Search for: microfluidics
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    Non-Newtonian droplet-based microfluidics logic gates

    , Article Scientific Reports ; Volume 10, Issue 1 , 2020 Asghari, E ; Moosavi, A ; Hannani, S. K ; Sharif University of Technology
    Nature Research  2020
    Droplet-based microfluidic logic gates have many applications in diagnostic assays and biosciences due to their automation and the ability to be cascaded. In spite of many bio-fluids, such as blood exhibit non-Newtonian characteristics, all the previous studies have been concerned with the Newtonian fluids. Moreover, none of the previous studies has investigated the operating regions of the logic gates. In this research, we consider a typical AND/OR logic gate with a power-law fluid. We study the effects of important parameters such as the power-law index, the droplet length, the capillary number, and the geometrical parameters of the microfluidic system on the operating regions of the... 

    Electrospun polyethersolfone nanofibrous membrane as novel platform for protein immobilization in microfluidic systems

    , Article Journal of Biomedical Materials Research - Part B Applied Biomaterials ; 2017 ; 15524973 (ISSN) Mahmoudifard, M ; Vossoughi, M ; Soudi, S ; Soleimani, M ; Sharif University of Technology
    John Wiley and Sons Inc  2017
    In the present study, the feasibility of electrospun polyethersolfone (PES) nanofibrous membrane as the solid substrate for microfluidic based immunoassays to enhance the density of immobilized antibody on the surface of membrane was assessed. Conversely, the efficacy of antibody immobilization was compared by two different strategies as 1-Ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC)/N-Hydroxysuccinimide (NHS) coupling chemistry and hydrophobic interaction. Compared to conventional immunoassays carried out in plates or gels, microfluidic based immunoassays grant a lot of advantages such as a consumption of little samples and reagents, shorter analysis time, and higher efficiency.... 

    Aggregation and detection of magnetic nanoparticles in microfluidic channels

    , Article Journal of Electrical Engineering ; Volume 63, Issue 7 SUPPL , 2012 , Pages 27-30 ; 13353632 (ISSN) Sarreshtedari, F ; Kokabi, H ; Gamby, J ; Ngo, K. A ; Krause, H. J ; Fardmanesh, M ; Sharif University of Technology
    Incorporating numerical simulation with COMSOL Multiphysics, the aggregation and detection of superparamagnetic nanoparticles in microfluidic channels are investigated. Considering the physical specifications of the implemented microchannels, the parameters which determine the ability of the system for aggregation and detection of the particles are examined and simulated. Based on the simulation results, we propose a new approach for both capturing and detecting of the magnetic nanoparticles passing through microchannels  

    Skin diseases modeling using combined tissue engineering and microfluidic technologies

    , Article Advanced Healthcare Materials ; Volume 5, Issue 19 , 2016 , Pages 2459-2480 ; 21922640 (ISSN) Mohammadi, M. H ; Heidary Araghi, B ; Beydaghi, V ; Geraili, A ; Moradi, F ; Jafari, P ; Janmaleki, M ; Valente, K. P ; Akbari, M ; Sanati Nezhad, A ; Sharif University of Technology
    Wiley-VCH Verlag 
    In recent years, both tissue engineering and microfluidics have significantly contributed in engineering of in vitro skin substitutes to test the penetration of chemicals or to replace damaged skins. Organ-on-chip platforms have been recently inspired by the integration of microfluidics and biomaterials in order to develop physiologically relevant disease models. However, the application of organ-on-chip on the development of skin disease models is still limited and needs to be further developed. The impact of tissue engineering, biomaterials and microfluidic platforms on the development of skin grafts and biomimetic in vitro skin models is reviewed. The integration of tissue engineering and... 

