
Texto completo
40
Fu, Hui-Ting y 傅薈廷. "Integrated Microfluidic System for Efficiency Enhancement of Sorting Sperm". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/57860456489149588995.
Texto completoResumen
碩士國立清華大學
奈米工程與微系統研究所
99
The thesis presents an integrated microfluidic system which consists of laminar stream-based microchannels, makler counting chamber and flow cytometric analysis to enhance the sperm motility sorting efficiency. The working concept lies in the design of multiple channel systems that successfully replace traditional methods, which could be achieved motile sperms without centrifugation steps. Simultaneously, the damage to the sperms could be avoided. The fabrication process of our bio-chip include SU8 thick-film photolithography and soft-lithography, which has the advantages of biocompatibility, low-cost, high-precision, disposable, and easy to produce etc., so that it is suitable for biomedical chip. With the advances in the technologies, reproductive medicine has become an important role in the field of medical science. The main reasons of infertility from male are the abnormality of sperms and the lack of sperms. IVF (in vitro fertilization) technology is a natural in vitro fertilization process that comes after a series of sample pre-treatment. The semen property, including motility, total number, and the concentration of sperms will directly affect the outcome. Therefore, the optimized microfluidic system provides a good opportunity to use and an inexpensive requirement to select the most appropriate sperms before IVF process. The study is divided into two parts. In the first part, the goal is to construct a microfluidic based sperm sorting system, which focus on the sorting and the classification based on sperm motility and viability. The details including chip design, flow field simulation, makler counting, flow cytometric analysis, and the experiments of semen samples. In the second part, the microfluidic system with multiple channels enhances the sorting efficiency in the quality and quantity of sperm. At the end, some ideas of future works were proposed.
41
Taylor, Jay Kendall. "The Design and Evaluation of a Microfluidic Cell Sorting Chip". Thesis, 2007. http://hdl.handle.net/10012/2641.
Texto completoResumen
Many applications for the analysis and processing of biological materials require the enrichment of cell subpopulations. Conventional cell sorting systems are large and expensive with complex equipment that necessitates specialized personnel for operation. Employing microfluidics technology for lab-on-a-chip adaptation of these devices provides several benefits: improved transport control, reduced sample volumes, simplicity of operation, portability, greater accessibility, and reduced cost. The designs of microfluidic cell sorting chips vary widely in literature; evaluation and optimization efforts are rarely reported. This study intends to investigate the primary components of the design to understand the effect of various parameters and to improve the performance of the microfluidic chip. Optimized individual elements are incorporated into a proposed cell sorter chip with the ability to dynamically sort target cells from a non-homogeneous solution using electrical driving forces.
Numerical and experimental results are used to evaluate the sample focusing element for controlled cell dispensing, the sorting configuration for target cell collection, and the flow elements for reduced pressure effects and prevention of flow blockages. Compact models are adapted to solve the potential field and flow field in the chip and to predict the focused sample stream width. A commercial CFD package is used to perform 2-D simulations of the potential, velocity, and concentration fields. A fluorescence microscopy visualization system is implemented to conduct experiments on several generations of chip designs. The data from sample focusing experiments, performed with fluorescent dye samples, is analyzed using a Gaussian distribution model proposed in this work. A technique for real-time monitoring of fluorescent microspheres in the microfluidic chip enables the use of dynamic cell sorting to emulate fully autonomous operation. The performance values obtained from these experiments are used to characterize the various design configurations.
Sample focusing is shown to depend largely on the relative size of the sheath fluid channel and the sample channel, but is virtually independent of the junction shape. Savings in the applied potential can be achieved by utilizing the size dependency. The focusing performance also provides information for optimizing the widths of the channels relative to the cell size. Successful sorting of desired cells is demonstrated for several designs. Key parameters that affect the sorting performance are discussed; a design employing the use of supplemental fluid streams to direct the particle during collection is chosen due to a high sorting evaluation and a low sensitivity to flow anomalies. The necessary reduction of pressure influences to achieve reliable flow conditions is accomplished by introducing channel constrictions to increase the hydrodynamic resistance. Also, prolonged operation is realized by including particle filters in the proposed design to prevent blockages caused by the accumulation of larger particles.
