scholarly journals Extracellular Biofabrication, Characterization, and Antimicrobial Efficacy of Silver Nanoparticles Loaded on Cotton Fabrics Using Newly IsolatedStreptomycessp. SSHH-1E

2016 ◽  
Vol 2016 ◽  
pp. 1-17 ◽  
Author(s):  
Noura El-Ahmady El-Naggar ◽  
Attiya Mohamedin ◽  
Sarah Shawqi Hamza ◽  
Abdel-Dayem Sherief
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Silver Nanoparticles ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Fourier Transform Infrared Spectroscopy ◽  
Fourier Transform Infrared ◽  
Cell Free Supernatant ◽  
Transmission Electron ◽  
Vis Spectroscopy

Biological method for silver nanoparticles synthesis has been developed to obtain cost effective, clean, nontoxic, and ecofriendly size-controlled nanoparticles. The objective of this study is extracellular biosynthesis of antimicrobial AgNPs using cell-free supernatant of a localStreptomycessp. strain SSHH-1E. Different medium composition and fermentation conditions were screened for maximal AgNPs biosynthesis using Plackett-Burman experimental design and the variables with statistically significant effects were selected to study their combined effects and to find out the optimum values using a Box-Behnken design. The synthesized AgNPs were characterized using UV-visible spectroscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and energy dispersive X-ray spectroscopy. Rapid biosynthesis of AgNPs was achieved by addition of 1 mM AgNO3solution to the cell-free supernatant. The produced particles showed a single surface plasmon resonance peak at 400 nm by UV-Vis spectroscopy which confirmed the presence of AgNPs.Streptomycessp. SSHH-1E was identified asStreptomyces narbonensisSSHH-1E. Transmission electron microscopy study indicated that the shape of AgNPs is spherical and the size is ranging from 20 to 40 nm. Fourier transform infrared spectroscopy analysis provides evidence for proteins as possible reducing and capping agents. Furthermore, the biosynthesized AgNPs significantly inhibited the growth of medically important pathogenic Gram-positive and Gram-negative bacteria and yeast. The maximum biosynthesis of AgNPs was achieved at initial pH of 8, peptone of 0.5 g, and inoculum age of 48 h. The statistical optimization resulted in a 4.5-fold increase in the production of AgNPs byStreptomyces narbonensisSSHH-1E.

scholarly journals A Comparative Study of Biosynthesized Silver-Nanoparticles from Citrus maxima Peel, Pulp and Seed: A Special Retrospect for Antimicrobial Activity

2021 ◽  
pp. 454-463
Author(s):  
Priyanka Mishra ◽  
Tanzeel Ahmed ◽  
Lalit Singh
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Silver Nanoparticles ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Fourier Transform Infrared Spectroscopy ◽  
Transmission Electron ◽  
Citrus Maxima ◽  
Uv Visible ◽  
Peel Extract

Background: Silver nanoparticles (AgNPs) have been used in various medicinal products because of its anti-microbial properties. This research study has reported a simplistic, cost effective and eco-friendly method for the synthesis of Silver nanoparticles. Objective: The objective of present study was to compare the synthesis of silver nanoparticles (AgNPs) from various parts of Citrus maxima fruit like pulp, peel and seed. Methodology: The synthesized nanoparticles were characterized by the use of UV-visible spectroscopy, fourier transform infrared spectroscopy and transmission electron microscopy. Time-dependent synthesis of AgNPs was studied spectrophotometrically. UV–visible spectrophotometer was used to confirm the synthesis of AgNPs which showed maximum absorption at 410 nm, 420 nm and 430 nm respectively. Expected Results: Fresh peel extract exhibited the highest concentration of silver nanoparticles in comparison to pulp and seed. Fourier-transform infrared spectroscopy (FTIR) spectra analysis confirmed the presence of possible functional groups in AgNPs which can be responsible for reduction of nanoparticles. Morphological characters of AgNPs were analyzed using transmission electron microscopy (TEM) depicting the particles size as 12.58-47.80 nm. The antibacterial property of synthesized AgNPs was analyzed viz Escherichia coli (MTCC 1687) and Staphylococcus aureus (MTCC 902), specify them to be effective against both gram positive and gram negative bacteria. Conclusion: These results suggested that the fresh peel extract of Citrus maxima is a high-quality bioreductant for the synthesis of silver nanoparticles and have prospective for various biomedical applications.