    Continuous synthesis of plate-like silica microparticles using microfluidics

    , Article Journal of Flow Chemistry ; Volume 9, Issue 3 , 2019 , Pages 161-174 ; 2062249X (ISSN) Tamtaji, M ; Mohammadi, A ; Sharif University of Technology
    Springer International Publishing  2019
    The synthesis of plate-like silica particles, which are of importance for a variety of applications, are mainly based on the widely adopted method of the sol-gel reaction of silicon alkoxides in traditional batch-wise instrumentation. In this study, continuous-flow synthesis of amorphous plate-like silica particles is reported through combining droplet-based microfluidics and the sol-gel reaction of tetraethyl orthosilicate. The reaction was conducted at the surface of oil droplets, comprising tetraethyl orthosilicate (TEOS), suspended in acidic (HCl) water, resulting in silica particles on the surface of the droplets, leaving the device with outlet flow. The synthesized particles had... 

    Effects of wax boundaries in combination with evaporation on dynamics of fluid flow in paper-based devices

    , Article Surfaces and Interfaces ; Volume 21 , 2020 Boodaghi, M ; Shamloo, A ; Sharif University of Technology
    Elsevier B.V  2020
    Since their introduction, paper-based microfluidic analytical devices (μPADs) have been ubiquitously utilized for different applications. The spontaneous imbibition of liquids in the paper-based devices that eliminates the requirement of an external pumping system has played a primary role in making paper an appropriate alternative for many other materials in the fabrication of microfluidic devices. Wax patterning is one of the most common methods to fabricate μPADs. Dynamics of the flow in channels with wax boundaries deviate from Washburn's law. Despite some research performed to model the effects of wax boundaries, some gaps remain in the presented models. A more general model is needed... 

    A microfluidic concentration gradient generator for simultaneous delivery of two reagents on a millimeter-sized sample

    , Article Journal of Flow Chemistry ; Volume 10, Issue 4 , 2020 , Pages 615-625 Rismanian, M ; Saidi, M. S ; Kashaninejad, N ; Sharif University of Technology
    Springer International Publishing  2020
    Microfluidic concentration gradient generators (μCGGs) are indispensable parts of many emerging lab-on-a-chip platforms for biological studies and drug delivery applications. Most of the μCGGs reported in the literature can only generate the desired concentration gradients in a micron-sized sample (e.g., cells). As such, there is an unmet need to design a μCGG that can generate continuous concentration gradients of multi reagents (e.g., drugs) in a millimeter-sized sample (e.g., tissue). Herein, we report the proof-of-concept of this class of μCGG by combining a modified tree-like CGG with a micromixer. By conducting both experimental investigation and numerical analysis, we show that the... 

    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 parameter study of integrated microfluidic platform for CTC isolation and enquiry; a numerical approach

    , Article Biosensors ; Volume 8, Issue 2 , 18 June , 2018 ; 20796374 (ISSN) Shamloo, A ; Ahmad, S ; Momeni, M ; Sharif University of Technology
    Being the second cause of mortality across the globe, there is now a persistent effort to establish new cancer medication and therapies. Any accomplishment in treating cancers entails the existence of accurate identification systems empowering the early diagnosis. Recent studies indicate CTCs’ potential in cancer prognosis as well as therapy monitoring. The chief shortcoming with CTCs is that they are exceedingly rare cells in their clinically relevant concentration. Here, we simulated a microfluidic construct devised for immunomagnetic separation of the particles of interest from the background cells. This separation unit is integrated with a mixer subunit. The mixer is envisioned for... 

    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... 

    Pressure-driven liquid-liquid separation in Y-shaped microfluidic junctions

    , Article Chemical Engineering Journal ; Volume 328 , 2017 , Pages 1075-1086 ; 13858947 (ISSN) Foroozan Jahromi, P ; Karimi Sabet, J ; Amini, Y ; Fadaei, H ; Sharif University of Technology
    On-chip phase separation of multiphase microflows at the divergence point of Y-shaped microfluidic junctions is an effective way for integrating continuous microstructured devices. In this study, flow pattern maps of various solvent pairs based on the volumetric flow rates of both phases have been drawn experimentally and compared with numerical prediction to investigate the effective domain for which complete phase separation occurred. Furthermore, sufficient separation of aqueous and organic phases at the end of the microchannel was achieved by controlling the pressure difference at the liquid-liquid interface via loading back-pressure on the organic phase. A mathematical model based on... 

