Engineering Commons^™

Ph Gradients In Spatially Non-Uniform Ac Electric Fields Around The Charging Frequency; A Study Of Two Different Geometries And Electrode Passivation, Azade Tahmasebi, Sanaz Habibi, Jeana Collins, Ran An, Esmaeil Dehdashti, Adrienne Minerick

Michigan Tech Publications, Part 2

Dielectrophoresis (DEP), a precision nonlinear electrokinetic tool utilized within microfluidic devices, can induce bioparticle polarization that manifests as motion in the electric field; this phenomenon has been leveraged for phenotypic cellular and biomolecular detection, making DEP invaluable for diagnostic applications. As device operation times lengthen, reproducibility and precision decrease, which has been postulated to be caused by ion gradients within the supporting electrolyte medium. This research focuses on characterizing pH gradients above, at, and below the electrode charging frequency (0.2–1.4 times charging frequency) in an aqueous electrolyte solution in order to extend the parameter space for which microdevice-imposed artifacts on …

Exploring Ph Gradient Phenomena In Non-Linear Electrokinetic Microfluidic Devices, Azade Tahmasebi

Dissertations, Master's Theses and Master's Reports

Electrokinetic microfluidics is a versatile technology utilized within lab on a chip (LOC) devices for diagnostic and analytical applications; advantages include reduced resource demands, flexibility, and simplicity of use. Dielectrophoresis (DEP) is a precision nonlinear electrokinetic tool utilized within microfluidic microdevices to induce polarization and control bioparticle motions for applications that range from hemoglobin separations to cancer cell isolation and detection. Despite promising results, undesired side phenomena can occur in electrokinetic systems which impede reproducibility and accuracy. These unfavorable phenomena have not been comprehensively explored in the literature. Prior preliminary research suggests the fundamental phenomena originate from microelectrodes utilized in …

Assembly Of Ceramic Particles In Aqueous Suspensions Induced By High-Frequency Ac Electric Field, James E. John Iv

Mechanical & Aerospace Engineering Theses & Dissertations

Ceramic materials processed using colloidal methods have been the focus of a great deal of research aimed at tailoring the final structure and microstructure of the finished ceramic sample. To this end, various external field effects have been investigated to modify the suspension microstructure without manipulating the ceramic particles directly. In a previous work in the field of ice templating it has been shown that AC electric fields are able to produce microstructural changes in ice templated ceramics that have significantly improved the final mechanical properties. However, the mechanisms for this process are still not well understood in ceramics.

To …

Assembly Of Alumina Particles In Aqueous Suspensions Induced By High‐Frequency Ac Electric Field, James E. John, Shizhi Qian, Dipankar Ghosh

Mechanical & Aerospace Engineering Faculty Publications

The role of high-frequency alternating current (AC) electric field in the assembly of alumina particles in aqueous media was investigated. Field–particle interactions were in situ investigated for coarse and fine powder particles in very dilute suspensions. For both coarse and fine particles, AC field-induced assembly led to the formation of chains of particles within a minute, which were aligned in the field direction. However, a much finer network of particle chains evolved in fine particle suspensions. Threshold field strength for chain formation was also lower for fine particles (28 V/mm) than for coarse particles (50 V/mm), suggesting stronger interactions for …

Optimization Of The Microfluidic Dielectrophoresis Trap Configuration For Nanoparticle Manipulation, Mohammad Rizwen Ur Rahman

Theses and Dissertations

Dielectrophoresis (DEP) is an electrokinetic phenomenon in which neutral but polarizable particles suspended in a liquid medium experience a net movement due to a force generated from the permittivity difference between the liquid medium and the particles when subjected to a non-uniform electric field. We have developed a microfluidic particle trapping system using alternating current (AC) based DEP force for trapping spherical polymeric beads and biological particles. The DEP microfluidic device was constructed using orthogonal electrode configuration and fitted with three different basic geometric shapes, i.e., triangular, square, and circular. Effect of trap shape on particle trapping dynamics was quantitatively …

Planar Corrugated Electrode Configuration For Manipulation Of Micro-Scale Entities In Dielectrophoretic Microfluidic Devices, Alia Mohammed Alblooshi

