Search for: cytoskeleton
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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... 

    Study the Interaction between Cytoskleton and Cell Membrane

    , M.Sc. Thesis Sharif University of Technology Sepehr Dehghani Ghahnaviyeh (Author) ; Nejat Pishkenari, Hossein (Supervisor) ; Salarieh, Hassasn (Supervisor)
    In this project the main aim is to model the interaction between the cytoskeleton and cell membrane. In order to model the membrane and cytoskeleton it is used a discrete model, which contains several beads. For modeling the interaction between the beads it is used different kinds of energies. It is used four potentials in a 2D model for modeling the interaction between the membrane beads and it is used SSLJ potential in order to model the interaction between the cytoskeleton and cell membrane. Furthermore, this potential is used to model the interaction between the cytoskeleton filaments. Due to this potential, the cytoskeleton filaments can cross each other in the 2D model. For modeling... 

    Studies of the Interaction between Actins Flow and Cell Adhesion Nucleation in Macro-and Micro-scale

    , Ph.D. Dissertation Sharif University of Technology Ghasemi Varnamkhasti, Amir (Author) ; Firouzabadi, Bahar (Supervisor) ; Saeedi, Mohammad Saeed (Supervisor)
    The network of actin filaments is one of the three elements of the Cytoskeleton and plays a role in cell shape and migration. The actin network is dynamic; it (de)polymerizes, and in migrating and spreading cells, it is in a retrograde motion from the cell periphery toward cell nucleus. Adhesion points, which link the cytoskeleton to the extracellular matrix, interact with the actin retrograde flow. Actin filaments can be identified in two distinct regions in which their structure, flow velocity, driving force and size of the adhesions are different; the outer region is called Lamellipodium and the inner one Lamellum. In macro scale and regarding spreading cells, considering adhesions... 

    Mechanical behavior Analysis of Cancerous Cells in the Micropipette Aspiration Using Finite Element Simulations

    , M.Sc. Thesis Sharif University of Technology Ghoytasi, Ebrahim (Author) ; Naghdabadi, Reza (Supervisor) ; Bavi, Omid (Co-Supervisor)
    Diseases such as cancer lead to extensive conversion in the biological structure of cells. These conversions can overshadow cell function. The dynamics of a cell directly depends on how it interacts with other cells and the extracellular environment. Most of these interactions are associated with the occurrence of mechanical phenomena and are due to forces that the cell has experienced. Cell mechanics manifests itself in the Mechanotransduction, the ability of a cell to sense and respond to external forces. Cancer alters the mechanical properties of the components of the cytoskeleton. Understanding the biomechanical behavior of cells and cytoskeleton can play an important role in early... 

    Molecular Dynamics Simulation of Actin: An Investigation into the Mechanical Properties

    , M.Sc. Thesis Sharif University of Technology Mehrafrooz, Behzad (Author) ; Shamloo, Amir (Supervisor) ; Firoozbakhsh, Keikhosrow (Supervisor)
    Actin is the most abundant protein in most eukaryotic cells. It is highly conserved and participates in more protein-protein interactions than any known protein. Actin plays a crucial role in cell motility, adhesion, morphology and intracellular transport. Its biologically active form is the filament (F-actin), which is assembled from monomeric G-actin. In this thesis, the mechanical properties and characteristics of both G- and F-actin are studied using molecular dynamics simulations. In general, this thesis can be categorized into two individual parts: First, steered molecular dynamics simulation was performed to assess tension of monomeric G-actin molecule, and stress-strain curves were... 

    Simulation of a Simple Model of Endothelial Cell Using Dissipative Particle Dynamics Method

    , M.Sc. Thesis Sharif University of Technology Kiyoumarsi Oskouei, Amir (Author) ; Saeedi, Mohammad Saeed (Supervisor) ; Firoozabadi, Bahar (Co-Advisor)
    Endothelium is the interior layer of an artery made up of tremendous number of endothelial cells which are located side by side. Finding the effective parameters that cause the cells to obtain mechanical strength in different morphologies is a major effort in cell engineering studies. In this work a numerical model for endothelial cells is developed. This model has included cell's plasma membrane (the outer membrane of the cell), nucleus and cytoskeleton main components including intermediate and actin filaments as well as microtubules. The model has been validated by simulating the adhesion of the cells to a flat substrate and also atomic force microscopy (AFM) experiments. The two most... 

