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1
Holmes, David. "Advanced dielectrophoretic cell separation systems." Thesis, University of Glasgow, 2003. http://theses.gla.ac.uk/1160/.
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This thesis describes experimental and theoretical investigations into new particle handling and separation methods and techniques. It makes a major contribution to the rapidly expanding field of cell separation technology. A novel dielectrophoretic cell separation system has been developed, which is capable of processing large sample volumes (~50mL) in a flow through system. Previously reported dielectrophoretic cell separator systems typically process sample volumes in the 100mL range. The electrode configuration developed for this work allows the isolation and concentration of single particle types from large sample volumes; a method which could be further developed into a new rare-cell separation technology. In addition, a new technique of particle fractionation was developed termed ‘Dielectrophoretic Chromatography’. A cell separation chip was designed and built using standard micro-fabrication techniques. Experimental work was undertaken to demonstrate the function and limitations of the device. Numerical modelling of the particle motion in the device is presented and compared with experimental work for a number of different particle types, applied voltages and fluid flow rates. The dielectrophoretic separation system comprises a microfluidic channel, of cross-section 100mm x 10mm and length 50mm, with two sets of interdigitated microelectrode arrays. The first set of arrays, with characteristic electrode size 40mm, called a focussing device, has electrodes patterned onto the top and bottom surfaces of the flow channel. The second electrode array, which is part of the same device, has an electrode array patterned only on the bottom of the channel. Two sizes of secondary electrode array were used 20mm and 40mm. AC voltages (from 1V to 10V peak) are applied to the microelectrode, with a frequency between 10kHz to 180MHz. A dielectrophoretic force is exerted on the particles as they flow along the channel. The first electrode array uses negative dielectrophoresis to focus the stream of particles entering the device into a narrow sheet (one particle diameter thick) midway between the upper and lower channel surfaces. The second electrode array, down stream from the first is separately controllable.
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Yunus, Md Nurul Amziah. "Continuous dielectrophoretic separation of colloidal particles." Thesis, University of Southampton, 2010. https://eprints.soton.ac.uk/79370/.
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Dielectrophoresis (DEP) is a technique that can be used to separate particle at microscale. It is of particular interest because it is a non-invasive, non-destructive and non-contact technique, which ensures that sample composition remains the same with only the particles being separated. On the microscale, DEP has been used to separate viable and non-viable cells, and cells with different dielectric properties, with the aid of a range of miniaturised, microfabricated devices. However, DEP at the nano-scale is a novel area and is still under research. Miniaturisation of devices in general has been an ongoing trend to improve the performance of analytical tools. In particular, processes for micro-device fabrication using dry film resist have been studied in order to reduce size, cost, sophisticated hardware usage and power consumption. This thesis presents an investigation into the novel design of dielectrophoretic particle separator, using rapid dry film resist methods to construct an integrated device. The development of analysis software for detecting particle movement in videos of experiments is presented, along with its use as a data analysis tool for determining particle position in the array. Characterisation measurements have been performed for a range of experimental parameters demonstrating the variability and behaviour of the device. Separation experiments were performed using test micron and submicron particles over a wide range of applied field frequencies, confirming the theoretical predictions and demonstrate the standard of separation efficiency. Preliminary investigations of other application of the device to larger particle and integrating micropump technology are also presented.
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Bock, Christopher Paul. "Particle separation through Taylor-Couette flow and dielectrophoretic trapping." Master's thesis, University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4625.
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As the world population approaches seven billion, a greater strain is put on the resources necessary to sustain life. One of the most basic and essential resources is water and while two thirds of the earth is covered by water, the majority is either salt water (oceans and seas) or it is too contaminated to drink. The purpose of this project is to develop a portable device capable of testing whether a specific source of water (i.e. lake, river, well ...) is potable. There are numerous filtration techniques that can remove contaminants and make even the dirtiest water clean enough for consumption but they are for the most part, very time consuming and immobile processes. The device is not a means of water purification but rather focuses on determining the content of the water and whether it is safe. Particles within the water are separated and trapped using a combination of a Taylor Couette fluid flow system and Dielectrophoretic electrodes. This paper explores Taylor Couette flow in a large gap and low aspect ratio system through theory and experimentation with early stage prototypes. Different inner cylinder radii, 2.12cm, 1.665cm and 1.075cm, were tested at different speeds approaching, at and passing the critical Taylor number, 3825, 4713 and 6923 respectively for each cylinder. Dielectrophoretic (DEP) electrodes were designed, fabricated, coated and tested using latex beads to determine the method of integrating them within the fluid flow system. Taylor Couette theory, in terms of the formation of vortices within the large gap, small aspect ratio system, was not validated during testing. The flow pattern generated was more akin to a chaotic circular Couette flow but still served to move the particles toward the outer wall. Fully integrated tests were run with limited success.; Recommendations were made to pursue both circular Couette flow as the basis for particle separation and dimensional changes in the setup to allow for the formation of Taylor vortices by increasing the radius ratio but still allowing for a larger volume of fluid.<br>ID: 028916599; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (M.S.M.E.)--University of Central Florida, 2010.; Includes bibliographical references (p. 108-109).<br>M.S.M.E.<br>Masters<br>Department of Mechanical, Materials and Aerospace Engineering<br>Engineering and Computer Science<br>Miniature Engineering Systems
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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.
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Yilmaz, Gurkan. "Design And Implementation Of A Mems Based Spiral Channel Dielectrophoretic Separator For Cytometry Applications." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612695/index.pdf.
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This thesis reports design and implementation of a MEMS based spiral channel
dielectrophoretic separator for cytometry applications. Main objective of the thesis is
to separate leukemia cells from healthy leukocytes with respect to the differences in
their dielectric properties.
A novel MEMS based dielectrophoretic separator with spiral channels and concentric
3D electrodes has been proposed. The proposed geometry decreased the footprint,
which reduces the device cost, without degrading the separation and quantization
performances. Concentric electrode geometry enables continuous electric-field
application with simple voltage supplies.
Theoretical explanation of the design has been presented and supported with finite
element method simulations. Evolution of the design has been explained in
conjunction with solutions to arising problems, chronologically. Comparisons of the
proposed system with respect to the existing systems in the literature have been
given.
The devices are fabricated using a 3-mask process utilizing suspended parylene
channel process. The experiments are realized with 1 &mu<br>m and 10 &mu<br>m polystyrene
beads. The results show that 1 &mu<br>m particles have an average speed of 4.57 &mu<br>m/s with
1.06 &mu<br>m/s standard deviation, and 10 &mu<br>m particles have an average speed of 544
&mu<br>m/s with 105 &mu<br>m/s standard deviation. The speed variation coefficient for 1 &mu<br>m
and 10 &mu<br>m beads can be calculated as 23% and 19%, respectively. The size accuracy
of the device is ±<br>10%, while the resolution is 20%, that is, particles with radii
different from each other by 20% can be separated. It is worthy to note that the
experimental results almost match the simulation results.
6
Sagar, Ambuj Daya. "Materials separation by dielectrophoresis." Thesis, Massachusetts Institute of Technology, 1989. http://hdl.handle.net/1721.1/14215.
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Aldaeus, Fredrik. "New Concepts for Dielectrophoretic Separations and Dielectric Measurements of Bioparticles." Licentiate thesis, Stockholm, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3894.
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Faraghat, Shabnam A. "Design and fabrication of novel 3D dielectrophoresis cell separation devices." Thesis, University of Surrey, 2017. http://epubs.surrey.ac.uk/844982/.
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Cell separation is an important component of modern medicine, with both clinical and research applications. Clinically, it is often desirable to isolate cell subpopulations providing focused treatment; on the research side, cell isolation is necessary for studies underpinning many discoveries in cell biology, further enabling research in areas such as regenerative medicine and cancer therapy. Cell separation requirements include high throughput, purity and recovery. Three cell separators dominate: fluorescence and magnetic-activated cell sorting and density-gradient centrifugation. Despite gold-standard establishing performances, they can be improved in affordability, throughput, and label-free cell separation implementation. A technology with potential to offer the next rotation of gold-standard cell separators is Dielectrophoresis, DEP. Two DEP cell separators are presented. The first, the Syringe Separator (SS), uses 3D-electrodes on a low-cost, disposable chip and a DEP field perpendicular to fluid flow; one cell type is passed through whilst the other is retained and subsequently recovered. Two-pass protocols achieved a 96.4% recovery at over 200,000 cells/second with <7% loss. Additionally, a three-step protocol removed 99.1% of RBCs spiked with cancer cells (100:1). Other SS implementations include hitherto unachieved separation of high and low quality nanowires and T-cell isolation. The second employs a novel electrode geometry termed the Canyon. Using a novel electrode fabrication method (Plotter-Canyon printing), Canyons were built of alternating layers of metal and non-metal. Cellular solutions flow through the Canyon directed to one of two outlets, one for each of the negative or positive DEP cell subpopulations. The Canyon cell separator achieved an 84% recovery and 10% loss at ~2,000 cells/second. We have demonstrated that DEP cell separators can be built to perform cell separations with high purity, rivalling established separators, at significantly higher throughput and recovery. The SS and Canyons are cheap, easy-to-operate and offer a stepwise improvement in conventional cell separation capabilities.