Synthesis and Characterisation of Hierarchically Porous HZSM-5 as Catalysts for the Synthesis of 2,3,5-Trimethyl-1,4-benzoquinone

2017 ◽  
Vol 70 (6) ◽  
pp. 691 ◽  
Author(s):  
Yu Shen ◽  
Fumin Wang ◽  
Chaoqun Yang ◽  
Xubin Zhang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Fourier Transform Infrared Spectroscopy ◽  
Hierarchical Structure ◽  
N2 Adsorption ◽  
Transmission Electron ◽  
The Hierarchical Structure ◽  
Adsorption Desorption

Hierarchical HZSM-5 were synthesised by controlled desilication in alkaline medium and characterised by field-emission scanning electron microscopy, X-ray diffraction, transmission electron microscopy, inductively coupled plasma–atomic emission spectrometry, N2 adsorption–desorption, and Fourier transform infrared spectroscopy. The catalytic performance of HZSM-5 towards the selective oxidation of 2,3,6-trimethylphenol by H2O2 was evaluated. Recyclability tests were also carried out. The results showed that 2,3,5-trimethyl-1,4-benzoquinone was produced in high yields (i.e. 90 %), corresponding to a 2,3,6-trimethylphenol percentage of 98 %. The N2 adsorption–desorption and XRD studies suggested that mesopores with an average size of 5 nm were produced and that the structural character of HZSM-5 was preserved after desilication. Transmission electron microscopy analysis of the spent catalyst indicated good stability of the hierarchical structure. The Fourier transform infrared spectroscopy studies revealed the development of acid sites. The combined results suggested that the nature of the solvent, intrinsic acidity, and shape selectivity of the hierarchical structure of the catalyst ensured high catalytic properties.

The Aggregation Study and Characterization of Silver Nanoparticles

2017 ◽  
Vol 263 ◽  
pp. 165-169
Author(s):  
Silvia Chowdhury ◽  
Faridah Yusof ◽  
Nadzril Sulaiman ◽  
Mohammad Omer Faruck
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Particle Size ◽  
Silver Nanoparticles ◽  
Absorption Spectrum ◽  
Average Particle Size ◽  
Average Particle ◽  
Transmission Electron ◽  
Vis Spectroscopy

In this article, we have studied the process of silver nanoparticles (AgNPs) aggregation and to stop aggregation 0.3% Polyvinylpyrrolidone (PVP) was used. Aggregation study carried out via UV-vis spectroscopy and it is reported that the absorption spectrum of spherical silver nanoparticles were found a maximum peak at 420 nm wavelength. Furthermore, Transmission Electron Microscopy (TEM) were used to characterized the size and shape of AgNPs, where the average particle size is around 10 to 25 nm in diameter and the AgNPs shape is spherical. Next, Dynamic Light Scattering (DLS) were used, owing to observed size distribution and self-correlation of AgNPs.

scholarly journals Catalytic performance of Ag, Au and Ag-Au nanoparticles synthesized by lichen extract

2018 ◽  
Vol 7 (5) ◽  
pp. 433-440 ◽  
Author(s):  
Zafer Çıplak ◽  
Ceren Gökalp ◽  
Bengü Getiren ◽  
Atila Yıldız ◽  
Nuray Yıldız
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fourier Transform ◽  
Catalytic Activity ◽  
Au Nanoparticles ◽  
Bimetallic Nanoparticles ◽  
Catalytic Performance ◽  
Catalytic Activities ◽  
Transmission Electron ◽  
Vis Spectroscopy

Abstract In the present study, the green chemistry approach for the biosynthesis of Ag, Au and Ag-Au bimetallic nanoparticles (NPs) was applied using lichen extract [Cetraria islandica (L.) Ach.]. The lichen extract acts both as a reducing and stabilizing agent. The monometallic and bimetallic NPs were characterized by transmission electron microscopy (TEM), ultraviolet-visible (UV-Vis) spectroscopy and Fourier transform infrared (FTIR) spectroscopy. The results showed that NPs were successfully synthesized and the prepared structures were generally spherical. The synthesized nanostructures exhibited excellent catalytic activities towards reduction of nitrophenols (4-nitrophenol; 4-NP) to aminophenols (4-aminophenol; 4-AP) with sodium borohydride (NaBH4). It was determined that bimetallic NPs exhibit more effective catalytic activity than monometallic Ag and Au nanostructures. This is the first report on 4-NP reduction with Ag, Au and Au-Ag NP catalysts prepared by lichen extract.

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