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Total 44 records

    Numerical Simulation and Enalysis of an Electrokinetically-driven Microdispenser

    , M.Sc. Thesis Sharif University of Technology Haroutunian, Artin (Author) ; Saeedi, Mohammad Saeed (Supervisor) ; Shafiee, Mohammad Behshad (Supervisor)
    Abstract
    Nowadays Lab-on-a-chip systems are being widely used in medical applications, especially in analyzing minute volumes of blood for diagnosis and treatment of some crucial diaseses like diabetic. A Lab-on-a-chip is comprised of a variety of components such as micromixer, microdispenser, detection and separation units and so on. In this thesis, however, we have analyzed and numerically simulated a microdispenser which is electrokinetically driven. In other words, electrical potentials are applied to electrodes in order to conduct two fluids within a cross microchannel, and distribution of a sample fluid takes place due to appropriately applied potentials. In order to analyze and simulate the... 

    Analysis and Design of an Electrokinetically-driven Micro-Mixer

    , M.Sc. Thesis Sharif University of Technology Anbari, Ali Mohammad (Author) ; Shafii, Mohammad Behshad (Supervisor) ; Saeedi, Mohammad Saeed (Supervisor)
    Abstract
    A Lab-On-A-Chip is a micro-scale system whic h utilizes some micro-scale components in order to implement detection tests on samples. One of the most important components of a lab-on-a-chip device is the micro-mixer, which is responsible for appropriately mixing of samples in a short period of time. The biggest problem relevant to mixing in micro scales is that since as the viscous forces are dominant in micro scale and dimensions are small, it is impractical to mix fluids via turbulence, and consequently mixing process is performed by diffusion mechanism. Two major strategies are being used in order to improve the mixing performance and two groups of micro-mixers, passive and active types,... 

    Numerical Simulation and Analysis of Electrokinetic Micromixer

    , M.Sc. Thesis Sharif University of Technology Raffiee, Amir Hossein (Author) ; Saidi, Mohammad Said (Supervisor)
    Abstract
    Lab-On-A-Chip is a micro-scale system which utilizes specific tools in order to operate detection tests on samples. One of the most important components of these devices is micromixers which is responsible for appropriate mixing of samples in short period of time. The biggest problem associated to the mixing in micro-scale is the regime that the flow takes during the process. Due to the small dimensions of micromixers the induced flow stream resides in the range of laminar flows and consequently the mixing is conducted solely by diffusion mechanism which is either time-taking or requires long micro-channel that causes the high cost of fabrication. In order to improve the mixing process two... 

    Flow of Saliva in a Lab-on-a-chip under Electrokinetic Body Force

    , M.Sc. Thesis Sharif University of Technology Zandi, Mohammad (Author) ; Saeedi, Mohammad Hassan (Supervisor)
    Abstract
    The lab-on-a-chip (LOC) devices utilizing electroosmosis for flow actuation are usually encountered with non-Newtonian behavior of working fluids. Hence, studying the flow of non-Newtonian fluids under an electroosmotic body force is of high importance for accurate design and active control of these devices. In this thesis, mixed electroosmotically and pressure driven flow of salivathrough a rectangular microchannel is examined utilizing two viscoelastic constitutive equations, namely PTT and FENE-P models. Since the hydrodynamic entry length is usually negligible for microflows, a hydrodynamically developed flow is considered in the analysis. The governing equations in dimensionless form... 

    Transport Phenomena in Electrokinetically Generated Microflows

    , Ph.D. Dissertation Sharif University of Technology Sadeghi, Arman (Author) ; Saeedi, Mohammad Hassan (Supervisor) ; Mozaffari, Ali Asghar (Supervisor) ; Chakraborty, Suman (Co-Advisor)
    Abstract
    This is a theoretical study on heat and mass transfer in electrokinetically driven microfluidic devices with particular consideration to the lab-on-a-chip (LOC) applications. Special attention is given to disclose the effects of the fluid rheology and the aspect ratio of the rectangular geometry on the surface reaction kinetics and the temperature rise due to the Joule heating. Along this line, two different viscoelastic constitutive equations namely PTT and FENE-P models along with the power-law viscosity model are being considered. The secondary aims also include exploring the influences of the fluid properties variations throughout the channel cross section on the hydrodynamic and thermal... 

