scholarly journals Stabilization of Silver Nanoparticles by Cationic Aminoethyl Methacrylate Copolymers in Aqueous Media—Effects of Component Ratios and Molar Masses of Copolymers

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1647 ◽  
Author(s):  
Mikhailova ◽  
Senchukova ◽  
Lezov ◽  
Gubarev ◽  
Trützschler ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Analytical Ultracentrifugation ◽  
Silver Salt ◽  
Aqueous Media ◽  
Reducing Agent ◽  
Methacrylate Copolymers ◽  
Vis Spectroscopy ◽  
Cationic Copolymers ◽  
Consistent Information ◽  
Scanning Electron

The ability of aminoethyl methacrylate cationic copolymers to stabilize silver nanoparticles in water was investigated. Sodium borohydride (NaBH4) was employed as a reducing agent for the preparation of silver nanoparticles. The objects were studied by ultraviolet-visible (UV-vis) spectroscopy, dynamic light scattering (DLS), analytical ultracentrifugation (AUC) and scanning electron microscopy (SEM). Formation of nanoparticles in different conditions was investigated by varying ratios between components (silver salt, reducing agent and polymer) and molar masses of copolymers. As a result, we were successful in obtaining nanoparticles with a relatively narrow size distribution that were stable for more than six months. Consistent information on nanoparticle size was obtained. The holding capacity of the copolymer was studied.

scholarly journals GREEN TECHNOLOGY MEDIATED SYNTHESIS OF SILVER NANOPARTICLES FROM MOMORDICA CHARANTIA FRUIT EXTRACT AND ITS BACTERICIDAL ACTIVITY

2017 ◽  
Vol 10 (3) ◽  
pp. 196 ◽  
Author(s):  
S C Joshi ◽  
Utkarsh Kaushik ◽  
Aproova Upadhyaya ◽  
Priyanka Sharma
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Silver Nanoparticles ◽  
Atomic Force Microscope ◽  
Momordica Charantia ◽  
Diffusion Method ◽  
Fruit Extract ◽  
Atomic Force ◽  
Vis Spectroscopy ◽  
Scanning Electron

ABSTRACTObjective: The synthesis of nanoparticles from biological processes is evolving a new era of research interests in nanotechnology. Silver nanoparticlesare usually synthesized by chemicals and physical method, which are quite toxic and flammable in nature. This study deals with an environmentfriendly biosynthesis process of antibacterial silver nanoparticles using Momordica charantia fruit.Methods: AgNO3 (5 mM) was allowed to react with fruit extract of M. charantia. Biosynthesis of AgNPs was optimized by changing temperature,pH, and solvent. The silver nanoparticles so formed were characterized using ultraviolet-visible (UV-VIS) spectroscopy, Fourier transform infraredspectroscopy (FTIR), dynamic light scattering (DLS), atomic force microscope (AFM), and scanning electron microscopy (SEM).Results: UV-VIS spectra show absorption peak between 420 and 430 nm. The FTIR analysis showed the alcoholic, lactam, and nitro group presentin the plant extract, which were responsible for the reduction in AgNPs. The SEM images showed the size distribution of the nanoparticles and theaverage size was found to be 50-100 nm. By DLS analysis and AFM analysis, average sizes of the silver nanoparticles were of 150 nm. The results ofthese analyses confirmed the formation of silver nanoparticles. Silver nanoparticles were tested against Bacillus cereus and Staphylococcus epidermidisstrains using disc diffusion method and were found to be effective.Conclusion: Silver nanoparticles so synthesized in this study using fruit extract of M. charantia are simple, easy, and effective technique of nanoparticlesproduction.Keywords: Silver nanoparticles, Momordica charantia, Optimization, Antibacterial, Atomic force microscope, Scanning electron microscopy.

On the Influence of Silver Nanoparticles Size in the Electrical Conductivity of PEDOT: PSS

2010 ◽  
Vol 644 ◽  
pp. 85-90 ◽  
Author(s):  
Rebeca G. Melendez ◽  
Karla J. Moreno ◽  
Ivana Moggio ◽  
Eduardo Arias ◽  
Arturo Ponce ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Particle Size ◽  
Silver Nanoparticles ◽  
Reducing Agent ◽  
Molar Ratio ◽  
Plasmon Band ◽  
Vis Spectroscopy

In this paper, we studied the influence of the silver nanoparticles size on the electrical conductivity of PEDOT:PSS in Ag(PEDOT:PSS) films. The silver nanoparticles were synthesized in presence of PEDOT:PSS by varying the molar ratio between AgNO3 and the reducing agent (NaBH4). Both the particle size determined by TEM and the plasmon band obtained by UV-Vis spectroscopy were found to be strongly dependent on the reducing agent concentration. The electrical conductivity increases inversely with the concentration of reducing agent from 5.24 x 10-4 up to 1.63 S/cm; three orders of magnitude higher than pristine PEDOT:PSS.

