A nano silver-xerogel (Ag nps@modified TEOS) as a newly developed nanocatalyst in the synthesis of benzopyranopyrimidines (with secondary and primary amines) and gem-bisamides

2017 ◽  
Vol 46 (21) ◽  
pp. 7039-7050 ◽  
Author(s):  
Gurpreet Kour ◽  
Monika Gupta
Keyword(s):  
Silver Nanoparticles ◽  
Chemical Reduction ◽  
Primary Amines ◽  
Ag Nps ◽  
Nano Silver ◽  
Reduction Approach

Silver nanoparticles have been prepared from a chemical reduction approach and supported on modified TEOS (tetraethylorthosilicate) xerogel to be studied as a nanocatalyst.

scholarly journals Size Control of Synthesized Silver Nanoparticles by Simultaneous Chemical Reduction and Laser Fragmentation in Origanum majorana Extract: Antibacterial Application

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2326
Author(s):  
Entesar Ali Ganash ◽  
Reem Mohammad Altuwirqi
Keyword(s):  
Silver Nanoparticles ◽  
Irradiation Time ◽  
Chemical Reduction ◽  
Size Control ◽  
Reduction Process ◽  
Laser Wavelength ◽  
X Ray Diffraction ◽  
Ag Nps ◽  
Transmission Electron ◽  
Origanum Majorana

In this work, silver nanoparticles (Ag NPs) were synthesized using a chemical reduction approach and a pulsed laser fragmentation in liquid (PLFL) technique, simultaneously. A laser wavelength of 532 nm was focused on the as produced Ag NPs, suspended in an Origanum majorana extract solution, with the aim of controlling their size. The effect of liquid medium concentration and irradiation time on the properties of the fabricated NPs was studied. While the X-ray diffraction (XRD) pattern confirmed the existence of Ag NPs, the UV–Vis spectrophotometry showed a significant absorption peak at about 420 nm, which is attributed to the characteristic surface plasmon resonance (SPR) peak of the obtained Ag NPs. By increasing the irradiation time and the Origanum majora extract concentration, the SPR peak shifted toward a shorter wavelength. This shift indicates a reduction in the NPs’ size. The effect of PLFL on size reduction was clearly revealed from the transmission electron microscopy images. The PLFL technique, depending on experimental parameters, reduced the size of the obtained Ag NPs to less than 10 nm. The mean zeta potential of the fabricated Ag NPs was found to be greater than −30 mV, signifying their stability. The Ag NPs were also found to effectively inhibit bacterial activity. The PLFL technique has proved to be a powerful method for controlling the size of NPs when it is simultaneously associated with a chemical reduction process.

scholarly journals Interaction of Pulses of Different Duration with Chemically Prepared Silver Nanoparticles: Analysis of Optical Nonlinearities

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Ke Zhang ◽  
Rashid A. Ganeev ◽  
Konda Srinivasa Rao ◽  
Sandeep Kumar Maurya ◽  
Ganjaboy S. Boltaev ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Nonlinear Absorption ◽  
Nonlinear Optical ◽  
Reduction Method ◽  
Chemical Reduction ◽  
Nonlinear Refraction ◽  
Optical Nonlinearities ◽  
Chemical Reduction Method ◽  
Ag Nps ◽  
Picosecond Pulses

The nonlinear optical properties of the aqueous solutions of silver nanoparticles (Ag NPs) prepared by chemical reduction method are analyzed using femtosecond and picosecond pulses at different wavelengths. In the case of 800 and 400 nm, the growths of nonlinear absorption and nonlinear refraction with the increase of Ag NP concentration, as well as a change at the signs of nonlinear optical processes, are determined. The nonlinear absorption coefficient and nonlinear refractive index of Ag NP solutions measured using picosecond pulses were a few orders of magnitude larger than those in the case of femtosecond probe pulses. We also demonstrate the optical limiting properties of Ag NPs using 800 nm, 60 fs pulses.

scholarly journals Fabrication, Characterization, and Antibacterial Properties of Electrospun Membrane Composed of Gum Karaya, Polyvinyl Alcohol, and Silver Nanoparticles

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Vinod Vellora Thekkae Padil ◽  
Nhung H. A. Nguyen ◽  
Alena Ševců ◽  
Miroslav Černík
Keyword(s):  
Electron Microscopy ◽  
Silver Nanoparticles ◽  
Polyvinyl Alcohol ◽  
Food Packaging ◽  
Chemical Reduction ◽  
Antibacterial Properties ◽  
Hydroxyl Groups ◽  
Ag Nps ◽  
Gum Karaya ◽  
Nanofiber Membranes