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Mohammadi, Mahdi. "Direct current insulator based dielectrophoresis (DC-iDEP) microfluidic chip for blood plasma separation." Doctoral thesis, Universitat Politècnica de Catalunya, 2015. http://hdl.handle.net/10803/299206.
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Lab-on-a-Chip (LOC) integrated microfluidics has been a powerful tool for new developments in analytical chemistry. These microfluidic systems enable the miniaturization, integration and automation of complex biochemical assays through the reduction of reagent use and enabling portability.Cell and particle separation in microfluidic systems has recently gained significant attention in many sample preparations for clinical procedures. Direct-current insulator-based dielectrophoresis (DC-iDEP) is a well-known technique that benefits from the electric field gradients generated by an array of posts for separating, moving and trapping biological particle samples. In this thesis a parametric optimization is used to determine the optimum radius of the post for particle separation. Results that are used to design a microfluidic device that with a novel combination of hydrodynamic and di-electrophoretic techniques can achieve plasma separation in a microfluidic channel from fresh blood and for the first time allows optical real-time monitoring of the components of plasma without pre or post processing. Finally, all the results are integrated to create a novel microfluidic chip for blood plasma separation, which combines microfluidics with conventional lateral flow immune chromatography to extract enough plasma to perform a blood panel. The microfluidic chip design is a combination of cross-flow filtration with a reversible electroosmotic flow that prevents clogging at the filter entrance and maximizes the amount of separated plasma. The main advantage of this design is its efficiency, since with a small amount of sample (a single droplet ~10µL) a considerable amount of plasma (more than 1µL) is extracted and collected with high purity (more than 99%) in a reasonable time (5 to 8 minutes). To validate the quality and quantity of the separated plasma and to show its potential as clinical tool, the microfluidic chip has been combined with lateral flow immune chromatography technology to perform a qualitative detection of the TSH (thyroid-stimulating hormone) and a blood panel for measuring cardiac Troponin and Creatine Kinase MB. The results obtained from the microfluidic system are comparable to previous commercial lateral flow assays that required more sample for implementing less tests.<br>Els dispositius Lab-on-a-Chip (LOC) són una eina de gran abast per als nous desenvolupaments de química analítica. Aquests sistemes de microfluids permeten la miniaturització, la integració i automatització d'assajos bioquímics complexos a través de la reducció del consum de reactiu i són portables. La separació de partícules i cél.lules mitjançant sistemes de microfluids ha guanyat recentment una atenció significativa en la preparació de mostres per als procediments clínics. La dielectroforesis amb corrent continu basada amb aïllants (DC-IDEP) és una tècnica ben coneguda que es beneficia dels gradients de camp elèctric generats per una sèrie de columnes d'aïllants que permeten la separació, el moviment i la captura de mostres de partícules biològiques. En aquesta tesis una optimització paramètrica s'utilitza per determinar el radi òptim de la columna necessària per a la separació de partícules. Resultats que s'utilitzen per dissenyar un dispositiu de microfluids que amb una nova combinació de tècniques hidrodinàmiques i di-electroforètiques pot aconseguir la separació de plasma en un microcanal a partir de sang fresca que per primera vegada permet la monitorització en temps real òptica dels components del plasma sense pre o post processament. Finalment, tots els resultats s'integren per crear un nou microxip per a la separació de plasma de la sang, que combina la microfluídica amb cromatografia de flux lateral convencional per extreure suficient plasma per dur a terme un panell de sang. El disseny del microxip és una combinació de filtració de flux creuat amb un flux electroosmòtic reversible que evita l'obstrucció a l'entrada del filtre i maximitza la quantitat de plasma separat. El principal avantatge d'aquest disseny és la seva eficiència, ja que amb una petita quantitat de mostra (una sola gota ~ 10µL) s'extreu una quantitat considerable de plasma (més de 1µL) i es recull amb gran puresa (més de 99%) en temps raonable (de 5 a 8 minuts). Per validar la qualitat i quantitat del plasma separat i per mostrar el seu potencial com a eina clínica, el xip de microfluids s'ha combinat amb la tecnologia de cromatografia de flux lateral per a realitzar una detecció qualitativa de la TSH (hormona estimulant de la tiroide) i un panell de sang per mesura la troponina cardíaca i la creatina quinasa MB. Els resultats obtinguts del sistema de microfluids són comparables als assajos de flux lateral comercials anteriors que requerien més mostra per a la realització de menys proves.
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Hanson, Cynthia. "The Use of Microfluidics and Dielectrophoresis for Separation, Concentration, and Identification of Bacteria." DigitalCommons@USU, 2018. https://digitalcommons.usu.edu/etd/7044.
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Typical bacterial analysis involves culturing and visualizing colonies on an array of agar plates. The growth patterns and colors among the array are used to identify the bacteria. For fast growing bacteria such as Escherichia coli, analysis will take one to two days. However, slow growing bacteria such as mycobacteria can take weeks to identify. In addition, there are some species of bacteria that are viable but nonculturable. This lengthy analysis time is unacceptable for life-threatening infections and emergency situations. It is clear that to decrease the analysis of the bacteria, the culturing and growth steps must be avoided. The goal of this research is to design, build, and test a device that could decrease the analysis time of bacteria.
Device design accommodates for the varied growth and environmental conditions of expected samples for bacterial analysis. Clinical samples containing bacteria come in a wide variety of forms including urine, saliva, sputum, blood, etc. Each medium will have associated debris and other contaminants that must be isolated from bacteria before identification. This process can be challenging as bacteria and debris can range in size from a fraction of a micrometer to tens of micrometers. In addition, a device must be equipped to accurately identify bacteria regardless of growth conditions. Thus, to decrease the analysis time of bacteria, a device must be capable of isolation, concentration, and identification at a micron level.
In this dissertation, a device was designed, built, and tested that incorporates dielectrophoresis for cell sorting and Raman spectroscopy for identification. Using the device, bacteria (1 μm in length) were successfully isolated away from 5 μm polystyrene spheres and Raman spectra of the trapped bacteria were collected. The simultaneous isolation and identification of bacteria from a mixed sample indicates the capability for the cDEP-Raman device to decrease the analysis time of bacteria from clinical samples.
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Pattanaik, Malisha. "Separation of cancer cells from peripheral blood mononuclear cells using pH control and dielectrophoresis." Diss., [La Jolla] : University of California, San Diego, 2009. http://wwwlib.umi.com/cr/ucsd/fullcit?p1469581.
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Thesis (M.S.)--University of California, San Diego, 2009.<br>Title from first page of PDF file (viewed October 22, 2009). Available via ProQuest Digital Dissertations. Includes bibliographical references (p. 56-59).
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Jung, Young Do. "Microfabricated continuous flow separation and manipulation systems for human whole blood." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34003.
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The objective of the research in this dissertation is to develop microsystem based separation technologies for whole cell cancer analysis using human whole blood as the input sample. This research work is carried out with two different approaches; one based on a miniaturized cascade magnetophoresis system and a second based on dielectrophoresis. The miniaturized systems can be fabricated using MEMS technologies combined with plastic fabrication techniques.
The design, fabrication, packaging, and characterization of several versions of the magnetophoresis and dielectrophoresis microsystems for whole cell cancer analysis in human whole blood sample are presented. The developed magnetophoresis systems have demonstrated improved throughput in the removal of RBC from a human whole blood sample and its application to the separation of tagged cancer cells based on their surface expression level of a specific protein. The dielectrophoresis microsystem has successfully shown the ability to steer a blood stream between two outlets and to separate WBCs or cancer cells from a human whole blood sample.
The developed microsystem based separation technologies can be further applied to the development of integrated system for cancer detection and treatments.
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Aldaeus, Fredrik. "New Tools for Trapping and Separation in Gas Chromatography and Dielectrophoresis : Improved Performance by Aid of Computer Simulation." Doctoral thesis, Stockholm : Department of Analytical Chemistry, Stockholm university, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-7170.
