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    Hydrolyzed Protein-Based Highly Porous Hydrogels: Synthesis and Characteristics

    , Ph.D. Dissertation Sharif University of Technology Kurdtabar, Mehran (Author) ; Pourjavadi, Ali (Supervisor)
    Abstract
    This thesis focuses on the preparation and super-swelling behavior of four highly porous hydrogels: 1. Firstly, we have developed a collagen-based highly porous hydrogel by neutralizing the grafted poly(acrylamide-co-acrylic acid) after gel formation. Systematically, the certain variables of the graft copolymerization were optimized to achieve maximum swelling capacity. Morphology of the samples was examined by scanning electron microscopy (SEM) and was shown the pores were induced into the hydrogel by water evaporation resulting from neutralization process. The absorbency under load (AUL) and centrifuge retention capacity (CRC) were measured. The synthesized hydrogel exhibited a... 

    Preparation of Porous PVA Nanocomposite Hydrogels Via Gamma Irradiation

    , M.Sc. Thesis Sharif University of Technology Sabourian, Parinaz (Author) ; Frounchi, Masoud (Supervisor) ; Dadbin, Susan (Supervisor)
    Abstract
    In this research, porous polyvinyl¬ alcohol (PVA)/Montmorillonite nanoclay and polyvinyl alcohol/polyvinyl pyrrolidone (PVP)/Montmorillonite nanoclay nanocomposite sponges (foams) were fabricated by freeze-drying method. The foams were crosslinked using gamma irradiation. The pore size and interconnectivity of nanocomposites characterized by scanning electron microscopy (SEM), showed bimodal pore size distribution resulting from preparation method.
    SEM micrographs displayed that addition of PVP ( wt% of total solid polymer) to the PVA sponges increased the pore size and interconnectivity, due to the optimal number of hydrogen bonds between functional groups of polymeric matrices.... 

    Study and Fabrication of a Multilayer Scaffold Containing Biological Agents for Skin Wounds Regeneration

    , Ph.D. Dissertation Sharif University of Technology Hajiabbas, Maryam (Author) ; Alemzadeh, Iran (Supervisor) ; Vossoughi, Manouchehr (Supervisor) ; Shamloo, Amir (Co-Supervisor)
    Abstract
    In recent years, it is expected that the fabrication of multilayer scaffolds and the use of different methodologies in one product can be a new progressing method in skin substitute production. Accordingly, this project aims to fabricate a bilayered composite scaffold with a combination of hydrogel and electrospinning method. We have tried to prepare a scaffold made of oxidized alginate (OAL), gelatin (G), and silk fibroin (SF) without using corrosive solvents and toxic crosslinking agents as a scaffold and drug delivery system. As different biological, chemical, physical, and mechanical factors play a vital role in the healing process, we have characterized the proposed scaffold via DSC,... 

    Effect of different bases and neutralization steps on porosity and properties of collagen-based hydrogels

    , Article Polymer International ; Volume 59, Issue 1 , 2010 , Pages 36-42 ; 09598103 (ISSN) Pourjavadi, A ; Kurdtabar, M ; Sharif University of Technology
    Abstract
    The aim of the work reported was to investigate the effect of bases and neutralization steps on hydrogel microstructures. A series of porous hydrogels with various pore sizes were prepared by neutralizing a conventional hydrogel after gel formation. Scanning electron microscopy was used to characterize the microstructure of the porous hydrogels. The morphology of the samples showed the pores were induced into the hydrogels by water evaporation and gas release resulting from the neutralization process. Experimental results indicated that the hydrogels had an absorbency of 200-220 and 48-50 g g-1 for distilled water and sodium chloride solutions, respectively. A simple method was used to... 

    Freeze-gelled alginate/gelatin scaffolds for wound healing applications: An in vitro, in vivo study

    , Article Materials Science and Engineering C ; Volume 113 , 2020 Afjoul, H ; Shamloo, A ; Kamali, A ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    In this study, fabrication of a three-dimensional porous scaffold was performed using freeze gelation method. Recently, fabrication of scaffolds using polymer blends has become common for many tissue engineering applications due to their unique tunable properties. In this work, we fabricated alginate-gelatin porous hydrogels for wound healing application using a new method based on some modifications to the freeze-gelation method. Alginate and gelatin were mixed in three different ratios and the resulting solutions underwent freeze gelation to obtain 3D porous matrices. We analyzed the samples using different characterization tests. The scanning electron microscopy (SEM) results indicated... 

    Novel nano-porous hydrogel as a carrier matrix for oral delivery of tetracycline hydrochloride

    , Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; Volume 392, Issue 1 , December , 2011 , Pages 16-24 ; 09277757 (ISSN) Bardajee, G. R ; Pourjavadi, A ; Soleyman, R ; Sharif University of Technology
    Abstract
    A novel nano-porous hydrogel (NPH) was synthesized via graft copolymerization of sodium acrylate (Na-AA) and acrylamide (AAm) onto salep backbones and its application as a carrier matrix for oral delivery of tetracycline hydrochloride (TH) was investigated. The Taguchi method as a strong experimental design tool was used for synthesis optimization. The swelling behavior of optimum hydrogel was measured in various media. The hydrogel formation was confirmed by Fourier transform infrared spectroscopy (FT-IR) and thermogravimetrical analysis (TGA). The study of the surface morphology of the hydrogels using SEM and AFM showed a nanoporous (average pore size: 180. nm) structure for the sample... 

    Fabrication and evaluation of a bilayer hydrogel-electrospinning scaffold prepared by the freeze-gelation method

    , Article Journal of Biomechanics ; Volume 98 , 2020 Kamali, A ; Shamloo, A ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    This study presents a bilayer structure as a skin scaffold comprised of an electrospun sheet layer made of polycaprolactone and polyvinil alcohol and a porous hydrogel layer made of chitosan and gelatin. The hydrogel layer was fabricated by employing the freeze-gelation technique. The bilayer structure was achieved by pouring the hydrogel solution on the electrospun sheet at the bottom of a mold followed by the freeze-gelation technique to obtain a porous structure in the hydrogel. The hydrogel and hydrogel-electrospun samples were characterized by scanning electron microscopy, swelling, tensile strength, in vitro and in vivo analyses. From a mechanical strength standpoint, the combination...