Time filter

Source Type

Fouda M.M.G.,King Saud University | Fouda M.M.G.,National Research Center of Egypt | El-Aassar M.R.,Institute of Advanced Technology and New Material | Al-Deyab S.S.,King Saud University
Carbohydrate Polymers | Year: 2013

A facile method to synthesize silver nanoparticles (AgNPs) using carboxymethyl chitosan (CMCTS), which act as reducing agent for silver ions as well as protecting agent for the formed AgNPs, is reported. CMCTS embedded AgNPs are mixed with polyethylene oxide (PEO). The blend polymers containing AgNPs are electrospun resulting in blend nano-fiber mats. The formation of AgNPs has been confirmed using UV-vis and TEM. The diameter range of 12-18 nm of well-dispersed AgNPs with a concentration of 100 ppm was obtained. The electrospun mats are characterized using SEM, EDX as well as TGA. Antimicrobial activity against different species of pathogenic/nonpathogenic; Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853 and Escherichia coli ATCC 25922 in addition to the fungus Candida albicans ATCC 10231 was studied. The results show excellent antimicrobial activity compared with nanofibers without AgNPs and AgNPs alone. © 2012 Elsevier Ltd.


El-Aassar M.R.,Institute of Advanced Technology and New Material | Fouda M.M.G.,King Saud University | Fouda M.M.G.,National Research Center of Egypt | Kenawy E.-R.,Tanta University
Advances in Polymer Technology | Year: 2013

Electrospinning has been recognized as a feasible process for fabrication of continuous fibers with diameters ranging from several micrometers to a few nanometers. In the present study, electrospinning of acrylonitrile (AN) and methyl methacrylate (MMA) copolymer in tetrahydrofuran (THF) solvent has been investigated. Poly(AN-co-MMA) nanofiber was modified and functionalized through introducing terminal amine groups by polyethyleneimine (PEI). Factors affecting the functionalizing process such as the PEI concentration and incubation time with PEI have been studied. Its influence on the amount of the coupled amine group in the nanofibers. PEI, with the highest concentration of amino groups, has been used as a carrier in a number of industrial immobilized bio-systems. The poly(AN-co-MMA) nanofibers were characterized by scanning electron microscopy, thermal characterization, and FT-IR spectroscopic analysis, before and after the functionalization process © 2012 Wiley Periodicals, Inc.


AbdElhafez S.E.,Alexandria University | AbdElhafez S.E.,Institute of Advanced Technology and New Material | El-Shazly A.H.,Alexandria University | El-Maghraby A.,Institute of Advanced Technology and New Material
Desalination and Water Treatment | Year: 2016

This work investigates the possibility of improving the solar heat recovery from copper–water nanofluids using a micro heat exchanger. This micro heat exchanger consisted of double brass tubes with a micro annular space. The effect of nanoparticles addition to the base fluid and its flow rate on the heat transfer characteristics and heating rate for both nanofluids in solar simulator section and water in shell side of micro heat exchanger were studied. The nanofluids was forced to flow in the tube side, while the fluid in the shell side was pure water. The effect of copper (Cu) weight fraction in nanofluids and the flow rate of nanofluids on the heat transfer coefficient (h), overall heat transfer coefficient (U), thermal resistance (R), and heating rate for both nanofluids in heating section and cold water in micro heat exchanger were studied. Four different concentrations of nanofluids in the range 0.01–0.1 wt.% had been used. The flow rate of nanofluids was changed in laminar region using a control valve. The temperature of heated nanofluids varied from 22 to 73°C. The heat transfer and overall heat transfer coefficients of the nanofluids 0.1 wt.% were found to increase by 49.9 and 42.08%, respectively, when it was compared with pure water. Also to be increased by increasing the nanofluid flow rate. Also, it was observed that the weight fraction has no significant effect on the final temperature of the nanofluid exit from heating section. © 2016 Balaban Desalination Publications. All rights reserved.