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Wang, Yan [Verfasser], Jorg [Akademischer Betreuer] [Gutachter] Thöming, and Kurosch [Gutachter] Rezwan. "Continuous separation of microparticles in aqueous medium by means of dielectrophoresis / Yan Wang ; Gutachter: Jorg Thöming, Kurosch Rezwan ; Betreuer: Jorg Thöming." Bremen : Staats- und Universitätsbibliothek Bremen, 2016. http://d-nb.info/1120555442/34.
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Wang, Cheng-Chih, and 王鎮之. "DESIGN AND FABRICATION OF BIOPARTICLE SEPARATION DEVICE BY 3D DIELECTROPHORETIC FORCE." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/11951554736102309764.
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碩士<br>大同大學<br>機械工程學系(所)<br>96<br>Biochip has developed effectively by using the MEMS(Micro Electro-Mechanical System) technologies recently. The technique let biochip become smaller, faster and easier. Now, since the number of old person is getting more and more than before, health and medical treatment are become more important. And because of this reason, the biochip is applied to control and separate cells or particles. In this paper, MEMS technologies and hot embossing process are used to fabricate the dielectrophoretic biochip.
In this research, the hot embedding method which is different from traditional MEMS technologies is used to make the electrode with the 3D electric field. The electric field will become huger than before. Using the thermal compression bonding technique to replace the traditional way-use PDMS to do adhesion bonding with glass wafer. Thermal compression bonding reaches the goal of low time-consuming and low cost.
The chip we fabricated is demonstrated that the electrode which is fabricated by hot embedding can manipulate the bioparticle. To compare with the traditional dielectrophoretic chip, the chip we made can work without elevating voltage.
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Huang, Ching-Te, and 黃景德. "Study on dielectrophoretic separation/focus and thermal therapy of carcinoma cells." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/41032306228466958498.
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博士<br>國立中正大學<br>機械工程所<br>98<br>When microfluidic chip applies in cancer detection, cell sorter and cell counter, the manipulation cell is the first thing for the other application. In recent research, focusing of biological cells often utilize complicated microchannel and structure to manipulate cells. The unnecessary materials must be separated from tested solution. Therefore, those method need to combine with cells separation and precise flow control. The main purpose of the present study is to design an insulator-based dielectrophoretic microdevice for effective separation and focusing of biological cells simultaneously without precise flow control. Four insulating structures which formed an X-pattern in the microchannel are employed to squeeze the electric field in a conducting solution, thereby generating the non-uniform electrical field. The gap of between two insulating structures will generate high electric-field. When cells are induced positive dielectrophoretic forces in non-uniform electrical field, the cells are trapped by high electric-field. The cells repelled toward the center of the microchannel, when negative dielectrophoretic forces are induced. The increase of the X-pattern structure is significantly to enhance the performance of focusing. The device proposed herein has successfully separate unnecessary materials and focus the biological cells. Experimental results indicate that the performance of focusing increases with the strength of the electric field applied or with a decrease in the inlet velocity and that results are agree with the predictions by numerical simulations. The surgery, radiotherapy, chemotherapy and multiple therapies are the main treatment in recent years. However, those treatments are hurtful for health. Thermotherapy (hyperthermia) is a method for treatment carcinoma cells. Mechanism of malignant tumor thermotherapy has been an important issue for human. The cellular proteins and organelles are suffer from structural alternations and irreversible denaturation duration of exposure to supraphysiological temperatures, which may induce cell death. Besides, most of researches for thermotherapy of cancer have been reported based on the biological levels of organ or tissue. The thermotolerance of two hepatocellular carcinoma cell lines, HepG2 and Hep3B (well-differentiated), and three human urinary bladder carcinoma cell lines, TSGH-8301, J82 and TCC-SUP (cytological grade 2, 3 and 4, respectively), are investigated in the present study. A home-made heating stage is used to provide a constant temperature for 40 to 70°C. The experimental data show that the HepG2 exhibit higher thermotolerances then Hep3B. Besides, the TCC-SUP and TSGH-8301 cells exhibit the lowest and highest thermotolerances, respectively, while J82 cells are intermediate. The results indicate that the high cytological grade of the cell line of bladder cancer exhibits a low thermotolerance. Heat shock proteins play an important role in protecting cells from heat stresses. In some literatures indicate that the heat shock proteins have connect with differentiated. The experimental results of thermotherapy are coincident with the literatures. Moreover, the cell membranes of these cells are damaged and ruptured duration thermal treatment.
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"Insulator Based Dielectrophoretic Trapping of Single Mammalian Cells." Doctoral diss., 2013. http://hdl.handle.net/2286/R.I.21032.
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abstract: This work demonstrated a novel microfluidic device based on direct current (DC) insulator based dielectrophoresis (iDEP) for trapping individual mammalian cells in a microfluidic device. The novel device is also applicable for selective trapping of weakly metastatic mammalian breast cancer cells (MCF-7) from mixtures with mammalian Peripheral Blood Mononuclear Cells (PBMC) and highly metastatic mammalian breast cancer cells, MDA-MB-231. The advantage of this approach is the ease of integration of iDEP structures in microfliudic channels using soft lithography, the use of DC electric fields, the addressability of the single cell traps for downstream analysis and the straightforward multiplexing for single cell trapping. These microfluidic devices are targeted for capturing of single cells based on their DEP behavior. The numerical simulations point out the trapping regions in which single cell DEP trapping occurs. This work also demonstrates the cell conductivity values of different cell types, calculated using the single-shell model. Low conductivity buffers are used for trapping experiments. These low conductivity buffers help reduce the Joule heating. Viability of the cells in the buffer system was studied in detail with a population size of approximately 100 cells for each study. The work also demonstrates the development of the parallelized single cell trap device with optimized traps. This device is also capable of being coupled detection of target protein using MALDI-MS.<br>Dissertation/Thesis<br>Ph.D. Chemistry 2013
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Wu, Chien-Hui, and 吳建輝. "Applying Dielectrophoretic Chip with Comb-shaped Electrode Array for Micro-Particles Separation." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/72755143298150897319.
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碩士<br>南台科技大學<br>奈米科技研究所<br>98<br>This research reported the separation of fluid carried particles of two different sizes by non-uniform electric field from alternating current (AC) in a dielectrophoretic chip, which was formed by an array of comb-shape electrodes at bottom and plane electrode of Indium Tin Oxide (ITO) at top. Comercial software, CFD-ACE+, was used to simulate the strength of electric filed and the gradient of square of electric filed within the electrodes of the chip, in order to investigate the relationship between the behaviors of particle separation and the size of comb-shap electrodes under different AC voltages and frequencies. The results showed the lower strength of electric filed and the gradient of electric filed square were within the center and the gap of electrodes. Those regions would be favorable to the particles trapping by negative dielectrophoretic force in the fluid of deionized water.
Latex particles with size of 8 μm and 16 μm were used in the experiments to characterize the separation behaviors at a fixed flow rate of 3 μL/hr. The results indicated the particles of 16 μm would have stronger force by negative dielectroporesis at frequency of 200 kHz than those of 8 μm. That caused particles of 16 μm to be trapped to the region of lower electric field strength (within the gap of comb-shape electrodes) and not to be flushed away. However for the particles of 8 μm would not be trapped and would be flushed away. That can be applied for separation of different-seze particles. This phenomenon satisfies with theory of dielectrophoresis, which indicates the dielectrophoretic force is proportional to the cubic power of particle diameter.
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Rebordão, Guilherme Santos. "Modelling and Development of a Microfluidic Platform for Dielectrophoretic Separation of Polymeric Nanoparticles." Master's thesis, 2019. http://hdl.handle.net/10362/112989.
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The interest surrounding particle separation techniques has increased significantly in the past
years, due to its importance in chemical and biological analysis, diagnostics, and food processing,
among other areas. Out of the vast array of ways that have been used to separate particles in
microfluidics, electric field may be the most common means of separation, given its applicability and
versatility. Dielectrophoresis (DEP) occurs in the presence of a non-uniform electric field, and in order
to achieve such field, there are two main approaches: by creating an array of metal electrodes along the
main channel or by utilizing an electrodeless design. This latter approach is based on creating
constrictions on the channel while applying an electric field between the inlet(s) and outlet(s) of the
channel.
In this work, done in the Department of Materials and Production of the University of Aalborg,
five different models were designed and fabricated on a single fused silica wafer via photolithography,
with the ultimate purpose of continuously separating particles with diameters of 20 nm and 150 nm. A
detailed overview of the designs and COMSOL simulations, as well as the fabrication techniques and
processes can be found throughout the work.