Synthesis and characterization of silver nanoparticles using as a reducing agent plant extract of Dandelion (Taraxacun officianale)

2019 ◽  
pp. 11-17
Author(s):  
Lidia Meléndez-Balbuena ◽  
Eric Reyes-Cervantes ◽  
Blanca Martha Cabrera-Vivas ◽  
Maribel Arroyo
Keyword(s):  
Silver Nanoparticles ◽  
Plant Extract ◽  
Plant Extracts ◽  
Low Cost ◽  
Coli Strain ◽  
Reducing Agent ◽  
Force Microscopy ◽  
Yellow Color ◽  
Golden Yellow ◽  
Vis Spectroscopy

The objective of this work was to synthesize the synthesis of silver nanoparticles using as a reducing agent of ionic silver the plant extract of Dandelion (Taraxacun officianale), vegetable of high availability and low cost, as an alternative to the processes conventional, based on the antioxidant capacity of plant extracts that reduce metals in solution. The nanoparticles prepared by this method were characterized by the golden yellow color characteristic of silver nanoparticle solutions. Measurements with UV-Vis spectroscopy of aqueous solutions of Ag1 + ions after coming into contact with plant extracts of Dandelion at different pHs showed an intense absorption band around 400-450 nm, characteristic of the resonance of the Plasmon of silver nanoparticles. Through the scanning of the samples by means of AFM (atomic force microscopy), morphological information of the nanoparticles is obtained, from 3D topographic images of them, such as distribution, size and shape of the silver nanoparticles. Finally, its antibacterial activity was tested against the Escherichia coli strain.

scholarly journals Efficient synthesis of plant-mediated silver nanoparticles and their screening for antimicrobial activity

2017 ◽  
Vol 4 (3) ◽  
pp. 143-150 ◽  
Author(s):  
Kamlesh Shukla ◽  
Bhoopander Giri ◽  
Rashmi Dwivede
Keyword(s):  
Antimicrobial Activity ◽  
Silver Nanoparticles ◽  
Silver Nitrate ◽  
Color Change ◽  
Bacterial Species ◽  
Nitrate Solution ◽  
Reducing Agent ◽  
Curvularia Lunata ◽  
Synthesis Of Nanoparticles ◽  
Vis Spectroscopy

Now days, the development of safe, cost effective, reliable and eco-friendly processes for the synthesis of nanoparticles is an important aspect of nanotechnology. Among the various agents, plants show immense potential for the synthesis of nanoparticles. The bio-molecules found in plants induce reduction of Ag+ ions from silver nitrate to silver nanoparticles (AgNPs); therefore, in the present work, the aqueous leaves extract of the plant was used as reducing agent for the synthesis of silver nanoparticles. We synthesized extracellular silver nanoparticles using extract of the leaves of four different medicinal plants which act as a reducing agent at room temperature. The characteristic color change was observed on addition of plant extract to the silver nitrate solution due to their specific properties (Surface Plasmon Resonance). UV-Vis spectroscopy was used for the characterization of the silver nanoparticles. Green synthesized nanoparticles are evaluated for their antimicrobial activity against the Gram-positive and Gram-negative bacteria as well as two pathogenic fungi Aspergillus fumigatus and Curvularia lunata. The silver nanoparticles (SNPs) of selected plant parts have shown more toxicity towards bacterial species than that of the fungal species. Comparing with simple plant extracts, the SNPs exhibited greater antimicrobial efficacy and advantage over conventional antibiotics to which these microorganisms usually impart resistance.

scholarly journals Highly Antibacterial Activity Against Methicillin-resistant Staphylococcus aureus of Silver Nanoparticles Synthesized by Citrus maxima Peel Extract

