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    Synthesis of novel water-soluble aminodeoxychitin derivatives

    , Article Starch/Staerke ; Volume 59, Issue 11 , 2007 , Pages 557-562 ; 00389056 (ISSN) Pourjavadi, A ; Seidi, F ; Salimi, H ; Sharif University of Technology
    Eight new chitin derivatives have been synthesized via SN2 reaction of primary and secondary amines with tosylchitin. The products were characterized using FTIR and 1H NMR spectroscopy. A degree of substitution ∼ 1 was achieved through this process. These materials are soluble in water at room temperature, which enable their further applications in the future. © 2007 WILEY-VCH Verlag GmbH & Co. KGaA  

    Chitosan based supramolecular polypseudorotaxane as a pH-responsive polymer and their hybridization with mesoporous silica-coated magnetic graphene oxide for triggered anticancer drug delivery

    , Article Polymer (United Kingdom) ; Volume 76 , October , 2015 , Pages 52-61 ; 00323861 (ISSN) Pourjavadi, A ; Mazaheri Tehrani, Z ; Jokar, S ; Sharif University of Technology
    Elsevier Ltd  2015
    Chitosan based polyseudorotaxane was designed as a pH-responsive supramolecular polymeric shell around the mesoporous silica-coated magnetic graphene oxide (Fe3O4@GO@mSiO2). It was used for doxorubicin delivery at cancerous tissue in a controlled manner. The core-shell nanocarrier was formed due to electrostatic interaction between chitosan and carboxylated surface of Fe3O4@GO@mSiO2. The maximum release occurred at pH 5.5 (pH of endosomes) because the shell collapsed at this pH. The drug nanocarrier has potential application in tumor therapy due to good pH-sensitive behavior, improved solubility and high colloidal stability in... 

    Synthesis and properties of highly swelling PAAm/chitosan semi-IPN hydrogels

    , Article Macromolecular Symposia ; Volume 274, Issue 1 , 2008 , Pages 171-176 ; 10221360 (ISSN) Mahdavinia, G. R ; Pourjavadi, A ; Zohuriaan Mehr, M. J ; Sharif University of Technology
    A semi-interpenetrating polymer network (semi-IPN) hydrogel composed of crosslinked chitosan and Polyacrylamide (PAAm) was prepared in the presence of formaldehyde as a crosslinker. The swelling capacity of hydrogel was shown to be affected by the crosslinker and the PAAm/chitosan ratio. The PAAm/chitosan semiIPN hydrogels are swelled at low pHs that attributed to both osmotic pressure and repulsion of -NH3+ groups on chitosan backbones. The swelling of hydrogel in acidic pHs showed that with increasing of chitosan content in the hydrogel, the swelling capacity was increased. But the swelling capacity of hydrogel in neutral pH is reversed, i.e. the higher the PAAm/chitosan ratio, the higher... 

    Green composites in bone tissue engineering

    , Article Emergent Materials ; 2021 ; 25225731 (ISSN) Jouyandeh, M ; Vahabi, H ; Rabiee, N ; Rabiee, M ; Bagherzadeh, M ; Saeb, M. R ; Sharif University of Technology
    Springer Nature  2021
    Natural and biodegradable polymers are of particular interest as green sources with low-cost and environmentally friendly features, and have been widely used for polymer composite development. The term “Green Composites” refers to polymer/filler systems in which polymer, filler, or sometimes both components are green in view of sources from which they are yielded or their biodegradability. Natural fibers obtained from plants, animals, and/or geological processes are a big class of green sources widely applied in green composite development. There has also been continued research on recycling of green composite as well as developing hybrid systems for advanced applications. In view of their... 

