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    Bioinspired multifunctional TiO2 hierarchical micro/nanostructures with tunable improved bone cell growth and inhibited bacteria adhesion

    , Article Ceramics International ; Volume 46, Issue 7 , 2020 , Pages 9669-9679 Rahnamaee, S. Y ; Bagheri, R ; Vossoughi, M ; Ahmadi Seyedkhani, S ; Samadikuchaksaraei, A ; Sharif University of Technology
    Elsevier Ltd  2020
    Two main origins of failure for hard tissue replacements are structural loosening and prosthetic implant infections (PIIs). Bioinspired multifunctional TiO2 hierarchical micro/nanostructures of conical-shaped TiO2 (CTO), regular TiO2 nanotubes (RTO) and irregular TiO2 nanotubes (ITO) with tunable improved cell growth and inhibited bacteria adhesion were synthesized. CTO and ITO samples indicated superhydrophilicity with contact angles of less than 5°. The MTT assay demonstrated excellent biological performance for RTO and CTO sample with 98.1% and 103.1% of cell viability, respectively. The bridging force for osteoblast cell attachment onto the synthesized porous coatings was presented as a... 

    Simulation of Flow's Effect on Microfluid Through 3-Dimentional Scaffold in a Bioreactor

    , M.Sc. Thesis Sharif University of Technology Seddiqi, Hadi (Author) ; Bastani, Dariush (Supervisor) ; Amoabediny, Ghassem (Supervisor)
    Tissue engineering aims to produce artificial tissues and organs to treat the damaged part, by implant in body of patients, is an important issue in research and development. In cases that tissue damage is sever or due to genetic defects or congenital disease, tissue in the body are not fully formed, tissue engineering can be used to regenerate, repair or replace organs or tissues. Cell culture on the scaffold and put it in the bioreactor is a critical step in the formation of tissues or organs. Among various bioreactors, perfusion bioreactor due to increase of convection in the structure of cell-scaffold is widely used. Enhancement of convection increases shear stress on the cells that is... 

    Embryonic stem cells maintain an undifferentiated state on dendrimer-immobilized surface with D-glucose display

    , Article Polymers ; Volume 3, Issue 4 , 2011 , Pages 2078-2087 ; 20734360 (ISSN) Mashayekhan, S ; Kim, M. H ; Kino Oka, M ; Miyazaki, J. I ; Taya, M ; Sharif University of Technology
    In serial passaging cultures of mouse embryonic stem (ES) cells, we employed a dendrimer-immobilized substrate that displayed D-glucose as a terminal ligand. The D-glucose-displaying dendrimer (GLU/D) surface caused the ES cells to form loosely attached spherical colonies, while those on a gelatin-coated surface formed flatter colonies that were firmly attached to the surface. Despite the morphological similarities between the colonies on the GLU/D surface and aggregates on a conventional bacteriological dish, immunostaining and RT-PCR analyses revealed the maintenance of cells within the spherical colonies on the GLU/D surface in an undifferentiated state with very low expressions of... 

    The application of corrugated parallel bundle model to immobilized cells in porous microcapsule membranes

    , Article Journal of Membrane Science ; Volume 311, Issue 1-2 , 2008 , Pages 159-164 ; 03767388 (ISSN) Biria, D ; Zarrabi, A ; Khosravi, A ; Sharif University of Technology
    To describe immobilized cells in porous microcapsule membranes with straight pores, a novel model called corrugated parallel bundle model (CPBM) was utilized. In this model, a network was developed with 10 main pores each composing 10 pore elements. Cell growth kinetic in the network was examined using non-structural models. Effectiveness factor and pore plugging time were calculated by solving reaction-diffusion equation set via finite difference method. The findings revealed that diffusion coefficient for lower order reactions will create a lesser impact on the reduction of effectiveness factor. These findings also indicated that the use of such supporting carrier for cell immobilization... 

    hysical and Chemical Surface Modification of Titanium by Nanostructured Materials, and Biological Characterization for Use in Bone Tissue Implants

