Search for: scaffolds--biology
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    Design, fabrication, and characterization of novel porous conductive scaffolds for nerve tissue engineering

    , Article International Journal of Polymeric Materials and Polymeric Biomaterials ; Volume 64, Issue 18 , 2015 , Pages 969-977 ; 00914037 (ISSN) Baniasadi, H ; Ahmad Ramazani, S. A ; Mashayekhan, S ; Farani, M. R ; Ghaderinezhad, F ; Dabaghi, M ; Sharif University of Technology
    Taylor and Francis Inc  2015
    Highly conductive polypyrrole/graphene (PYG) nanocomposite was synthesized with chemical oxidation process via emulsion polymerization and used for the preparation of novel porous conductive gelatin/chitosan-based scaffolds. The effect of PYG loading on various properties of scaffolds was investigated. The obtained results indicated that by introducing PYG into the polymeric matrix, the porosity and swelling capacity decreased while electrical conductivity and Young's modulus demonstrated increasing trend. The in vitro biodegradation test revealed that pure gelatin/chitosan matrix lost 80% of its weight after six weeks in the presence of lysozyme whilst the biodegradation rate was... 

    Rolled graphene oxide foams as three-dimensional scaffolds for growth of neural fibers using electrical stimulation of stem cells

    , Article Carbon ; Volume 97 , 2016 , Pages 71-77 ; 00086223 (ISSN) Akhavan, O ; Ghaderi, E ; Shirazian, S. A ; Rahighi, R ; Sharif University of Technology
    Elsevier Ltd 
    Graphene oxide foam (GOF) layers with thicknesses of ∼15-50 μm and density of ∼10 graphene oxide (GO) sheets/μm were fabricated by precipitation of chemically exfoliated GO sheets in an aqueous suspension at ∼80 °C under UV irradiation. Then, rolled GOFs with desirable scales were developed as electrically conductive 3D-scaffolds and applied in directional growth of neural fibers, through differentiation of human neural stem cells (hNSCs) into neurons under an electrical stimulation. X-ray photoelectron spectroscopy indicated that the UV irradiation resulted in partial deoxygenation of the layers. Scanning electron microscopy and Raman spectroscopy confirmed the presence of multilayer GO... 

    Graphene scaffolds in progressive nanotechnology/stem cell-based tissue engineering of the nervous system

    , Article Journal of Materials Chemistry B ; Volume 4, Issue 19 , 2016 , Pages 3169-3190 ; 20507518 (ISSN) Akhavan, O ; Sharif University of Technology
    Royal Society of Chemistry  2016
    Although graphene/stem cell-based tissue engineering has recently emerged and has promisingly and progressively been utilized for developing one of the most effective regenerative nanomedicines, it suffers from low differentiation efficiency, low hybridization after transplantation and lack of appropriate scaffolds required in implantations without any degrading in functionality of the cells. In fact, recent studies have demonstrated that the unique properties of graphene can successfully resolve all of these challenges. Among various stem cells, neural stem cells (NSCs) and their neural differentiation on graphene have attracted a lot of interest, because graphene-based neuronal tissue... 

    An alternative mechanism for the formation of high density lipoprotein in peripheral tissue

    , Article Scientia Iranica ; Volume 23, Issue 2 , 2016 , Pages 600-608 ; 10263098 (ISSN) Damirchi, B ; Saidi, M. S ; Rismanian, M ; Firoozabadi, B ; Amininasab, M ; Sharif University of Technology
    Sharif University of Technology  2016
    High Density Lipoprotein (HDL) is a lipid-protein complex responsible for transporting cholesterol and triglyceride molecules, as these compounds are unable to dissolve in aqueous environments such as a bloodstream. Among the most well-known possible structures, the belt-like structure is the most common shape proposed for this vital bimolecular complex. In this structure, the protein scaffold encompasses the lipid bilayer and a planar circular structure is formed. Several HDL simulations with embedded components in the lipid section were performed. Here, we applied a series of molecular dynamic simulations using the MARTINI coarse grain force field to investigate an HDL model, with pores of... 

