Loading...
Search for: alginate
0.007 seconds
Total 112 records

    Removal of phenols from wastewater with encapsulated horseradish peroxidase in calcium alginate

    , Article Engineering Letters ; Volume 17, Issue 4 , 2009 ; 1816093X (ISSN) Alemzadeh, I ; Nejati, S ; Vossoughi, M ; Sharif University of Technology
    2009
    Abstract
    Horseradish peroxidase was encapsulated in calcium alginate for the purpose of phenol removal. Upon immobilization, pH profile of enzyme activity changes as it shows higher value at basic and acidic solution. Investigation into time course of phenol removal for both encapsulated and free enzyme showed that encapsulated enzyme had nearly similar efficiency in comparison with the same concentration of free enzyme; however the capsules were reusable up to four cycles without any changes in their retention activity  

    Partially hydrolyzed crosslinked alginate-graft-polymethacrylamide as a novel biopolymer-based superabsorbent hydrogel having pH-responsive Properties [electronic resource]

    , Article Macromolecular Research ; January 2005, Volume 13, Issue 1, pp 45-53 Pourjavadi, A. (Ali) ; Aminfazl, M. S ; Hosseinzadeh, H
    Abstract
    In this study, a series of highly swelling hydrogels based on sodium alginate (NaAlg) and polymethacrylamide (PMAM) was prepared through free radical polymerization. The graft copolymerization reaction was performed in a homogeneous medium and in the presence of ammonium persulfate (APS) as an initiator andN,N′-methylenebisacrylamide (MBA) as a crosslinker. The crosslinked graft copolymer, alginate-graft-polymethacrylamide (Alg-g-PMAM), was then partially hydrolyzed by NaOH solution to yield a hydrogel, hydrolyzed alginate-graft-polymethacrylamide (H-Alg-g-PMAM). During alkaline hydrolysis, the carboxamide groups of Alg-g-PMAM were converted into hydrophilic carboxylate anions. Either the... 

    Removal of phenols with encapsulated horseradish peroxidase in calcium alginate

    , Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 28, Issue 2 , 2009 , Pages 43-49 ; 10219986 (ISSN) Alemzadeh, I ; Nejati, S ; Sharif University of Technology
    2009
    Abstract
    Horseradish peroxidase was encapsulated in calcium alginate for the purpose of phenol removal. Considering enzyme encapsulation efficiency, retention activity and enzyme leakage of the capsules, the best gelation condition was found to be 1 % w/v of sodium alginate solution and 5.5 % w/v of calcium chloride hexahydrate. Upon immobilization, pH profile of enzyme activity changes as it shows higher value at basic and acidic solution. Besides, for each phenol concentration there would be an enzyme concentration which going further than this value has no significant effect on phenol removal. Investigation into time course of phenol removal for both encapsulated and free enzyme showed that... 

    Effects of sucrose, skim milk and yeast powder on survival of lactobacillus rhamnosus gg encapsulated with alginate during one-week storage at room conditions

    , Article Applied Food Biotechnology ; Volume 9, Issue 3 , 2022 , Pages 251-259 ; 23455357 (ISSN) Khodadadi, P ; Tabandeh, F ; Alemzadeh, I ; Soltani, M ; Sharif University of Technology
    National Nutrition and Food Technology Research Institute  2022
    Abstract
    Background and Objective: During the manufacture and storage of probiotic products, there are always possibilities that probiotics be exposed to harmful stresses such as high temperature, low pH, various osmotic pressures and high oxygen levels, which can decrease the number of living cells. Encapsulation is one of the methods used to protect living cells such as probiotic bacteria from environmental challenges. Up-to-date, various compounds with abilities to protect bacteria during freeze-drying and to increase viability during storage have been identified. In this study, alginate with calcium chloride was used to encapsulate probiotic bacteria using extrusion method. Then, effects of... 

    Survivability and oxidative stability of co-microencapsulated L. Plantarum PTCC 1058 and DHA as a juice carrier

    , Article Food Bioscience ; Volume 32 , 2019 ; 22124292 (ISSN) Vaziri, A. S ; Alemzadeh, I ; Vossoughi, M ; Sharif University of Technology
    Elsevier Ltd  2019
    Abstract
    Lactobacillus Plantarum PTCC 1058 bacteria and DHA-rich oil were microencapsulated together or individually in an optimized alginate-pectin-gelatin biocomposite hydrogel. The survivability of L. plantarum and oxidative stability of DHA were evaluated using simulated gastrointestinal (SGI) conditions and 4 wk storage in commercial orange juice at 4 and 25 °C. The results showed that the multilayer biocomposite had significant influence on the stability of the microcapsules in terms of survivability of probiotic bacteria and oxidative stability of DHA with SGI conditions and storage at 4 and 25 °C compared to the free cells. Incorporation of probiotic bacteria and DHA showed the synergistic... 

