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    Effect of particle size on the in vitro bioactivity, hydrophilicity and mechanical properties of bioactive glass-reinforced polycaprolactone composites [electronic resource]

    , Article Journal of Materials Science and Engineering: C ; 10 October 2011, Volume 31, Issue 7, Pages 1526–1533 Tamjid, E ; Bagheri, R ; Vossoughi, M ; Simchi, A. (Abdolreza) ; Sharif University of Technology
    Polycaprolactone (PCL) composite films containing 5 wt.% bioactive glass (BG) particles of different sizes (6 μm, 250 nm, < 100 nm) were prepared by solvent casting methods. The ultra-fine BG particles were prepared by high-energy mechanical milling of commercial 45S5 Bioglass® particles. The characteristics of bioactive glass particles were studied by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS), and X-ray diffraction (XRD) methods. In vitro bioactivity of the PCL/BG composite films was evaluated through immersion in the simulated body fluid (SBF). The films were analyzed by FE-SEM, energy dispersive... 

    Bioglass Coating on 316L Stainless Steel

    , M.Sc. Thesis Sharif University of Technology Pourhashem, Sepideh (Author) ; Afshar, Abdollah (Supervisor)
    Bioactive glasses are able to bond to soft and hard tissues in living body and their application as coating on metallic implants like 316L stainless steel has two important effects: (1) intimate link between bone and materials and (2) corrosion protection of metallic implant in body fluid and protection from tissues in front of corrosion products. Therefore, in this research, 45S5 bioactive glass prepared via sol- gel method was dip coated on 316L stainless steel substrates and its characteristics was investigated.Results of phase analysis showed that by sintering 45S5 bioglass at 600 ˚C for 5 h, an amorph sample with small amount of Na2Ca2Si3O9 was obtained. So, the bioglass coated samples... 

    Long-term antibiotic delivery by chitosan-based composite coatings with bone regenerative potential

    , Article Applied Surface Science ; Vol. 317, issue , 2014 , p. 56-66 Ordikhani, F ; Simchi, A ; Sharif University of Technology
    Composite coatings with bone-bioactivity and drug-eluting capacity are considered as promising materials for titanium bone implants. In this work, drug-eluting chitosan-bioactive glass coatings were fabricated by a single-step electrophoretic deposition technique. Drug-loading and -releasing capacity of the composite coatings were carried out using the vancomycin antibiotic. Uniform coatings with a thickness of ∼55 μm containing 23.7 wt% bioactive glass particles and various amounts of the antibiotic (380-630 μg/cm2) were produced. The coatings were bioactive in terms of apatite-forming ability in simulated body fluid and showed favorable cell adhesion and growth. In vitro biological tests... 

    Glass-ceramics for cancer treatment: So close, or yet so far?

    , Article Acta Biomaterialia ; 2018 ; 17427061 (ISSN) Miola, M ; Pakzad, Y ; Banijamali, S ; Kargozar, S ; Vitale Brovarone, C ; Yazdanpanah, A ; Bretcanu, O ; Ramedani, A ; Vernè, E ; Mozafari, M ; Sharif University of Technology
    After years of research on the ability of glass-ceramics in bone regeneration, this family of biomaterials has shown revolutionary potentials in a couple of emerging applications such as cancer treatment. Although glass-ceramics have not yet reached their actual potential in cancer therapy, the relevant research activity is significantly growing in this field. It has been projected that this idea and the advent of magnetic bioactive glass-ceramics and mesoporous bioactive glasses could result in major future developments in the field of cancer. Undoubtedly, this strategy needs further developments to better answer the critical questions essential for clinical usage. This review aims to... 

