Search for: microtechnology
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    Improvement of size-based particle separation throughput in slanted spiral microchannel by modifying outlet geometry

    , Article Electrophoresis ; Volume 41, Issue 5-6 , February , 2020 , Pages 353-359 Mihandoust, A ; Maleki Jirsaraei, N ; Rouhani, S ; Safi, S ; Alizadeh, M ; Sharif University of Technology
    Wiley-VCH Verlag  2020
    The inertial microfluidic technique, as a powerful new tool for accurate cell/particle separation based on the hydrodynamic phenomenon, has drawn considerable interest in recent years. Despite numerous microfluidic techniques of particle separation, there are few articles in the literature on separation techniques addressing external outlet geometry to increase the throughput efficiency and purity. In this work, we report on a spiral inertial microfluidic device with high efficiency (>98%). Herein, we demonstrate how changing the outlet geometry can improve the particle separation throughput. We present a complete separation of 4 and 6 μm from 10 μm particles potentially applicable to... 

    A novel laparoscopic grasper with two parallel jaws capable of extracting the mechanical behaviour of soft tissues

    , Article Journal of Medical Engineering and Technology ; Volume 41, Issue 5 , 2017 , Pages 339-345 ; 03091902 (ISSN) Nazarynasab, D ; Farahmand, F ; Mirbagheri, A ; Afshari, E ; Sharif University of Technology
    Taylor and Francis Ltd  2017
    Data related to force-deformation behaviour of soft tissue plays an important role in medical/surgical applications such as realistically modelling mechanical behaviour of soft tissue as well as minimally invasive surgery (MIS) and medical diagnosis. While the mechanical behaviour of soft tissue is very complex due to its different constitutive components, some issues increase its complexity like behavioural changes between the live and dead tissues. Indeed, an adequate quantitative description of mechanical behaviour of soft tissues requires high quality in vivo experimental data to be obtained and analysed. This paper describes a novel laparoscopic grasper with two parallel jaws capable of... 

    Drug delivery systems and materials for wound healing applications

    , Article Advanced Drug Delivery Reviews ; Volume 127 , 2018 , Pages 138-166 ; 0169409X (ISSN) Saghazadeh, S ; Rinoldi, C ; Schot, M ; Saheb Kashaf, S ; Sharifi, F ; Jalilian, E ; Nuutila, K ; Giatsidis, G ; Mostafalu, P ; Derakhshandeh, H ; Yue, K ; Swieszkowski, W ; Memic, A ; Tamayol, A ; Khademhosseini, A ; Sharif University of Technology
    Elsevier B.V  2018
    Chronic, non-healing wounds place a significant burden on patients and healthcare systems, resulting in impaired mobility, limb amputation, or even death. Chronic wounds result from a disruption in the highly orchestrated cascade of events involved in wound closure. Significant advances in our understanding of the pathophysiology of chronic wounds have resulted in the development of drugs designed to target different aspects of the impaired processes. However, the hostility of the wound environment rich in degradative enzymes and its elevated pH, combined with differences in the time scales of different physiological processes involved in tissue regeneration require the use of effective drug... 

    Complete steric exclusion of ions and proton transport through confined monolayer water

    , Article Science ; Volume 363, Issue 6423 , 2019 , Pages 145-148 ; 00368075 (ISSN) Gopinadhan, K ; Hu, S ; Esfandiar, A ; Lozada Hidalgo, M ; Wang, F. C ; Yang, Q ; Tyurnina, A. V ; Keerthi, A ; Radha, B ; Geim, A. K ; Sharif University of Technology
    American Association for the Advancement of Science  2019
    It has long been an aspirational goal to create artificial structures that allow fast permeation of water but reject even the smallest hydrated ions, replicating the feat achieved by nature in protein channels (e.g., aquaporins). Despite recent progress in creating nanoscale pores and capillaries, these structures still remain distinctly larger than protein channels. We report capillaries made by effectively extracting one atomic plane from bulk crystals, which leaves a two-dimensional slit of a few angstroms in height. Water moves through these capillaries with little resistance, whereas no permeation could be detected even for such small ions as Na + and Cl − . Only protons (H + ) can... 