A greater understanding of the behaviour of various components is demonstrated and a design is presented that incorporates the elements with the best performance. The capability of the microfluidic chip is summarized based on experimental results of the tested designs and theoretical cell sorting relationships. Adaptation of this chip to a stand-alone, autonomous device can be accomplished by integrating an optical detection system and further miniaturization of the critical components.
42
Zhou, Yao. "Microfluidic Concentration Gradient Generation and Integrated Magnetic Sorting of Microparticles". Thesis, 2013. https://doi.org/10.7916/D8XD17V1.
Texto completoResumen
Microfluidic systems, with their feature size similar to that of biological cells, have great potential for cell manipulation and interrogation. On the other hand, the process of drug discovery involves vast amount of tests of candidate drug molecules with cells, and hence requires intensive manipulation and interrogation of cells. Therefore, it is conceivable that microfluidics can be and should be sufficiently exploited to facilitate drug discovery process. This dissertation investigates two of the most frequently performed cell operations in drug discovery, which are often performed in series, i.e., chemical stimulation of cells (cell treatment and chemotaxis) and cell sorting. For chemical stimulation of cells, rapid and novel designs of concentration gradient generation (CGG) devices are presented; for cell sorting, a magnetically The most prevalent type of CGG devices, i.e., complete mixing-based laminar-flow CGG devices, involves massive channel networks. The design of alternative laminar-flow CGG devices suffers lack of efficient and systematic design framework, and is currently implemented through time-consuming numerical simulations. Therefore, we first propose passive mixing-based laminar-flow CGG devices, for which an analytical diffusion-convection model is developed and incorporated into an iterative design framework to achieve modular design. Secondly, to eliminate the undesirable stimulation of fluid flow on cells as existing in both complete and partial mixing-based laminar-flow CGG devices, a novel class of CGG devices featuring two-layer design sandwiching a semipermeable membrane is presented. The devices effectively eliminate fluid flow while maintain a stable concentration gradient in the gradient generation region. Thirdly, the flow-free CGG devices are extended to realize arbitrary concentration gradients, which significantly enhance the CGG capability of the devices. The designs of all CGG devices are realized through microfabrication and tested against complex concentration gradients. The generated gradients generally agree with the specified gradients in less than 10%. Magnetic-activated cell sorting (MACS) is a high-throughput cell sorting scheme that recognizes cells specifically by their membrane proteins. The quality of magnetic incubation largely determines the final separation efficiency. To enhance magnetic incubation prior to separation, a magnetic incubator is designed utilizing a target acquisition by repetitive traversal (TART) mechanism, which significantly improves target capture efficiency and reduces incubation time. The magnetic incubator module is then integrated to the separator module, with both modules using the same magnetic setup, which facilitates the entire MACS process and promotes the target separation efficiency to over 90%. The microfluidic methods and tools developed in this work are potentially used for cell manipulation and interrogation and thus can be expected to facilitate the drug discovery process that involves intensive cell operations and testing.
43
Huang, Po Wei y 黃博威. "TO ENHANCE SPERM MOTILITY SORTING EFFICIENCY BY UTILIZING MICROFLUIDIC CHIP". Thesis, 2015. http://ndltd.ncl.edu.tw/handle/91098108519664397906.
