Search for: microfluidic-device
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    Cell-cell interactions mediate cytoskeleton organization and collective endothelial cell chemotaxis

    , Article Cytoskeleton ; Vol. 71, issue. 9 , 2014 , p. 501-512 Shamloo, A ; Sharif University of Technology
    This study investigates the role of cell-cell and cell-ligand interactions in cytoskeleton organization of endothelial cells (ECs) and their directional migration within a microfluidic device. The migration of ECs in response to a biochemical factor was studied. Mathematical analysis of the cell migration pathways and cellular cytoskeleton revealed that directional migration, migration persistence length, migration speed, and cytoskeletal stress fiber alignment can be mediated by the level of cell contacts as well as the presence or absence of a biochemical polarizing factor. It was shown that in the presence of a biochemical polarizing factor, higher cell density and more frequent cell... 

    Halogen-lithium exchange reaction using an integrated glass microfluidic device: an optimized synthetic approach

    , Article Organic Process Research and Development ; Volume 21, Issue 3 , 2017 , Pages 292-303 ; 10836160 (ISSN) Zeibi Shirejini, S ; Mohammadi, A ; Sharif University of Technology
    American Chemical Society  2017
    A telescoped approach was developed for the efficient synthesis of methoxybenzene through the generation of an unstable intermediate reagent, based on the Br-Li exchange reaction of p-bromoanisole and n-BuLi, followed by its reaction with water. In the first stage, p-methoxyphenyllithium was synthesized and consumed immediately in the second stage. For this purpose, an integrated glass microfluidic device was fabricated using laser ablation followed by the thermal fusion bonding method. The impact of various parameters, including solvent, reaction time, molar ratio, concentration of reagents, and flow rates were investigated to achieve the highest yield of the desired product, leading to an... 

    Rapid Determination of Histamine by an Enzyme-based Microfluidic Biosensor

    , M.Sc. Thesis Sharif University of Technology Moradi, Mohammad Reza (Author) ; Vossoughi, Manouchehr (Supervisor) ; Shamloo, Amir (Supervisor)
    Design, simulation, optimization and manufacturing of an enzyme-based microfluidic biosensor has been carried out during this research to measure histamine concentration in a sample. The designed biosensor is composed of a micro-bioreactor to degrade histamine and yield hydrogen peroxide, and a chemical reactor to measure the amount of hydrogen peroxide, using chemiluminescence methods. The geometry of the bioreactor and chemical reactor is developed through comparison and optimization of several different geometries. In theory, the designed sensor can determine histamine concentration in a range of 10M to 1mM under one minute, with a maximum error of 5%. Designed biosensor is built using... 

    Design and Simulation (& Manufacturing) of A Micro-Gyroscope

    , M.Sc. Thesis Sharif University of Technology Soltani, Arman (Author) ; Akbari, Javad (Supervisor)
    Nowadays, microgyroscopes are among the most important products of MEMS. The production of small, precise and inexpensive gyroscopes has become possible as the result of recent developments in fabrication technology. In this thesis it is intended to introduce a new method for manufacturing more precise microgyroscopes regarding manufacture facilities. Using this new method, sensitivity and resistance of microgyroscopes are increased against noises which are primarily caused by vibration and rotation about undesirable axes. The rotational movement imposed on the gyro is detected through fluid flow within its torus channel. This transformation facilitates the measurement of the initial motion.... 

    Implementation of Paper Sheets into the Microfluidic Systems as an Appropriate Platform for Micro-Solid Phase Extraction

    , M.Sc. Thesis Sharif University of Technology Hashemi Hedeshi, Mahin (Author) ; Bagheri, Habib (Supervisor)
    In this research, the surface of cellulose paper was modified with Hexadecyltrimethoxysilane, Phenyltriethoxysilane, (3-Aminopropyl)triethoxysilane and 3-(2,3-epoxypropoxy)propyltrimethoxysilane via chemical bonding. Afterwards, the prepared papers were placed in the microfluidic device as sorbent in a sandwiched format. A syringe pump was used to drive the sample into the microfluidic channel. In order to investigated the performance of these sorbents, two types of anlaytes including toxins and antidepressant drugs were chosen as target analytes. In the case of toxins, ethion, fenthion, profenfose, diazinon, atrazine and ametryn were studied. among the antidepressant drugs,... 