Mechanical Engineering Theses

This thesis conceptualizes the design of a planar electrode for employment in microfluidic devices to achieve dielectrophoretic focusing and separation of micro-scale entities. The planar electrode has corrugations with two such electrodes placed parallelly to form a pair and the electric field is generated between them; the presence of corrugations enhances the non-uniformity of the electric field. For purposes of 3D focusing, two pairs of electrodes are used with each pair on both sides of the microchannel. When the applied electric voltages are equal, the micro-scale entity is focused at the center of the microchannel and when the applied electric …

Investigation Of Dielectrophoretic Microfluidic Trap System For Separation And Parallel Analysis Of Single Particles, Tae Joon Kwak

Theses and Dissertations

Separation and identification of single molecules and particles based on their chemical, biochemical and physical properties are critical in wide range of biomedical applications. Manipulating a single biomolecule requires sensitive approaches to avoid damage to the molecule. Recent progress in micro- and nano-technology enabled the development of various novel methods and devices to trap, separate, and characterize micro- and nano-particles. In this dissertation, a microfluidic particle trap system to electrically separate particles at the single particle level was developed through particle manipulation methods using dielectrophoresis. The research in this dissertation will explain the operation strategy and setup of the novel …

A Numerical Simulation Optimizing Droplet Motion Driven By Electrowetting, Jake M. Lesinski

Master's Theses

A numerical simulation of electrowetting on a dielectric was performed in COMSOL to grant insight on various parameters that play a critical role in system performance. The specific system being simulated was the Open Drop experiment and the parameters being investigated were the applied voltage, contact angle at the advancing triple point, and droplet overlap onto neighboring actuated electrodes. These parameters were investigated with respect to their effect on droplet locomotion performance. This performance was quantified by the droplets velocity and the dielectrophortic (DEP) force’s magnitude; the DEP force was calculated from integration of the Maxwell Stress Tensor, however, the …

Study Of Optical Propulsion Concepts And Techniques For Small-Satellites, Jaykob Neil Maser

Doctoral Dissertations

"The first objective of this research is to manufacture and investigate the characteristics and use of asymmetric, metallic, nanostructures for plasmonic force propulsion, a developing method of nano-/picosatellite thrust generation. This project developed a higher-fidelity model of a recently envisioned small spacecraft propulsion system for precision pointing and proximity control. Plasmonic force propulsion harnesses solar light focused onto plasmon reactive sub-wavelength nanostructures to generate polarized oscillations of electrons on the surface of metallic nanostructures which accelerate and expel nanoparticle propellant via strong optical forces. This research also explores how material selection affects the electromagnetic response of the closely positioned asymmetric …

Electrical Characterization Of Graphene And Nanodiamond Nanostructures, A Z M Nowzesh Hasan

Doctoral Dissertations

The electrical characterization on two-dimensional carbon-based graphene and nanodiamond materials was performed to improve charge transport properties for the label-free electrical biosensors. The charge transport in solution-gated graphene devices is affected by the impurities and disorders of the underlying dielectric interface and its interaction with the electrolytes. Advancement in field-effect ion sensing by introducing a dielectric isomorph, hexagonal boron nitride between graphene and silicon dioxide of a solution-gated graphene field-effect transistor was investigated. Increased transconductance due to increased charge carrier mobility is accompanied with larger ionic sensitivity. These findings define a standard to construct future graphene devices for biosensing and …

The Use Of Microfluidics And Dielectrophoresis For Separation, Concentration, And Identification Of Bacteria, Cynthia Hanson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

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. …

Electric-Field Assisted Manipulation And Self-Assembly Of Particle Suspensions, Edison Chijioke Amah

Dissertations

The aim of this dissertation is to model the processes by which particles suspended in liquids and at liquid surfaces self-assemble when they are subjected to uniform and non-uniform electric fields. To understand the role of electric forces, three related problems were studied numerically and experimentally.