    Interface engineering of perovskite solar cell using a reduced-graphene scaffold

    , Article Journal of Physical Chemistry C ; Volume 120, Issue 35 , Volume 120, Issue 35 , 2016 , Pages 19531-19536 ; 19327447 (ISSN) Tavakoli, M. M ; Tavakoli, R ; Hasanzadeh, S ; Mirfasih, M. H ; Sharif University of Technology
    American Chemical Society 
    Interface engineering of solar cell device is a prominent strategy to improve the device performance. Herein, we synthesize reduced-graphene scaffold (rGS) by using a new and simple chemical approach. In this regard, we synthesize a hollow structure of graphene and then fabricate a three-dimensional scaffold of graphene with a superior surface area using electrophoretic process. We employ this scaffold as an interface layer between the electron transfer and absorber layers in perovskite solar cell. The characterization tests and photovoltaic results show that rGS improves the carrier transportation, yielding a 27% improvement in device performance as compared to conventional device. Finally,... 

    Preparation of biodegradable gelatin/PVA porous scaffolds for skin regeneration

    , Article Artificial Cells, Nanomedicine and Biotechnology ; 2016 , Pages 1-8 ; 21691401 (ISSN) Mahnama, H ; Dadbin, S ; Frounchi, M ; Rajabi, S ; Sharif University of Technology
    Taylor and Francis Ltd  2016
    Porous scaffolds composed of gelatin/poly (vinyl alcohol), (Gel/PVA), were prepared using combination of freeze gelation and freeze drying methods. The effect of polymer concentration, gelatin/PVA ratio, and glutaraldehyde/gelatin ratio (GA/Gel) was investigated on morphology of pores, swelling ratio, biodegradation, and skin cell culture. At optimum preparation conditions the scaffolds had uniform pore size distributions showing high swelling ratio of 23.6. The scaffolds were of biodegradable nature and almost degraded in 28 days. Human dermal fibroblast cells (HDF) were cultured on the scaffolds and MTS assay was conducted to evaluate the influence of PVA on growth and proliferation of the... 

    Study of hole-transporter-free perovskite solar cells based on fully printable components

    , Article Micromachines ; Volume 10, Issue 4 , 2019 ; 2072666X (ISSN) Raminafshar, C ; Raptis, D ; Mohammadi, M. R ; Lianos, P ; Sharif University of Technology
    MDPI AG  2019
    Hole-transporter-free perovskite solar cells carrying a carbon back contact electrode provide the possibility of making full printable low cost and stable devices, even though their efficiency is substantially lower than those made in the standard configuration. The present work searched for simple and easy routes for constructing such devices, demonstrating that organic components do enhance device efficiency but only to a level that is not worth the trouble nor the cost. Devices based on a triple mesoporous layer of titania/zirconia/carbon with perovskite infiltration gave an efficiency of 10.7%. After 180 days of storing under ambient conditions, a small loss of efficiency has been... 

    A hybrid scaffold of gelatin glycosaminoglycan matrix and fibrin as a carrier of human corneal fibroblast cells

    , Article Materials Science and Engineering C ; Volume 118 , 2021 ; 09284931 (ISSN) Hajian Foroushani, Z ; Mahdavi salimi, S ; Abdekhodaie, M. J ; Baradaran Rafii, A ; Tabatabei, M. R ; Mehrvar, M ; Sharif University of Technology
    Elsevier Ltd  2021
    A hybrid scaffold of gelatin-glycosaminoglycan matrix and fibrin (FGG) has been synthesized to improve the mechanical properties, degradation time and cell response of fibrin-like scaffolds. The FGG scaffold was fabricated by optimizing some properties of fibrin-only gel and gelatin-glycosaminoglycan (GG) scaffolds. Mechanical analysis of optimized fibrin-only gel showed the Young module and tensile strength of up to 72 and 121 KPa, respectively. Significantly, the nine-fold increase in the Young modulus and a seven-fold increase in tensile strength was observed when fibrin reinforced with GG scaffold. Additionally, the results demonstrated that the degradation time of fibrin was enhanced... 