    Fabrication and Experimental Investigation of Rotary Agnetohydrodynamic Micropump

    , M.Sc. Thesis Sharif University of Technology Esmaily Moghaddam, Mahdi (Author) ; Behshad Shafii, Mohammad (Supervisor)
    Considering the advantages and disadvantages of reported micropumps, we aimed to introduce a novel idea to diminish the disadvantages and promote the advantages of Magnetohydrodynamic (MHD) micropumps. This novel idea operates based on a mercury slug rotation in a circular microchannel. This cyclic motion of the mercury slug which is similar to a piston, push the fluid in the microchannel and pump the flow. However, to bring this idea into the practice, it must be integrated with a specific valve. Fluid has not to go through this specific valve. In contrary, mercury slug has to pass across this valve. These two specifications must be considered during the design process of the valve. On the... 

    Designing and Developing an Active Micromixer Based on Optical Tweezers for Microfluidics

    , M.Sc. Thesis Sharif University of Technology Taheri, Saeed (Author) ; Seyed Reihani, Nader (Supervisor)
    Microfluidics is a field of science that studies micron-scale characteristics of fluids. In this scale fluids show fascinating behavior far beyond our expectation compared to their large-scale counterparts. One of such peculiar behavior is the mixing of two different liquids flowing inside a microchannel. Due to low Reynolds number, the flow inside such a channel would be dominated by laminar behavior. In this regime mixing of the fluids is only mediated by molecular diffusion which is a rather slow process. In the current thesis, we utilized the rotating ability of optical tweezers to construct an active micromixer for Microfluidics. In order to do this we used birefringent microbeads. The... 

    Nanoparticle Synthesis Using Droplet-based Microfluidics

    , M.Sc. Thesis Sharif University of Technology Ghasemi, Mohammad Javad (Author) ; Mohammadi , Aliasghar (Supervisor) ; Molaei Dehkordi, Asghar (Co-Advisor)
    The purpose of this research is the synthesis of nanoparticles using micro fluid glass.The microfluidic glassy building is studied. Glass microfluidic microchannels making hydrophobic the continuing experiments carried out so that the water droplets in the organic phase and at the end of nanoparticles should be synthesized. Tests hydrophobic microchannels and water droplets in the organic phase was formed. In order to ensure an escape water contact angle and FTIR micro-channel test is taken and to avoid the droplets merged with each of surfactant SDS was used. In the end, DLS and FESEM nanoparticles synthesized using the tests have been evaluated and the concentrations of reactants and flow... 

    Design and Simulation of a Passive Microfluidic Device for Particle Separation

    , M.Sc. Thesis Sharif University of Technology Vatankhah, Parham (Author) ; Shamloo, Amir (Supervisor)
    Nowadays, separation and filtration of particles has many industrial applications in biology and medicine. In this thesis, passive microfluidics are designed and simulated which are able to separate and filter particles. Although particles aer generally expected to follow laminar flow streamlines in the absence of external forces, inertial forxes van cause particles to migrate across mictochannels in an accurate and predictable manner. The effect of these forces is invedtigated, and by using previous research, a model is developed to predict these forces. First design is a microchannel with Archimedean spiral which utilizes both inertial forces and Dean flow to separate particles in the... 

    Design, Simulation and Construction of a Microfluidic Device for the Purpose of Target Cells Separation and DNA Extraction

    , M.Sc. Thesis Sharif University of Technology Amani, Ali (Author) ; Shamloo, Amir (Supervisor) ; Nouri Borujerdi, Ali (Supervisor)
    Today, microfluidic experiments have found wide applications in medical sciences, engineering, and chemistry. Because of their small size, microfluidic devices help us to be able to use very little amount of sample for the experiments and also easily control and observe the under-experiment fluid. One of the most important applications of these devices is the separation of cancer cells in blood for counting their number and DNA genetic studies. In the current project we have tried to do the separation of cancer cells from other cells by designing an inertia microchannel. For this purpose, in the first step a geometry for the channel is designed with analyzing the induced forces on the cells.... 