Texto completoResumen
碩士國立清華大學
動力機械工程學系
104
The thesis presents acontrolled microfluidic system which consists of laminar stream-based microchannels. This characteristic is useful for selecting motile sperm.There is some laminar flow phenomenon in chip because flow rate of sperm and buffer are different. Motile sperm has ability to pass through the laminar flow boundary, and reach the reservoir we want to collect. The bio-chip method is different from traditional methods and centrifugation. Centrifugation need to select sperm by rotating at fast speed, the great gravity maybe will cause the damage to sperm. Finally, the flow cytometric analysis is utilizedto confirm the sorting efficiency of this system. The result showed that our study is successfully for sorting sperm. Assisted Reproductive Technology (ART) has become an important role in the field of medical science. It provides an important solution to some couple which is suffer from infertility.No matter ICSI (Intracytoplasmic sperm injection) or IVF (in vitro fertilization), sperm motility, quantity, concentration are the main reason for fertilization. Therefore, the optimized microfluidic system provides a perfect opportunity to use an inexpensive requirement to select the most appropriate sperms before IVF process. The fabrication process of bio-chip include SU8 thick-film photolithography and soft-lithography which is used by PDMS (Polydimethylsiloxanes), which has the advantages of biocompatibility, low-cost, high-precision, disposable, and easy to produce etc., so that it is suitable and common used for biomedical chip. The study is to construct a microfluidic based controlled microfluidic system, which focus on the sorting and the classification based on sperm motility and viability. The experimental details including chip design, flow field simulation, pump parameter setup, flow cytometric analysis. All parts are a key point associated with the final result.Slow flow rate has favorable environment to increase the opportunity of motile sperm to pass through the laminar flow boundary. Moreover, this environment can reduce interference with direction of sperm swim forward. At the last, more progressive quantity and quality can be observed by the flow cytometric analysis. The result show that counted ratio of motile sperm can increase a lot. Therefore, using controlled microfluidic system is successful to enhance the sperm motility sorting efficiency. It confirms that the microchannel really has an advantage in Assisted Reproductive Technology.
44
Chiu, Po-Lin y 邱博霖. "Using Spiral Microfluidic Channel for High Efficiency Lymphocyte Cell Sorting". Thesis, 2018. http://ndltd.ncl.edu.tw/handle/vj3z7r.
Texto completo
45
"Computational Models for Microfluidic Sorting and Mechanotype Analysis of Circulating Cells". Tulane University, 2020.
Buscar texto completoResumen
archives@tulane.eduStructural changes in the cytoskeleton during metastatic transformation make cancer cells more deformable, and recent experimental studies confirm a direct correlation between cell invasiveness and cell deformability. Several microfluidic approaches have recently developed to exploit this cellular property for high-throughput assessment of metastatic risk from small samples of patient’s blood. While demonstrating feasibility in the lab, these technologies often lack a solid theoretical foundation or do not show adequate sensitivity to cellular mechanical properties (“mechanotype”). The long-term goal of this project is to optimize microfluidic tests for metastatic risk assessment, including circulating tumor cell (CTC) isolation and mechanotype analysis, through predictive computational modeling. Specific aims of the presented study are 1) to expand the capability of our custom computational algorithm for viscoelastic cell deformation and migration to simulate cell sorting and CTC isolation in channels with complex geometry, including channels with pillars and bifurcations, and 2) to demonstrate the capability of our algorithm to optimize microfluidic methods for cancer cell mechanotype measurement.
1
Scott J. Hymel
46
Tseng, Hsin-Yao y 曾新堯. "Using Controlled Microfluidic System to Enhance the Sperm Motility Sorting Efficiency". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/87669069962044040288.