2021 ◽  
Author(s):  
Thu Ha Bui ◽  
Ngoc Dai Nghia Tran ◽  
Phung Anh Nguyen ◽  
Nhat Linh Duong ◽  
Van Minh Nguyen ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Silver Nanoparticles ◽  
Antibacterial Activity ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Average Diameter ◽  
Reducing Agent ◽  
Face Centered Cubic ◽  
Methicillin Resistant ◽  
Vis Spectroscopy ◽  
Citrus Maxima

Abstract A cost-effective and green technique was performed for the synthesis of silver nanoparticles (AgNPs) from a plant resource using Citrus maxima peel (CMP) extract as a reducing agent. The formation of AgNPs was confirmed by UV-Vis Spectroscopy at the wavelength range of 400−500 nm. The optimized conditions for the AgNPs synthesis using CMP extract as a reducing agent were determined. At these conditions, the X-ray diffraction (XRD) and the high-resolution transmission electron microscopy (HRTEM) results revealed the face-centered cubic structure of AgNPs had a highly crystalline with the particle size in a range of 10−20 nm. The Fourier transform infrared spectroscopy (FT-IR) demonstrated the presence of flavonoid, terpenoid, phenolic, and glycosides in phytochemical compositions of CMP extract which can act as the reducing agents for AgNPs formation. The antibacterial effect of the AgNPs was evaluated against Methicillin-resistant Staphylococcus aureus (MRSA) by implementing the minimum inhibitory concentration (MIC), minimum batericidal concentration (MBC), and the zone of inhibition tests. The AgNPs exhibited effective antibacterial activity against bacteria with an average diameter of inhibition zones of 11.7 mm, the MIC of 8.27 µg/mL, and the MBC of the 16.54 µg/mL.

scholarly journals Enhancement of Photoconductive Detector Based on Carbon Nanotubes Decorated with Silver Nanoparticles by Adding Conductive Polymer

2021 ◽  
Vol 19 (50) ◽  
pp. 84-93
Author(s):  
Taqwa Yousif ◽  
Asama Naje
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Scanning Electron Microscopy ◽  
Silver Nanoparticles ◽  
Forward Bias ◽  
X Ray Diffraction ◽  
Ag Nps ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Scanning Electron

In this work, wide band range photo detector operating in UV, Visible and IR was fabricated using carbon nanotubes (MWCNTs, SWCNTs) decorated with silver nanoparticles (Ag NPs). Silicon was used as a substrate to deposited CNTs/Ag NPs by the drop casting technique. Polyamide nylon polymer was used to coat CNTs/Ag NPs to enhance the photo-response of the detector. The electro-exploding wire technology was used to synthesize Ag NPs. Good dispersion of silver NPs achieved by a simple chemistry process on the surface of CNTs. The optical, structure and electrical characteristic of CNTs decorated with Ag NPs were characterized by X-Ray diffraction and Field Emission Scanning Electron Microscopy.  X-ray diffraction patterns of Ag NPs exhibited 2θ values (38.1°,44.3°) corresponding to the Ag nanocrystal, while the XRD pattern of MWCNTs and SWCNTs /Ag NPs peaks appeared at 2θ = 26.2° corresponding to the (002) and at 2theta=44° which corresponds with miller indices (100) for CNTs and (200) for Ag NPs. The optical properties measured by UV-Vis. Spectroscopy. Broad and strong surface plasmon resonance (SPR) peak was detected at 420 nm, for Ag NPs. The absorption of CNTs/Ag NPs increased significantly from UV to near IR region (300-1000 nm).  Ag NPs decorated CNTs without any impurities, according to field mission scanning electron microscopy examination, with typical particle sizes of (50-80nm) for Ag-NPs, 44nm for MWCNTs/Ag-NPs, and 30nm for SWCNTs/Ag NPs. ֹThe I-V characteristics at forward bias voltage (0.5-10) volt were studied. The figure of merits (responsivity, photocurrent gain, NEP and detectivity) after coating with polymer of the detector were measured in the dark and after illumination with UV LED (365 nm), Tungsten lamp (500-800 nm) and Laser diode (808 nm).

scholarly journals Silver Nanoparticles Obtained by Semicontinuous Chemical Reduction Using Carboxymethyl Cellulose as a Stabilizing Agent and Its Antibacterial Capacity