    Spheroids-on-a-chip: recent advances and design considerations in microfluidic platforms for spheroid formation and culture

    , Article Sensors and Actuators, B: Chemical ; Volume 263 , 15 June , 2018 , Pages 151-176 ; 09254005 (ISSN) Moshksayan, K ; Kashaninejad, N ; Ebrahimi Warkiani, M ; Lock, J. G ; Moghadas, H ; Firoozabadi, B ; Saidi, M. S ; Nguyen, N. T ; Sharif University of Technology
    Elsevier B.V  2018
    A cell spheroid is a three-dimensional (3D) aggregation of cells. Synthetic, in-vitro spheroids provide similar metabolism, proliferation, and species concentration gradients to those found in-vivo. For instance, cancer cell spheroids have been demonstrated to mimic in-vivo tumor microenvironments, and are thus suitable for in-vitro drug screening. The first part of this paper discusses the latest microfluidic designs for spheroid formation and culture, comparing their strategies and efficacy. The most recent microfluidic techniques for spheroid formation utilize emulsion, microwells, U-shaped microstructures, or digital microfluidics. The engineering aspects underpinning spheroid formation... 

    Design and Fabrication of Impedance Flowcytometric based Microfluidic Sorter

    , M.Sc. Thesis Sharif University of Technology Esmaeili Dokht, Pouria (Author) ; Fardmanesh, Mehdi (Supervisor)
    Microfluidic technology is a field of science that deals with the design, fabrication, and experimental tests of small-scale fluid systems and has made great strides over the past decade. As an interdisciplinary field, this growing field of technology has many applications in medicine, diagnostics, chemical analysis, electronics industry, etc. One of the primary applications of the microfluidic devices is the development of " laboratory on-chip (LOC)" tools as point-of-care (POC) diagnostic tools, such as, rapid detection during surgery. A LOC device includes various application modules, sample transfer and preparation modules, separation modules, and detection and analysis modules. The... 

    Numerical simulation of centrifugal serpentine micromixers and analyzing mixing quality parameters

    , Article Chemical Engineering and Processing: Process Intensification ; Volume 104 , 2016 , Pages 243-252 ; 02552701 (ISSN) Shamloo, A ; Madadelahi, M ; Akbari, A ; Sharif University of Technology
    Elsevier, B.V  2016
    Centrifugal microfluidics or the Lab on a CD (LOCD) has developed vast applications in biomedical researches and analyses. Fluid mixing is an application of the LOCD. In this paper, multiple centrifugal micromixers were simulated. Various parameters were originally presumed to have an effect on mixing performance. These parameters include inlet angle, angular velocity, cross-sectional profile, perpendicular length ratio and the number of channels in series. They were each analyzed through simulations. It was gathered that the inlet angle does not significantly affect the mixing quality. Increasing angular velocity steadily increases mixing quality for all geometries. The vertical triangular... 

    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... 

    A centrifugal microfluidic platform to measure hemoglobin of whole blood

    , Article 2017 24th Iranian Conference on Biomedical Engineering and 2017 2nd International Iranian Conference on Biomedical Engineering, ICBME 2017, 30 November 2017 through 1 December 2017 ; 2018 ; 9781538636091 (ISBN) Mahmodi Arjmand, E ; Saadatmand, M ; Bakhtiari, M. R ; Eghbal, M ; Balaei, A ; Sharif University of Technology
    Microfluidics has been becoming more and more popular over last two decades. The reason for this, is inherent features of microfluidics including low consumption of samples and reagents, high sensitivity, short analysis time, and low cost. As well as, centrifugal microfluidics as a subset of microfluidics has been able to prove itself as a helpful tool in analytic assays. The main application of centrifugal microfluidic devices is being used in point-of-care testing systems. Herein, we presented a microfluidic disc for measuring hemoglobin(Hb) concentration in the EDTA-anticoagulated venous blood using cyanmethemoglobin method. In this experiment, at first a hand-made standard solution was... 