    , Ph.D. Dissertation Sharif University of Technology Rahnamaee, Yahya (Author) ; Bagheri, Reza (Supervisor) ; Vossoughi, Manochehr (Supervisor) ; Samadi Kuchaksaraei, Ali (Supervisor)
    According to human needs and in line with the development of advanced technologies, different biomedical Engineering fields like hard tissue implants are growing rapidly. Despite significant biotechnology Developments in recent years, some problems to the recognition of implants related osseointegration phenomena persist. The deficient osseointegration and implant-associated infections are key issues for the long-term clinical success of titanium and titanium alloy implants, while development of multifunctional surfaces that can simultaneously overcome these problems remains highly challenging. Therefore, the ultimate goal of this paper was to improve bone cell attachment and simultaneously... 

    Pore control in SMA NiTi scaffolds via space holder usage

    , Article Materials Science and Engineering C ; Volume 32, Issue 5 , 2012 , Pages 1266-1270 ; 09284931 (ISSN) Ghasemi, A ; Hosseini, S. R ; Sadrnezhaad, S. K ; Sharif University of Technology
    Porous NiTi shape memory alloy (SMA) was fabricated by sintering of compressed constituent elements pre-mixed with NaCl or urea spacer holders. Effect of spacer to metal volume-ratio (r S) on shape, size, distribution and openness of the voids was probed by optical metallography, X-ray diffraction (XRD) and scanning electron microscopy (SEM). Differential scanning calorimetry (DSC) was used to determine the SMA transformation temperatures. Controllable void geometry helping osteoblast proliferation and bone cell growth was gained by addition of the spacers. At r S = 0.7, percentage of the open pores reached 52% while at r S = 1.43, interconnected pores with 200 to 500 μm diameter were... 

    Designed amino acid feed in improvement of production and quality targets of a therapeutic monoclonal antibody

    , Article PLoS ONE ; Volume 10, Issue 10 , October , 2015 ; 19326203 (ISSN) Torkashvand, F ; Vaziri, B ; Maleknia, S ; Heydari, A ; Vossoughi, M ; Davami, F ; Mahboudi, F ; Sharif University of Technology
    Public Library of Science  2015
    Cell culture feeds optimization is a critical step in process development of pharmaceutical recombinant protein production. Amino acids are the basic supplements of mammalian cell culture feeds with known effect on their growth promotion and productivity. In this study, we reported the implementation of the Plackett-Burman (PB) multifactorial design to screen the effects of amino acids on the growth promotion and productivity of a Chinese hamster ovary DG-44 (CHO-DG44) cell line producing bevacizumab. After this screening, the amino acid combinations were optimized by the response surface methodology (RSM) to determine the most effective concentration in feeds. Through this strategy, the... 

    Directional migration and differentiation of neural stem cells within three-dimensional microenvironments

    , Article Integrative Biology (United Kingdom) ; Volume 7, Issue 3 , Jan , 2015 , Pages 335-344 ; 17579694 (ISSN) Shamloo, A ; Heibatollahi, M ; Mofrad, M. R. K ; Sharif University of Technology
    Royal Society of Chemistry  2015
    Harnessing neural stem cells to repair neuronal damage is a promising potential treatment for neuronal diseases. To enable future therapeutic efficacy, the survival, proliferation, migration and differentiation of neural stem/progenitor cells (NPCs) should be accurately studied and optimized in in vitro platforms before transplanting these cells into the body for treatment purposes. Such studies can determine the appropriate quantities of the biochemical and biomechanical factors needed to control and optimize NPC behavior in vivo. In this study, NPCs were cultured within a microfluidic device while being encapsulated within the collagen matrix. The migration and differentiation of NPCs were... 