Gum karaya (GK), a natural hydrocolloid, was mixed with polyvinyl alcohol (PVA) at different weight ratios and electrospun to produce PVA/GK nanofibers. An 80 : 20 PVA/GK ratio produced the most suitable nanofiber for further testing. Silver nanoparticles (Ag-NPs) were synthesised through chemical reduction of AgNO3(at different concentrations) in the PVA/GK solution, the GK hydroxyl groups being oxidised to carbonyl groups, and Ag+cations reduced to metallic Ag-NPs. These PVA/GK/Ag solutions were then electrospun to produce nanofiber membranes containing Ag-NPs (Ag-MEMs). Membrane morphology and other characteristics were analysed using scanning electron microscopy coupled with energy dispersive X-ray analysis, transmission electron microscopy, and UV-Vis and ATR-FTIR spectroscopy. The antibacterial activity of the Ag-NP solution and Ag-MEM was then investigated against Gram-negativeEscherichia coliandPseudomonas aeruginosaand Gram-positiveStaphylococcus aureus. Our results show that electrospun nanofiber membranes based on natural hydrocolloid, synthetic polymer, and Ag-NPs have many potential uses in medical applications, food packaging, and water treatment.

scholarly journals Subinhibitory concentrations of silver nanoparticles and silver nitrate on the adaptative and cross-resistance to antibiotics on bovine mastitis pathogens

2021 ◽  
Vol 51 (12) ◽  
Author(s):  
Patrícia Érica Fernandes ◽  
Roberta Barbosa Teodoro Alves ◽  
Natan de Jesus Pimentel-Filho ◽  
João Paulo Natalino de Sá ◽  
Hilário Cuquetto Mantovani ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Silver Nitrate ◽  
Chemical Reduction ◽  
Bovine Mastitis ◽  
Cross Resistance ◽  
Ag Nps ◽  
Adaptive Resistance ◽  
Subinhibitory Concentrations ◽  
Mastitis Pathogens ◽  
Sensitivity Profile

ABSTRACT: Biocides and/or antibiotics used in subinhibitory concentrations can promote the development of adaptive resistance or even cross-resistance in microorganisms. However, studies on these responses following silver treatments are scarce in the literature. Silver-based compounds, including silver nanoparticles (Ag-NPs), can be an alternative in the prevention and treatment of bovine mastitis. Thus, this research evaluated the effect of subinhibitory dosages of Ag-NPs and Ag+ ions from silver nitrate (AgNO3) on Staphylococcus aureus and Escherichia coli isolated from milk of cows with mastitis. Ag-NPs were synthesized by chemical reduction using AgNO3 and sodium citrate and the minimum inhibitory concentration (MIC) of Ag-NPs and Ag+ ions on the mastitis pathogens were determined. Isolates were exposed to subinhibitory concentrations of Ag-NPs or AgNO3 for 10 consecutive days to verify the development of adaptive resistance evaluated by changes in the MIC values. The development of cross-resistance with antibiotics was also studied, being verified by comparing the sensitivity profile of treated cells with non-treated cells. AgNO3 was more effective against all isolates. There was no change in the MIC values or in the antibiotic sensitivity profile for both bacteria following consecutive exposure to subinhibitory dosages of Ag-NPs or AgNO3, indicating that silver was not able to select adaptive resistance or cross resistance to the tested antibiotics. The potential of silver presented by these results is favorable to the continuity of studies aiming to elaborate silver-based therapies for the treatment of bovine mastitis.

scholarly journals Photo-induced chemical reduction of silver bromide to silver nanoparticles

2011 ◽  
Vol 9 (6) ◽  
pp. 982-989 ◽  
Author(s):  
Agnieszka Król-Gracz ◽  
Ewa Michalak ◽  
Piotr Nowak ◽  
Agnieszka Dyonizy
Keyword(s):  
Silver Nanoparticles ◽  
Chemical Reduction ◽  
Silver Bromide ◽  
Molar Ratio ◽  
Efficient Production ◽  
Ag Nps ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Nanoparticle Suspensions ◽  
Actinic Radiation

