Search for: lab-on-a-chip
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    Advancement of sensor integrated organ-on-chip devices

    , Article Sensors (Switzerland) ; Volume 21, Issue 4 , 2021 , Pages 1-44 ; 14248220 (ISSN) Clarke, G.A ; Hartse, B. X ; Niaraki Asli, A. E ; Taghavimehr, M ; Hashemi, N ; Abbasi Shirsavar, M ; Montazami, R ; Alimoradi, N ; Nasirian, V ; Ouedraogo, L. J ; Hashemi, N. N ; Sharif University of Technology
    MDPI AG  2021
    Organ-on-chip devices have provided the pharmaceutical and tissue engineering worlds much hope since they arrived and began to grow in sophistication. However, limitations for their applicability were soon realized as they lacked real-time monitoring and sensing capabilities. The users of these devices relied solely on endpoint analysis for the results of their tests, which created a chasm in the understanding of life between the lab the natural world. However, this gap is being bridged with sensors that are integrated into organ-on-chip devices. This review goes in-depth on different sensing methods, giving examples for various research on mechanical, electrical resistance, and bead-based... 

    Label-free electrochemical microfluidic biosensors: futuristic point-of-care analytical devices for monitoring diseases

    , Article Microchimica Acta ; Volume 189, Issue 7 , 2022 ; 00263672 (ISSN) Ebrahimi, G ; Samadi Pakchin, P ; Shamloo, A ; Mota, A ; de la Guardia, M ; Omidian, H ; Omidi, Y ; Sharif University of Technology
    Springer  2022
    The integration of microfluidics with electrochemical analysis has resulted in the development of single miniaturized detection systems, which allows the precise control of sample volume with multianalyte detection capability in a cost- and time-effective manner. Microfluidic electrochemical sensing devices (MESDs) can potentially serve as precise sensing and monitoring systems for the detection of molecular markers in various detrimental diseases. MESDs offer several advantages, including (i) automated sample preparation and detection, (ii) low sample and reagent requirement, (iii) detection of multianalyte in a single run, (iv) multiplex analysis in a single integrated device, and (v)... 

    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)
    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... 

    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)
    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... 

    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)
    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... 

    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)
    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)
    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... 

    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)
    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)
    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... 

    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)
    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... 

    Particle Focusing on a Lab on a Disk System

    , M.Sc. Thesis Sharif University of Technology Heydarabadipour, Adel (Author) ; Shamloo, Amir (Supervisor)
    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... 

    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)
    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)
    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 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)
    % 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... 

    Improving the Accuracy of a Microparticle Biosensor by Artificial Intelligence

    , M.Sc. Thesis Sharif University of Technology Ghassab, Hamid Reza (Author) ; Taghipoor, Mojtaba (Supervisor)
    In this research, the ability of artificial intelligence to improve the biosensor performance of a microfluidic system has been investigated. Coulter counter is a microfluidic system that measures the concentration of particles in a fluid using signals obtained from a biosensor. The method of this system is called " Resistive Pulse Sensing (RPS)" method. The pulses in the Coulter counter signals are affected by the number, shape, size and speed of particles passing through the orifice. The pulse of two particles of the same size and different shape in these systems are very similar and this makes it difficult for an operator to distinguish the type of particle. Another disadvantage of... 

    Reduction of production rate in y-shaped microreactors in the presence of viscoelasticity

    , Article Analytica Chimica Acta ; Volume 990 , 2017 , Pages 121-134 ; 00032670 (ISSN) Helisaz, H ; Saidi, M. H ; Sadeghi, A ; Sharif University of Technology
    The viscoelasticity effects on the reaction-diffusion rates in a Y-shaped microreactor are studied utilizing the PTT rheological model. The flow is assumed to be fully developed and considered to be created under a combined action of electroosmotic and pressure forces. In general, finite-volume-based numerical simulations are conducted to handle the problem; however, analytical solutions based on the depthwise averaging approach are also obtained for the case for which there is no reaction between the inlet components. The analytical solutions are found to predict accurate results when the width to height ratio is at least 10 and acceptable results for lower aspect ratios. An investigation... 

