Publications by authors named "Yasser A Attia"

9 Publications

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Carbon nanotubes catalyzed UV-trigger production of hyaluronic acid from .

Saudi J Biol Sci 2021 Jan 28;28(1):484-491. Epub 2020 Oct 28.

Microbiology Department, Faculty of Agriculture, Cairo University, Giza 12613, Egypt.

Hyaluronic acid (HA) has great importance in biomedical applications. In this work, a novel nanoparticle-based method that stimulates the hyaluronic acid (HA) production by the bacteria subsp. Zooepidemicus has been reported. CNTs with diameters of 40-50 nm and lengths of about 20 mm were used at four different concentrations (0, 10, 25, 50, and 100 μg) to the bacteria and determined the mass of the produced HA in dependence on the exposure time under UV-irradiation. The results clearly showed that the exposure for one minute with low power UV light (254 nm) and 100 µg (CNTs) treatments steadily increased HA production from the control (0.062 g/L) to the highest value (0.992) g/L of HA. The incubation of the streptococci with CNTs led to an increase of the HA production by a factor of 4.23 after 300S exposure time under UV light, whereas the HA production was no significant enhancement under visible light. It is explained that the CNTs nanoparticle-stimulated increase of the HA production with the internalization of the nanoparticles by the bacteria since they "serve as co-enzymes" under induced mutation by UV-irradiation. Transformation process was carried out and showed that the major protein band of was observed in the Streptococcus DH5α. RAPD analysis indicates that the amplified DNA fragments and the percentage of polymorphism was similar between and Streptococcus DH50α. The chemical structure and molecular weight of the photoproduced HA from was similar to the chemical structure of the standard sample.
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http://dx.doi.org/10.1016/j.sjbs.2020.10.032DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7783678PMC
January 2021

Photochromic and fluorescent ink using photoluminescent strontium aluminate pigment and screen printing towards anticounterfeiting documents.

Luminescence 2020 Nov 20. Epub 2020 Nov 20.

Dyeing, Printing and Auxiliaries Department, National Research Centre, Cairo, Egypt.

Novel inorganic-organic hybrid photochromic and fluorescent ink for anticounterfeiting documents was developed using a pigment/resin ink formula enclosing a long-lived luminescent inorganic pigment with good thermal photostability. The produced ink exhibited an optimal excitation wavelength at 360 nm with an absorption colour and fluorescence changes in the printed document. To develop a transparent printed film from pigment/resin ink, the phosphorescent pigment has to be well dispersed physically without agglomeration. The pigment/resin hybrid was applied effectively onto commercial cellulose paper sheets using screen-printing technology. An homogeneous photochromic layer was deposited on cellulose paper document surface to afford a considerable greenish-yellow colour as demonstrated by CIE coloration measurements under a UV lamp, even at a pigment concentration as low as 0.1 wt% of the ink formulation. The printed paper sheets exhibited three excitation bands at 235, 274 and 378 nm and three emission bands at 416, 418 and 436 nm. Fluorescence optical microscopy, Fourier-transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and wavelength-dispersive X-ray fluorescence spectrometry of the printed paper sheet were explored. The screen-printed paper sheets displayed a reversible and fast photochromism during ultraviolet irradiation without fatigue. The rheological properties, stability, and printability of the ink were studied.
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http://dx.doi.org/10.1002/bio.3987DOI Listing
November 2020

Exploring optical spectroscopic techniques and nanomaterials for virus detection.

Saudi J Biol Sci 2021 Jan 27;28(1):78-89. Epub 2020 Aug 27.

Council for Scientific and Industrial Research (CSIR), National Laser Centre, P.O. Box 395, Pretoria 0001, South Africa.