AbstractThis paper discusses the experimental results of the production of nanocolloidal silver using photoreduction method. Ultrafine crystalline gelatine-stabilised aqueous suspensions of silver bromide were used as a substrate for the synthesis of silver nanoparticles (Ag NPs). The influences of the reductant to substrate molar ratio, the medium’s pH, the type of the source of actinic radiation and the time of exposure to the efficient production of the Ag NPs were studied. A typical reaction was suggested, which involves the photo-induced reduction of silver bromide nanocrystals in the presence of ascorbic acid under specified physicochemical conditions. The properties of resultant silver particles were examined using UV-Vis spectroscopy and Dynamic Light Scattering (DLS). In addition, Transmission Electron Microscopy (TEM) was used for imaging the silver nanoparticle suspensions.

scholarly journals Artificial Intelligence in Numerical Modeling of Silver Nanoparticles Prepared in Montmorillonite Interlayer Space

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Parvaneh Shabanzadeh ◽  
Norazak Senu ◽  
Kamyar Shameli ◽  
Maryam Mohaghegh Tabar
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Silver Nanoparticles ◽  
Reaction Temperature ◽  
Chemical Reduction ◽  
Size Control ◽  
Design Parameters ◽  
Ag Nps ◽  
Factors Affecting ◽  
Artificial Neural

Artificial neural network (ANN) models have the capacity to eliminate the need for expensive experimental investigation in various areas of manufacturing processes, including the casting methods. An understanding of the interrelationships between input variables is essential for interpreting the sensitivity data and optimizing the design parameters. Silver nanoparticles (Ag-NPs) have attracted considerable attention for chemical, physical, and medical applications due to their exceptional properties. The nanocrystal silver was synthesized into an interlamellar space of montmorillonite by using the chemical reduction technique. The method has an advantage of size control which is essential in nanometals synthesis. Silver nanoparticles with nanosize and devoid of aggregation are favorable for several properties. In this investigation, the accuracy of artificial neural network training algorithm was applied in studying the effects of different parameters on the particles, including the AgNO3concentration, reaction temperature, UV-visible wavelength, and montmorillonite (MMT) d-spacing on the prediction of size of silver nanoparticles. Analysis of the variance showed that the AgNO3concentration and temperature were the most significant factors affecting the size of silver nanoparticles. Using the best performing artificial neural network, the optimum conditions predicted were a concentration of AgNO3of 1.0 (M), MMT d-spacing of 1.27 nm, reaction temperature of 27°C, and wavelength of 397.50 nm.

scholarly journals Use of Pluronic P103 Triblock Copolymer as Structural Agent during Synthesis of Hybrid Silver Nanoparticles

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Nancy Tepale ◽  
Víctor V. A. Fernández-Escamilla ◽  
Eric Flores-Aquino ◽  
Manuel Sánchez-Cantú ◽  
Adan Luna-Flores ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Triblock Copolymer ◽  
Chemical Reduction ◽  
Critical Micellar Concentration ◽  
Soft Template ◽  
Ag Nps ◽  
Uniform Size ◽  
Transmission Electron ◽  
Measuring Surface ◽  
Dilute Aqueous Solutions

Dilute aqueous solutions of triblock copolymer Pluronic P103 were used to synthesize silver nanoparticles (Ag-NPs) by chemical reduction of silver nitrate (AgNO3) with sodium borohydride (NaBH4). This copolymer was used as a structural agent since monomers act as a stabilizer and micelles act as nanoreactors for nucleation and growth of Ag-NPs. The growth of the nanoparticles (NPs) was monitored by UV-visible spectroscopy on the basis of measuring surface plasmon resonance absorption over a temperature range of 25 to 70°C. Shape and size of hybrid silver/P103 nanomaterials were tuned by varying the micellar structure of Pluronic P103 using a simple synthesis procedure. Dynamic Light Scattering (DLS) and Transmission Electron Microscopy (TEM) were used to study the size and shape of the hybrid nanomaterials. It was observed that Ag-NPs synthesized without Pluronic P103 at 25°C exhibited a great variety of sizes. However, when Pluronic P103 was used below its critical micellar concentration (CMC), spherical-shaped Ag-NPs with uniform size were formed, suggesting that the copolymer had a stabilizing effect. On the other hand, when Ag-NPs were prepared with Pluronic P103 above the CMC, NPs with similar sizes as the micelles were detected, suggesting that the copolymer functioned as a nanoreactor. Furthermore, as temperature reached 35°C, oval-shaped micelles were formed and small NPs were incorporated into the crown of the micelles. Independent Ag-NPs were not observed since they used the surface of the micelles as a soft template. Therefore, it was possible to obtain tiny Ag-NPs with homogeneous size.