    Construction of scaffolds composed of acellular cardiac extracellular matrix for myocardial tissue engineering

    , Article Biologicals ; Volume 53 , 2018 , Pages 10-18 ; 10451056 (ISSN) Esmaeili Pourfarhangi, K ; Mashayekhan, S ; Ghanbari Asl, S ; Hajebrahimi, Z ; Sharif University of Technology
    Academic Press  2018
    High rates of mortality and morbidity stemming from cardiovascular diseases unveil extreme limitations in current therapies despite enormous advances in medical and pharmaceutical sciences. Following myocardial infarction (MI), parts of myocardium undergo irreversible remodeling and is substituted by a scar tissue which eventually leads to heart failure (HF). To address this issue, cardiac patches have been utilized to initiate myocardial regeneration. In this study, a porous cardiac patch is fabricated using a mixture of decellularized myocardium extracellular matrix (ECM) and chitosan (CS). Results of rheological measurements, SEM, biodegradation test, and MTT assay showed that the... 

    Evaluation of bioactivity and biocompatibility of silk fibroin/TiO2 nanocomposite

    , Article Journal of Medical and Biological Engineering ; Volume 38, Issue 1 , February , 2018 , Pages 99-105 ; 16090985 (ISSN) Johari, N ; Madaah Hosseini, H. R ; Taromi, N ; Arasteh, S ; Kazemnejad, S ; Samadi Kuchaksaraei, A ; Sharif University of Technology
    Springer Berlin Heidelberg  2018
    Biodegradable polymer/bioceramic nanocomposites are osteoconductive and can accelerate healing of bone tissue. In this research, silk fibroin (SF)/titanium dioxide (TiO2) nanocomposites were synthesized using different concentrations of TiO2 nanoparticles (0, 5, 10, 15 and 20 wt%). The SF/TiO2 nanocomposites were studied in terms of bioactivity and biocompatibility. The in vitro assessment of osteoblasts compatibility indicated that SF inclusion rendered nanocomposite biocompatible whereas presence of TiO2 nanoparticles allowed the cells to adhere and grow on nanocomposite surface and enhanced the bioactivity of the composite. © 2017, Taiwanese Society of Biomedical Engineering  

    Magnetoelectric nanocomposite scaffold for high yield differentiation of mesenchymal stem cells to neural-like cells

    , Article Journal of Cellular Physiology ; Volume 234, Issue 8 , 2019 , Pages 13617-13628 ; 00219541 (ISSN) Esmaeili, E ; Soleimani, M ; Ghiass, M. A ; Hatamie, S ; Vakilian, S ; Zomorrod, M. S ; Sadeghzadeh, N ; Vossoughi, M ; Hosseinzadeh, S ; Sharif University of Technology
    Wiley-Liss Inc  2019
    While the differentiation factors have been widely used to differentiate mesenchymal stem cells (MSCs) into various cell types, they can cause harm at the same time. Therefore, it is beneficial to propose methods to differentiate MSCs without factors. Herein, magnetoelectric (ME) nanofibers were synthesized as the scaffold for the growth of MSCs and their differentiation into neural cells without factors. This nanocomposite takes the advantage of the synergies of the magnetostrictive filler, CoFe 2 O 4 nanoparticles (CFO), and piezoelectric polymer, polyvinylidene difluoride (PVDF). Graphene oxide nanosheets were decorated with CFO nanoparticles for a proper dispersion in the polymer through... 

    Development of a genetic algorithm based biomechanical simulation of sagittal lifting tasks

    , Article Biomedical Engineering - Applications, Basis and Communications ; Volume 17, Issue 1 , 2005 , Pages 12-18 ; 10162372 (ISSN) Gündoǧdu, Ö ; Anderson, K. S ; Parnianpour, M ; Sharif University of Technology
    Institute of Biomedical Engineering  2005
    Fibrin sealant and platelet gels are human blood-derived, biodegradable, non toxic, surgical products obtained by mixing a fibrinogen concentrate or a platelet rich plasma with thrombin, respectively. Fibrin sealant is now a well known surgical tool increasingly used to stop or control bleeding, or to provide air and fluid tightness in many surgical situations. Platelet gels are newly developed preparations that are of specific interest because they contain numerous physiological growth factors and cytikines that are released upon the activation of blood platelets by thrombin. These growth factors, including PDGF, TGF-β1, BMP, and VEGF have been shown to stimulate cell growth and... 