Viral infections pose significant health challenges globally by affecting millions of people worldwide and consequently resulting in a negative impact on both socioeconomic development and health. Corona virus disease 2019 (COVID-19) is a clear example of how a virus can have a global impact in the society and has demonstrated the limitations of detection and diagnostic capabilities globally. Another virus which has posed serious threats to world health is the human immunodeficiency virus (HIV) which is a lentivirus of the retroviridae family responsible for causing acquired immunodeficiency syndrome (AIDS). Even though there has been a significant progress in the HIV biosensing over the past years, there is still a great need for the development of point of care (POC) biosensors that are affordable, robust, portable, easy to use and sensitive enough to provide accurate results to enable clinical decision making. The aim of this study was to present a proof of concept for detecting HIV-1 pseudoviruses by using anti-HIV1 gp41 antibodies as capturing antibodies. In our study, glass substrates were treated with a uniform layer of silane in order to immobilize HIV gp41 antibodies on their surfaces. Thereafter, the HIV pseudovirus was added to the treated substrates followed by addition of anti-HIV gp41 antibodies conjugated to selenium nanoparticle (SeNPs) and gold nanoclusters (AuNCs). The conjugation of SeNPs and AuNCs to anti-HIV gp41 antibodies was characterized using UV-vis spectroscopy, transmission electron microscopy (TEM) and zeta potential while the surface morphology was characterized by fluorescence microscopy, atomic force microscopy (AFM) and Raman spectroscopy. The UV-vis and zeta potential results showed that there was successful conjugation of SeNPs and AuNCs to anti-HIV gp41 antibodies and fluorescence microscopy showed that antibodies immobilized on glass substrates were able to capture intact HIV pseudoviruses. Furthermore, AFM also confirmed the capturing HIV pseudoviruses and we were able to differentiate between substrates with and without the HIV pseudoviruses. Raman spectroscopy confirmed the presence of biomolecules related to HIV and therefore this system has potential in HIV biosensing applications.
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http://dx.doi.org/10.1016/j.sjbs.2020.08.034DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7449958PMC
January 2021

Protective effects of hesperidin against MTX-induced hepatotoxicity in male albino rats.

Naunyn Schmiedebergs Arch Pharmacol 2020 08 26;393(8):1405-1417. Epub 2020 Feb 26.

National Institute of Laser Enhanced Sciences, Cairo University, Giza, 12613, Egypt.

Hesperidin (HD), a bioflavonoid, has been shown to exert hepatoprotective effects. Our aim is to investigate the possible protective effects of HD against methotrexate (MTX) hepatotoxicity in adult male Sprague-Dawley (SD) rats that were divided into four groups (10 rats/each) and were exposed to MTX with or without HD co-administration for consecutive 28 days. The results showed that HD significantly ameliorated MTX-induced increase in liver enzymes and histopathological changes. Hepatic oxidative stress was suppressed by HD, as evidenced by the decrease in malondialdehyde (MDA), with a concomitant increase in total antioxidant activity (TAC), catalase (CAT), and glutathione (GSH) levels. Moreover, co-administration of HD with MTX remarkably upregulated the expression of Nrf2 and HO-1 compared with the MTX group. By the decrease in nuclear factor-kB (NF-κB) pathway and tumor necrosis factor α (TNF-α), HD obviously attenuated inflammatory response in MTX-lesioned livers. Likewise, the downregulation of P53 by HD could explain its antiapoptotic effects as indicated by increase BCl2 and the significant decrease of caspase-9 mRNA expression as compared with the MTX group. Thus, these findings revealed the hepatoprotective nature of HD against MTX hepatotoxicity by attenuating the pro-inflammatory and apoptotic mediators and improving antioxidant aptitude.
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http://dx.doi.org/10.1007/s00210-020-01843-zDOI Listing
August 2020

Morin ameliorates the testicular apoptosis, oxidative stress, and impact on blood-testis barrier induced by photo-extracellularly synthesized silver nanoparticles.

Environ Sci Pollut Res Int 2019 Oct 2;26(28):28749-28762. Epub 2019 Aug 2.

Department of Biochemistry, Faculty of Veterinary Medicine, Zagazig University, Zagazig, 44519, Egypt.

Silver nanoparticles (AgNPs) have been widely produced for different industrial purposes. Recently, biogenic synthesis of AgNPs has emerged although the extent of effects from exposure, oral exposure in particular, to nanomaterials synthesized in such a manner remains elusive. The main objective of this study was to evaluate the effects of oral administration of a dose of 50 mg/Kg body weight AgNPs biosynthesized in baker's yeast (Saccharomyces cerevisiae) over a period of eight weeks on the reproductive performance and the possibility of a protective effect through co-administration of morin. Forty-eight male Sprague-Dawley rats were used in four experimental groups (control, morin-treated group, AgNP-treated, and AgNP + morin co-treatment). AgNPs produced no significant alteration in daily food intake or body weight. Both the absolute and relative testicular weights were significantly reduced but not the epididymal weight. Also, serum levels of urea, creatinine, uric acid, and liver enzymes were significantly elevated. Furthermore, AgNPs significantly downregulated the hypothalamic-pituitary-gonadal axis. This corresponds to lower motility and viability percent, reduced sperm concentration, and a higher abnormality ratio as well as a prominent alteration in the blood-testis barrier (BTB) and testicular histology and induction of testicular apoptosis and oxidative stress. The supplementation of morin evidently restored most of the reproductive characters to its physiological range. We can conclude that exposure to the biologically synthesized AgNPs for an extended period of time has proven to be a health risk that can be ameliorated via oral administration of some bioactive agents including morin.
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http://dx.doi.org/10.1007/s11356-019-06066-1DOI Listing
October 2019

Evaluation of magnetic nanoparticles influence on hyaluronic acid production from Streptococcus equi.