    Improvement in CO2/H2 separation by fabrication of poly(ether-b-amide6)/glycerol triacetate gel membranes

    , Article Journal of Membrane Science ; Vol. 469, issue , 2014 , pp. 43-58 ; ISSN: 03767388 Rabiee, H ; Soltanieh, M ; Mousavi, S. A ; Ghadimi, A ; Sharif University of Technology
    The purpose of this study is to investigate separation performance of poly(ether-b-amide6) (Pebax1657)/glycerol triacetate (GTA) gel membranes for CO2 removal from H2, N2 and CH4. GTA as a low molecular weight and highly CO2-phill compound was added to membrane structure at various weight fractions, 20%, 40%, 60% and 80% of Pebax, to fabricate a new high solubility selective membrane with improved performance. Permeation of pure gases was studied at different temperatures from 25 to 65°C and pressures from 4 to 24bar and ideal selectivities were calculated. Results indicated enhancement in permeation for all tested gases. For example, at a pressure of 4bar and a temperature of 25°C, membrane... 

    Challenge in particle delivery to cells in a microfluidic device

    , Article Drug Delivery and Translational Research ; Volume 8, Issue 3 , 2018 , Pages 830-842 ; 2190393X (ISSN) Moghadas, H ; Saidi, M. S ; Kashaninejad, N ; Nguyen, N. T ; Sharif University of Technology
    Springer Verlag  2018
    Micro and nanotechnology can potentially revolutionize drug delivery systems. Novel microfluidic systems have been employed for the cell culture applications and drug delivery by micro and nanocarriers. Cells in the microchannels are under static and dynamic flow perfusion of culture media that provides nutrition and removes waste from the cells. This exerts hydrostatic and hydrodynamic forces on the cells. These forces can considerably affect the functions of the living cells. In this paper, we simulated the flow of air, culture medium, and the particle transport and deposition in the microchannels under different angles of connection inlet. It was found that the shear stress induced by the... 

    Controlling differentiation of stem cells for developing personalized organ-on-chip platforms

    , Article Advanced Healthcare Materials ; Volume 7, Issue 2 , 2018 ; 21922640 (ISSN) Geraili, A ; Jafari, P ; Sheikh Hassani, M ; Heidary Araghi, B ; Mohammadi, M. H ; Ghafari, A. M ; Hassanpour Tamrin, S ; Pezeshgi Modarres, H ; Rezaei Kolahchi, A ; Ahadian, S ; Sanati Nezhad, A ; Sharif University of Technology
    Wiley-VCH Verlag  2018
    Organ-on-chip (OOC) platforms have attracted attentions of pharmaceutical companies as powerful tools for screening of existing drugs and development of new drug candidates. OOCs have primarily used human cell lines or primary cells to develop biomimetic tissue models. However, the ability of human stem cells in unlimited self-renewal and differentiation into multiple lineages has made them attractive for OOCs. The microfluidic technology has enabled precise control of stem cell differentiation using soluble factors, biophysical cues, and electromagnetic signals. This study discusses different tissue- and organ-on-chip platforms (i.e., skin, brain, blood–brain barrier, bone marrow, heart,... 

    Gut-on-a-chip: Current progress and future opportunities

    , Article Biomaterials ; Volume 255 , 2020 Ashammakhi, N ; Nasiri, R ; Barros, N. R. D ; Tebon, P ; Thakor, J ; Goudie, M ; Shamloo, A ; Martin, M. G ; Khademhosseni, A ; Sharif University of Technology
    Elsevier Ltd  2020
    Organ-on-a-chip technology tries to mimic the complexity of native tissues in vitro. Important progress has recently been made in using this technology to study the gut with and without microbiota. These in vitro models can serve as an alternative to animal models for studying physiology, pathology, and pharmacology. While these models have greater physiological relevance than two-dimensional (2D) cell systems in vitro, endocrine and immunological functions in gut-on-a-chip models are still poorly represented. Furthermore, the construction of complex models, in which different cell types and structures interact, remains a challenge. Generally, gut-on-a-chip models have the potential to... 

    A microfabricated platform for the study of chondrogenesis under different compressive loads

    , Article Journal of the Mechanical Behavior of Biomedical Materials ; Volume 78 , 2018 , Pages 404-413 ; 17516161 (ISSN) Kowsari Esfahan, R ; Jahanbakhsh, A ; Saidi, M. S ; Bonakdar, S ; Sharif University of Technology
    Elsevier Ltd  2018
    Microfluidic devices are beneficial in miniaturizing and multiplexing various cellular assays in a single platform. Chondrogenesis is known to pertain to chemical, topographical, and mechanical cues in the microenvironment. Mechanical cues themselves have numerous parameters such as strain magnitude, frequency, and stimulation time. Effects of different strain magnitudes on the chondrogenic differentiation of adult stem cells have not been explored thoroughly. Here, a new multilayer microdevice is presented for the unidirectional compressive stimulation of cells in a three-dimensional cell culture. Numerical simulations were performed to evaluate and optimize the design. Results showed a... 