In the first problem, particles are assumed to be suspended inside a liquid and a nonuniform electric field is applied using electrodes mounted in the domain walls which causes positively polarized particles to collect in the regions where the electric field intensity is locally maximal and the negatively polarized particles collect in the regions …

Review: Electric Field Driven Pumping In Microfluidic Device, Mohammad R. Hossan, Diganta Dutta, Nazmul Islam, Prashanta Dutta

Electrical and Computer Engineering Faculty Publications and Presentations

Pumping of fluids with precise control is one of the key components in a microfluidic device. The electric field has been used as one of the most popular and efficient nonmechanical pumping mechanism to transport fluids in microchannels from the very early stage of microfluidic technology development. This review presents fundamental physics and theories of the different microscale phenomena that arise due to the application of an electric field in fluids, which can be applied for pumping of fluids in microdevices. Specific mechanisms considered in this report are electroosmosis, AC electroosmosis, AC electrothermal, induced charge electroosmosis, traveling wave dielectrophoresis, and …

Reverse Insulator Dielectrophoresis: Utilizing Droplet Microenvironments For Discerning Molecular Expressions On Cell Surfaces, Jeana Collins

Dissertations, Master's Theses and Master's Reports

Lab-on-a-chip (LOC) technologies enable the development of portable analysis devices that use small sample and reagent volumes, allow for multiple unit operations, and couple with detectors to achieve high resolution and sensitivity, while having small footprints, low cost, short analysis times, and portability. Droplet microfluidics is a subset of LOCs with the unique benefit of enabling parallel analysis since each droplet can be utilized as an isolated microenvironment. This work explored adaptation of droplet microfluidics into a unique, previously unexplored application where the water/oil interface was harnessed to bend electric field lines within individual droplets for insulator dielectrophoretic (iDEP) characterizations. …

Integrative Computational Modeling For Developing Means To Manipulate Biological Cells And For Solving Complex Engineering Problems, Yu Zhao, Guigen Zhang

Commonwealth Computational Summit

A brief discussion on reductive vs integrative investigation

A case study: how integrative computational modeling helps advance the understanding and application of dielectrophoresis (DEP) in various situations

Other applications in advancing the design and development of nanopore, medical devices, novel materials, actuation devices, and coupled spectroscopic techniques, etc.

An Array Of Circular Dielectrophoresis Traps To Separate And Charaterize Individual Microparticles From Population, Hwangjae Lee

Theses and Dissertations

Dielectrophoretic traps have been broadly studied in light of their many advantages of high controllability, ease of operation, and high efficiency. In the previous studies, however, it was challenging to count captured particles or required work to capture particles. In the thesis, an array of circular dielectrophoresis (DEP) traps was developed and tested to manipulate population of microparticles in single particle level. The circular DEP traps enable more precise control of the force field than conventionally used interdigitated electrodes due to its omnidirectional and symmetric properties. The location of the captured microparticle inside the trap was confirmed by both of …

The Oxygen Binding Protein, Hemoxcell(R), Increases Cho Cell Growth And Extends Viability By Enhancing Oxygen Delivery, Katrin Braasch

Cell Culture Engineering XV

The continuous monitoring of cell growth and viability is an integral part of biopharmaceutical production. Measurements of changes in the polarizability of individual cells can identify early emerging sub-populations of apoptotic cells in a dielectrophoretic (DEP) cytometer designed at the University of Manitoba. In this instrument the trajectory of individual cells was tracked as they passed through a bank of electrodes (sensitivity: 0.1 µm; rate: 5 cells per second) designed to differentially perturb the cells according to their polarizability. This perturbation was recorded as a force index (FI), which was related to the electrical displacement of the cells. Using this …

The Differential Polarizability Of Cho Cells Can Be Used To Monitor Changes In Metabolism, Katrin Braasch

Cell Culture Engineering XV

The continuous monitoring of cell growth and viability is an integral part of biopharmaceutical production. Measurements of changes in the polarizability of individual cells can identify early emerging sub-populations of apoptotic cells in a dielectrophoretic (DEP) cytometer designed at the University of Manitoba. In this instrument the trajectory of individual cells was tracked as they passed through a bank of electrodes (sensitivity: 0.1 µm; rate: 5 cells per second) designed to differentially perturb the cells according to their polarizability. This perturbation was recorded as a force index (FI), which was related to the electrical displacement of the cells. Using this …

Diagnostics And Degradation Investigations Of Li-Ion Battery Electrodes Using Single Nanowire Electrochemical Cells, Naveen Kumar Reddy Palapati, Naveen Kumar Reddy Palapati