    Carbon nanotubes in microfluidic lab-on-a-chip technology: current trends and future perspectives

    , Article Microfluidics and Nanofluidics ; Volume 21, Issue 9 , 2017 ; 16134982 (ISSN) Ghasemi, A ; Amiri, H ; Zare, H ; Masroor, M ; Hasanzadeh, A ; Beyzavi, A ; Aref, A. R ; Karimi, M ; Hamblin, M. R ; Sharif University of Technology
    Advanced nanomaterials such as carbon nanotubes (CNTs) display unprecedented properties such as strength, electrical conductance, thermal stability, and intriguing optical properties. These properties of CNT allow construction of small microfluidic devices leading to miniaturization of analyses previously conducted on a laboratory bench. With dimensions of only millimeters to a few square centimeters, these devices are called lab-on-a-chip (LOC). A LOC device requires a multidisciplinary contribution from different fields and offers automation, portability, and high-throughput screening along with a significant reduction in reagent consumption. Today, CNT can play a vital role in many parts... 

    Design and fabrication of a centrifugal microfluidic disc including septum valve for measuring hemoglobin A1c in human whole blood using immunoturbidimetry method

    , Article Talanta ; Volume 190 , 2018 , Pages 134-139 ; 00399140 (ISSN) Mahmodi Arjmand, E ; Saadatmand, M ; Bakhtiari, M. R ; Eghbal, M ; Sharif University of Technology
    Elsevier B.V  2018
    Diabetes mellitus is a global endemic with a rapidly increasing prevalence in both developing and developed countries. Recently, hemoglobin A1c has been recommended by the American Diabetes Associations as a possible substitute for fasting blood glucose for the diagnosis of diabetes, because it is an indicator of long-term glycemic control. Also, centrifugal microfluidic systems have good potential for use in the point of care testing systems. In this study, a centrifugal microfluidic disc was designed and manufactured to measure hemoglobin A1c in whole blood using an immunoturbidimetry based method. Also, a new passive valve, named septum valve, was presented to precisely control the entry... 

    Nanotechnology-assisted microfluidic systems: From bench to bedside

    , Article Nanomedicine ; Volume 16, Issue 3 , 2021 , Pages 237-258 ; 17435889 (ISSN) Rabiee, N ; Ahmadi, S ; Fatahi, Y ; Rabiee, M ; Bagherzadeh, M ; Dinarvand, R ; Bagheri, B ; Zarrintaj, P ; Saeb, M. R ; Webster, T. J ; Sharif University of Technology
    Future Medicine Ltd  2021
    With significant advancements in research technologies, and an increasing global population, microfluidic and nanofluidic systems (such as point-of-care, lab-on-a-chip, organ-on-a-chip, etc) have started to revolutionize medicine. Devices that combine micron and nanotechnologies have increased sensitivity, precision and versatility for numerous medical applications. However, while there has been extensive research on microfluidic and nanofluidic systems, very few have experienced wide-spread commercialization which is puzzling and deserves our collective attention. For the above reasons, in this article, we review research advances that combine micro and nanotechnologies to create the next... 

    Cancer cell enrichment on a centrifugal microfluidic platform using hydrodynamic and magnetophoretic techniques

    , Article Scientific Reports ; Volume 11, Issue 1 , 2021 ; 20452322 (ISSN) Shamloo, A ; Naghdloo, A ; Besanjideh, M ; Sharif University of Technology
    Nature Research  2021
    Isolation of rare cancer cells is one of the important and valuable stages of cancer research. Regarding the rarity of cancer cells in blood samples, it is important to invent an efficient separation device for cell enrichment. In this study, two centrifugal microfluidic devices were designed and fabricated for the isolation of rare cancer cells. The first design (passive plan) employs a contraction–expansion array (CEA) microchannel which is connected to a bifurcation region. This device is able to isolate the target cells through inertial effects and bifurcation law. The second design (hybrid plan) also utilizes a CEA microchannel, but instead of using the bifurcation region, it is...