Successful particle separation was achieved in the simulations, at voltages as low as 35 V, with
the use of separation channels with a maximum length of 3.1 mm. The fabrication stage of the work was
focused on the development of a robust microfabrication process suitable for small, well-defined
channels, and its alignment with metal electrodes. Two different fabrication approaches were presented
and analysed.
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Shim, Sangjo. "Antibody-free isolation of circulating tumor cells by dielectrophoretic field-flow fractionation." Thesis, 2013. http://hdl.handle.net/2152/25909.
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This work focuses on the integration of microfluidics and dielectrophoresis(DEP) with the principles of field flow fractionation (FFF) to create a continuous-flow isolator for rare and viable circulating tumor cells (CTCs) from peripheral blood mononuclear cells (PBMNs) drawn from cancer patients. The method exploits differences in the plasma membrane capacitances of tumor and blood cells, which correspond to differences in the membrane surface areas of these cell types. DEP-FFF was first adapted to measure cell membrane capacitance, cell density and deformability profiles of cell populations. These properties of the NCI-60 panel of cancer cell types, which represents the wide functional diversity of cancers from 9 organs and leukemia, were compared with the normal cell subpopulations of peripheral blood. In every case, the NCI-60 cells exhibited membrane capacitance characteristics that were distinct from blood and, as a result, they could be isolated from blood by DEP. The heightened cancer cell membrane capacitances correlated strongly with membrane-rich morphological characteristics at their growth sites, including cell flattening, dendritic projections, and surface wrinkling. Following harvest from culture and maintenance in suspension, cancer cells were found to shed cytoplasm and membrane area over time and the suspended cell populations developed considerable morphological diversity. The shedding changed the cancer cell DEP properties but they could still be isolated from blood cells. A similar shedding process in the peripheral blood could account for the surprisingly wide morphological diversity seen among circulating cells isolated from clinical specimens. A continuous flow DEP-FFF method was devised to exploit these findings by allowing CTCs to be isolated from the nucleated cells of 10 mL clinical blood specimens in 40 minutes, an extremely high throughput rate for a microfluidic-based method. Cultured cancer cells could be isolated at 70-80% efficiency using this approach and the isolation of CTCs from clinical specimens was demonstrated. The results showed that the continuous DEP-FFF method delivers unmodified, viable CTCs for analysis, is perhaps universally applicable to isolation of CTCs from different cancer types and is independent of surface antigens - making it suitable for cells lacking the epithelial markers used in currently accepted CTC isolation methods.<br>text
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Lin, Sheng-Kai, and 林聖凱. "Development of a Dielectrophoretic Chip for Separation of Microorganisms with Different Characteristics and Antimicrobial Susceptivity Test." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/73327492782095420600.
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碩士<br>國立成功大學<br>醫學工程研究所碩博士班<br>92<br>It is important to develope a method for rapid identification a antimicrobial susceptibility test of pathogens isolated from clinical samples. Although conventional methods could provide accurate results, the procedures are relatively time-consuming. In this research, a dielectrophoretic (DEP) technique has been successfully applied for rapid identification and antimicrobial susceptibility testing of pathogens. Dielectrophoresis is the motion imparted on electrically neutral, but polarized, particles subjected to non-uniform electric fields.
The DEP chip based on obviously DEP force was produced by the polynomial electrodes. The research showed that DEP force (FDEP) varied with dielectric properties of particles and medium and the applied voltage across the electrodes. Electric signal of frequency range is from 0.1 MHz to 20 MHz and a voltage smaller than 12 Vpp were used in the experiments. The results showed that the different yeasts could be separated based on different cell size. Larger yeasts were attracted to the electrode edge by positive DEP force at 1 MHz in 10 mM KCl medium. On the other hand, in the antimicrobial susceptivity test of E. coli, the inhibited E. coli cells could be separated at 10 MHz in 280 mM mannitol medium due to negative DEP force. Finally, it was shown that H. pylori cells expression BabA and SabA could be separated from those without expression of these two genes at 10 MHz and 5 MHz in DI water. H. pylori having flagella or not also could be separated at 10 MHz in 280 mM mannitol medium.
The above results demonstrate a good method for separating microorganisms based on their differences in size and cell structure.
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Li, Chien Ting, and 李建廷. "Application of optically induced dielectrophoretic (ODEP) force-based microfluidic platform for label-free and high-efficiency live and dead cell separation." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/14801371201494513059.
Full textAbstract:
碩士<br>長庚大學<br>生化與生醫工程研究所<br>102<br>This study reports an optically induced dielectrophoretic (ODEP)force-based microfluidic platform for the separation and collection live and dead cells. The mechanism is based on the fact that live and dead cells have reverse property in under ODEP force field. Under an ODEP background, the live cells are attracted by the applied ODEP force,whereas the dead cells are repelled from the ODEP force. Combining above phenomenon and the flow control in a microfluidic system, the live and dead cells can be separated and subsequently collected in a label-free, efficient and effective manner. In this study, the operating conditions of ODEP force for manipulating the live and dead chondrocytes were first characterized. The performance of live and dead separation was experimentally evaluated. In addition, the impact of ODEP force field on the physiology of the cells manipulated was also investigated. Our results revealed that the applied voltage of 8Vp-p was suitable for the cell separation due to the maximum difference of manipulation force for the live (49.4 pN) and dead (-20.1 pN) cells. In addition, the use of the proposed scheme for live and dead cell separation was successfully demonstrated. We also showed that the recovery rate and purity of the isolated live cells are as high as 78.3±6.8% and 96.4 ±2.2%, respectively.
In addition, the purified and isolated live chondrocytes were cultured and observed growth and physiology for eight days. Comparing to electrical unstimulated chondrocytes, experimental cells had no significant difference in cell growth, proliferation and morphology. Also, experimental group and control group have no significant difference in
metabolic analysis of lactic acid production and DNA content analysis.
In a sum, the proposed cell separation method is found particularly valuable for the biological researches in which the isolation of highly pure live or dead cells is important.
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Lo, Ying Jie. "Dielectrophoresis on Plasma/RBC Separation and RBC Manipulation." 2004. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-2607200411101400.
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Lo, Ying Jie, and 羅英傑. "Dielectrophoresis on Plasma/RBC Separation and RBC Manipulation." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/55952934965144409799.
Full textAbstract:
碩士<br>國立臺灣大學<br>應用力學研究所<br>92<br>This thesis takes advantage of dielectric property of material, where a dielectrophoretic (DEP) force is induced in a sinusoidally time-variant electric field to achieve cell-plasma separation and cell manipulation. Dielectrophoretic theory is based on the distinct dielectric and conductive properties of cell and medium. This distinction will physically induce a directional force depending on frequency, spatial electric strength, and spatial electric phase distribution.
Through fabrication of MEMS, devices miniaturized are to increase the influence of DEP force on separation and manipulation of cells. Additionally, with the aid of numerical simulation of electric field and cell trajectory, more effective devices are designed. The use of bio-compatible material polydimethysilloxane (PDMS) proved ease of fabrication and integration [1].
Types of cell-plasma separator tested various electrode design include stair, inclined, and gradient confuguration, and 3D channel assisting design. For cell manipulation, traveling wave, cell concentrator, and cell portioning devices are all tested and their performance quantified.
Results show successful separation of red blood cell (RBC) and plasma vis DEP. for a wide range of electrode geometry configurations. Traveling wave DEP, however, was more difficult to implement. Manipulation of RBC proved viable using the non-uniform E-field at the tip of multi-electrode design.
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Lin, Yu-Min, and 林鈺閔. "Separation of Bio-particles using Dielectrophoresis and Microfluidics." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/55804979427100902376.
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碩士<br>國立臺灣大學<br>應用力學研究所<br>98<br>Trapping and separation of particles entrained in a moving liquid stream were studied in this thesis via negative dielectrophoresis (nDEP). The nDEP force can be generated by applying ac voltage with 180 degree phase shift at two electrodes (separated by a 20 μm gap) built on the bottom wall of a straight micro channel. When a particle approaches the location of the electrode gap (called the DEP gate), it will be lifted by the negative DEP force, and held before the DEP gate if the negative DEP force is suitably designed such that it can resist the fluid drag. Much effort in previous literature aims to determine the critical condition (the maximum background flow rate at a given applied voltage, or the minimum applied voltage at a given flow rate) for a single particle (or rare particles) in a given microfluidic system. In practical applications, the flow through area decreases, and thus the fluid drag increases, as more particles are trapped at the DEP gate. Furthermore, the succeeding particles may impact on the previously trapped particles. Sooner or later, the trapped particles may gather enough momentum to cross the DEP gate, and thus the critical condition for single particle (or rare particles) fails to apply. The present thesis thus introduce the concept of capacity (define as the average number of particles trapped at the DEP gate when the system reaches its quasi steady state), and propose that the capacity as a suitable indicator for quantifying the performance of the related micro system with DEP gates.