    Design a Microfluidics System for Drug Testing of Leukemia Patient's Bone Marrow Aspirate

    , M.Sc. Thesis Sharif University of Technology Rahimi, Ali (Author) ; Saidi, Mohammad Said (Supervisor)
    Abstract
    Cancer is one of the most causes of mortality in the world. Leukemia is a type of cancer initiated by the rapid proliferation of blood cells including WBCs, RBCs, and Platelets, that classified into four general types of AML, ALL, CML, and CLL. The main treatment of leukemia is chemotherapy. Because of many problems that patients have with this treatment and not so good results of chemotherapy, we design a microfluidic chip that can perform personalized medicine treatment for leukemia patients.This microchip consists of two main parts, Concentration Gradient Generator (CGG), and cell culture. CGG system is a tree CGG with two inlets and four outlets, which makes a linear concentration of... 

    Design and Numerical Simulation of a Micro-chip for Separating CTCs from Peripheral Blood

    , M.Sc. Thesis Sharif University of Technology Niknam, Hamid Reza (Author) ; Saeedi, Mohammad Saeed (Supervisor)
    Abstract
    According to studies, cancer is the second leading cause of death in the world and millions of people die from this disease every year. Early diagnosis is one of the most important factors in controlling and treating the disease. The ability of circulating tumor cells to diagnose and monitor the disease has led many researchers to focus on studying and researching these cells in recent years. However, due to the fact that the concentration of this type of cells in the blood is very low, their isolation is associated with challenges. Various methods isolate CTCs based on physical, biological and other differences in characteristics. In this study, we investigate performance of a microfluidic... 

    Numerical Simulation of Organ on Chip Systems

    , M.Sc. Thesis Sharif University of Technology Mehrdel, Pouya (Author) ; Saeedi, Mohammad Saeed (Supervisor) ; Sani, Mehdi ($item.subfieldsMap.e)
    Abstract
    Discovering new medicines and generally medical researches, are time consuming and expensive. But recent achievements in cell culturing methods and micro and nano-engineering techniques have enabled the researchers to investigate new medicines in a lesser time and price. Huh et al. successfully fabricated the lung on chip device. This device is consisted of three chambers. The middle chamber is separated in two equal parts and side chambers were considered in order to apply normal breathing. Periodic deformation was needed to apply the natural condition of cultured cells by expansion and contraction. Numerical simulation was needed to investigate the properties of flow in this kind of... 

    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)
    Abstract
    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,... 

    Numerical Simulation and Characterization of an Electro-kinetic Micro-Mixer

    , M.Sc. Thesis Sharif University of Technology Ghaderian, Sepideh (Author) ; Saeedi, Mohammad Saeed (Supervisor) ; Sani, Mahdi (Supervisor)
    Abstract
    Most of the current literature on the simulation of the electro-osmotic flow in micro-channels decompose electric potential to two components; internal and external potentials. They usually approximate the near wall changes in the ion concentration (called double layer) which is physically responsible for electro-osmotic force by a model (like Poisson equilibrium distribution or Debye-Huckel approximation). There are reports in the literature which show that the approximations lose their fidelity for more complex situations. In this thesis we solve the full system of Nernst-Planck and Navier-Stokes equations by resolving electric double layer. The proposed... 

    Particle Focusing on a Lab on a Disk System

    , M.Sc. Thesis Sharif University of Technology Heydarabadipour, Adel (Author) ; Shamloo, Amir (Supervisor)
    Abstract
    In many microfluidic devices, focusing particles into a narrow stream is usually an essential step prior to counting, detecting, and sorting them. By installation of microfluidic laboratory functions on a rotating disk, new devices called Lab-on-a-disks, which have plenty of advantages in comparison to ordinary Lab-on-a-chips, shape. In this study, to the best of our knowledge for the first time, a Lab-on-a-disk device is designed and fabricated in order to focus particles prior to detecting them by a conventional CD-ROM as a strong optical system. Hydrophoresis method, using slanted obstacles to induce transverse pressure gradients, is utilized to focus particles. In this regard, the... 