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
M. A. Pedroza-Toscano ◽  
S. López-Cuenca ◽  
M. Rabelero-Velasco ◽  
E. D. Moreno-Medrano ◽  
A. P. Mendizabal-Ruiz ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Carboxymethyl Cellulose ◽  
Chemical Reduction ◽  
Weight Ratio ◽  
Visible Spectrum ◽  
Reducing Agent ◽  
Diffusion Method ◽  
Disk Diffusion Method ◽  
E Coli ◽  
Vis Spectroscopy

Preparation of silver nanoparticles was carried out by semicontinuous reduction of Ag+ ions at low temperatures. Silver nitrate was used as the Ag0 precursor, the carboxymethyl cellulose (CMC) as stabilizer and primary reducing agent, and sodium borohydride as reducing agent. Weight ratios of 1 : 1 and 1 : 2 of AgNO3 : CMC were used for carrying out the reactions. Silver nanoparticles were characterized by UV-VIS spectroscopy, transmission electronic microscopy (TEM), and X-ray diffraction (XRD). The formation of silver nanoparticles was confirmed by XRD spectroscopy and by the presence of an absorption peak around 400 nm in the UV-visible spectrum. Unimodal size distributions of spheroidal nanoparticles were observed by TEM. Greater productivities than those reported by other authors were obtained with the advantage of using a lower temperature and minor reaction times. By using a higher CMC/AgNO3 weight ratio or a higher concentration of AgNO3, AgNPs with larger average size were produced. Antibacterial activity of AgNPs against S. aureus and E. coli was determined by the agar disk diffusion method. The higher the AgNPs concentration, the larger the inhibition zone. The minimum inhibitory concentration (MIC) of AgNPs against S. aureus and E. coli was 5 μg/disk.

Green Synthesis of Silver Nanoparticles for Control of Biodeterioration

2014 ◽  
Vol 1618 ◽  
pp. 241-246 ◽  
Author(s):  
M.A. Martínez Gómez ◽  
M.C. González Chávez ◽  
J.C. Mendoza Hernández ◽  
R. Carrillo González
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Silver Nanoparticles ◽  
Cultural Heritage ◽  
Green Synthesis ◽  
Biological Synthesis ◽  
Vis Spectroscopy ◽  
Heritage Buildings ◽  
Biofilm Development ◽  
Scanning Electron

ABSTRACTChemical and biological deterioration of surfaces of historic constructions is one of the main causes of destruction of cultural heritage buildings. Effective techniques are searched in order to control the biofilm development of cultural heritage without damaging the environment. Nanotechnology is an emerging option with several applications, including those for improving stability and corrosion resistance in surfaces. Production of nanomaterials from organic nature or green synthesis offers ecological advantages such as low environmental impact. This paper proposes the use of silver nanoparticles of biological synthesis as an alternative for control of microorganisms that cause biodeterioration. The present study highlights the effect of these nanoparticles in the inhibition of bacterial growth. These particles were produced by biological synthesis with Tecoma stans L. extracts. Their characterization included analysis UV / Vis spectroscopy, scanning electron microscopy (SEM) and particle size distribution.

scholarly journals Green Synthesis of Silver Nanoparticles Using Apple Extract and Its Antibacterial Properties

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Zainal Abidin Ali ◽  
Rosiyah Yahya ◽  
Shamala Devi Sekaran ◽  
R. Puteh
Keyword(s):  
Silver Nanoparticles ◽  
Green Synthesis ◽  
Color Change ◽  
Antibacterial Properties ◽  
Reducing Agent ◽  
X Ray Diffraction ◽  
Gram Positive Bacteria ◽  
Clean Synthesis ◽  
Vis Spectroscopy ◽  
Ag Crystallites

Silver nanoparticles (AgNPs) were synthesized using apple extract as a reducing agent and aqueous silver nitrate as the precursor. The AgNPs formation was observed as a color change of the mixture from colorless to dark-brownish. The X-ray diffraction pattern confirmed the presence of only Ag crystallites, and the dynamic light scattering estimates the average sizes of the AgNPs to be 30.25 ± 5.26 nm. Furthermore, Fourier Transform Infrared as well as UV-vis spectroscopy identifies ethylene groups as the reducing agent and capping agent for the formation of the AgNPs. This green synthesis provides an economic, eco-friendly, and clean synthesis route to AgNPs. AgNPs in suspension showed activity against Gram-negative and Gram-positive bacteria with minimum bactericidal concentrations (MBCs) to be in the range from 125 μg/mL to 1000 μg/mL.

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