The capacity of colorectal cancer cells (Colo205, 15~20 μm) was measured in a system with a straight electrode gap. It equals 15.7 cells per 200 μm channel width at 1 MHz frequency, 7 Vpp (peak-to-peak-voltage) and 156μm/s in flow rate. Separation between Colo205 cells and E. Coli was also performed using such a system: the Colo205 cells were blocked, with E. Coli past through the DEP gate. This suggests that the precision for the current Stool DNA test (less than 50% now) can be enhanced if the sample is pre-treated using the devices with DEP gate.
It was found that the device with curved electrode gap performs better for particle trapping over straight electrode gap, and up to 267% times when it is operated at 1MHz and 7Vpp with an average background flow speed at 156μm/s. The capacity can be further increased up to 367% for a two-step channel design. The negative DEP force possesses a larger component resisting the background flow for the curved electrodes, and thus the capacity is increased. The capacity of the two-step channel is enhanced because of the physical blockage as well as the additional DEP force associated with the intensified electric field generated at the corner of the flow geometry.
In literature, particle separation using DEP relies mainly on the particle size as the DEP force depends on the cubic power of its size. It is not easy to separate negative DEP particles with similar sizes. In this thesis, we have separated successfully the Colo205 cells and the polystyrene particles (at 15±0.15μm) based on their differences in Clausius-Mossotti factor using the straight electrode gap device. The operation parameters were 1MHz, 6V_pp and 468~624μm/s in flow speed.
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Tsai, Han-Sheng, and 蔡瀚陞. "Cell Separation Biochip via Dielectrophoresis and Microfluidic Focusing." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/44598221713580645469.
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碩士<br>國立清華大學<br>奈米工程與微系統研究所<br>96<br>Recently, researches about manipulation and analysis of bio-particles by MEMS technology are growing because of the fabrication development, and it is an important field ob bio-technology. The main purpose is to integrate the functions we need into a Lab-On-a-Chip system, and the chips have the function of bio-detection and analysis. Taking the micro-device of cell sorting for example, there are many technology have been presented, such as microgripper. But each of them has some restrications. Therefore, we want to design a bio-chip which could separate cells easily and efficiently.
In this thesis, we use the characteristic of microfluid and design the bio-chip to combine with DEP (dielectrophoresis) and microchannel to sort cells. By collecting the two fluids with different flow rates, all cells will close the wall in the microchannel. At the same time, the cells will separate preliminary because of the sizes of the cells and the drag force. By applying input AC voltage within specific frequency range on the micro electrodes, cells could be separate and collect with negative DEP force. We through numerical simulation software, CFDRC, and the design concepts are realized by MEME fabrication process. At last, we use polystyrene beads in place of cells to demonstrate the functions of our chip.
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Liu, Nan-Ching, and 劉南青. "The Application of Dielectrophoresis Biochip on Cell Separation." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/97235825906560449075.
Full textAbstract:
碩士<br>大同大學<br>機械工程學系(所)<br>94<br>The most importance of separating small cells is the accuracy and efficiency, the more important consideration is that cells won’t suffer destroy from the separating process. Thus, we designed the dielectrophoresis separation chip according to the consideration. The designed electrode will cause non-uniform electric field, polarized cells would move to the place where the electric field magnitude is bigger or smaller, by the characteristic cells can separated. The dielectric properties of suspending medium and cells are relating to conductivity, dielectric constant and applied frequency. In experiment we changed medium conductivity and applied frequency to observe the dielectrophoretic phenomenon of live and dead yeast cells. We used PDMS as channel, it is easily to observe dielectrophoretic effect and bond with electrode chip.
We mainly use CFDRC software to find out the place of bigger or smaller electric field magnitude, let us know the place where positive and negative dielectrophoretic force occurred.
We separate live and dead cells successfully with two ways mention in the thesis. We discuss the dielectrophoretic force distribution and separation effect with different electrode shape.
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Chang, Ya-Chu, and 張雅筑. "Cell Capture and Separation Using Dielectrophoresis and Microfluidics." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/95232894883571988326.
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碩士<br>國立臺灣大學<br>應用力學研究所<br>103<br>A device for selective particle capture and separation using microfluidics and dielectrophoresis was developed in the thesis. The device is a micro channel with grooves built on its ceiling. Electrodes are built on the bottom surface of the device on both the upstream and downstream sides of the groove. Negative dielectrophoretic force is exerted on the test particle when it passes through the electrode gap. Particles with selected Kr (the real part of the Clausius-Mossotti factor) will be pushed into the channel and are thus captured. Other particles with different Kr will be carried downstream, and thus particles with different dielectric properties are separated. The device was reported in the literature, but here we propose a modify version of the device such that the two particles to be separated can be counted, and thus the capture rate and purity of separation can be evaluated accurately. Therefore, the modified device proposed here is capable of determining suitable operation parameters for a given separation, which is necessary for a separating device based on the intrinsic physical properties of particles. As for the separation of polystyrene particles and cancer cells (including the lung cancer cells CL1-0 and CL1-5, and the colorectal cancer cells Colo205), 100% can be separated under a frequency 1 MHz and a background flow rate below 40ul/hr. 80% separation can be achieved for the mixture of CL1-0 and Colo205 in a medium with conductivity 0.11S/m, at a flow rate 30ul/hr and frequency 70kHz. The geometric and operation parameters of the device were also studied numerically and experimentally.
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Kua, C. H., Yee Cheong Lam, C. Yang, and Kamal Youcef-Toumi. "Review of bio-particle manipulation using dielectrophoresis." 2004. http://hdl.handle.net/1721.1/7464.
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During the last decade, large and costly instruments are being replaced by system based on microfluidic devices. Microfluidic devices hold the promise of combining a small analytical laboratory onto a chip-sized substrate to identify, immobilize, separate, and purify cells, bio-molecules, toxins, and other chemical and biological materials. Compared to conventional instruments, microfluidic devices would perform these tasks faster with higher sensitivity and efficiency, and greater affordability. Dielectrophoresis is one of the enabling technologies for these devices. It exploits the differences in particle dielectric properties to allow manipulation and characterization of particles suspended in a fluidic medium. Particles can be trapped or moved between regions of high or low electric fields due to the polarization effects in non-uniform electric fields. By varying the applied electric field frequency, the magnitude and direction of the dielectrophoretic force on the particle can be controlled. Dielectrophoresis has been successfully demonstrated in the separation, transportation, trapping, and sorting of various biological particles.<br>Singapore-MIT Alliance (SMA)
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Jah-Ming, Lai. "Computational Study of Separation of Size-Specific Microparticles Using Dielectrophoresis." 2007. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-0602200715193800.
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Lai, Jah-Ming, and 賴志銘. "Computational Study of Separation of Size-Specific Microparticles Using Dielectrophoresis." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/52459934449387353981.
Full textAbstract:
碩士<br>國立臺灣大學<br>應用力學研究所<br>95<br>This thesis presents the computation of separation of size-specific particles using dielectrophoresis (DEP) in a microfluidic device. The goal of the study is to separate heterogeneous population of particles into bins downstream. Different configurations of electrodes are designed, such as gradual, step, and deterministic, in order to achieve non-uniform electric field strength. Particles of diameters 5μm, 10μm, 15μm, and 20μm are used. Parameters of the Clausius-Mossotti (CM) factor were determined to achieve negative dielectrophoresis (nDEP) at the range of specified frequencies. The relations between negative dielectrophoretic force (nDEP) and drag force are used to derive the governing equation of particle trajectories. An overarching parameter, called sorting factor, was derived to account for the force balance on the particle and it also serves to compare performance among the three electrode designs.
Results of computation showed that size-specific particles could be separated at the frequency above 600Hz by using gradual and step electrode designs. As a whole, the sorting factor serves well to correlate the efficacy of separation in most cases studies. According to sorting factor analysis, if the input A.C. signals increases, the range of the flow velocity also increases which is an important consideration for this device. Furthermore, the suitable input A.C. signals are chosen for this experiment. However, the deterministic electrodes of these devices may separate particles of 10μm, 15μm, and 20μm in diameters and particles of 5μm and 10μm in diameters. For the moment of the result of computation, the deterministic electrode of this device may not completely separate size-specific bioparticles.