    Toward higher extraction and enrichment factors via a double-reservoirs microfluidic device as a micro-extractive platform

    , Article Journal of Separation Science ; Volume 42, Issue 18 , 2019 , Pages 2985-2992 ; 16159306 (ISSN) Rezvani, O ; Baraazandeh, M ; Bagheri, H ; Sharif University of Technology
    Wiley-VCH Verlag  2019
    In this study, firstly, a double-reservoir and switchable prototype of a micro-chip along with the respective holders were fabricated. A cyclic desorption process using microliter volume of organic solvent was adopted to prevent any outdoor contamination. As extractive phases, two identical sheets of electrospun polyamide/polypyrrole/titania nanofibers were synthesized using core–shell electro-spinning technique and utilized for determination of memantine in plasma samples. Field emission scanning electron microscopy images showed a high degree of porosity and homogeneity throughout the sheet structure. Also, energy dispersive X-ray analysis confirmed the presence of titania, while the... 

    Introducing an affordable catalyst for biohydrogen production in microbial electrolysis cells

    , Article Journal of Bioscience and Bioengineering ; Volume 129, Issue 1 , 2020 , Pages 67-76 Ghasemi, B ; Yaghmaei, S ; Abdi, K ; Mardanpour, M. M ; Haddadi, S. A ; Sharif University of Technology
    Elsevier B.V  2020
    This study reports the fabrication of a new cathode electrode assembly using polyaniline (PANI) and graphene on a stainless steel mesh (SSM) as an alternative for the conventional expensive cathode of microbial electrolysis cells (MECs). With respect to the previous efforts to propose an efficient and cost-effective alternative for platinum (Pt) catalysts and cathode electrodes, the present study investigates the assessment of different catalysts to elucidate the potential of the modified SSM cathode electrode for larger-scale MECs. In the case of feeding dairy wastewater to the MEC, the maximum hydrogen production rate and COD removal were obtained by SSM/PANI/graphene cathode and had the... 

    Margination and adhesion of micro- and nanoparticles in the coronary circulation: A step towards optimised drug carrier design

    , Article Biomechanics and Modeling in Mechanobiology ; Volume 17, Issue 1 , 2018 , Pages 205-221 ; 16177959 (ISSN) Forouzandehmehr, M ; Shamloo, A ; Sharif University of Technology
    Springer Verlag  2018
    Obstruction of left anterior descending artery (LAD) due to the thrombosis or atherosclerotic plaques is the leading cause of death worldwide. Targeted delivery of drugs through micro- and nanoparticles is a very promising approach for developing new strategies in clot-busting or treating restenosis. In this work, we modelled the blood flow characteristics in a patient-specific reconstructed LAD artery by the fluid–solid interaction method and based on physiological boundary conditions. Next, we provided a Lagrangian description of micro- and nanoparticles dynamics in the blood flow considering their Brownian motion and the particle–particle interactions. Our results state that the number of... 

    A foreign body response-on-a-chip platform

    , Article Advanced Healthcare Materials ; Volume 8, Issue 4 , 2019 ; 21922640 (ISSN) Sharifi, F ; Htwe, S. S ; Righi, M ; Liu, H ; Pietralunga, A ; Yesil Celiktas, O ; Maharjan, S ; Cha, B. H ; Shin, S. R ; Dokmeci, M. R ; Vrana, N. E ; Ghaemmaghami, A. M ; Khademhosseini, A ; Zhang, Y. S ; Sharif University of Technology
    Wiley-VCH Verlag  2019
    Understanding the foreign body response (FBR) and desiging strategies to modulate such a response represent a grand challenge for implant devices and biomaterials. Here, the development of a microfluidic platform is reported, i.e., the FBR-on-a-chip (FBROC) for modeling the cascade of events during immune cell response to implants. The platform models the native implant microenvironment where the implants are interfaced directly with surrounding tissues, as well as vasculature with circulating immune cells. The study demonstrates that the release of cytokines such as monocyte chemoattractant protein 1 (MCP-1) from the extracellular matrix (ECM)-like hydrogels in the bottom tissue chamber...