Theses and Dissertations

Portable energy storage devices, which drive advanced technological devices, are improving the productivity and quality of our everyday lives. In order to meet the growing needs for energy storage in transportation applications, the current lithium-ion (Li-ion) battery technology requires new electrode materials with performance improvements in multiple aspects: (1) energy and power densities, (2) safety, and (3) performance lifetime. While a number of interesting nanomaterials have been synthesized in recent years with promising performance, accurate capabilities to probe the intrinsic performance of these high-performance materials within a battery environment are lacking. Most studies on electrode nanomaterials have so far used …

Blood Typing Device Without Reagents: Sensing Electrodes To Replace Optics, Nupur Bihari

Dissertations, Master's Theses and Master's Reports - Open

There is need to develop a fast and efficient procedure for detecting blood type that makes use of an electronic measurement to minimize human error and is portable so that it can be used in triage situations. A process to develop a crossover frequency based blood typing device is described. Alternating field drives red blood cells over the sensing electrodes and depending on the capacitance measured between pairs of sensing electrodes, the position of these RBCs can be determined. The convergence/divergence of these cells at a particular frequency determines blood type, since each type has a characteristic frequency. This project …

An Integrated Dielectrophoresis-Active Hydrophoretic Microchip For Continuous Particle Filtration And Separation, Sheng Yan, Jun Zhang, Chao Pan, Dan Yuan, Gursel Alici, Haiping Du, Yonggang Zhu, Weihua Li

Faculty of Engineering and Information Sciences - Papers: Part A

Microfluidic manipulation of biological objects from mixture has a significant application in sample preparation and clinical diagnosis. This work presents a dielectrophoresis-active hydrophoretic device for continuous label-free particle separation and filtration. This device comprises interdigitated electrodes and a hydrophoretic channel. According to the difference of lateral positions of polystyrene particles, the device can run at separation or filtration modes by altering the power supply voltages. With an applied voltage of 24 Vp-p, both 3 and 10 μm beads had close lateral positions and were redirected to the same outlet. Under a voltage of 36 Vp-p, beads with the diameters of …

Development Of A Lab-On-A-Chip Device For Rapid Nanotoxicity Assessment In Vitro, Pratikkumar Shah

FIU Electronic Theses and Dissertations

Increasing useof nanomaterials in consumer products and biomedical applications creates the possibilities of intentional/unintentional exposure to humans and the environment. Beyond the physiological limit, the nanomaterialexposure to humans can induce toxicity. It is difficult to define toxicity of nanoparticles on humans as it varies by nanomaterialcomposition, size, surface properties and the target organ/cell line. Traditional tests for nanomaterialtoxicity assessment are mostly based on bulk-colorimetric assays. In many studies, nanomaterials have found to interfere with assay-dye to produce false results and usually require several hours or days to collect results. Therefore, there is a clear need for alternative tools that can …

Single Cuo Nanowires Electrical Properties And Application On Photoelectrochemical Water Splitting, Junnan Wu

McKelvey School of Engineering Theses & Dissertations

Charge transport in single crystal, p type copper oxide (CuO) nanowires (NWs) was studied through temperature based (120 K – 400 K) current-voltage (I-V) measurements of 2-terminal single NW devices. Individual CuO NWs with an average diameter of 220 nm were attached to Au electrodes 2.5 µm apart, using a dielectrophoresis method. I-V curves showed a transition from linear behavior at low bias to strong power law dependence (I ~ V^a) at high bias, which can be attributed to space charge limited current (SCLC) mechanism. At low electrical fields (< 0.89 × 10³ V·cm^-1), the number of …

Electrokinetic Particle Manipulations In Spiral Microchannels, John Dubose

All Theses

Recent developments in the field of microfluidics have created a multitude of new useful techniques for practical particle and cellular assays. Among them is the use of dielectrophoretic forces in 'lab-on-a-chip' devices. This sub-domain of electrokinetic flow is particularly popular due to its advantages in simplicity and versatility. This thesis makes use of dielectrophoretic particle manipulations in three distinct spiral microchannels. In the first of these experiments, we demonstrate the utility of a novel single-spiral curved microchannel with a single inlet reservoir and a single outlet reservoir for the continuous focusing and filtration of particles. The insulator-based negative-dielectrophoretic (repulsive) force …

Study Of Mechanisms Governing Electromagnetic Alteration Of Hydraulic Conductivity Of Soils, Atena Najafi, Sahba Azad, Arvin Farid, Jim Browning, Elisa Barney Smith