    Rheology Effects on Reaction-diffusion Mechanisms in a Y-shaped Micro Fluidic Mixer

    , M.Sc. Thesis Sharif University of Technology Hellisaz, Hamed (Author) ; Saeedi, Mohammad Hassan (Supervisor) ; Kazemzadeh Hannani, Siamak ($item.subfieldsMap.e)
    Abstract
    Numerous applications of Lab on a Chips (LOCs) in chemical/biochemical analyses as well as the emergence of advanced methods for their manufacture attracts many researchers’ attention to these micro instruments. Low sample volume consumption and their high controllability are accounted as the main advantage of LOC systems. Micromixers are among the main components of any LOC in which mixing and/or reaction among two components occur. Micromixers have many potential applications in biological and medical sciences, and so they are repeatedly charged by biofluids. Due to sensibility of biofluids, to avoid disintegration, applying electroosmotic flow instead of pressure-induced flow has priority... 

    Design and Fabrication of a Microfluidic Chip for Live and Dead Cell Separation

    , M.Sc. Thesis Sharif University of Technology Tajik, Parham (Author) ; Firouzbakhsh, Keykhosrow (Supervisor) ; Saeedi, Mohammad Saeed (Supervisor)
    Abstract
    The recent breakthroughs in the lab-on-a-chip technology will not be directly used as clinical devices unless the specific applications are carefully tested and certified. As there is a growing trend towards microfluidic devices for biomedical research, an active microfluidic device was developed. Common microfabrication methods were used to develop a microchip to separate and concentrate live and dead cells based on the dielectrophoresis phenomenon. Unique capabilities of the dielectrophoresis phenomenon make it a powerful tool for micro particle manipulation in micro scale. In this research, geometry for the mentioned purpose is designed and optimized. Three-dimensional microelectrodes are... 

    Designing and Manufactureing a Concentration Gradient Generator

    , M.Sc. Thesis Sharif University of Technology Ebadi, Milad (Author) ; kashaninezhad, navid (Supervisor)
    Abstract
    Nowadays, due to the growing need of the human to further improve the health of the community, research in the field of pharmacology as well as simulation of the cell culture environment is increasing. One of the most important requirements for simulating cell culture is the use of concentration gradient in culture media. The reason for this is the dependence of cellular activity on the presence of a gradient of concentration in the environment. Also, in drug investigations, in order to speed up the examination of different drugs and reduce the amount of drug that will used, different concentrations of the drug should be considered simultaneously in the microchips. Therefore, to make the... 

    Separation and Microfluidic Analysis of one Cancer Biomarker (Exosome) by Means of Microfluidic Chip Microfluidc Analysis Exosome Toward Liquid Biopsy for Cancer Tumor Cell

    , M.Sc. Thesis Sharif University of Technology Madani, Mohammad (Author) ; Saidi, Mohammad Said (Supervisor) ; Firouzabadi, Bahar (Co-Supervisor)
    Abstract
    The recent breakthroughs in the lab-on-a-chip technology will not be directly used as clinical devices unless the specific applications are carefully tested and certified. As there is a growing trend towards microfluidic devices for biomedical research, an active microfluidic device was developed. Common microfabrication methods were used to develop a microchip to separate and concentrate exosome and particular cell based on the dielectrophoresis phenomenon. Unique capabilities of the dielectrophoresis phenomenon make it a powerful tool for micro particle manipulation in micro scale. In this research, geometry for the mentioned purpose is designed and optimized. Three-dimensional... 