    Simulation of the effects of oxygen carriers and scaffold geometry on oxygen distribution and cell growth in a channeled scaffold for engineering myocardium

    , Article Mathematical Biosciences ; Volume 294 , 2017 , Pages 160-171 ; 00255564 (ISSN) Zehi Mofrad, A ; Mashayekhan, S ; Bastani, D ; Sharif University of Technology
    This study proposes a mathematical model to evaluate the impact of oxygen carriers and scaffold geometry on oxygen distribution and cell growth in a 3D cardiac construct using computational fluid dynamics (CFD). Flow equations, oxygen balance equation and cell balance equation were solved using special initial and boundary conditions. The modeling results revealed that 55% increase in cardiac cell density occurred by using 6.4% perfluorocarbon oxygen carrier (PFC) compared to pure culture medium without PFC supplementation. Moreover, the effects of the scaffold geometry on cell density were examined by changing the channel numbers and the construct length. A 30% increase in the average cells... 

    In vitro co-culture of human skin keratinocytes and fibroblasts on a biocompatible and biodegradable scaffold

    , Article Iranian Biomedical Journal ; Volume 13, Issue 3 , 2009 , Pages 169-177 ; 1028852X (ISSN) Shariati, S. R. P ; Shokrgozar, M. A ; Vossoughi, M ; Eslamifar, A ; Sharif University of Technology
    Background: Extensive full-thickness burns require replacement of both epidermis and dermis. In designing skin replacements, the goal has been to re-create this model and make a product which has both essential components. Methods: In the present study, we developed procedures for establishing confluent, stratified layers of cultured human keratinocytes on the surface of modified collagen-chitosan scaffold that contains fibroblasts. The culture methods for propagation of keratinocytes and fibroblasts isolated from human neonatal foreskin were developed. The growth and proliferation of normal human keratinocytes were evaluated in serum-free (keratinocyte growth medium) and our modified... 

    Fabrication and characterization of core-shell electrospun fibrous mats containing medicinal herbs for wound healing and skin tissue engineering

    , Article Marine Drugs ; Volume 17, Issue 1 , 2019 ; 16603397 (ISSN) Zahedi, E ; Esmaeili, A ; Eslahi, N ; Shokrgozar, M. A ; Simchi, A ; Sharif University of Technology
    MDPI AG  2019
    Nanofibrous structures mimicking the native extracellular matrix have attracted considerable attention for biomedical applications. The present study aims to design and produce drug-eluting core-shell fibrous scaffolds for wound healing and skin tissue engineering. Aloe vera extracts were encapsulated inside polymer fibers containing chitosan, polycaprolactone, and keratin using the co-axial electrospinning technique. Electron microscopic studies show that continuous and uniform fibers with an average diameter of 209 ± 47 nm were successfully fabricated. The fibers have a core-shell structure with a shell thickness of about 90 nm, as confirmed by transmission electron microscopy. By... 

    Stereolithography 3D bioprinting method for fabrication of human corneal stroma equivalent

    , Article Annals of Biomedical Engineering ; Volume 48, Issue 7 , June , 2020 , Pages 1955-1970 Mahdavi, S. S ; Abdekhodaie, M. J ; Kumar, H ; Mashayekhan, S ; Baradaran Rafii, A ; Kim, K ; Sharif University of Technology
    Springer  2020
    Abstract: 3D bioprinting technology is a promising approach for corneal stromal tissue regeneration. In this study, gelatin methacrylate (GelMA) mixed with corneal stromal cells was used as a bioink. The visible light-based stereolithography (SLA) 3D bioprinting method was utilized to print the anatomically similar dome-shaped structure of the human corneal stroma. Two different concentrations of GelMA macromer (7.5 and 12.5%) were tested for corneal stroma bioprinting. Due to high macromer concentrations, 12.5% GelMA was stiffer than 7.5% GelMA, which made it easier to handle. In terms of water content and optical transmittance of the bioprinted scaffolds, we observed that scaffold with... 