El-Aassar M.R.,King Saud University | El-Aassar M.R.,Institute of Advanced Technology and New Material | Al-Deyab S.S.,King Saud University | Kenawy E.-R.,Tanta University
Journal of Applied Polymer Science | Year: 2013

Immobilization of β-galactosidase in poly (acrylonitrile-co-methyl methacrylate) poly (AN-co-MMA) Nanofibers was studied by electrospinning, and a spacer-arm i.e., (Polyethyleneimine (PEI)) was covalently attached by the reaction of carbonyl groups of Poly (AN-co-MMA) nanofibers. β-galactosidase was then covalently immobilized through the spacer-arm of the Poly (AN-co-MMA) nanofibers by using glutaraldehyde (GA) as a coupling agent. Nanofibers mode of interaction was proven by FTIR and thermal gravimetric analysis and supported by morphological changes recognized through SEM examination. Factors affecting the modification process such as PEI concentration, reaction time, and reaction temperature have been studied. Its influence on the amount of coupled PEI was consequently correlated to the changes of the catalytic activity and the retained activity of immobilized enzyme, the main parameters judging the success of the immobilization process. Evidences of Poly (AN-co-MMA) nanofibers modification were extracted from morphological changes recognized through SEM examination. The maximum activity (V max) and michaelis constant (K m) of immobilized enzyme were found to be 8.8 μmole/min mg protein and 236.7 mM, respectively. Stabilities of the immobilized β-galactosidase were obviously improved. The optimum temperature for β-galactosidase immobilized on the spacer-arm attached nanofiber was 5°C higher than that of the free enzyme and was also significantly broader. The immobilized β-galactosidase had better resistance to temperature inactivation than did the free form. © 2012 Wiley Periodicals, Inc.


Fouda M.M.G.,King Saud University | Fouda M.M.G.,National Research Center of Egypt | El-Aassar M.R.,Institute of Advanced Technology and New Material | El Fawal G.F.,Institute of Advanced Technology and New Material | And 4 more authors.
International Journal of Biological Macromolecules | Year: 2015

Biopolymer composite film containing k-carrageenan (KC), polyvinyl pyrrolidone (PVP), and polyethylene glycol (PEG) was formulated by dissolving KC and PVP in water containing PEG. Silver nanoparticles (AgNPs), was produced by Honeybee and added to solution. Finally, all solutions were poured onto dishes and dried overnight at 40. °C to form the final films. Tensile strength (TS) and elongation (. E %) is evaluated. The water contact angle is inspected. Thermal properties (TGA) and swelling behavior for water were considered. Fungal activity is also examined. Morphology of all films was also explored using scanning electron microscope. AgNPs induced significant hydrophilicity to KC-PVP-PEG film with contact angle of 41.6 and 34.7 for KC-PVP-PEG-AgNPs. Films with AgNPs exhibited higher thermal stability and strength properties than other films without. Films with AgNPs explore lower swelling behavior than other films without. Both SEM and EDX proved the deposition of AgNPs on the surface of films. Films with AgNPs showed higher activity against pathogenic fungi compared with the chemical fungicide; fluconazole. © 2014 Elsevier B.V.


El-Aassar M.R.,Institute of Advanced Technology and New Material
Journal of Molecular Catalysis B: Enzymatic | Year: 2013

β-Galactosidase from Aspergillus oryzae was immobilized on amino functionalized poly (Acrylonitrile-co-Methyl methacrylate) poly (AN-co-MMA) nanofibers using glutaraldehyde. Among the four different factor used for activation, the activation of poly (AN-co-MMA) nanofibers by glutaraldehyde followed by covalent enzyme on activated support could stabilize the enzyme β-galactosidase and was found to be effective. Different factors affecting the activation process were investigated and their impact on the activity and the retention of immobilized enzyme's activity was monitored. Concentration of glutaraldehyde and activation temperature, time, and activation pH were found of a determined effect. The optimum concentration, reaction time, reaction temperatures, and activation pH value of glutaraldehyde are 5.0, 180 min, 65 °C and 11.0, respectively. The scanning electron micrographs showed the change on the poly (AN-co-MMA) nanofibers surface revealing the successful immobilization of β-galactosidase. Thermal and pH stabilities were found to be increased upon immobilization. The immobilized β-galactosidase had better resistance to temperature and pH inactivation than did the free form. Finally, the immobilized β-galactosidase retained 35% of its initial activity when stored at 4 °C for 70 days and retained 64% of its initial activity after ten consecutive reactor batch cycles. © 2012 Elsevier B.V. All rights reserved.