    Simultaneous evaluation of magnesia and silica contents’ effect on in-vitro bioactivity of novel bioglasses in the SiO2-CaO-MgO system

    , Article Transactions of the Indian Ceramic Society ; Volume 75, Issue 1 , 2016 , Pages 7-11 ; 0371750X (ISSN) Eslami, M ; Mahdieh, Z ; Maddahi, V ; Shokrgozar, M. A ; Mehrjoo, M ; Sharif University of Technology
    Taylor and Francis Ltd  2016
    In this study, bioglasses in SiO2-CaO-MgO system were synthesized through sol-gel method and the effect of silica and magnesia contents on in-vitro bioactivity of the bioglasses were investigated. XRD patterns showed an amorphous structure after heat treatment at 600°C for 2 h for all glasses and also indicated that after immersion in SBF, apatite particles precipitated on glass surfaces and the rate of apatite formation decreased with increasing Mg/Ca ratio. On the other hand, the apatite formation rate was enhanced with increasing the silica content. Furthermore, magnesia contents increased the compressive strength of the samples. According to SEM, higher Mg/Ca ratio led to increase in... 

    Encapsulation of food components and bioactive ingredients and targeted release

    , Article International Journal of Engineering, Transactions A: Basics ; Volume 33, Issue 1 , 2020 , Pages 1-11 Alemzadeh, I ; Hajiabbas, M ; Pakzad, H ; Sajadi Dehkordi, S ; Vossoughi, A ; Sharif University of Technology
    Materials and Energy Research Center  2020
    The potential utilization of encapsulation techniques in food, pharmaceutical and agricultural products preparation, presents a new alternative for complementary technologies such as targeting delivery vehicles and carriers for active food ingredients. Encapsulation could be accomplished by different techniques like: simple or complex coacervation, emulsification technique, phase separation, spray drying, spray chilling or spray cooling, extrusion coating, freeze drying, fluidized-bed coating, liposomal entrapment, centrifugal suspension separation, co-crystallization and molecular inclusion complexation. Encapsulation is a method by which one bioactive material or mixture of materials is... 

    Study & Synthesis of Biocompatible Scaffolds for Animal Cell Cultures

    , M.Sc. Thesis Sharif University of Technology Riazi Esfahani, Bahar (Author) ; Vosoughi, Manouchehr (Supervisor) ; Alemzadeh, Iran (Co-Advisor) ; Pajoum Shariati, Ramin (Co-Advisor)
    Natural tissues of body consist of Extra Cellular Matrix (ECM) and cells. Scaffold produces a temporary matrix for cells and facilitates oxygen and nutrients transport which enhances tissue regeneration. Therefore, attempts in regeneration of tissues and organs by scaffolds attracted great interest in today’s researchs. Choosing scaffold fabrication method and its polymer type, play a key role in scaffold specifications as they determine scaffold properties. In this project electrospinning was chosen as the scaffold fabrication method which is because of the unique properties of scaffolds fabricated by this method and also its ability in producing micro and nano fibers. At first set of... 

    Effect of Surface Treatment on Bioactivity of Ti-6Al-4V Alloy

    , M.Sc. Thesis Sharif University of Technology Omidi Razani, Abbas Ali (Author) ; Asgari, Sirous (Supervisor)
    In this research Ti-6Al-4V samples were surface treated with acid, alkali and sandblasting treatment. Alkali treatment parameter was the NaOH concentration. The results of roughness measurement demonstrate that increase in NaOH Concentration results in rougher surface. Sandblasting produces rough surfaces in the scale of 1 to 10 micrometers. Acid treatment reduces initial roughness and the resultant roughness is in the under micrometer scale. After surface treatment, samples were soaked in simulated body fluid for invitro assessment. Results of this analysis indicate that sample with sandblasting+chemical treatment has the best invitro bioactivity. Chemical+sandblasting treated sample shows... 