Civil Engineering Faculty Publications and Presentations

Hydraulic conductivity is a measure of the rate at which water flows through porous media. Because of the dipole properties of water molecules, electric field can affect hydraulic conductivity. In this study, the effect of radio-frequency (RF) waves on hydraulic conductivity is investigated. This is important both for the geophysical measurement of hydraulic conductivity as well as remediation using electromagnetic waves. Bentonite clay and sandy samples are tested in rigid-wall, cylindrical permeameters and stimulated using a CPVC-cased monopole antenna vertically centered in the permeameters. The permeameters are encased within RF cavities constructed of aluminum mesh in order to prevent interference …

Electromagnetically Induced Transport In Water For Geoenvironmental Applications, Arvin Farid, Atena Najafi, Mahsa Azad, Jim Browning, Elisa Barney Smith

Civil Engineering Faculty Publications and Presentations

Air sparging is a popular soil remediation technique that enables the removal of contaminants through diffusing air into soil. The removal process is, however, slow. The goal of this work is to study the effect of electromagnetic (EM) waves —with minimal heat generation— on transport mechanisms such as diffusion, in order to improve airflow or contaminant transport in order to expedite the cleanup process using air sparging or similar technologies. This effect is studied through an experimental setup that examines the diffusion of a nonreactive dye in water under EM waves at a range of frequencies (50-200 MHz). The electric …

Utilizing Dielectrophoresis To Determine The Physiological Differences Of Eukaryotic Cells, Tayloria Nicole Gail Adams

Dissertations, Master's Theses and Master's Reports - Open

Type 1 diabetes affects over 108,000 children, and this number is steadily increasing. Current insulin therapies help manage the disease but are not a cure. Over a child’s lifetime they can develop kidney disease, blindness, cardiovascular disease and many other issues due to the complications of type 1 diabetes. This autoimmune disease destroys beta cells located in the pancreas, which are used to regulate glucose levels in the body. Because there is no cure and many children are affected by the disease there is a need for alternative therapeutic options that can lead to a cure.

Human mesenchymal stem cells …

Isolating Plasma From Blood Using A Dielectrophoresis-Active Hydrophoretic Device, Sheng Yan, Jun Zhang, Gursel Alici, Haiping Du, Yonggang Zhu, Weihua Li

Faculty of Engineering and Information Sciences - Papers: Part A

Plasma is a complex substance that contains proteins and circulating nucleic acids and viruses that can be utilised for clinical diagnostics, albeit a precise analysis depends on the plasma being totally free of cells. We proposed the use of a dielectrophoresis (DEP)-active hydrophoretic method to isolate plasma from blood in a high-throughput manner. This microfluidic device consists of anisotropic microstructures embedded on the top of the channel which generate lateral pressure gradients while interdigitised electrodes lay on the bottom of the channel which can push particles or cells into a higher level using a negative DEP force. Large and small …

On-Chip High-Throughput Manipulation Of Particles In A Dielectrophoresis-Active Hydrophoretic Focuser, Sheng Yan, Jun Zhang, Ming Li, Gursel Alici, Haiping Du, Ronald Sluyter, Weihua Li

Faculty of Engineering and Information Sciences - Papers: Part A

This paper proposes a novel concept of dielectrophoresis (DEP)-active hydrophoretic focusing of micro-particles and murine erythroleukemia (MEL) cells. The DEP-active hydrophoretic platform consists of crescent shaped grooves and interdigitated electrodes that generate lateral pressure gradients. These embedded electrodes exert a negative DEP force onto the particles by pushing them into a narrow space in the channel where the particle to groove interaction is intensive and hydrophoretic ordering occurs. Particles passing through the microfluidic device are directed towards the sidewalls of the channel. The critical limitation of DEP operating at a low flow rate and the specific hydrophoretic device for focusing …

Experimental Development And Analysis Of A Novel Setup For Insulated Dielectrophoresis, Johnie Hodge

All Theses

Dielectrophoresis has long been studied and utilized for the manipulation of microscale particles in solution. This phenomenon is due to the induced polarization of dielectric particles subjected to an electric field. When the field is also inhomogeneous in terms of the distribution of its strength through space, the polarized particles move and come to rest in certain areas due to the relationship between their and the solvent's relative permittivities. If the electric field is homogenous, such as within a parallel plate capacitor, the particles are polarized according to their permittivity and the field's frequency, but they will not move.
These …