    Comparison of solid substrate and submerged fermentation for chitosan production by aspergillus niger

    , Article Scientia Iranica ; Volume 17, Issue 2 C , 2010 , Pages 153-157 ; 10263098 (ISSN) Maghsoodi, V ; Yaghmaei, S ; Sharif University of Technology
    Production yield of solid-state (SSF) and submerged fermentation (SMF) on chitosan from Aspergillus niger was investigated. A. niger BBRC 20004 was grown on soybean residue and Sabouraud Dextrose Broth medium (2% glucose). Chitosan was extracted from the fungal mycelia using hot alkaline and acid treatment. Soybean residue at a moisture content of 37%, and 8-4 ± 0.26% of nitrogen content produced the highest amount of chitosan, 17.053 ± 0.95 g/kg dry substrate after 12 days. Also, chitosan was extracted from A. niger on Sabouraud Dextrose Broth medium in submerged fermentation (0.8455 g/l after 12 days of cultivation). The yield of chitosan isolated in SSF was about 15-20 times more than in... 

    Smart and fragrant garment via surface modification of cotton fabric with cinnamon oil/stimuli responsive PNIPAAm/chitosan nano hydrogels

    , Article IEEE Transactions on Nanobioscience ; Volume 16, Issue 6 , 2017 , Pages 455-462 ; 15361241 (ISSN) Bashari, A ; Hemmatinejad, N ; Pourjavadi, A ; Sharif University of Technology
    This paper deals with obtaining aromatherapic textiles via applying stimuli-responsive poly N-isopropyl acryl amide (PNIPAAm) chitosan (PNCS) nano hydrogels containing cinnamon oil on cotton fabric and looks into the treated fabric characteristics as an antibacterial and temperaturepH responsive fabric. The semi-batch surfactant-free dispersion polymerization method was proposed to the synthesis of PNCS nano particles. The incorporation of modified β -cyclodextrin ( β-CD) into the PNCS nanohydrogel was performed in order to prepare a hydrophobic(cinnamon oil) carrier embedded in stimuli-responsive nanohydrogel. The β -CD postloading process of cinnamon oil in to the hydrogel nano particles... 

    Solid state fermentation for production of chitosan by aspergillus niger

    , Article International Journal of Engineering, Transactions B: Applications ; Volume 22, Issue 1 , 2009 , Pages 1-6 ; 1728-144X (ISSN) Maghsoodi, V ; Razavi, J ; Yaghmaei, S ; Sharif University of Technology
    Materials and Energy Research Center  2009
    The effect of Solid State Fermentation (SSF) on Chitosan production by A. niger was investigated. A. niger BBRC 20004 from Biochemical and Bioenvironmental Research Centre of Sharif University of Technology (Tehran, Iran), was grown on corn residue. Chitosan was extracted from the fungal mycelia using hot alkaline and acid treatment. A. niger was incubated for 12 days on corn residue with moisture content of 35 % and 1.12 % of nitrogen. The Chitosan was obtained and 10.9 g/kg of Urea dry residue was added in various amounts to the medium in order to evaluate the effect of the nitrogen concentration in the production of Chitosan. The highest amount of Chitosan obtained by 6.5 g of urea after... 

    Electrophoretic deposition of chitosan

    , Article Materials Letters ; Volume 63, Issue 26 , 2009 , Pages 2253-2256 ; 0167577X (ISSN) Simchi, A ; Pishbin, F ; Boccaccini, A. R ; Sharif University of Technology
    The electrophoretic deposition (EPD) of chitosan on metallic substrates was investigated. The electrophoretic mobility of the natural biopolymer in aqueous solution as a function of pH was studied. Because the protonation/deporotonation of chitosan is pH-dependent, the electrophoretic mobility and deposition rate is shown to increase with increasing pH from 2.9 to 4.1. The film growth rate is estimated to vary in the range 0.02-0.08 μm/s depending on the pH value. At high growth rates (> 0.05 μm/s), a porous film is obtained due to hydrogen entrapment. The EPD method developed here is applicable for the surface modification of metal implants by chitosan to develop novel bioactive coatings. ©... 