    Electrophoretic deposition of porous hydroxyapatite coatings using polytetrafluoroethylene particles as templates

    , Article Materials Science and Engineering C ; Volume 27, Issue 5-8 SPEC. ISS , 2007 , Pages 1482-1486 ; 09284931 (ISSN) Yousefpour, M ; Afshar, A ; Chen, J ; Zhang, X ; Sharif University of Technology
    The formation of macroporous bioactive hydroxyapatite(HA) coatings using polytetrafluoroethylene(PTFE) particles were studied. The porous HA coatings were prepared onto a pure titanium substrate by electrophoretic deposition(EPD) at 120 V for 1.5 min using ethanol suspensions mixture of HA (500 nm in size) and PTFE (1-3 μm in size) particles. Subsequently, the composite coatings obtained by EPD were heated at 900 °C for 60 min to disintegrate the organic PTFE particles and sinter the inorganic HA particles. The calcinations of the PTFE led to the formation of porosity in the HA coating. These results demonstrate a new method for creating porous HA coatings on titanium. © 2006 Elsevier B.V.... 

    Bioactive layer formation on alkaline-acid treated titanium in simulated body fluid

    , Article Materials and Design ; Volume 28, Issue 7 , 2007 , Pages 2154-2159 ; 02613069 (ISSN) Yousefpour, M ; Afshar, A ; Chen, J ; Zhang, X ; Sharif University of Technology
    Elsevier Ltd  2007
    Porous surface on titanium induces apatite formation in simulated body fluid (SBF). This work shows alkaline, acid and polishing treatment, which lead to create apatite coating. Specimens were soaked in 5 M solution of NaOH, 85% HCl-6% HF-9% H3PO4 and 2% HF-4% HNO3-94% H2O. Also many samples were polished with sandpaper. Specimens treated under the above conditions were soaked in simulated body fluid (SBF) for 5 days. Apatite formed within 5 days. The evaluation of Ca/P ratio of samples were made by EDAX analysis to get information of the Ca/P ratio. The values obtained for the apatite were in the range of 1.55, which is near to the stoichiometric value of apatite, for the sample, which was... 

    Effect of Bioglass Particle Size and Titania Morphology on the Bioactivity and Kinetics of Tissue Growth in Three-Dimensional Poly(ɛ-Caprolactone) Scaffolds with Controlled Pore Structure Produced by 3D-Printing Process

    , Ph.D. Dissertation Sharif University of Technology Tamjid Shabestary, Elnaz (Author) ; Bagheri, Reza (Supervisor) ; Vossoughi, Manouchehr (Supervisor) ; Simchi, Abdolreza (Co-Advisor)
    Polycaprolactone (PCL) scaffolds and its composites containing bioactive glass particles (45S5) and TiO2 nanostructures with pre-defined and controlled external and internal architecture were prepared via an indirect three-dimensional (3D) printing process. The scaffolds had an interconnected structure with macro- (400-500 μm) and micro- (~25 μm) pores. Bioactivity, mechanical behavior and kinetics of tissue growth in 3D scaffolds were studied. The size effect of biogactive glass particles (6 μm, 250 nm, <100 nm) and morphology of titania nanostructures (spherical, tube, leaf-like, and flower-like particles) were elaborated. The biogactive glass particles with different sizes were prepared... 

    Effect of TiO2 morphology on in vitro bioactivity of polycaprolactone/TiO2 nanocomposites

    , Article Materials Letters ; Volume 65, Issue 15-16 , 2011 , Pages 2530-2533 ; 0167577X (ISSN) Tamjid, E ; Bagheri, R ; Vossoughi, M ; Simchi, A ; Sharif University of Technology
    TiO2 nanostructures with different morphologies (spherical, tube, leaf-like and flower-like particles) were synthesized via a facile hydrothermal process. Polycaprolactone (PCL)/10 vol.% TiO2 nanocomposites were prepared by solvent casting methods. In vitro bioactivity of the nanocomposite films was examined by immersion in the simulated body fluid (SBF) for up to 28 days. It was found that the morphology of titania nanostructures significantly influence the in vitro bioactivity of PCL/TiO 2 nanocomposites. This observation was attributed to the amount of anatase phase and the specific surface area of the TiO2 nanostructures, which provide high surface exposure to SBF  

    Chitosan–Bioactive Glass Composite Coating on Nd-Fe-B Magnetic Alloy Substrate by Electrophoretic Deposition