    Full-polysaccharide superabsorbent hydrogels based on carboxymethylcellulose and sodium alginate

    , Article Journal of Polymer Materials ; Volume 23, Issue 1 , 2006 , Pages 61-69 ; 09738622 (ISSN) Hosseinzadeh, H ; Pourjavadi, A ; Madhavinia, G. R ; Sharif University of Technology
    2006
    Abstract
    A novel full-polysaccharide superabsorbent hydrogel was synthesized via chemical crosslinking of carboxymethylcellulose (CMC) and sodium alginate (Alg) using epichlorohydrine (ECH) as a crosslinker. A proposed mechanism for hydrogel formation was suggested and the structure of the product was established using FTIR spectroscopy. The influence of ECH concentration and Alg/CMC weight ratio as well as reaction time and temperature on water and saline (0.9 wt% NaCl) absorbency of the hydrogels were systematically investigated. Meanwhile, the overall activation energy for the crosslinking reaction between CMC and Alg polysaccharides was estimated to be 11.6 kj/mol. Under the optimised conditions... 

    Phenols removal by immobilized horseradish peroxidase

    , Article Journal of Hazardous Materials ; Volume 166, Issue 2-3 , 2009 , Pages 1082-1086 ; 03043894 (ISSN) Alemzadeh, I ; Nejati, S ; Sharif University of Technology
    2009
    Abstract
    Application of immobilized horseradish peroxidase (HRP) in porous calcium alginate (ca-alginate) for the purpose of phenol removal is reported. The optimal conditions for immobilization of HRP in ca-alginate were identified. Gelation (encapsulation) was optimized at 1.0% (w/v) sodium alginate in the presence of 5.5% (w/v) of calcium chloride. Upon immobilization, pH profile of enzyme activity changes as it shows higher value at basic and acidic solution. Increasing initial phenol concentration results in a decrease in % conversion. The highest conversion belongs to phenol concentration of 2 mM. Investigation into time course of phenol removal for both encapsulated and free enzymes showed... 

    Fabrication of a magnetic alginate-silk fibroin hydrogel, containing halloysite nanotubes as a novel nanocomposite for biological and hyperthermia applications

    , Article Scientific Reports ; Volume 12, Issue 1 , 2022 ; 20452322 (ISSN) Eivazzadeh Keihan, R ; Sadat, Z ; Aghamirza Moghim Aliabadi, H ; Ganjali, F ; Kashtiaray, A ; Salimi Bani, M ; Komijani, S ; Ahadian, M. M ; salehpour, N ; Ahangari Cohan, R ; Maleki, A ; Sharif University of Technology
    Nature Research  2022
    Abstract
    In this study, the main focus was on designing and synthesizing a novel magnetic nanobiocomposite and its application in hyperthermia cancer treatment. Regarding this aim, sodium alginate (SA) hydrogel with CaCl2 cross-linker formed and modified by silk fibroin (SF) natural polymer and halloysite nanotubes (HNTs), followed by in situ Fe3O4 magnetic nanoparticles preparation. No important differences were detected in red blood cells (RBCs) hemolysis, confirming the high blood compatibility of the treated erythrocytes with this nanobiocomposite. Moreover, the synthesized SA hydrogel/SF/HNTs/Fe3O4 nanobiocomposite does not demonstrate toxicity toward HEK293T normal cell line after 48 and 72 h.... 

    Preparation of Gelatin-Alginate Hydrogel for Using as Cell Culture Scaffold

    , M.Sc. Thesis Sharif University of Technology Fadaodini, Samira (Author) ; Mashayekhan, Shohreh (Supervisor) ; Maghsoudi, Vida (Supervisor)
    Abstract
    Hydrogels are polymeric three-dimensional networks able to swell in the presence of an aqueous medium. Hydrogels from natural proteins and polysaccharides are ideal scaffolds for tissue engineering since they resemble the extracellular matrices of tissue comprised of various amino acids and sugar-based macromolecules.The biocompatible and biodegradable hydrogel scaffolds are promising materials for tissue engineering. Here, we report a new class of hydrogels derived from oxidized alginate (OA) and gelatin. The prepared oxidized alginate was shown to be efficient in crosslinking gelatin, leading to hydrogel formation. The effect of degree of oxidation and concentration of OA on the mechanical... 