    The impact of zirconium oxide nanoparticles content on alginate dialdehyde-gelatin scaffolds in cartilage tissue engineering

    , Article Journal of Molecular Liquids ; Volume 335 , 2021 ; 01677322 (ISSN) Ghanbari, M ; Salavati Niasari, M ; Mohandes, F ; Firouzi, Z ; Mousavi, S.-D ; Sharif University of Technology
    Elsevier B.V  2021
    The desire to regenerate and repair native tissues can be immediately performed by multiple tissue engineering procedures. Gelatin and alginate are biocompatible and biodegradable polymers. The addition of ZrO2 nanoparticles (NPs) into the alginate-gelatin hydrogel is considered to improve mechanical and chemical properties. Therefore, nanocomposite hydrogels have been manufactured by the freeze-drying procedure utilizing oxidized alginate-gelatin with ZrO2 NPs as a reinforcement. The fabricated nanocomposite hydrogels were character-ized by FTIR, FESEM, and rheometer. The hydrogels containing a higher ZrO2 NPs content (1.5%) have better mechanical properties than the hydrogels without NPs.... 

    Alginate/cartilage extracellular matrix-based injectable interpenetrating polymer network hydrogel for cartilage tissue engineering

    , Article Journal of Biomaterials Applications ; Volume 36, Issue 5 , 2021 , Pages 803-817 ; 08853282 (ISSN) Shojarazavi, N ; Mashayekhan, S ; Pazooki, H ; Mohsenifard, S ; Baniasadi, H ; Sharif University of Technology
    SAGE Publications Ltd  2021
    In the present study, alginate/cartilage extracellular matrix (ECM)-based injectable hydrogel was developed incorporated with silk fibroin nanofibers (SFN) for cartilage tissue engineering. The in situ forming hydrogels were composed of different ionic crosslinked alginate concentrations with 1% w/v enzymatically crosslinked phenolized cartilage ECM, resulting in an interpenetrating polymer network (IPN). The response surface methodology (RSM) approach was applied to optimize IPN hydrogel's mechanical properties by varying alginate and SFN concentrations. The results demonstrated that upon increasing the alginate concentration, the compression modulus improved. The SFN concentration was... 

    Human olfactory mucosa stem cells delivery using a collagen hydrogel: As a potential candidate for bone tissue engineering

    , Article Materials ; Volume 14, Issue 14 , 2021 ; 19961944 (ISSN) Simorgh, S ; Milan, P. B ; Saadatmand, M ; Bagher, Z ; Gholipourmalekabadi, M ; Alizadeh, R ; Hivechi, A ; Arabpour, Z ; Hamidi, M ; Delattre, C ; Sharif University of Technology
    MDPI AG  2021
    For bone tissue engineering, stem cell‐based therapy has become a promising option. Re-cently, cell transplantation supported by polymeric carriers has been increasingly evaluated. Herein, we encapsulated human olfactory ectomesenchymal stem cells (OE‐MSC) in the collagen hydrogel system, and their osteogenic potential was assessed in vitro and in vivo conditions. Col-lagen type I was composed of four different concentrations of (4 mg/mL, 5 mg/mL, 6 mg/mL, 7 mg/mL). SDS‐Page, FTIR, rheologic test, resazurin assay, live/dead assay, and SEM were used to characterize collagen hydrogels. OE‐MSCs encapsulated in the optimum concentration of collagen hydrogel and transplanted in rat calvarial... 