    , M.Sc. Thesis Sharif University of Technology Mehdipour, Mehrad (Author) ; Afshar, Abdollah (Supervisor)
    This research work deals with application of poly-saccharide to improve coating process of bioactive ceramic composite on aNd-Fe-B magnetic alloy substrate. Bioactive glass particles were synthesized through a sol-gel process and coated in the form of composite with poly-saccharide onto a magnetic substrate by electrophoretic deposition technique. Stable suspensions of 0.5 gr/lit polysaccharide polymer-ceramic were prepared using bioactive glass particles (<1µm), acetic acid 1%. The influence of added water to ethanol, pH and tri-ethanol-amine (TEA) additive on suspension stability, deposition rate and coating’s structure was investigated. It was shown that by increasing the water to ethanol... 

    Design and Construction of PCL Nanofiber Scaffold for Bladder Tissue Engineering

    , M.Sc. Thesis Sharif University of Technology Vakilian, Saeed (Author) ; Yaghmaei, Soheyla (Supervisor) ; Mashayekhan, Shohreh (Co-Advisor)
    In this project, a novel system of bioactive electrospun scaffold for bladder tissue engineering , has been investigated to control in vitro cell differentiation, and utilize in in vivo vascularization and tissue formation. This method doesn’t have custom bioactive scaffolds problems such as, protein instability, technical complexity and, difficulties in accurate kinetics prediction. First of all, protein loaded chitosan nanoparticles based on ionic gelation interaction between chitosan and Sodium tripolyphosphate were prepared. Maximum protein loading efficiency (80% for BSA & 99% for TGF-beta1) in chitosan nanoparticles was obtained at mean diameter of 51nm. Moreover polycaprolactone... 

    Designing a planar vector field to investigate the role of a slow variable in an enhanced mean-field model during general anesthesia

    , Article 28th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS'06, New York, NY, 30 August 2006 through 3 September 2006 ; 2006 , Pages 6121-6124 ; 05891019 (ISSN); 1424400325 (ISBN); 9781424400324 (ISBN) Molaee Ardekani, B ; Shamsollahi, M. B ; Senhadji, L ; Vosoughi Vahdat, B ; Wodey, E ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2006
    Local mean-field models (MFMs) describe regional brain activities by some connected differential equations. In an overall view, constituting variables of these differential equations can be divided to very fast, fast and slow variables. In this article we propose a method that can be used to determine role of a slow variable in behavior of MFMs. Very fast variables can be adiabatically removed from the equations. Isoclines of fast and slow variables and their corresponding vector field can provide valuable information about model behavior and role of the slow variable in it. The vector field of our interested MFM that is an enhanced MFM designed specially for general anesthesia, is a 3D... 

    Investigation of morphology and bioactive properties of composite coating of HA/vinyl acetate on pure titanium

    , Article Materials Science and Engineering B: Solid-State Materials for Advanced Technology ; Volume 128, Issue 1-3 , 2006 , Pages 243-249 ; 09215107 (ISSN) Afshar, A ; Yousefpour, M ; Xiudong, Y ; Li, X ; Yang, B ; Wu, Y ; Chen, J ; Xingdong, Z ; Sharif University of Technology
    Electrochemical co-deposition approach was expanded to prepare composite bio-ceramic coating of hydroxyapatite (HA)/polyvinyl acetate on the surface of titanium. The role is to improve the bioactive and crystallization properties. The results of XRD, XPS, SEM and TEM characterization showed that by increasing amount of vinyl acetate in the composite bio-ceramic coating before and after immersing in the simulated body fluid (SBF), an oriented growth of HA planes on the (0 0 2) direction had been observed on titanium substrate. Also significant surface morphology changes were obtained  

    In vitro bioactivity and corrosion resistance enhancement of Ti-6Al-4V by highly ordered TiO 2 nanotube arrays