Texto completoResumen
碩士國立清華大學
奈米工程與微系統研究所
101
The thesis presents a controlled microfluidic system which consists of laminar stream-based microchannels. The control microfluidic system is consists of syringe pump and connective tube module. The working concept lies in the microfluidic systems that successfully replace traditional methods, which could select motile sperms without centrifugation steps. Simultaneously, the damage to the sperms could be avoided. The flow cytometric analysis is utilized to confirm the sorting efficiency of this system. The result showed that our study is successfully for sorting sperm. The fabrication process of our bio-chip include SU8 thick-film photolithography and soft-lithography, which has the advantages of biocompatibility, low-cost, high-precision, disposable, and easy to produce etc., so that it is suitable for biomedical chip. Reproductive medicine has become an important role in the field of medical science. The main reasons of infertility from male are the abnormality of sperms and the lack of sperms. IVF (in vitro fertilization) technology is a natural in vitro fertilization process that comes after a series of sample pre-treatment. The semen property, including motility, total number, and the concentration of sperms will directly affect the outcome. Therefore, the optimized microfluidic system provides a good opportunity to use and an inexpensive requirement to select the most appropriate sperms before IVF process. The study is divided into two parts. In the first part, the goal is to construct a microfluidic based controlled microfluidic system, which focus on the sorting and the classification based on sperm motility and viability. The details including chip design, flow field simulation, pump parameter setup, flow cytometric analysis, and the experiments of semen samples. In the second part, the sorting efficiency and chip redesign were focused to enhance the sorting efficiency in the quality and quantity of sperm. The result show that counted ratio of motile sperm can increase to 90%. Therefore, using controlled microfluidic system is successful to enhance the sperm motility sorting efficiency. At the end, some ideas of future works were proposed.
47
Ruei-KaiSung y 宋瑞鎧. "Design of a microfluidic continuous sorting system with DPE-shaped optical fields". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/76260215780782616826.
Texto completoResumen
碩士國立成功大學
物理學系
102
This dissertation proposes a system which can sort multi-sized particles successively. This system includes a micro-channel structure, flow field, and light field which is set up by Diffractive Phase Elements (DPE). This system combines the gradient force of light field and the drag force of flow field to separate multi-sized particles to different branch channels to achieve the purpose of particle sorting.
48
Huei-WenWu y 吳慧紋. "Microfluidic systems for separation, counting, sorting, culture and differentiation of stem cells". Thesis, 2012. http://ndltd.ncl.edu.tw/handle/21188844130002589661.
Texto completoResumen
博士國立成功大學
工程科學系碩博士班
100
Microfluidic techniques have been recently developed for cell-based assays. In microfluidic systems, the objective is for these microenvironments to mimic in-vivo surroundings. With advantageous characteristics such as optical transparency and the capability for automating protocols, different types of cells can be cultured, screened and monitored in real time to systematically investigate their morphology and functions under well-controlled microenvironments in response to various stimuli. Recently, the study of stem cells using microfluidic platforms has attracted considerable interest. Even though stem cells have been studied extensively using bench-top systems, an understanding of their behavior in in-vivo-like microenvironments which stimulate stem cell proliferation and differentiation is still lacking. In this paper, several stem cell studies using microfluidic systems are purposed. The various miniature systems for stem cell separation/isolation, sorting, isolation, culture, differentiation, and stimulation, are then systematically introduced. Compared with conventional cell culture protocols, the microfluidic techniques provide versatile approaches to mimic more in vivo-like extracellular conditions for more realistic cell-based assay research. There still exist several inherent advantages including low biosamples/reagents consumption, a single integrated chip with multiple functions, and ability to run the array assays simultaneously. In this study, it was presented several new microfluidic devices fabricated based on SU-8 lithography process, a computer numerical controlled (CNC) milling for molds, and polydimethylsiloxane (PDMS) replica molding processes for stem cells researches. First, a passive separation chip with louver-like structures in the microchannel is proposed as a filter to separate mesenchymal stem cells (MSCs) from amniotic fluid. Buffer solution is used to squeeze the sample flow by using the syringe pumps to form a narrow stream so that the sample flows close to the louver-like structures to obtain a higher separating efficiency. The device can alleviate the clogging problem and avoid the use of the external force such that cells will not be damaged during the separation process. Preliminary results show