    Designing and modeling a centrifugal microfluidic device to separate target blood cells

    , Article Journal of Micromechanics and Microengineering ; Volume 26, Issue 3 , 2016 ; 09601317 (ISSN) Shamloo, A ; Selahi, Aa ; Madadelahi, M ; Sharif University of Technology
    Institute of Physics Publishing  2016
    The objective of this study is to design a novel and efficient portable lab-on-a-CD (LOCD) microfluidic device for separation of specific cells (target cells) using magnetic beads. In this study the results are shown for neutrophils as target cells. However, other kinds of target cells can be separated in a similar approach. The designed microfluidics can be utilized as a point of care system for neutrophil detection. This microfluidic system employs centrifugal and magnetic forces for separation. After model validation by the experimental data in the literature (that may be used as a design tool for developing centrifugo-magnetophoretic devices), two models are presented for separation of... 

    Design and Simulation of a Microfluidic Blood Cells Counting Device

    , M.Sc. Thesis Sharif University of Technology Yavari, Meysam (Author) ; Saeedi, Mohammad Saeed (Supervisor) ; Sani, Mehdi (Supervisor)
    A Lab-On-a-Chip (LOC) is a device which can integrate one or many laboratory functions on a small chip with millimeters to few square centimeters in size. LOC is a subset of MEMS devices and known as “Micro Total Analysis Systems” (µTAS) as well. LOC technology is closely related to microfluidics which primarily describes the physics, manipulation and study of minute amount of fluids.In this research we tried to simulate the performance of a microfluidic device for counting blood cells to find main factors of it for design and manufacturing. This research has two main sections, hydrodynamics of fluid inside the microchannels and finding electrical performance of designed Coulter counter for... 

    Simulation, Design and fabrication of Kidney on a Chip

    , Ph.D. Dissertation Sharif University of Technology Kiyoumarsioskouei, Amir (Author) ; Saeedi, Mohammad Saeed (Supervisor) ; Firoozabadi, Bahar (Supervisor) ; Mosadegh, Bobak ($item.subfieldsMap.e)
    Renal diseases and consequently kidney failure is one of the important death factors around the world in recent years. It causes hundreds of thousands die every year and is in progress. Researchers believe that increasing chemical and nonchemical materials density in the blood which is the air pollution, use of tobacco and other parameters cause renal cells misfunction in urine filtration and regulation of blood pressure. The goal of this work is design and fabrication of a microfluidic device which provides different cell types to be cultured and imposed pressure. To do this, a high throughput microfluidic device is needed to mimic kidney biologically. Having such a device helps to analyze... 

    Numerical Modeling of Endothelial Cell’s Groups Migration in a Microfluidics Device

    , M.Sc. Thesis Sharif University of Technology Abeddoust, Mohammad (Author) ; Shamloo, Amir (Supervisor)
    Cell migration plays a key role in many biological processes including metastasis, wound healing, inflammatory response, body immune response and formation of new blood vessels. The migration of cells in response to the gradient of concentration gradient is regarded as chemotaxis. In the present study, the group chemotaxis of endothelial cells is simulated in response to gradient concentration of biochemical species using a developed cell migration model. At the first step, the numerical simulation of fluid flow and concentration transport of biochemical species is performed using a developed FVM code. At the second part, a model is developed to mimic the group migration of endothelial... 

    Ionic Size and Rheology Effects on the Mixing Process of Electroosmotic Flows

    , M.Sc. Thesis Sharif University of Technology Ahmadian Yazdi, Alireza (Author) ; Saeedi, Mohammad Hassan (Supervisor) ; Mozaffari, Ali Asghar (Supervisor)
    In recent years, there have been huge advancements in fabrication of micron-sized devices such that they enabled engineers to create a wide range of miniaturized systems, each of which is utilized in mechanical, electrical, and thermal applications. Micromixers are one of these devices with the role of mixing various micro flows. These devices are broadly used for chemical, biological, and biomedical assays. Among variety of micromixers, one that employs electrokinetic transport phenomenon is of great popularity. For instance, mixing under electroosmotic flow enables accurate process control and eliminates the need for moving components inside micromixer. The very complex nature of electric... 