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Çeti̇n, Barbaros. "Microfluidic continuous separation of particles and cells by AC-dielectrophoresis." Diss., 2009. http://etd.library.vanderbilt.edu/available/etd-07272009-145740/.
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"New Developments in Isoelectric Focusing and Dielectrophoresis for Bioanalysis." Doctoral diss., 2011. http://hdl.handle.net/2286/R.I.14280.
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abstract: Bioanalytes such as protein, cells, and viruses provide vital information but are inherently challenging to measure with selective and sensitive detection. Gradient separation technologies can provide solutions to these challenges by enabling the selective isolation and pre-concentration of bioanalytes for improved detection and monitoring. Some fundamental aspects of two of these techniques, isoelectric focusing and dielectrophoresis, are examined and novel developments are presented. A reproducible and automatable method for coupling capillary isoelectric focusing (cIEF) and matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS) based on syringe pump mobilization is found. Results show high resolution is maintained during mobilization and &beta-lactoglobulin; protein isoforms differing by two amino acids are resolved. Subsequently, the instrumental advantages of this approach are utilized to clarify the microheterogeneity of serum amyloid P component. Comprehensive, quantitative results support a relatively uniform glycoprotein model, contrary to inconsistent and equivocal observations in several gel isoelectric focusing studies. Fundamental studies of MALDI-MS on novel superhydrophobic substrates yield unique insights towards an optimal interface between cIEF and MALDI-MS. Finally, the fundamentals of isoelectric focusing in an open drop are explored. Findings suggest this could be a robust sample preparation technique for droplet-based microfluidic systems. Fundamental advancements in dielectrophoresis are also presented. Microfluidic channels for dielectrophoretic mobility characterization are designed which enable particle standardization, new insights to be deduced, and future devices to be intelligently designed. Dielectrophoretic mobilities are obtained for 1 µm polystyrene particles and red blood cells under select conditions. Employing velocimetry techniques allows models of particle motion to be improved which in turn improves the experimental methodology. Together this work contributes a quantitative framework which improves dielectrophoretic particle separation and analysis.<br>Dissertation/Thesis<br>Ph.D. Chemistry 2011
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"Analyzing Cellular Properties with Dielectrophoresis." Doctoral diss., 2019. http://hdl.handle.net/2286/R.I.53727.
Full textAbstract:
abstract: Dielectrophoresis (DEP) is a technique that influences the motion of polarizable particles in an electric field gradient. DEP can be combined with other effects that influence the motion of a particle in a microchannel, such as electrophoresis and electroosmosis. Together, these three can be used to probe properties of an analyte, including charge, conductivity, and zeta potential. DEP shows promise as a high-resolution differentiation and separation method, with the ability to distinguish between subtly-different populations. This, combined with the fast (on the order of minutes) analysis times offered by the technique, lend it many of the features necessary to be used in rapid diagnostics and point-of-care devices.
Here, a mathematical model of dielectrophoretic data is presented to connect analyte properties with data features, including the intercept and slope, enabling DEP to be used in applications which require this information. The promise of DEP to distinguish between analytes with small differences is illustrated with antibiotic resistant bacteria. The DEP system is shown to differentiate between methicillin-resistant and susceptible Staphylococcus aureus. This differentiation was achieved both label free and with bacteria that had been fluorescently-labeled. Klebsiella pneumoniae carbapenemase-positive and negative Klebsiella pneumoniae were also distinguished, demonstrating the differentiation for a different mechanism of antibiotic resistance. Differences in dielectrophoretic behavior as displayed by S. aureus and K. pneumoniae were also shown by Staphylococcus epidermidis. These differences were exploited for a separation in space of gentamicin-resistant and -susceptible S. epidermidis. Besides establishing the ability of DEP to distinguish between populations with small biophysical differences, these studies illustrate the possibility for the use of DEP in applications such as rapid diagnostics.<br>Dissertation/Thesis<br>Doctoral Dissertation Chemistry 2019
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YEN, HSIEH HUNG, and 謝鴻彥. "Plasma and cell separator using traveling wave dielectrophoresis." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/77114835218322521604.
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Chen, Tsan-I., and 陳燦議. "A Dielectrophoresis Cell Separation Device Using Multiple Frequencies and Micro-structures." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/11295435674175087068.
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碩士<br>國立清華大學<br>動力機械工程學系<br>92<br>MEMS (Micro Electro Mechanical Systems) have been developed over twenty years. Because of the rapid development of biological technology, there are a lot of applications for MEMS in bio-medical field. The bio-chips developed nowadays include cell sorting\separation chip, cell lysis chip, PCR (Polymer Chain Reaction) chip, DNA detection chip etc. These chips could be integrated into a Lab-On-a-Chip system for full functional disease detection and analysis. This thesis focuses on cell sorting\separation and the design of a new chip in substitution for traditional cell separation process. There are a few MEMS cell separation measurements have been presented, including micro filter, micro hydraulic switch and dielectrophoresis. Therefore, the micro filter has stuffing problem while the hydraulic switch requires extra external real-time detection. Dielectrophoresis has been known as a powerful tool for cell separation because of its good cell selectivity. Presently, the published dielectrophoretic cell sorting methods are limited to separate no more than three cell types due to the single frequency signal. We firstly proposed the concept of multi-frequency dielectrophoresis. With special structure design, we can separate multiple cell types by applying multiple frequencies simultaneously.
The thesis starts with the survey of literatures, via theoretical analysis to evaluate the feasibility of design concept and to define the design regulations. Through numerical analysis, the design concepts are verified and realized by MEMS fabrication process. Furthermore, a driving signal generator is also designed and tested. Finally, we use polystyrene beads and glass beads to simulate cells to complete the preliminary experimental results.
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Chang, Yuan-Yao, and 張元耀. "Microdevices for Manipulation, Separation, and Trapping of Micro-Particles by Dielectrophoresis." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/54360759297844935679.
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碩士<br>國立清華大學<br>微機電工程研究所<br>94<br>As the development of the modern molecular biology, drug screening, and diagnosis, modern biotechnology requires the isolation and analysis of a single cell. In the past, handling a single cell was a hard process of dilution. The approach is disadvantageous especially for rare cells. Microdevices designed by dielectrophoresis can not only reduce sample volume but also trap the designated cell more efficiently.
On the research, I constructed a three dimension (3D) microelectrode systems embedded in a 30μm resist, SU-8, forming a flow channel. The microelectrodes include symmetric and asymmetric elements driven by alternating current (AC) signal. The symmetric and asymmetric elements are designed to concentrating, deflecting, turning, and trapping polystyrene (PS) beads and human umbilical vein endothelial cell (HUVEC) and human embryonic lung cell(HEL 299). The concentration electrodes operated at 10Vp-p and 1MHz，and 6μm and 10μm polystyrene beads can be concentrated at the flow velocity 800μm/s and 1,400μm/s, respectively. Deflection and Turning Electrodes can provide function of switch and separation of polystyrene beads. Polystyrene beads was separated when they passed the turning region, and we employ a numerical analysis method combined with electrical field and flow field simulation data to predict the route of beads of different size. On this research experimental devices can trap a single polystyrene bead, human umbilical vein endothelial cell, and human embryonic lung cell (HEL 299). Especially, it can trap 6μm polystyrene beads at 225μm/s flow velocity under 40μm inter-space of electrode, 10Vp-p, and 1MHz. We used charge-coupled device and Image-process software to calculate flow velocity and rotation frequency of particles.
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Liang, Cheng-Hao, and 梁程皓. "Application of Dielectrophoresis on the separation of YeastCells and Carbon Nanotubes." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/02892872660001109242.
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碩士<br>大同大學<br>機械工程學系(所)<br>96<br>Dielectrophoresis (DEP) is a phenomenon resulted from the inhomogeneous
electric field and has been used to sort out colloids with different dielectric properties.
Based on DEP theory, we fabricated a microfluidic chip to sort out yeast cells and
identify the electric properties of multi-walled carbon nanotubes. For yeast cells
separation, a divergent interdigitated electrode was employed and the viable and dead
cells were separated via positive and negative DEP force. The results show the
collection efficiency for viable cells collected by positive DEP is 91.8% and the
efficiency for dead cell collected by negative DEP is 77.9%. The high collection
efficiency from positive is due to the high DEP force which is frequency dependent.