    Production of chitosan by submerged fermentation from Aspergillus niger

    , Article Scientia Iranica ; Volume 16, Issue 2 C , 2009 , Pages 145-148 ; 10263098 (ISSN) Maghsoodi, V ; Razavi, J ; Yaghmaei, S ; Sharif University of Technology
    The effect of glucose concentration in submerged fermentation (SMF) on chitosan production by Aspergillus niger was investigated. A. niger, BBRC, 20004, from the Biochemical and Bioenvironmental Research Centre at Sharif University of Technology, Tehran, Iran, was grown in a Sabouro Dextrose media. Chitosan was extracted from the fungal mycelia using hot alkaline and acid treatment and after 12 days of cultivation, 0.8455 g chitosan /l of the fermentation medium was obtained. The content of glucose in the Sobouro Dextrose Broth media was also changed and the highest yield of chitosan 0.9121 g/l was obtained in Sobouro Dextrose Broth media containing 8% glucose. © Sharif University of... 

    Hydrogel nanocomposite based on chitosan-g-acrylic acid and modified nanosilica with high adsorption capacity for heavy metal ion removal

    , Article Iranian Polymer Journal (English Edition) ; Volume 24, Issue 9 , September , 2015 , Pages 725-734 ; 10261265 (ISSN) Pourjavadi, A ; Mazaheri Tehrani, Z ; Salimi, H ; Banazadeh, A ; Abedini, N ; Sharif University of Technology
    Springer-Verlag London Ltd  2015
    In this study, a novel hybrid hydrogel based on chitosan, acrylic acid and amine-functionalized nanosilica was prepared and characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis and scanning electron microscopy. This hydrogel nanocomposite was used for removal of Co2+, Cu2+, Pb2+ and Zn2+ ions from aqueous solution. The metal ion adsorption was measured by inductively coupled plasma mass spectrometry. The adsorption behavior showed that the presence of modified nanosilica enhanced the porosity of the hydrogel network and affected its adsorption capacity in response to different parameters such as nanosilica content, metal ion concentration, adsorbent content,... 

    Effect of formulation factors on the bioactivity of glucose oxidase encapsulated chitosan-alginate microspheres: In vitro investigation and mathematical model prediction

    , Article Chemical Engineering Science ; Volume 125 , March , 2015 , Pages 4-12 ; 00092509 (ISSN) Abdekhodaie, M. J ; Cheng, J ; Wu, X. Y ; Sharif University of Technology
    Elsevier Ltd  2015
    Higher reactive oxygen species (ROS) levels in cancer cells than normal cells have long been recognized, which makes cancer cells more susceptible to excess ROS. Thus oxidation (also called pro-oxidant) therapy has been explored as new cancer therapy regimens. To produce additional ROS, e.g. H2O2 in situ within tumor, we encapsulated glucose oxidase in chitosan-coated alginate-calcium microspheres (GOX-MS) for locoregional treatment and demonstrated its efficacy against cancer cells in vitro and in vivo. Owing to the complex biological functions of ROS, the production rate and amount of H2O2 are critical to achieve therapeutic benefits without causing normal tissue toxicity. This work was... 

    Development of chitosan/bacterial cellulose composite films containing nanodiamonds as a potential flexible platform for wound dressing

    , Article Materials ; Volume 8, Issue 9 , 2015 , Pages 6401-6418 ; 19961944 (ISSN) Ostadhossein, F ; Mahmoudi, N ; Morales Cid, G ; Tamjid, E ; Navas Martos, F. J ; Soriano Cuadrado, B ; Paniza, J. M. L ; Simchi, A ; Sharif University of Technology
    MDPI AG  2015
    Chitosan/bacterial cellulose composite films containing diamond nanoparticles (NDs) with potential application as wound dressing are introduced. Microstructural studies show that NDs are uniformly dispersed in the matrix, although slight agglomeration at concentrations above 2 wt % is seen. Fourier transform infrared spectroscopy reveals formation of hydrogen bonds between NDs and the polymer matrix. X-ray diffraction analysis indicates reduced crystallinity of the polymer matrix in the presence of NDs. Approximately 3.5-fold increase in the elastic modulus of the composite film is obtained by the addition of 2 wt % NDs. The results of colorimetric analysis show that the composite films are... 