    Separation of Plasma from Blood Using a Dielectrophoresis-Assisted Microfluidic Device

    , M.Sc. Thesis Sharif University of Technology Shams, Mehran (Author) ; Mohammadi, Ali Asghar (Supervisor) ; Soltanieh, Mohammad (Supervisor)
    Abstract
    % of human blood makes up of plasma, that this plasma is a rich source of proteins that can be used as biomarkers for a variety of clinical diseases and laboratory research, therefore, it is necessary that the plasma be separate by a high purity percentage. Using a centrifuge It is a common method used to separate plasma from blood, but because it requires large equipment and a large volume of blood, as well as stress caused by centrifugal force, increases the probability of damage to the biomarkers, so it has been tried today that Use methods that are easy to transport and require a small amount of blood. The idea of using the microfluidic device has been put forward for the purpose of... 

    Design and Simulation of CMOS Based Magnetic Sensor for Biosensing Applications

    , M.Sc. Thesis Sharif University of Technology Mafi, Alireza (Author) ; Akbari, Mahmood (Supervisor) ; Fotowat-Ahmady, Ali (Supervisor)
    Abstract
    This paper presents a scalable and ultrasensitive magnetic biosensing scheme based on on-chip LC resonance frequency-shifting. The sensor transducer gain is demonstrated as being location-dependent on the sensing surface and proportional to the local polarization magnetic field strength |B|2 generated by the sensing inductor. To improve the gain uniformity, a periodic coil is proposed as a substitution for the standard process coil. As an implementation example, the circuit is designed in a 65nm CMOS process. The spatially uniform sensor gain of the array is verified by COMSOL simulations. Overall, the presented sensor demonstrates an improvement in the uniformity of the inductor’s magnetic... 

    Numerical Study of Enhancement of Inflection Point Focusing for Blood Cell Separation

    , M.Sc. Thesis Sharif University of Technology Mirtalebi, Elnaz (Author) ; Moosavi, Ali (Supervisor) ; Sadrhosseini, Hani (Co-Supervisor)
    Abstract
    Today, the determination and therapy of numerous illnesses, including malignant growth, relies upon the information and assessment of platelets, so blood testing and cell examination is fundamental to survey the movement of disease. The lab on a chip innovation is utilized as an extremely productive device in cell studies. The lab on a chip is used as a foundation and a substrate for making a legitimate stream for cell processes in medication. This innovation is a gadget or framework with millimeters or centimeters aspects like a chip, and it performs research facility handling on a micron-scale. In spite of the fact that it has a few impediments, it has so many values; for example, it... 

    Design and Manufacturing of a Setup for Solid-state Nanopore Fabrication

    , M.Sc. Thesis Sharif University of Technology Bayat, Alireza (Author) ; Akbari, Javad (Supervisor) ; Taghipour, Mojtaba (Supervisor)
    Abstract
    The aim of the current research is to study the process of making a solidstate nanopore by molding from PDMS polymer and to make a laboratory sample of a solidstate nanopore manufacturing device using this method. Solid-state nanopores are used to control ion transport in microfluidic channels,lab-on-a-chip detection to study nucleic acids and proteins, desalination, nanofluidic transistors,single-cell sensing tools, and particle classification. In general, the smaller the nanopore, the shorter the length and the higher the mechanical stability, the better the performance. In this research, chips have been made on which there is a blade with a sharpness of 10 nanometers and a height of 10... 

    Urine Analysis by a Microfluidic Paper-Based Device for Renal Function Test

    , M.Sc. Thesis Sharif University of Technology Pourghanbari Marvast, Mohadeseh (Author) ; Saadatmand, Maryam (Supervisor)
    Abstract
    Chronic kidney disease is one of the silent diseases that progresses slowly, often without symptoms, and can eventually lead to kidney loss. Early detection of this disease can help diagnose it and prevent further problems. Urinary creatinine is an effective biomarker for early diagnosis of chronic kidney disease, but methods available in clinics are problematic for people living in disadvantaged areas because of the high cost and the need for 24-hour urine collection. Currently, paper-based microfluidic devices are being developed because they are easy to manufacture, inexpensive, the fluid is permeable by capillary force, and no additional equipment is needed. In this work, to fabricate a...