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    Modified Chitosan. 3. Superabsorbency, Salt- and pH-Sensivity of Smart Ampholitic hydrogels from Chitosan-g-PAN [electronic resource]

    , Article Polymers for Advanced Technologies ; Volume 15, Issue 4, pages 173–180, April 2004 Mahdavinia, G. R. (Golam Reza) ; Zohuriaan-Mehr, M. J ; Pourjavadi, M. J
    Polyacrylonitrile (PAN) grafted chitosan was prepared by ceric-initiated graft polymerization of acrylonitrile onto chitosan in a homogenous medium. The copolymer chitosan-g-PAN product was then hydrolyzed to yield a novel smart hydrogel (H-chitoPAN) with superabsorbing properties. The influence of add-on values as well as temperature and time of hydrolysis of the initial chitosan-g-PAN on swelling behavior of the hydrogel was evaluated in water and various salt solutions. The swelling kinetics of the superabsorbing hydrogel was studied as well. The hydrogels exhibited ampholytic and pH-sensitivity characteristics. Several sharp swelling changes were observed in lieu of pH variations in a... 

    Batch equilibrium and kinetics studies of Cd (II) ion removal from aqueous solution using porous chitosan hydrogel beads

    , Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 28, Issue 3 , 2009 , Pages 81-89 ; 10219986 (ISSN) Mohammad Beigi, S ; Babapoor, A ; Maghsoodi, V ; Mousavi, S. M ; Rajabi, N ; Sharif University of Technology
    In this study chitosan hydrogel beads with porosity ∼ 0.86 and diameter ∼ 2 ± 0.07 mm were prepared from 85 % deacetylated chitosan for removal of Cd2+ ions from aqueous solutions. Chitosan powder was dissolved into dilute acetic acid as solvent and formed into spherical beads using a phase inversion technique. The effect of temperature, initial concentration of Cd2+ ions, and the period of agitation were perused to achieve the best isotherm model. Freundlich model was better fitted than Langmuir model (R2 > 0.99 and R2> 0.93 respectively, at pH of 6.3, and shaker speed of 200 rpm), the constants of Langmuir and Freundlich models were calculated, which RL value and qmax (mg/g wet weight) at... 

    Superabsorbency, pH-sensitivity and swelling kinetics of partially hydrolyzed chitosan-g-poly(acrylamide) hydrogels

    , Article Turkish Journal of Chemistry ; Volume 30, Issue 5 , 2006 , Pages 595-608 ; 13000527 (ISSN) Pourjavadi, A ; Mahdavinia, G.R ; Sharif University of Technology
    Acrylamide (AAm) monomer was directly grafted onto chitosan using ammonium persulfate (APS) as an initiator and methylenebisacrylamide (MBA) as a crosslinking agent under an inert atmosphere. Two factors affecting the swelling capacity of the obtained hydrogel, AAm and MBA concentrations, were studied. The polymer structures were characterized by FTIR spectroscopy. Water absorbencies of the hydrogels were compared between before and after the alkaline hydrolysis treatment. Saponification of chitosan-g-poly(acrylamide) (chitosan-g-PAAm) with a hot sodium hydroxide solution gave rise to a high water absorbency. Swelling of the hydrogel samples in saline solution (0.15 mol/L NaCl, CaCl2 and... 

    Modified chitosan 4. Superabsorbent hydrogels from poly(acrylic acid-co-acrylamide) grafted chitosan with salt- and pH-responsiveness properties

    , Article European Polymer Journal ; Volume 40, Issue 7 , 2004 , Pages 1399-1407 ; 00143057 (ISSN) Mahdavinia, G. R ; Pourjavadi, A ; Hosseinzadeh, H ; Zohuriaan, M. J ; Sharif University of Technology
    Graft copolymerization of mixtures of acrylic acid (AA) and acrylamide (AAm) onto chitosan was carried out by using potassium persulfate (KPS) as a free radical initiator in the presence of methylenebisacrylamide (MBA) as a crosslinker. The effect of reaction variables, such as MBA concentration and AA/AAm ratio on the water absorbency capacity have been investigated. The polymer structures were confirmed by FTIR spectroscopy. Water absorbencies were compared for the hydrogels before and after alkaline hydrolysis. In the non-hydrolyzed hydrogel, enhanced water absorbency was obtained with increasing AA in monomer feed. However, after saponification, the sample with high AAm ratio exhibited... 