Another application for DEP is its ability to characterize the electric property for
cells and colloidal particles. In this thesis, we use DEP to purify the contents of
multi-walled carbon nanotubes (MWCNTs). An interdigitated triangular electrode was
fabricated where the maxima and the minima of the electric field is easy to identify by
numerical simulation. The DEP frequency spectrum was established by operating
different frequency where the sign of DEP is obtained. The different electric property of
MWCNTs will be sorted accordingly. The microstructure and electric property of the
unsorted, positive DEP sorted and negative sorted samples of MWCNTs were examined
by Raman spectra and I-V curves, respectively. The positive DEP sorted MWCNTs
were more conducting and negative DEP sorted is less conducting. This procedure can
be applied for purification and identification of electrical property of MWCNTs.
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"Development of a New Approach to Biophysical Separations Using Dielectrophoresis." Doctoral diss., 2015. http://hdl.handle.net/2286/R.I.29892.
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abstract: Biological fluids contain information-rich mixtures of biochemicals and particles such as cells, proteins, and viruses. Selective and sensitive analysis of these fluids can enable clinicians to accurately diagnose a wide range of pathologies. Fluid samples such as these present an intriguing challenge to researchers; they are packed with potentially vital information, but notoriously difficult to analyze. Rapid and inexpensive analysis of blood and other bodily fluids is a topic gaining substantial attention in both science and medicine. Current limitations to many analyses include long culture times, expensive reagents, and the need for specialized laboratory facilities and personnel. Improving these tests and overcoming their limitations would allow faster and more widespread testing for disease and pathogens, potentially providing a significant advantage for healthcare in many settings.
Both gradient separation techniques and dielectrophoresis can solve some of the difficulties presented by complex biological samples, thanks to selective capture, isolation, and concentration of analytes. By merging dielectrophoresis with a gradient separation-based approach, gradient insulator dielectrophoresis (g-iDEP) promises benefits in the form of rapid and specific separation of extremely similar bioparticles. High-resolution capture can be achieved by exploiting variations in the characteristic physical properties of cells and other bioparticles.
Novel implementation and application of the technique has demonstrated the isolation and concentration of blood cells from a complex biological sample, differentiation of bacterial strains within a single species, and separation of antibiotic-resistant and antibiotic-susceptible bacteria. Furthermore, this approach allows simultaneous concentration of analyte, facilitating detection and downstream analysis. A theoretical description of the resolving capabilities of g-iDEP was also developed. This theory explores the relationship between experimental parameters and resolution. Results indicate the possibility of differentiating particles with dielectrophoretic mobilities that differ by as little as one part in 100,000,000, or electrophoretic mobilities differing by as little as one part in 100,000. These results indicate the potential g-iDEP holds in terms of both separatory power and the possibility for diagnostic applications.<br>Dissertation/Thesis<br>Doctoral Dissertation Biochemistry 2015
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"Protein Dielectrophoresis Using Insulator-based Microfluidic Platforms." Doctoral diss., 2014. http://hdl.handle.net/2286/R.I.24979.
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abstract: Rapid and reliable separation and analysis of proteins require powerful analytical methods. The analysis of proteins becomes especially challenging when only small sample volumes are available, concomitantly with low concentrations of proteins. Time critical situations pose additional challenges. Due to these challenges, conventional macro-scale separation techniques reach their limitations. While microfluidic devices require only pL-nL sample volumes, they offer several advantages such as speed, efficiency, and high throughput. This work elucidates the capability to manipulate proteins in a rapid and reliable manner with a novel migration technique, namely dielectrophoresis (DEP). Since protein analysis can often be achieved through a combination of orthogonal techniques, adding DEP as a gradient technique to the portfolio of protein manipulation methods can extend and improve combinatorial approaches. To this aim, microfluidic devices tailored with integrated insulating obstacles were fabricated to create inhomogeneous electric fields evoking insulator-based DEP (iDEP). A main focus of this work was the development of pre-concentration devices where topological micropost arrays are fabricated using standard photo- and soft lithographic techniques. With these devices, positive DEP-driven streaming of proteins was demonstrated for the first time using immunoglobulin G (IgG) and bovine serum albumin. Experimentally observed iDEP concentrations of both proteins were in excellent agreement with positive DEP concentration profiles obtained by numerical simulations. Moreover, the micropost iDEP devices were improved by introducing nano-constrictions with focused ion beam milling with which numerical simulations suggested enhancement of the DEP effect, leading to a 12-fold increase in concentration of IgG. Additionally, concentration of β-galactosidase was observed, which seems to occur due to an interplay of negative DEP, electroosmosis, electrokinesis, diffusion, and ion concentration polarization. A detailed study was performed to investigate factors influencing protein DEP under DC conditions, including electroosmosis, electrophoresis, and Joule heating. Specifically, temperature rise within the iDEP device due to Joule heating was measured experimentally with spatial and temporal resolution by employing the thermosensitive dye Rhodamine B. Unlike DNA and cells, protein DEP behavior is not well understood to date. Therefore, this detailed study of protein DEP provides novel information to eventually optimize this protein migration method for pre-concentration, separation, and fractionation.<br>Dissertation/Thesis<br>Ph.D. Chemistry 2014
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Du, Fei [Verfasser]. "Separation of solid-liquid and liquid-liquid phases using dielectrophoresis / Fei Du." 2010. http://d-nb.info/1010641530/34.
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Ou, Tein-Kai, and 歐天凱. "Technique development for separation of mercury adsorbed bacterial cells by using dielectrophoresis." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/56884976775512736798.
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碩士<br>國立中興大學<br>生命科學系<br>93<br>A mercuric ion binding protein, MerP, from mercury resistance operon of Gram-positive bacteria Bacillus cereus RC607, was expressed in bacterial host and served as the biosorbent for heavy metals. The MerP protein was expressed via pET30a vector system with E.coli BL21(DE3) host cell. A cell surface protein, ompC, was used to fuse with MerP and display the fused protein on the cell surface through the same expression system. Their mercury resistance level, biosorption ability, specificity of biosorption were compared for evaluating of the feasibility for using as the bioabsorbents that can deal with heavy metal pollution. Furthermore, for the purpose of mercury recycling, the dielectrophoretic separation system was integrated after the biosorption. The result shows that cell surface expressed MerP-OmpC fusion enhanced 19% in mercuric ion accumulation while that of MerP over expression was 21%. In the resistence test, surface expressed of MerP fusion protein get higher resistance than express in cytoplasma. In the coexistence of zinc , copper, lead and cadmium, the transformant of MerP-OmpC fusion protein still keep more than 90% of mercury biosorption rate, and demonstrated that the transformant have potential to serve as a biosorbent to solve the heavy metal pollution. By using the dielectrophoretic separation system, although different concentrations of KCL or mannitol buffer have been discussed, the result shows that it is unable to separate the bacteria by whether mercury was adsorbed or not in the condition of AC frequency band between 0.10~20 MHz. It’s the first report for the research trying to apply the electrophoretic separation technology for the heavy metal recycling. Further studies are needed for the separating conditions.
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Lee, Don-Lin, and 李東霖. "Trapping and separation of particles and cells using dielectrophoresis in microfluidic system." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/84389103309634033116.
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碩士<br>國立臺灣大學<br>應用力學研究所<br>101<br>A method was proposed for selective isolation and separation of particles/cells of similar sizes based on their different Clausius-Mossotti factors using dielectrophoresis and microfluidics in the literature. The associated device is a straight micro channel (glass for the bottom wall and PDMS for the rest walls) with four grooves on its ceiling for capturing particles, and two electrodes on both sides of the groove region for generating electric field. A particle may be carried downstream by the imposed fluid stream or pushed into the groove, depending on the local force balance between dielectrophoretic force, fluid drag, gravity and buoyancy. The present study aims to clarify the capturing efficiency of various particles/cells under different geometric designs and operating conditions, and hope to develop a microfluidic chip capable of separating different cells of similar size efficiently. In order to simplify the problem, a single groove design is employed in the present experiment. Capture rates for polystyrene particles, two lung cancer cells, CL1-0 and CL1-5 (more invasive), and one colorectal cancer cells, Colo205, were measured for different channel heights, groove widths, applied electric frequencies, and background volume flow rates. The device was also demonstrated of capturing CL1-0 cells from a mixture of CL1-0 and blood cells. A modified design of the device was also proposed and tested. The groove and the electrodes are orientated obliquely to the background flow in the modified design (but are perpendicular in the original design), such that the captured particles/cells in the groove can be guided smoothly and effectively to designed destination downstream.
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"Ultrafine Dielectrophoresis-based Technique for Virus and Biofluid Manipulation." Doctoral diss., 2017. http://hdl.handle.net/2286/R.I.46255.