    Effect of stimuli-responsive nano haydrogel finishing on cotton fabric properties

    , Article Indian Journal of Fibre and Textile Research ; Volume 40, Issue 4 , 2015 , Pages 431-436 ; 09710426 (ISSN) Bashari, A ; Hemmati Nejad, N ; Pourjavadi, A ; Sharif University of Technology
    National Institute of Science Communication and Information Resources (NISCAIR)  2015
    Cotton fabrics have been prepared with smart properties by functional finishing with stimuli-responsive nano gel. A biopolymer (chitosan) and a synthetic polymer (poly-NiPAAm) have been used for the synthesis of nano gel through semi-batch surfactant-free dispersion polymerization (SB-SFDP) method. The incorporation of nano gel to textile fabrics is achieved by pad-dry-cure procedure, using an aqueous nano gel dispersion and 1,2,3,4-butantetracarboxylic acid as a crosslinking agent. With this cross linking method, it is possible to integrate the nano gel into the cotton fabric’s structure with good resistance to washing. The changes in physiological comfort parameters of cotton fabric such... 

    Physicochemical and biological properties of electrodeposited graphene oxide/chitosan films with drug-eluting capacity

    , Article Carbon ; Volume 84, Issue C , April , 2015 , Pages 91-102 ; 00086223 (ISSN) Ordikhani, F ; Ramezani Farani, M ; Dehghani, M ; Tamjid, E ; Simchi, A ; Sharif University of Technology
    Elsevier Ltd  2015
    In this study, novel graphene oxide/chitosan nanocomposite coatings with long term drugeluting potential are presented. The coatings are fabricated by the facile and reproducible electrophoretic deposition technique. Analysis of the prepared films shows that the graphene oxide nanosheets are exfoliated in the chitosan matrix. Fourier-transform infrared spectrometry reveals polymer attachment to the carboxylic bonds of graphene oxide, providing a strong interaction and exfoliation of the nanolayers. In vitro viability assay by human osteosarcoma cells (MG-63) demonstrates that the nanocomposite films are highly biocompatible up to 30 wt% graphene oxide, but at higher concentrations a slight... 

    The effects of reaction conditions on block copolymerization of chitosan and poly(ethylene glycol)

    , Article Carbohydrate Polymers ; Volume 81, Issue 4 , July , 2010 , Pages 799-804 ; 01448617 (ISSN) Ganji, F ; Abdekhodaie, M. J ; Sharif University of Technology
    A novel injectable in situ gelling thermosensitive chitosan-block-poly(ethylene glycol) formulation was synthesized for drug delivery applications. Block copolymerization of monomethoxy-poly(ethylene glycol) onto chitosan using potassium persulfate as an initiator was carried under a nitrogen atmosphere in aqueous solution. The effects of potassium persulfate and poly(ethylene glycol) concentrations, reaction time and reaction temperature on block polymerization were studied by determining the yield of reaction (%Y), polymerization efficiency (%E) and add-on percentage (%Add-on). Keeping the other conditions constant, the optimum reaction conditions were found to be initiator = 0.01 M,... 

    Glassy carbon electrodes modified with a film of nanodiamond-graphite/chitosan: Application to the highly sensitive electrochemical determination of Azathioprine

    , Article Electrochimica Acta ; Volume 55, Issue 11 , 2010 , Pages 3621-3627 ; 00134686 (ISSN) Shahrokhian, S ; Ghalkhani, M ; Sharif University of Technology
    A novel modified glassy carbon electrode with a film of nanodiamond-graphite/chitosan is constructed and used for the sensitive voltammetric determination of azathioprine (Aza). The surface morphology and thickness of the film modifier are characterized using atomic force microscopy. The electrochemical response characteristics of the electrode toward Aza are investigated by means of cyclic voltammetry. The modified electrode showed an efficient catalytic role for the electrochemical reduction of Aza, leading to a remarkable decrease in reduction overpotential and enhancement of the kinetics of the electrode reaction with a significant increase of peak current. The effects of experimental... 