    Microfluidic Systems as Solid Phase Microextraction Media

    , Ph.D. Dissertation Sharif University of Technology Allahdadlalouni, Misagh (Author) ; Bagheri, Habib (Supervisor) ; Zamani, Cyrus (Co-Supervisor)
    An inexpensive microfluidic chip–silicon rubber–based system was fabricated. A triangle–shaped micro canal with a 135 µm width and 234 µm depth was grooved by laser ablation technique. The groove was sealed by a thin glass cover while two pieces of stainless steel tubings were connected to each side of canal. Then, a polyaniline film with a thickness of 17±1 µm was synthesized on the walls of the canal by chemical oxidation using a syringe pump to deliver the relevant reagents. The microfluidic system was eventually connected to gas chromatography-mass spectrometry. To evaluate the capability of the constructed fluidic system, it was implemented to the analysis of sub–mL volumes of... 

    Simulation of Cell and Particle Separation by Combination of Dielectrophoretic and Inertial Forces in a Microfluidic Device

    , M.Sc. Thesis Sharif University of Technology Sorour Amini, Hossein (Author) ; Mohammadi, Ali Asghar (Supervisor)
    In this study, the dynamics of microparticles in a straight microchannel in the presence of an inhomogeneous oscillating electric field have been simulated by the immersed boundary method in combination with the lattice Boltzmann Navier-Stokes solver and the lattice Boltzmann method for solving the Poisson equation. The effect of the electric field on the location and number of particle equilibrium positions have been examined. In the absence of the electric field, circular particles will migrate to two stable equilibrium positions. The site of these equilibrium positions depends on the particle size and the fluid flow rate and is independent of the particle density. In the case of negative... 

    Design and Fabrication of a Microfluidic Device for the Formation of Multicellular Aggregates and Using in Tissue Engineering

    , Ph.D. Dissertation Sharif University of Technology Salehi, Sarah (Author) ; Shamloo, Amir (Supervisor) ; Kazemzadeh, Siamak (Supervisor)
    Three-dimensional cell culture and forming multicellular aggregates is superior over traditional monolayer approaches due to better mimicking in vivo conditions and hence functions of a tissue. A considerable amount of attention has been devoted to devising efficient methods for the rapid formation of uniform sized multicellular aggregates. Restoring cartilage to healthy state is difficult due to low cell density and hence low regenerative capacity. Currently used platforms are not compatible with clinical translation and require dedicated handling of trained personnel. However, when engineering and implanting cell microaggregates in a higher concentration, new cartilage is efficiently... 

    Numerical Simulation of Micro channel for Cells Counting Based on the Impedance Measurement of Cell Lysate

    , M.Sc. Thesis Sharif University of Technology Khademi, Maryam (Author) ; Saidi, Mohammad Said (Supervisor) ; Sani, Mahdi ($item.subfieldsMap.e)
    Nowadays cell-based microfluidic devices have many applications. One of the applications is disease diagnosis according to number of cells. Cell counting has different methods, such as optical cell counting, flow cytometry, hemocytometry, coulter counters,and so on. One of the methods of cells counting is based on measurement of changes in impedance or conductivity of surrounding medium because ions are released from surface-immobilized cells inside a micr of luidic channel.The method of cell lysate impedance spectroscopy is sensitive enough and it was offered for detecting and enumerating CD4+ cells in HIV patients. In this study,... 

    Design and Optimization of Microfluidic-Based Systems for Bioimpedance Spectroscopy in Cell Sorting

    , M.Sc. Thesis Sharif University of Technology Esmaeili, Fatemeh (Author) ; Fardmanesh, Mehdi (Supervisor) ; Fotowat Ahmady, Ali (Co-Supervisor)
    Microfluidics is an emerging technology that has attracted lots of attention in recent years due to its remarkable capabilities. This technology that operates fluids in micron dimensions, has led to the emergence of lab-on-a-chip platforms that have the ability to perform one or more laboratory operations on a small scale. One of the most important applications of lab-on-a-chip devices is cell sorting which is done in various methods. In this study, we intend to provide a simple and practical solution for cell sorting by designing a comprehensive and optimized system. In this regard, we design a new generation of microfluidic devices, known as digital microfluidics, which has the ability to...