    Adsorption Of Uranium from Phosphoric acid and Waste Water with Microcapsules Contains Selective Extractants

    , M.Sc. Thesis Sharif University of Technology Tayebi, Ahmad (Author) ; Ghofrani, Mohammad Bagher (Supervisor) ; Khanchi, Alireza (Supervisor) ; Outokesh, Mohammad (Co-Advisor)
    Abstract
    Uptake characteristics of alginate microcapsules containing D2EHPA/TOPO for adsorption of uranium from industrial effluent were examined using batch, stirred and column method .stable alginate microcapsules in dried form was developed by immobilizing of D2EHPA/TOPO in porous matrix of calcium alginate. Characteristics of microcapsules were carrying out by destructive chemical analysis, BET, SEM and TG .the synthesized microcapsules showed a good column properties and high selectivity and reusability. In addition, isotherm adsorption of calcium alginate and microcapsules were fitted with frendlich's equation .the microcapsules also demonstrated that, the uptake percentage was constantly high... 

    Granulated copper oxide nano-catalyst: A novel and efficient catalyst for C-N cross-coupling of amines with iodobenzene

    , Article Monatshefte fur Chemie ; Volume 142, Issue 8 , 2011 , Pages 801-806 ; 00269247 (ISSN) Ahmadi, S. J ; Sadjadi, S ; Hosseinpour, M ; Abdollahi, M ; Sharif University of Technology
    Abstract
    Nano-structured CuO granules catalyze the C-N cross-coupling of amines with iodobenzene in excellent yields. The reaction is simple, efficient, and operates in air under ligand-free conditions  

    Optimization of l-asparaginase immobilization onto calcium alginate beads

    , Article Chemical Engineering Communications ; Volume 204, Issue 2 , 2017 , Pages 216-220 ; 00986445 (ISSN) Bahraman, F ; Alemzadeh, I ; Sharif University of Technology
    Taylor and Francis Ltd  2017
    Abstract
    In this study, anti-leukemic enzyme L-asparaginase (E.C.3.5.1.1) from Escherichia coli ATCC 11303 was modified by the microencapsulation technique onto calcium alginate beads. Using response surface methodology (RSM), a three-level full factorial design, the values of concentration of sodium alginate, concentration of calcium chloride, and enzyme loading were investigated to obtain the highest residual L-asparaginase (L-ASNase) activity % (immobilized enzyme activity/free enzyme activity). The effects of the studied factors on immobilization were evaluated The predicted values by the model were close to the experimental values, indicating suitability of the model. The results presented that... 

    Removal of Cu (ll) from industrial wastewater using poly (acrylamide-co-2-acrylamide-2-methyl propane sulfonic acid)/graphene oxide/sodium alginate hydrogel: Isotherm, kinetics, and optimization study

    , Article Journal of Water Process Engineering ; Volume 42 , 2021 ; 22147144 (ISSN) Pishnamazi, M ; Ghasemi, S ; Khosravi, A ; ZabihiSahebi, A ; Hasan Zadeh, A ; Borghei, S. M ; Sharif University of Technology
    Elsevier Ltd  2021
    Abstract
    Here, Graphene oxide/poly (acrylamide -2-acrylamide-methyl-propanesulfonic acid)/sodium alginate (GO/PA-AMPS/SA) hydrogel was synthesized through a free-radical polymerization approach. The impact of Graphene Oxide (GO) content on mechanical strength, swelling behavior, and the adsorption performance of prepared hydrogel was studied. The operating parameters, including contact time, solution pH, and initial Cu(II) content on the adsorption capacity of the hydrogel, were studied. The maximum Cu(II) adsorption capacity of 230.8 mg/g was obtained for GO/PA-AMPS/SA under a pH of 5, the contact time of 270 min, and adsorbent content of 0.5 g/L at 25 °C. The high value of adsorption capacity after... 

    Investigating the effects of precursor concentration and gelling parameters on droplet-based generation of Ca-Alginate microgels: identifying new stable modes of droplet formation

    , Article Materials Today Chemistry ; Volume 24 , 2022 ; 24685194 (ISSN) Besanjideh, M ; Rezaeian, M ; Mahmoudi, Z ; Shamloo, A ; Kazemzadeh Hannani, S ; Sharif University of Technology
    Elsevier Ltd  2022
    Abstract
    Droplet-based microfluidics is an attractive approach for producing microgels due to its high potential to control the size and shape of the particles and precisely entrap the substances within the hydrogel matrix. However, the microfluidic generation of monodisperse microgels with desired structures is still challenging. Indeed, the rheological and interfacial properties of the immiscible fluids, as well as the adopted gelling strategy, play important roles in microfluidic methods. Herein, sodium alginate droplets with different concentrations are generated via a microfluidic device with a flow-focusing unit. Besides, a combined in situ and ex situ strategy is optimized to crosslink sodium... 