El-Aassar M.R.,Institute of Advanced Technology and New Material | Hafez E.E.,Egyptian Plant Protection Res Institute | El-Deeb N.M.,Genetic Engineering And Biotech Institute | Fouda M.M.G.,King Saud University | Fouda M.M.G.,National Research Center of Egypt
International Journal of Biological Macromolecules | Year: 2014

Hepatocellular carcinoma (HCC) is considered as one of the most aggressive cancer worldwide. In Egypt, the prevalence of HCC is increasing during last years. Recently, drug-loaded microparticles were used to improve the efficiency of various medical treatments. This study is designed to evaluate the anticancer potentialities of lectins against HCC while hinting to its safety usage. The aim is also extended to encapsulate lectins in alginate microbeads for oral drug delivery purposes. The extracted lectins showed anti-proliferative effect against HCC with a percentage of 60.76% by using its nontoxic dose with an up-regulation of P53 gene expression. Concerning the handling of lectin alginate microbeads for oral drug delivery, the prepared lectin alginate beads were ~100. μm in diameter. The efficiency of the microcapsules was checked by scanning electron microscopy, the SEM showed the change on the alginate beads surface revealing the successful lectin encapsulation. The release of lectins from the microbeads depended on a variety of factors as the microbeads forming carriers and the amount-encapsulated lectins. The Pisum sativum extracted lectins may be considered as a promising agent in controlling HCC and this solid dosage form could be suitable for oral administration complemented with/or without the standard HCC drugs. © 2014 Elsevier B.V.


El-Aassar M.R.,Institute of Advanced Technology and New Material | Hafez E.E.,Egyptian Plant Pathology Research Institute | Fouda M.M.G.,King Saud University | Fouda M.M.G.,National Research Center of Egypt | Al-Deyab S.S.,King Saud University
Applied Biochemistry and Biotechnology | Year: 2013

Nanotechnology is expected to open some new aspects to fight and prevent diseases using atomic-scale tailoring of materials. The main aim of this study is to biosynthesize silver nanoparticles (AgNPs) using Trichoderma viride (HQ438699); the metabolite of this fungus will help either in reduction of the silver nitrate-adding active materials which will be loaded on the surface of the produced AgNPs. Poly(acrylonitrile-co-methyl methacrylate) copolymer (poly (AN-co-MMA)) was grafted with the prepared AgNPs. The poly(AN-co-MMA)/AgNPs were examined against ten different pathogenic bacterial strains, and the result was compared with another four different generic antibiotics. The produced poly(AN-co-MMA)/AgNPs showed high antibacterial activity compared with the four standard antibiotics. Moreover, the grafting of these AgNPs into the copolymer has potential application in the biomedical field. © 2013 Springer Science+Business Media New York.


PubMed | Egyptian Plant Protection Res Institute, King Saud University, Institute of Advanced Technology and New Material and National Research Center of Egypt
Type: | Journal: International journal of biological macromolecules | Year: 2015

Biopolymer composite film containing k-carrageenan (KC), polyvinyl pyrrolidone (PVP), and polyethylene glycol (PEG) was formulated by dissolving KC and PVP in water containing PEG. Silver nanoparticles (AgNPs), was produced by Honeybee and added to solution. Finally, all solutions were poured onto dishes and dried overnight at 40C to form the final films. Tensile strength (TS) and elongation (E %) is evaluated. The water contact angle is inspected. Thermal properties (TGA) and swelling behavior for water were considered. Fungal activity is also examined. Morphology of all films was also explored using scanning electron microscope. AgNPs induced significant hydrophilicity to KC-PVP-PEG film with contact angle of 41.6 and 34.7 for KC-PVP-PEG-AgNPs. Films with AgNPs exhibited higher thermal stability and strength properties than other films without. Films with AgNPs explore lower swelling behavior than other films without. Both SEM and EDX proved the deposition of AgNPs on the surface of films. Films with AgNPs showed higher activity against pathogenic fungi compared with the chemical fungicide; fluconazole.

Loading Institute of Advanced Technology and New Material collaborators
Loading Institute of Advanced Technology and New Material collaborators