    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... 

    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... 

    A hepatocellular carcinoma–bone metastasis-on-a-chip model for studying thymoquinone-loaded anticancer nanoparticles

    , Article Bio-Design and Manufacturing ; Volume 3, Issue 3 , 2020 , Pages 189-202 Sharifi, F ; Yesil Celiktas, O ; Kazan, A ; Maharjan, S ; Saghazadeh, S ; Firoozbakhsh, K ; Firoozabadi, B ; Zhang, Y. S ; Sharif University of Technology
    Springer  2020
    We report the development of a metastasis-on-a-chip platform to model and track hepatocellular carcinoma (HCC)–bone metastasis and to analyze the inhibitory effect of an herb-based compound, thymoquinone (TQ), in hindering the migration of liver cancer cells into the bone compartment. The bioreactor consisted of two chambers, one accommodating encapsulated HepG2 cells and one bone-mimetic niche containing hydroxyapatite (HAp). Above these chambers, a microporous membrane was placed to resemble the vascular barrier, where medium was circulated over the membrane. It was observed that the liver cancer cells proliferated inside the tumor microtissue and disseminated from the HCC chamber to the... 

    Modified chitosan as a polymeric nanoreactor for fabrication of pure zno nano particles

    , Article Journal of Applied Polymer Science ; Volume 117, Issue 2 , March , 2010 , Pages 1035-1040 ; 00218995 (ISSN) Jajarmi, P ; Barzegar, S ; Pourjavadi, A ; Sharif University of Technology
    ZnO nanoparticles have been prepared successfully by hydrogel decomposition method (HDM). Synthesized ZnO nanoparticles were characterized by X-ray diffraction (XRD), fourier transforms infrared spectroscopy (FTIR), and transition electron microscopy (TEM) techniques. Narrow distribution of sizes with a 20-30 nm diameter and regular distribution of ZnO nanoparticles are attributed to the application of poly(acrylic acid-co-acrylamide) grafted chitosan hydrogel as coating agent. The results show that the polymer thermal decomposition technique is a perfect method for the synthesis of ZnO nano particles  

    Fabrication and characterization of an injectable reinforced composite scaffold for cartilage tissue engineering: An in vitro study

    , Article Biomedical Materials (Bristol) ; Volume 16, Issue 4 , 2021 ; 17486041 (ISSN) Khozaei Ravari, M ; Mashayekhan, S ; Zarei, F ; Sayyahpour, F. A ; Taghiyar, L ; Eslaminejad, M. B ; Sharif University of Technology
    IOP Publishing Ltd  2021
    There are limitations in current medications of articular cartilage injuries. Although injectable bioactive hydrogels are promising options, they have decreased biomechanical performance. Researchers should consider many factors when providing solutions to overcome these challenges. In this study, we created an injectable composite hydrogel from chitosan and human acellular cartilage extracellular matrix (ECM) particles. In order to enhance its mechanical properties, we reinforced this hydrogel with microporous microspheres composed of the same materials as the structural building blocks of the scaffold. Articular cartilage from human donors was decellularized by a combination of physical,... 

    Injectable in situ forming kartogenin-loaded chitosan hydrogel with tunable rheological properties for cartilage tissue engineering

    , Article Colloids and Surfaces B: Biointerfaces ; Volume 192 , 2020 Dehghan-Baniani, D ; Chen, Y ; Wang, D ; Bagheri, R ; Solouk, A ; Wu, H ; Sharif University of Technology
    Elsevier B.V  2020
    Limited regeneration capacity of cartilage can be addressed by tissue engineering approaches including localized delivery of bioactive agents using biomaterials. Although chitosan hydrogels have been considered as appropriate candidates for these purposes, however, their poor mechanical properties limit their real applications. Here, we develop in situ forming chitosan hydrogels with enhanced shear modulus by chemical modification of chitosan using N-(β-maleimidopropyloxy) succinimide ester (BMPS). Moreover, we utilize β-Glycerophosphate (β-GP) in the hydrogels for achieving thermosensitivity. We investigate the effects of BMPS, β-GP and chitosan concentration on rheological and swelling...