    Three-dimensional bioprinting of functional skeletal muscle tissue using gelatin methacryloyl-alginate bioinks

    , Article Micromachines ; Volume 10, Issue 10 , 2019 ; 2072666X (ISSN) Seyedmahmoud, R ; Çelebi Saltik, B ; Barros, N ; Nasiri, R ; Banton, E ; Shamloo, A ; Ashammakhi, N ; Dokmeci, M. R ; Ahadian, S ; Sharif University of Technology
    MDPI AG  2019
    Abstract
    Skeletal muscle tissue engineering aims to fabricate tissue constructs to replace or restore diseased or injured skeletal muscle tissues in the body. Several biomaterials and microscale technologies have been used in muscle tissue engineering. However, it is still challenging to mimic the function and structure of the native muscle tissues. Three-dimensional (3D) bioprinting is a powerful tool to mimic the hierarchical structure of native tissues. Here, 3D bioprinting was used to fabricate tissue constructs using gelatin methacryloyl (GelMA)-alginate bioinks. Mechanical and rheological properties of GelMA-alginate hydrogels were characterized. C2C12 myoblasts at the density 8 × 106 cells/mL... 

    Potential effects of alginate–pectin biocomposite on the release of folic acid and their physicochemical characteristics

    , Article Journal of Food Science and Technology ; Volume 57, Issue 9 , March , 2020 , Pages 3363-3370 Kiaei Pour, P ; Alemzadeh, I ; Vaziri, A. S ; Beiroti, A ; Sharif University of Technology
    Springer  2020
    Abstract
    Potential effects of folates on the treatment of several human diseases like cognitive function, neural tube defects, coronary heart disease and certain kinds of cancers have been discovered. However, the stability of folic acid against adverse conditions is a great concern. The present study investigates various alginate (A)–pectin (P) gastrointestinal-resistant hydrogel to immobilize folic acid. This involves evaluating different compositions of alginate–pectin to achieve higher encapsulation efficiency and stability during simulated gastric (SG) and simulated intestinal (SI) conditions. Coated alginate hydrogels with pectin resulted significant (p < 0.05) better protection of folic acid... 

    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
    Abstract
    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.... 

    Human Cells Separation Via Imprinted Polymer

    , M.Sc. Thesis Sharif University of Technology Sabaghi, Davood (Author) ; Abdekhodaie, Mohammad Jafar (Supervisor)
    Abstract
    The goal of this research is to elucidate the mechanism of Cell recognition in molecularly imprinted polymers (MIPs) using already utilized techniques. Our approach employs a more flexible non-covalent imprinting method which starts from a readily available polymer and utilizes an aqueous environment for both MIP synthesis and testing. Cell MIPs against MG-63 cell were synthesized. The synthesis procedure was optimized to obtain better binding characteristics to the targeted cell. Adsorption of target cell onto imprinted Alginate Spheres was facilitated by these macromolecular fingerprints as revealed by various microscopical examinations The imprinted Spheres showed high selectivity toward... 

    Folic Acid Microencapsulation

    , M.Sc. Thesis Sharif University of Technology Kiaeipour, Pegah (Author) ; Alemzadeh, Iran (Supervisor)
    Abstract
    Most natural folate derivatives are highly sensitive to temperature, oxygen and light and their stability depends on food process condition. Alginate and pectin were evaluated for folic acid encapsulation and increasing its stability. By combining them and optimising encapsulation condition the efficiency was enhanced up to 90% . Furthermore, using polymers in combined form caused decrease in folic acid leakage from capsules in acidic condition of stomach. First of all, the time of encapsulation was measured which was 140-180 minutes. In this study the effect of Calcium Chloride concentration on encapsulation was studied. Therefore, two variables were selected which were pectin to algine... 

    Optimization of Asparaginase Immobilization on Carrier

    , M.Sc. Thesis Sharif University of Technology Bahraman, Fatemeh (Author) ; Alemzadeh , Iran (Supervisor) ; Kazemi, Akhtarolmolok (Supervisor)
    Abstract
    The enzyme L-asparaginase (L-asparagine amidohydroxylase , EC 3.5.1.1) is utilizable in the treatment of acute childhood lymphoblastic leukaemia. L-asparaginase catalyses the hydrolysis of the amino acid L- asparagines to L-aspartic acid and ammonia. Unlike normal cells,malignant cells which can only slowly synthesize L-asparagine , are killed by lacking exogenous supply. In contrast, normal cells are protected from Asn-starvation due to their ability to produce this amino acid.
    In this study , L- asparaginase from E.coli, was immobilized onto a polymeric compound, poly(vinyl alcohol)(PVA) with cross-linking agent glutaraldehyde and calcium alginate beads .. Herein ,with the use of the...