    Comparison of using formaldehyde and carboxy methyl chitosan in preparation of Fe3O4 superparamagnetic nanoparticles-chitosan hydrogel network: Sorption behavior toward bovine serum albumin

    , Article Process Safety and Environmental Protection ; Volume 102 , 2016 , Pages 119-128 ; 09575820 (ISSN) Sadeghi, M ; Hanifpour, F ; Taheri, R ; Javadian, H ; Ghasemi, M ; Sharif University of Technology
    Institution of Chemical Engineers 
    A novel and cost effective method of bio-separation developed recently is magnetic separation technology. In this study, super paramagnetic Fe3O4 nanoparticles are used for separation of bovine serum albumin (BSA) protein from plasma/serum samples at optimized conditions. The synthesis of chitosan hydrogel networks by two variant approaches that involve (1) crosslinking of chitosan with formaldehyde and (2) formation of carboxy methyl chitosan mediated complex, was investigated and the percent of gelation, swelling ratio and equilibrium water content were calculated. The results revealed the formation of better quality hydrogel from the first approach. In step 1, to quantify the BSA... 

    Effect of graphene oxide nanosheets on the physico-mechanical properties of chitosan/bacterial cellulose nanofibrous composites

    , Article Composites Part A: Applied Science and Manufacturing ; Volume 85 , 2016 , Pages 113-122 ; 1359835X (ISSN) Azarniya, A ; Eslahi, N ; Mahmoudi, N ; Simchi, A ; Sharif University of Technology
    Elsevier Ltd 
    In this work, novel chitosan/bacterial cellulose (CS/BC) nanofibrous composites reinforced with graphene oxide (GO) nanosheets are introduced. As cell attachment and permeability of nanofibrous membranes highly depend on their fiber diameter, the working window for successful electrospinning to attain sound nanofibrous composites with a minimum fiber diameter was determined by using the response surface methodology. It is shown that the addition of GO nanosheets to CS/BC significantly reduces the average size of the polymeric fibers. Their mechanical properties are also influenced and can be tailored by the concentration of GO. Fourier transform infrared spectroscopy reveals hydrogen bonding... 

    Physicochemical and antibacterial properties of chitosan-polyvinylpyrrolidone films containing self-organized graphene oxide nanolayers

    , Article Journal of Applied Polymer Science ; Volume 133, Issue 11 , 2016 ; 00218995 (ISSN) Mahmoudi, N ; Ostadhossein, F ; Simchi, A ; Sharif University of Technology
    John Wiley and Sons Inc  2016
    Chitosan films have a great potential to be used for wound dressing and food-packaging applications if their physicochemical properties including water vapor permeability, optical transparency, and hydrophilicity are tailored to practical demands. To address these points, in this study, chitosan (CS) was combined with polyvinylpyrrolidone (PVP) and graphene oxide (GO) nanosheets (with a thickness of ∼1 nm and lateral dimensions of few micrometers). Flexible and transparent films with a high antibacterial capacity were prepared by solvent casting methods. By controlling the evaporation rate of the utilized solvent (1 vol % acidic acid in deionized water), self-organization of GO in the... 

    Preparation and characterization of a composite biomaterial including starch micro/nano particles loaded chitosan gel

    , Article Carbohydrate Polymers ; Volume 174 , 2017 , Pages 633-645 ; 01448617 (ISSN) Dehghan Baniani, D ; Bagheri, R ; Solouk, A ; Sharif University of Technology
    Thermosensitive Chitosan hydrogels which can be injected into defects with minimally invasive approach were prepared. Also starch micro/nano particles were synthesized via water-in-oil (W/O) miniemulsion technique. The starch particles were incorporated into the chitosan hydrogel to prepare injectable thermosensitive hydrogel composites. Tube inverting method, compression tests, swelling studies, XRD, SEM, OM, DLS, UV–vis spectroscopy were used for investigations. Results revealed that increasing crosslinker and surfactant contents and stirring rate leads to particle size reduction. Particle size was modeled using design of experiments (DOE) via the response surface method (RSM). Due to...