    A viscoelastic model for axonal microtubule rupture

    , Article Journal of Biomechanics ; Volume 48, Issue 7 , 2015 , Pages 1241-1247 ; 00219290 (ISSN) Shamloo, A ; Manuchehrfar, F ; Rafii Tabar, H ; Sharif University of Technology
    Elsevier Ltd  2015
    Axon is an important part of the neuronal cells and axonal microtubules are bundles in axons. In axons, microtubules are coated with microtubule-associated protein tau, a natively unfolded filamentous protein in the central nervous system. These proteins are responsible for cross-linking axonal microtubule bundles. Through complimentary dimerization with other tau proteins, bridges are formed between nearby microtubules creating bundles. Formation of bundles of microtubules causes their transverse reinforcement and has been shown to enhance their ability to bear compressive loads. Though microtubules are conventionally regarded as bearing compressive loads, in certain circumstances during... 

    A mechanical model for morphological response of endothelial cells under combined wall shear stress and cyclic stretch loadings

    , Article Biomechanics and Modeling in Mechanobiology ; Volume 15, Issue 5 , 2016 , Pages 1229-1243 ; 16177959 (ISSN) Pakravan, H. A ; Saidi, M. S ; Firoozabadi, B ; Sharif University of Technology
    Springer Verlag 
    The shape and morphology of endothelial cells (ECs) lining the blood vessels are a good indicator for atheroprone and atheroprotected sites. ECs of blood vessels experience both wall shear stress (WSS) and cyclic stretch (CS). These mechanical stimuli influence the shape and morphology of ECs. A few models have been proposed for predicting the morphology of ECs under WSS or CS. In the present study, a mathematical cell population model is developed to simulate the morphology of ECs under combined WSS and CS conditions. The model considers the cytoskeletal filaments, cell–cell interactions, and cell–extracellular matrix interactions. In addition, the reorientation and polymerization of... 

    Hyperthermia of breast cancer tumor using graphene oxide-cobalt ferrite magnetic nanoparticles in mice

    , Article Journal of Drug Delivery Science and Technology ; Volume 65 , 2021 ; 17732247 (ISSN) Hatamie, S ; Balasi, Z. M ; Ahadian, M. M ; Mortezazadeh, T ; Shams, F ; Hosseinzadeh, S ; Sharif University of Technology
    Editions de Sante  2021
    Herein, the graphene oxide (GO)/cobalt ferrite nanoparticles were used to apply the heat treatment on the breast cancer cell line of MCF7. The synthesized nanoparticles were evaluated before in vitro and in vivo studies, using transmission electron microscopy (TEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), X-ray photoelectron spectroscopy (XPS), thermal property and relaxivity measurement. The nanoparticles showed a diameter of 5 nm with the ferrimagnetic property. Also, the nanoparticles were well distributed on the GO nanosheets. The related peaks of cobalt ferrite nanoparticles were approved by using XRD and XPS assays. During the in vitro investigations, IC50 with... 

    Theoretical modeling of actin-retrograde-flow passing clusters of confined T cell receptors

    , Article Mathematical Biosciences ; Volume 283 , 2017 , Pages 1-6 ; 00255564 (ISSN) Ghasemi V., A ; Firoozabadi, B ; Saidi, M. S ; Sharif University of Technology
    Elsevier Inc  2017
    Through the activation process of T cells, actin filaments move from the cell periphery toward the cell center. The moving filaments engage with T cell receptors and thus contribute to transportation of the signaling molecules. To study the connection between the moving actin filaments and T cell receptors, an experiment available in the literature has measured filaments flow velocity passing over a region of confined clusters of receptors. It shows that flow velocity decreases in the proximity of the receptors, and then regains its normal value after traversing the region, suggesting a dissipative friction-like connection. In this work, we develop a minimal theoretical model to re-examine...