    , Article Journal of the Australian Ceramic Society ; Volume 55, Issue 1 , 2019 , Pages 187-200 ; 25101560 (ISSN) Sarraf, M ; Sukiman, N. L ; Bushroa, A. R ; Nasiri Tabrizi, B ; Dabbagh, A ; Abu Kasim, N. H ; Basirun, W. J ; Sharif University of Technology
    Springer International Publishing  2019
    In the present study, the structural features, corrosion behavior, and in vitro bioactivity of TiO 2 nanotubular arrays coated on Ti–6Al–4V (Ti64) alloy were investigated. For this reason, Ti64 plates were anodized in an ammonium fluoride electrolyte dissolved in a 90:10 ethylene glycol and water solvent mixture at room temperature under a constant potential of 60 V for 1 h. Subsequently, the anodized specimens were annealed in an argon gas furnace at 500 and 700 °C for 1.5 h with a heating and cooling rate of 5 °C min −1 . From XRD analysis and Raman spectroscopy, a highly crystalline anatase phase with tetragonal symmetry was formed from the thermally induced crystallization at 500 °C.... 

    Effects of Sr and Mg dopants on biological and mechanical properties of SiO2–CaO–P2O5 bioactive glass

    , Article Ceramics International ; Volume 46, Issue 14 , 2020 , Pages 22674-22682 Sharifianjazi, F ; Moradi, M ; Abouchenari, A ; Pakseresht, A.H ; Esmaeilkhanian, A ; Shokouhimehr, M ; Shahedi Asl, M ; Sharif University of Technology
    Elsevier Ltd  2020
    In the present study, the effects of Sr and Mg were investigated on mechanical and biological properties of 58S bioactive glass (BG). SiO2-P2O5-CaO BG with different contents of Sr and Mg were synthesized via the sol-gel method and immersed in simulated body fluid (SBF) for several days to explore their biocompatibility. Precise analyses of the BG using X-ray powder diffraction, scanning electron microscopy, and transmission electron microscopy showed that the Mg-doped BG containing 8 wt % MgO possessed better biocompatibility. It was also found that mechanical properties of the BG could be improved by increasing the amounts of MgO and SrO. Both 5Sr-BG and 8Mg-BG samples did not exhibit any... 

    Hydroxy Apatite/Titania Nanostructure Biocoating on Ti-6Al-4V Alloy by Sol-Gel Dip-Coating

    , M.Sc. Thesis Sharif University of Technology Dabir, Fatemeh (Author) ; Faghihi Sani, Mohammad Ali (Supervisor)
    Ceramic coatings on metallic substrates are used in many different applications. In biomaterials science, hydroxyapatite coating due to its similarity to the mineral part of bone structure is used to modification of implants surface. In this research, the HA/TiO2 double layer was coated on Ti-6Al-4V by sol- gel dip-coating method. After preparation of stable TiO2 sol, the Ti-6Al-4V substrate was dipped into the TiO2 sol. The speed of dipping was 10cm/min. After drying at 80°C, the TiO2 layer heat-treated at different temperature (350-500°C) for 1h. The HA outer layer was coated by dipping of Ti-6Al-4V substrate with TiO2 layer into HA sol, followed by heat-treatment at different temperatures... 

    Electrophoretic Deposition of Alginate-Bioglass-Nanodiamond Nanocomposites and Evolution of their Bioactivity

    , M.Sc. Thesis Sharif University of Technology Mansoorianfar, Mojtaba (Author) ; Simchi, Abdollreza (Supervisor)
    Recently, diamond nanoparticles have attracted interest for biomedical applications such as drug delivery, targeted cancer therapies, fabrication of tissue scaffolds and biosensors. In the present work, elecrophoretic deposition (EPD) of nanodiamond-bioactive glass-alginate nanocomposite was studied. In vitro bioactivity and biocompatibility of the nanocomposite were evaluated in simulated body fluid (SBF) and by MTT assay. The EPD process was performed under different conditions in order to obtain a uniform coating on the surface of 316L stainless steel substrate. The stability of the suspension was determined via optical sedimentation method and zeta potential analysis. It was found that...