    An optimized procedure to develop a 3-dimensional microfluidic hydrogel with parallel transport networks

    , Article International Journal for Numerical Methods in Biomedical Engineering ; 2018 ; 20407939 (ISSN) Jafarkhani, M ; Salehi, Z ; Shokrgozar, M. A ; Mashayekhan, S ; Sharif University of Technology
    Wiley-Blackwell  2018
    The development of microfluidic hydrogels is an attractive method to generate continuous perfusion, induce vascularization, increase solute delivery, and ultimately improve cell viability. However, the transport processes in many in vitro studies still have not been realized completely. To address this problem, we have developed a microchanneled hydrogel with different collagen type I concentrations of 1, 2, and 3 wt% and assessed its physical properties and obtained diffusion coefficient of nutrient within the hydrogel. It is well known that microchannel geometry has critical role in maintaining stable perfusion rate. Therefore, in this study, a computational modeling was applied to... 

    Exploring contraction–expansion inertial microfluidic-based particle separation devices integrated with curved channels

    , Article AIChE Journal ; Volume 65, Issue 11 , 2019 ; 00011541 (ISSN) Shamloo, A ; Abdorahimzadeh, S ; Nasiri, R ; Sharif University of Technology
    John Wiley and Sons Inc  2019
    Separation of particles or cells has various applications in biotechnology, pharmaceutical and chemical industry. Inertial cell separation, in particular, has been gaining a great attention in the recent years since it has exhibited a label-free, high-throughput and efficient performance. In this work, first, an inertial contraction–expansion array microchannel device, capable of passively separating two particles with diameters of 4 and 10 μm, was numerically studied. Then, the validated model was combined with curved geometries in order to investigate the effect of curve features on the separation process. The overall purpose was to investigate the interaction between the two different... 

    Investigating the effect of reagent parameters on the efficiency of cell lysis within droplets

    , Article Physics of Fluids ; Volume 32, Issue 6 , 2020 Shamloo, A ; Hassani Gangaraj, M ; Sharif University of Technology
    American Institute of Physics Inc  2020
    Cell lysis is an essential primary step in cell assays. In the process of cell lysis, the cell membrane is destroyed and the substances inside the cell are extracted. By utilizing a droplet-based microfluidic platform for cell lysis, the mixer unit that is required for mixing lysis reagents with the cells can be excluded, and thus, the complexity of the fabrication process is reduced. In addition, lysing the cells within the droplets will prevent the cells from exposure to the channel walls, and as a result, cleanliness of the samples and the device is maintained. In this study, cell lysis within the droplets and the parameters affecting the efficiency of this process are investigated using... 

    Separation of Metal Ions-based Microfluidic Platform for Liquid-liquid Extraction

    , M.Sc. Thesis Sharif University of Technology Foroozan, Peyman (Author) ; Mohammadi, Ali Asghar (Supervisor) ; Karimi Sabet, Javad (Co-Advisor)
    Continuous separation processes in microfluidic devices experienced a steep rise in attention during the last two decades. Among the different separation processes, liquid-liquid extraction especially benefits from the short molecular diffusion distance and large specific interfacial area, as these are advantageous for effective mass transport. In the present study, glass-based microfluidic devices have been fabricated utilizing laser ablation and wet chemical etching methods then experiments and numerical simulation were carried out to investigate hydrodynamic behavior of fluid flow in Y-junction microfluidic. In order to achieve phase separation at the end of the microchannel, a phase...