    In-situ crosslinking of electrospun gelatin-carbodiimide nanofibers: fabrication, characterization, and modeling of solution parameters

    , Article Chemical Engineering Communications ; Volume 208, Issue 7 , 2021 , Pages 976-992 ; 00986445 (ISSN) Hajiabbas, M ; Alemzadeh, I ; Vossoughi, M ; Shamloo, A ; Sharif University of Technology
    Taylor and Francis Ltd  2021
    This work has focused on in-situ crosslinking of gelatin (G) to produce electrospun scaffold with improved fiber morphology retention and mechanical properties. As per this approach, we prepared G nanofibers through mixing G, 1-ethyl-3-(3 dimethylaminopropyl) carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) in the new solvent system. Response surface methodology (RSM) was employed to study the influence of solution parameters on fiber diameter. The morphological structure was examined, and the appropriate level of setting to obtain smooth fibers with a favorable diameter was reported. Results revealed using EDC/NHS for in-situ crosslinking improves the mechanical properties... 

    Nanodiamonds for surface engineering of orthopedic implants: Enhanced biocompatibility in human osteosarcoma cell culture

    , Article Diamond and Related Materials ; Volume: 40 , 2013 , Pages: 107-114 ; 09259635 (ISSN) Mansoorianfar, M ; Shokrgozar, M. A ; Mehrjoo, M ; Tamjid, E ; Simchi, A ; Sharif University of Technology
    Recently, nanodiamonds have attracted interest in biomedical applications such as drug delivery, targeted cancer therapies, fabrication of tissue scaffolds, and biosensors. We incorporated diamond nanoparticles in alginate-bioactive glass films by electrophoretic process to prepare functional coatings for biomedical implants. Turbidity examination by time-resolved laser transmittance measurement revealed that a stable multi-component aqueous suspension of alginate, bioactive glass and diamond particles could be obtained at concentrations of 0.6, 1.3, and 0.65 g/l, respectively. Uniform films with ~ 5 μm thickness were deposited on 316 stainless steel foils by employing constant field... 

    Development of hydroxyapatite nanorods-polycaprolactone composites and scaffolds derived from a novel in-situ sol-gel process

    , Article Tissue Engineering and Regenerative Medicine ; Volume 9, Issue 6 , 2012 , Pages 295-303 ; 17382696 (ISSN) Rezaei, A ; Mohammadi, M. R ; Sharif University of Technology
    Hydroxyapatite (HA) is the most substantial mineral constituent of a bone which displays splendid biocompatibility and bioactivity properties. Nevertheless, its mechanical property is not utmost appropriate for a bone substitution. Therefore, a composite consist of HA and a biodegradable polymer is usually prepared to generate an apt bone scaffold. In the present work polycaprolactone (PCL) was employed as a matrix and hydroxyapatite nanorods were used as a reinforcement element of the composite. HA/PCL nanocomposites were synthesized by a new in-situ sol-gel process using low cost chemicals. Chemical and physical characteristics of the nanocomposite were studied by X-ray diffraction (XRD),... 

    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... 

    Fabrication of a highly ordered hierarchically designed porous nanocomposite via indirect 3D printing: Mechanical properties and in vitro cell responses

    , Article Materials and Design ; Volume 88 , 2015 , Pages 924-931 ; 02641275 (ISSN) Tamjid, E ; Simchi, A ; Sharif University of Technology
    Elsevier Ltd  2015
    Design and development of biodegradable scaffolds with highly uniform and controlled internal structure that stimulate tissue regeneration are the focus of many studies. The aim of this work is to apply a modified three-dimensional (3D) printing process to fabricate polymer-matrix composites with controlled internal architecture. Computationally-designed plaster molds with various pore sizes in the range of 300-800. μm were prepared by employing 3D printing of a water-based binder. The molds were converted to ε-polycaprolactone (PCL) and PCL/bioactive glass (BG) composite scaffolds by solvent casting and freeze drying methods. Optical and electron microscopy studies revealed that the pore... 