scholarly journals Low-Cost Synthesis and Characterization of Silver Nanoparticles for Diverse Sensing Application

2019 ◽  
Vol 9 (2) ◽  
pp. 3915-3917
Author(s):  
S. Akhtar ◽  
Z. Farid ◽  
H. Ahmed ◽  
S. A. Khan ◽  
Z. N. Khan
Keyword(s):  
Silver Nanoparticles ◽  
Chemical Reduction ◽  
Low Cost ◽  
Industrial Applications ◽  
X Ray Diffraction ◽  
Ag Nps ◽  
X Ray ◽  
Wide Range ◽  
Range Of Functions

Silver (Ag) nanoparticles (NPs) are synthesized and characterized by a low-cost chemical reduction method. Silver nanoparticles (Ag NPs) have pre-occupied the consideration of the scientific community due to their wide range of functions, utility and industrial applications, particularly in the fields of sensing technologies and medicine (particularly their efficiency against microbes, the ability of healing the wound and anti-inflammatory properties). Ag NPs are synthesized by a low-cost fabrication method. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray diffraction (EDX) and photometry techniques are used in this work to identify their nature and potentiality for diverse applications in sensing technologies.

scholarly journals Economic Perspective in the Production of Silver Nanoparticles on the Bacterial Cellulose Membrane as Antibacterial Material

2019 ◽  
Vol 4 (1) ◽  
pp. 17
Author(s):  
Asep NANDIYANTO
Keyword(s):  
Silver Nanoparticles ◽  
Economic Evaluation ◽  
Large Scale ◽  
Raw Materials ◽  
Chemical Reduction ◽  
Ideal Condition ◽  
Cellulose Membrane ◽  
Scale Production ◽  
Ag Nps ◽  
Large Scale Production

Silver nanoparticles (Ag NPs) are the most frequently studied material with superiority as antibacterial that currently increasing the production of Ag NPs. Hence, feasibility study is needed for the development on the production of Ag NPs in industrial scale, especially in Indonesia and other developing countries. The chemical reduction with sodium citrate is used to produce Ag NPs. The purpose of this study is to analysis the prospect of large-scale industrial production in engineering perspective and economic evaluation. This study also gave recommendations for profitability of the production. Perspective of engineering in the production gave information about capability of large-scale production because the easy process and low-cost apparatuses of production can be done. Various economic parameters were used to completed the analysis. Then, the ideal condition to the worst issues of production was estimated to completed the calculation of economic evaluation by effects of raw materials. From this study, those all parameters gave positive result which mean it has good profitability. However, further analysis of strategies in sales and investment must be done in the future to developing the production of Ag NPs that promising in capability on large-scale production.

scholarly journals Effect of Silver Nanoparticles on Fluorescence Intensity of Fluoreseina Dye Mixed in One Solution

2021 ◽  
Vol 19 (51) ◽  
pp. 54-63
Author(s):  
Ruwaida Tahseen Shbeeb ◽  
Sarmed S. Mahdi ◽  
Sabreen A. Khalaf
Keyword(s):  
Silver Nanoparticles ◽  
Fluorescence Intensity ◽  
Chemical Reduction ◽  
Metal Nanoparticle ◽  
Metal Nanostructures ◽  
Enhanced Fluorescence ◽  
Ag Nps ◽  
Study Results ◽  
Layer Coating ◽  
Dye Solutions

Metal enhanced fluorescence (MEF) is an unequaled phenomenon of metal nanoparticle surface plasmons, when light interacts with the metal nanostructures (silver nanoparticles) which result electromagnetic fields to promote the sensitivity of fluorescence. This work endeavor to study the influence of silver nanoparticles on fluorescence intensity of Fluoreseina dye by employment mixture solution with different mixing ratio. Silver nanoparticles had been manufactured by the chemical reduction method so that Ag NP layer coating had been done by hot rotation liquid method. The optical properties of the prepared samples (mixture solution of Fluoreseina dye solutions and colloidal solution with 5 minutes prepared of Ag NPs) tested by using UV-VIS absorption and Fluorescence spectrophotometer. by using AFM, SEM testes, the structure of silver nanoparticles had been estimated. the result of this work showed that adding Ag NPs colloidal to Fluoreseina dye solution help get a significant increase in the fluorescence intensity of this dye. this study results show that its significant to recent related studies in MEF.

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