that the developed microfluidic device can perform a good separation of 86% (beads). It also shows that that the developed microfluidic device can perform a good separation of 82.8 % for MSCs. Furthermore, the separation process can be repeated to improve the separation efficiency to 97.1 %. Another magnetic-bead technology integrated with the microfluidic system was purposed to develop a platform capable of isolating, counting, and sorting the hematopoietic stem cells. Since there is only an extremely small amount of stem cells existing in the umbilical cord blood, it is crucial to isolate and count the cell sample. In this research, the processes including mixing, transporting, counting and sorting can be completed automatically using the microfluidic control module. The target stem cells will be first captured by the antibody coated onto the magnetic beads, and then be successfully counted and sorted by a detection system. In addition, a continuous microfluidic device capable of automating culturing and differentiating the MSCs was proposed. Microfluidic-based pneumatic trumpet-like micropump activated by two electromagnetic valves (EMVs) with three air chambers plus an elusive side-channel was used to suck the culture medium so that the medium in the culture area can be continuously supplied. Moreover, the waste can be moved through the elusive side-channel without contamination. The results represented that MSCs can be cultured and differentiated into different kinds of phenotypes stably for a long time. The stem cell culture chip not only can provide stable and well-defined microenvironments, but also features in low consumption of research resource. Finally, an integrated microfluidic system capable of fine-tuning the insulin concentration automatically and applying different levels of shear stresses simultaneously was developed to investigate the effects of chemical and mechanical stresses on adipogenic differentiation of MSCs. It is comprised of a dilution device which can automatically fine-tune the concentrations of insulin for chemical stimulation on stem cells and three different levels of shear stresses produced by deflecting the PDMS membranes used to induce stem cells at the same time. The experimental results showed that an optimum insulin concentration of 10 μg/ml for differentiation of adipocytes can be determined. Moreover, the adipogenic differentiation can be suppressed by applying stronger shear stress and higher pulsation frequency of mechanical stimulation. In summary, we have demonstrated several microfluidic based platforms of separation/isolation, counting, sorting, culture, differentiation and stimulation for the stem cell which may provide a promising development in the this new medical field.
49
王姵茹. "Microfluidic Chip For High Sensitive Sequential Electrical Concentration And Sorting Of Neurotrasmitter". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/24925182898024684866.
Texto completo
50
Wu, Tsung-Lin y 吳宗臨. "Sorting and Separation Sperms based on a Novel Laminar-Stream-Based Microfluidic Chip". Thesis, 2008. http://ndltd.ncl.edu.tw/handle/74401466111459257108.
Texto completoResumen
碩士國立清華大學
奈米工程與微系統研究所
96
The thesis presents a novel microfluidic based sperm sorting system that the whole process can be done in only one step. The difference in sperm motility or concentration between raw semen samples can be ignored before the sorting process using this device. The fabrication process of our bio-chip include SU8 thick-film photolithography and soft-lithography, which has the advantages of low-cost, high-precision, volume production, disposable, and easy to produce etc., so that it is suitable for biomedical chip. Besides, the new idea that combines both SU-8 structure and PDMS part to construct the mode have the advantage that high aspect ratio structure can be easily made without losing the precision of micro flow channel. Since the emerging of in vitro fertilization (IVF) technology and intracytoplasmic sperm injection (ICSI), assisted reproductive technology (ART) has become an important part of medical field over the past 10 years. ISCI technology focus on the genetic normality of sperm, because the process consist the direct injection of a single sperm into an oocyte; IVF technology is an natural in vitro fertilization process that come after a series of sample pre-treatment. Since the frequency of collisions between sperms and oocytes plays a key role in the fertilization, the semen property, including motility, total number, and the concentration of sperms, will directly affect the outcome. It is difficult to determine whether the genetic materials is normal or not through micro electro mechanical system (MEMS) technology, but there is a good opportunity to use a MEMS based biochips to selected the most suitable sperms before IVF process. The study is divided into two parts. In the first part, the goal is to construct a microfluidic based sperm sorting system, which focus on the screening and the classification based on sperm motility. The details including chip design, flow field simulation, and the experiments of boar semen samples are show in chapter 3. The second part improves the screening efficiency using disjunctive design, which is present in chapter 4. At the end, some ideas of future works were proposed in Chapter 5.