    Controlled release of doxorubicin from electrospun PEO/chitosan/graphene oxide nanocomposite nanofibrous scaffolds

    , Article Materials Science and Engineering C ; Volume 48 , March , 2015 , Pages 384-390 ; 09284931 (ISSN) Ardeshirzadeh, B ; Aboutalebi Anaraki, N ; Irani, M ; Roshanfekr Rad, L ; Shamshiri, S ; Sharif University of Technology
    Elsevier Ltd  2015
    Polyethylene oxide (PEO)/chitosan (CS)/graphene oxide (GO) electrospun nanofibrous scaffolds were successfully developed via electrospinning process for controlled release of doxorubicin (DOX). The SEM analysis of nanofibrous scaffolds with different contents of GO (0.1, 0.2, 0.5 and 0.7 wt.%) indicated that the minimum diameter of nanofibers was found to be 85 nm for PEO/CS/GO 0.5% nanofibers. The π-π stacking interaction between DOX and GO with fine pores of nanofibrous scaffolds exhibited higher drug loading (98%) and controlled release of the DOX loaded PEO/CS/GO nanofibers. The results of DOX release from nanofibrous scaffolds at pH 5.3 and 7.4 indicated strong pH dependence. The... 

    Fabrication of PLA/PEG/MWCNT electrospun nanofibrous scaffolds for anticancer drug delivery

    , Article Journal of Applied Polymer Science ; Volume 132, Issue 3 , August , 2015 ; 00218995 (ISSN) Anaraki, N. A ; Rad, L. R ; Irani, M ; Haririan, I ; Sharif University of Technology
    John Wiley and Sons Inc  2015
    In the present study, polylactic acid (PLA)/polyethylene glycol (PEG)/multiwalled carbon nanotube (MWCNT) electrospun nanofibrous scaffolds were prepared via electrospinning process and their applications for the anticancer drug delivery system were investigated. A response surface methodology based on Box-Behnken design (BBD) was used to evaluate the effect of key parameters of electrospinning process including solution concentration, feeding rate, tip-collector distance (TCD) and applied voltage on the morphology of PLA/PEG/MWCNT nanofibrous scaffolds. In optimum conditions (concentration of 8.15%, feeding rate of 0.2 mL/h, voltage of 18.50 kV and TCD of 13.0 cm), the minimum experimental... 

    Thermoplastic starch/ethylene vinyl alcohol/forsterite nanocomposite as a candidate material for bone tissue engineering

    , Article Materials Science and Engineering C ; Volume 69 , 2016 , Pages 301-310 ; 09284931 (ISSN) Mahdieh, Z ; Bagheri, R ; Eslami, M ; Amiri, M ; Shokrgozar, M. A ; Mehrjoo, M ; Sharif University of Technology
    Elsevier Ltd 
    Recently, biodegradable polymers such as starch based blends have been well renowned in the biomedical field. Studies have considered them suitable for bone scaffolds, bone cements, tissue engineering scaffolds, drug delivery systems and hydrogels. The aim of this study was to synthesize nanocomposite biomaterial consisting a blend of thermoplastic starch and ethylene vinyl alcohol as the polymer matrix, and nano-structured forsterite as the ceramic reinforcing phase for bone tissue engineering applications. Furthermore, vitamin E was applied as a thermal stabilizer during melt compounding. Extrusion and injection molding were incorporated for melt blending and shaping of samples,... 

    Biomimetic apatite layer formation on a novel citrate starch scaffold suitable for bone tissue engineering applications

    , Article Starch/Staerke ; Volume 68, Issue 11-12 , 2016 , Pages 1275-1281 ; 00389056 (ISSN) Nourmohammadi, J ; Shahriarpanah, S ; Asadzadehzanjani, N ; Khaleghpanah, S ; Heidari, S ; Sharif University of Technology
    Wiley-VCH Verlag  2016
    The formation of biomimetic bone-like apatite layers throughout the biopolymer-based hydrogel scaffold is an attractive approach in bone tissue engineering. Here, the starch scaffold was prepared using a combination of particulate leaching and freeze-drying techniques. The fabricated structures were then modified by citric acid to investigate the formation of bone-like apatite layer on the porous citrate-based scaffold after soaking in simulated body fluid (SBF). The Fourier Transform Infrared (FTIR) spectra and X-ray diffraction (XRD) patterns revealed that the B-type carbonated apatite has successfully deposited on the scaffold after immersing in SBF for 28 days. Indeed, high chemical...