Carbohydr Polym 2018 Jul 19;192:135-142. Epub 2018 Mar 19.

Department of Agricultural Engineering, Faculty of Agriculture, Cairo University, 12613 Giza, Egypt. Electronic address:

This work aims at developing a novel hyaluronic acid (HA) production method using magnetic nanoparticles (NPs). In a separate process, HA was produced with the addition of the amino acids (AA) as bio-additives. Regarding the NPs additives, the results showed that the highest dry weight of the produced HA was 0.264 g/l with the addition of 20 mg/l of FeO NPs. Concerning the AA additives, the results showed that the highest dry weight of the produced HA was 0.079 g/l with the addition of 0.26 g/l of glutamic acid (GA) compared to the control produced 0.065 g/l. These results led to further develop a novel HA production method which is preparing the FeO NPs using GA as stabilizer, where the results showed that dry weight of the produced HA was 0.435 g/l with the addition of 20 mg/l of FeO-GA NPs.
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http://dx.doi.org/10.1016/j.carbpol.2018.03.037DOI Listing
July 2018

Gold nanorod synthesis catalysed by Au clusters.

Faraday Discuss 2016 10 18;191:205-213. Epub 2016 Jul 18.

Instituto de Investigacións Tecnolóxicas & Facultade de Química, Departamento de Química Física, Universidade de Santiago de Compostela, E-15782 Santiago de Compostela, Spain.

Gold nanorods have been successfully synthesized by the seed mediated method using Au clusters. This synthesis does not require silver ions to obtain large amounts of Au nanorods and has good control over their aspect ratio. Au clusters are produced with the same recipe as for Au seeds, but using shorter reaction times. This very simple scheme confirms the important catalytic influence of clusters in the anisotropic growth control.
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http://dx.doi.org/10.1039/c6fd00015kDOI Listing
October 2016

Photostability of gold nanoparticles with different shapes: the role of Ag clusters.

Nanoscale 2015 Jul;7(26):11273-9

Laboratorio de Magnetismo y Nanotecnología, Technological Research Institute, University of Santiago de Compostela, E-15782 Santiago de Compostela, Spain.

Anisotropic gold nanostructures prepared by the seed method in the presence of Ag ions have been used to study their photostability to low-power UV irradiation (254 nm) at room temperature. It has been observed that, whereas spheres are very stable to photoirradiation, rods and prisms suffer from photocorrosion and finally dissolve completely with the production of Au(III) ions. Interpretation of these differences is based on the presence of semiconductor-like Ag clusters, adsorbed onto rods and prisms, able to photocorrode the Au nanoparticles, which are absent in the case of Au spheres. We further show direct evidence of the presence of Ag clusters in Au nanorods by XANES. These results confirm a previous hypothesis (J. Am. Chem. Soc., 2014, 136, 1182-1185) about the major influence of very stable small Ag clusters, not only on the anisotropic formation of nanostructures but also on their photostability.
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http://dx.doi.org/10.1039/c5nr01887kDOI Listing
July 2015

Structure-directing and high-efficiency photocatalytic hydrogen production by Ag clusters.

J Am Chem Soc 2014 Jan 15;136(4):1182-5. Epub 2014 Jan 15.

Physical Chemistry Department, Faculty of Chemistry, and NANOMAG Laboratory, University of Santiago de Compostela , E-15782 Santiago de Compostela, Spain.

H2 production by water splitting is hindered mainly by the lack of low-cost and efficient photocatalysts. Here we show that sub-nanometric silver clusters can catalyze the anisotropic growth of gold nanostructures by preferential adsorption at certain crystal planes of Au seeds, with the result that the final nanostructure can be tuned via the cluster/seed ratio. Such semiconducting Ag clusters are extremely stable and retain their electronic structure even after adsorption at the tips of Au nanorods, enabling various photocatalytic experiments, such as oxygen evolution from basic solutions. In the absence of electron scavengers, UV irradiation generates photoelectrons, which are stored within the nanorods, increasing their Au Fermi level up to the redox pinning limit at 0 V (RHE), where hydrogen evolution occurs with an estimated high efficiency of 10%. This illustrates the considerable potential of very small zerovalent, nonmetallic clusters as novel atomic-level photocatalysts.
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http://dx.doi.org/10.1021/ja410451mDOI Listing
January 2014