    Bio-oxidation of ferrous ions by Acidithioobacillus ferrooxidans in amonolithic bioreactor

    , Article Journal of Chemical Technology and Biotechnology ; Volume 84, Issue 4 , 2009 , Pages 504-510 ; 02682575 (ISSN) Kahrizi, E ; Alemzadeh, I ; Vossoughi, M ; Sharif University of Technology
    Background: The bio-oxidation of ferrous iron is a potential industrial process in the regeneration of ferric iron and the removal of H2S in combustible gases. Bio-oxidation of ferrous iron may be an alternative method of producing ferric sulfate, which is a reagent used for removal of H2S from biogas, tail gas and in the pulp and paper industry. For practical use of this process, this study evaluated the optimal pH and initial ferric concentration. pH control looks like a key factor as it acts both on growth rate and on solubility ofmaterials in the system. Results: Process variables such as pH and amount of initial ferrous ions on oxidation by A. ferrooxidans and the effects of process... 

    Injectable chitosan/κ-carrageenan hydrogel designed with au nanoparticles: A conductive scaffold for tissue engineering demands

    , Article International Journal of Biological Macromolecules ; Volume 126 , 2019 , Pages 310-317 ; 01418130 (ISSN) Pourjavadi, A ; Doroudian, M ; Ahadpour, A ; Azari, S ; Sharif University of Technology
    Elsevier B.V  2019
    Scaffolds for tissue engineering of specific sites such as cardiac, nerve, and bone tissues need a comprehensive design of three dimensional materials that covers all aspects of chemical composition and physical structures, required for regeneration of desired cells. Hydrogels, possessing highly hydrated and interconnected structures, are promising materials for tissue engineering applications. Improvement of an injectable hydrogel from biocompatible polysaccharides and poly‑N‑isopropyl acryl amide enriched with Au nanoparticles are the main goal of this study. Two main enhancements in this study are included mixture design of the components and addition of Au nanoparticles to access a... 

    Near infrared laser stimulation of human neural stem cells into neurons on graphene nanomesh semiconductors

    , Article Colloids and Surfaces B: Biointerfaces ; Volume 126 , 2015 , Pages 313-321 ; 09277765 (ISSN) Akhavan, O ; Ghaderi, E ; Shirazian, S. A ; Sharif University of Technology
    Reduced graphene oxide nanomeshes (rGONMs), as p-type semiconductors with band-gap energy of ~1. eV, were developed and applied in near infrared (NIR) laser stimulation of human neural stem cells (hNSCs) into neurons. The biocompatibility of the rGONMs in growth of hNSCs was found similar to that of the graphene oxide (GO) sheets. Proliferation of the hNSCs on the GONMs was assigned to the excess oxygen functional groups formed on edge defects of the GONMs, resulting in superhydrophilicity of the surface. Under NIR laser stimulation, the graphene layers (especially the rGONMs) exhibited significant cell differentiations, including more elongations of the cells and higher differentiation of... 

    Small RNA sequencing reveals dlk1-dio3 locus-embedded microRNAs as major drivers of ground-state pluripotency

    , Article Stem Cell Reports ; Volume 9, Issue 6 , 2017 , Pages 2081-2096 ; 22136711 (ISSN) Moradi, S ; Sharifi Zarchi, A ; Ahmadi, A ; Mollamohammadi, S ; Stubenvoll, A ; Günther, S ; Hosseini Salekdeh, G ; Asgari, S ; Braun, T ; Baharvand, H ; Sharif University of Technology
    Ground-state pluripotency is a cell state in which pluripotency is established and maintained through efficient repression of endogenous differentiation pathways. Self-renewal and pluripotency of embryonic stem cells (ESCs) are influenced by ESC-associated microRNAs (miRNAs). Here, we provide a comprehensive assessment of the “miRNome” of ESCs cultured under conditions favoring ground-state pluripotency. We found that ground-state ESCs express a distinct set of miRNAs compared with ESCs grown in serum. Interestingly, most “ground-state miRNAs” are encoded by an imprinted region on chromosome 12 within the Dlk1-Dio3 locus. Functional analysis revealed that ground-state miRNAs embedded in the...