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abstract: Microfluidics has shown great potential in rapid isolation, sorting, and concentration of bioparticles upon its discovery. Over the past decades, significant improvements have been made in device fabrication techniques and microfluidic methodologies. As a result, considerable microfluidic-based isolation and concentration techniques have been developed, particularly for rapid pathogen detection. Among all microfluidic techniques, dielectrophoresis (DEP) is one of the most effective and efficient techniques to quickly isolate and separate polarizable particles under inhomogeneous electric field. To date, extensive studies have demonstrated that DEP devices are able to precisely manipulate cells ranging from over 10 μm (mammalian cells) down to about 1 μm (small bacteria). However, very limited DEP studies on manipulating submicron bioparticles, such as viruses, have been reported.
In this dissertation, rapid capture and concentration of two different and representative types of virus particles (Sindbis virus and bacteriophage M13) with gradient insulator-based DEP (g-iDEP) has been demonstrated. Sindbis virus has a near-spherical shape with a diameter ~68 nm, while bacteriophage M13 has a filamentous shape with a length ~900 nm and a diameter ~6 nm. Under specific g-iDEP experimental conditions, the concentration of Sindbis virus can be increased two to six times within only a few seconds, using easily accessible voltages as low as 70 V. A similar phenomenon is also observed with bacteriophage M13. Meanwhile, their different DEP behavior predicts the potential of separating viruses with carefully designed microchannels and choices of experimental condition.
DEP-based microfluidics also shows great potential in manipulating blood samples, specifically rapid separations of blood cells and proteins. To investigate the ability of g-iDEP device in blood sample manipulation, some proofs of principle work was accomplished including separating two cardiac disease-related proteins (myoglobin and heart-type fatty acid binding protein) and red blood cells (RBCs). Consistent separation was observed, showing retention of RBCs and passage of the two spiked protein biomarkers. The numerical concentration of RBCs was reduced (~70 percent after one minute) with the purified proteins available for detection or further processing. This study explores and extends the use of the device from differentiating similar particles to acting as a sample pretreatment step.<br>Dissertation/Thesis<br>Doctoral Dissertation Chemistry 2017
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WENG, TSUNG-CHIEH, and 翁琮傑. "Continuous Separation of Microalgae with Different Lipid Contents by Dielectrophoresis in a Microchannel." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/76bmdg.
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碩士<br>國立雲林科技大學<br>化學工程與材料工程系<br>105<br>Microalgae have great potential in cosmeceutical, biomedical, and green energy conversion applications. Developing an effective methodology enabling fast and high-throughput analysis of the physicochemical properties of microalgae in aqueous solution is still of great-demand. In this study, we develop a new microfluidic method that combines a sheath flow and the cell dielectrophoresis in a designed serpentine microchannel to continuously separate microalgae with different lipid contents. Due to the different extents of non-uniform electric field between theserpentine microchannel and microalgae with different cell conductivities, microalgae with different lipid contents experience different magnitudes of dielectrophoretic force. The parametric effects of the applied potentials in the driving and sheath flow-controlled electrodes on the dielectrophoretic separation of microalgae with lower and higher lipid contents are investigated systematically. It is found that a mixture of microalgae with lower and higher lipid contents can be continuously separated when a 250V DC is applied in the electrokinetic driving electrode and a 300~330V DC is applied in the sheath flow-controlled electrode when the surfactant is absent.
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Zhi-FengLiao and 廖志峰. "Separating Plasma and Blood Cells by Dielectrophoresis in Micro-Fluidic Chip." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/60074774144630869687.
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Shing-LunLiu and 劉興倫. "The Passive and Continuous Separation of Bioparticles based on Gray-Scale Light-induced Dielectrophoresis." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/28995616777673172524.
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Ho, Tzu-I., and 賀子懿. "DESIGN AND FABRICATION OF 3-D DIELECTROPHORETIC CHIP ON SEPARATING 2-TYPE OF BACTERIA." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/47382302389014596828.
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碩士<br>大同大學<br>機械工程學系(所)<br>98<br>Biochip has developed effectively with the MEMS(Micro Electro-Mechanical System) technologies recently. The technique let biochip become smaller, faster and easier. Now, since the number of old person is getting more and more than before, health and medical treatment are become more important. And because of this reason, the biochip is applied to control and separate cells or particles. In this paper, MEMS technologies process are used to fabricate the dielectrophoretic biochip.
In this research, the MEMS technologies which is used to make the 3-D electrode with the 3D electric field. The electric field will become huger than before. Fabrication 3D-electrode on glass can reach low cost and low time-consuming.
The chip we fabricated is demonstrated that the electrode which is fabricated by MEMS technologies can manipulate the bioparticle. To compare with the traditional dielectrophoretic chip, the chip we made can work without elevating voltage.
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"Electric Field Driven Migration and Separation in the Microenvironment." Doctoral diss., 2020. http://hdl.handle.net/2286/R.I.62691.
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abstract: Novel electric field-assisted microfluidic platforms were developed to exploit unique migration phenomena, particle manipulation, and enhanced droplet control. The platforms can facilitate various analytical challenges such as size-based separations, and delivery of protein crystals for structural discovery with both high selectivity and sensitivity. The vast complexity of biological analytes requires efficient transport and fractionation approaches to understand variations of biomolecular processes and signatures. Size heterogeneity is one characteristic that is especially important to understand for sub-micron organelles such as mitochondria and lipid droplets. It is crucial to resolve populations of sub-cellular or diagnostically relevant bioparticles when these often cannot be resolved with traditional methods. Herein, novel microfluidic tools were developed for the unique migration mechanism capable of separating sub-micron sized bioparticles by size. This based on a deterministic ratchet effect in a symmetrical post array with dielectrophoresis (DEP) for the fast migration allowing separation of polystyrene beads, mitochondria, and liposomes in tens of seconds. This mechanism was further demonstrated using high throughput DEP-based ratchet devices for versatile, continuous sub-micron size particle separation with large sample volumes. Serial femtosecond crystallography (SFX) with X-ray free-electron lasers (XFELs) revolutionized protein structure determination. In SFX experiments, a majority of the continuously injected liquid crystal suspension is wasted due to the unique X-ray pulse structure of XFELs, requiring a large amount (up to grams) of crystal sample to determine a protein structure. To reduce the sample consumption in such experiments, 3D printed droplet-based microfluidic platforms were developed for the generation of aqueous droplets in an oil phase. The implemented droplet-based sample delivery method showed 60% less sample volume consumption compared to the continuous injection at the European XFEL. For the enhanced control of aqueous droplet generation, the device allowed dynamic triggering of droplets for further improvement in synchronization between droplets and the X-ray pulses. This innovative technique of triggering droplets can play a crucial role in saving protein crystals in future SFX experiments. The electric field-assisted unique migration and separation phenomena in microfluidic platforms will be the key solution for revolutionizing the field of organelle separation and structural analysis of proteins.<br>Dissertation/Thesis<br>Doctoral Dissertation Chemistry 2020
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Chen, Yung-Chou, and 陳勇州. "DESIGN AND ANALYZE DEVICE INTEGRATE QUARTZ CRYSTAL MICROBALANCE FOR DIELECTROPHORESIS SEPARATING NANO PARTICLES." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/27425407936957741049.
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碩士<br>大同大學<br>機械工程學系(所)<br>99<br>In recent years, MEMS technology have been developed and applied in various kinds of fields, such as, optics, power, sensor, bioengineer and etc. However, with the improvement of quality of the life, people want to have better medical treatment. MEMS technology is applied by biotechnology such as PCR chip, detection chip, separated chip and etc.
This research is focus on biotechnology research in the separation of nano particles, we use the MEMS processing technology to design and produce a fast separation of nanol particles with the components, combined with quartz crystal microbalance to enable rapid detection of separation.
The separation of nano particles in the study, this paper proposes a 3D DEP (Dielectrophoretic) for the separation, which allows flow through the electrode surface after the samples were separated quickly. Course of the study using CFD ACE + software for 3D simulation of the electric field in the electric field distribution. Embedded technology by hot-embedding , the electrode embedded in the flow channel.
In the quartz crystal microbalance study, to design and produce a measurement of the vehicle. CNC machining to produce the traditional mold carrier, and then to measure the compression molding technology to complete the vehicle and the flow distribution. The quartz crystal microbalance proposed as one of the DEP electrodes, the DEP and the quartz crystal microbalance electrodes integrated into the vehicle in order to complete the separation of particles. Detection, the quartz crystal microbalance as a test platform to verify the separation efficiency.