scholarly journals Hydrothermal Assisted Biogenic Synthesis of Silver Nanoparticles And Their Anticandidal Activity On Virulent Candida Isolates From COVID-19 Patients

2021 ◽  
Author(s):  
Fatma O Khalil ◽  
Enas M. Ghonaim ◽  
Shimaa Abed El-sattar ◽  
Sally W. Elkhadry ◽  
Hala El-Refai ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Fourier Transforms ◽  
Silver Ions ◽  
Thymus Vulgaris ◽  
Remarkable Change ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Anticandidal Activity

Abstract Till now the exact mechanism and effect of biogenic silver nanoparticles on fungus is an indefinable question. To focus on this issue, we prepared hydrothermal assisted thyme coated silver nanoparticles (T/AgNPs) and their toxic effect on Candida isolates is described. The role of thyme (Thymus Vulgaris) in the reduction of silver ions and stabilization of T/AgNPs are estimated by Fourier transforms infrared spectroscopy, structure and size of present silver nanoparticles were detected via atomic force microscopy as well as high-resolution transmission electron microscopy. The biological activity of T/AgNPs was observed against Candida isolates from COVID-19 Patients. Testing of virulence of Candida species using Multiplex PCR. T/AgNPs proved highly effective against Candida albicans, Candida kruzei, Candida glabrata and MIC values ranging from 156.25 to 1,250 µg/mL and MFC values ranging from 312.5 to 5,000 µg/mL. The structural and morphological modifications due to T/AgNPs on Candida albicans were detected by TEM. It was highly observed that when Candida albicans cells were subjected to 50 and 100 µg/mL T/AgNPs, a remarkable change in the cell wall and cell membrane was observed.

Antimicrobial Activity of Silver Nanoparticles Synthesized by Streptomyces Species JF714876

2012 ◽  
Vol 5 (1) ◽  
pp. 1638-1642 ◽  
Author(s):  
Vidyasagar G M ◽  
Shankaravva B ◽  
R Begum ◽  
Imrose ◽  
Sagar R ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Silver Nanoparticles ◽  
Silver Ions ◽  
Human Beings ◽  
Streptomyces Species ◽  
Force Microscopy ◽  
E Coli ◽  
Extracellular Synthesis ◽  
Atomic Force ◽  
Uv Visible

Microorganisms like fungi, actinomycetes and bacteria are considered nanofactories and are helpful in the production of nanoparticles useful in the welfare of human beings. In the present study, we investigated the production of silver nanoparticles from Streptomyces species JF714876. Extracellular synthesis of silver nanoparticles by Streptomyces species was carried out using two different media. Silver nanoparticles were examined using UV-visible, IR and atomic force microscopy. The size of silver nanoparticles was in the range of 80-100 nm. Antimicrobial activity of silver nanoparticle against bacteria such as E. coli, S. aureus, and dermatophytes like T. rubrum and T. tonsurans was determined. Thus, this study suggests that the Streptomyces sp. JF741876 can produce silver ions that can be used as an antimicrobial substance.

scholarly journals First identification of nanoparticles on thorax, abdomen and wings of the worker bee Apis dorsata Fabricius

2016 ◽  
Vol 60 (1) ◽  
pp. 87-96
Author(s):  
Atanu Bhattacharyya ◽  
Shashidhar Viraktamath ◽  
Fani Hatjina ◽  
Santanu Bhattacharyya ◽  
Bhaktibhavana Rajankar ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Average Diameter ◽  
The Body ◽  
Apis Dorsata ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Calcium Phosphate Nanoparticles ◽  
First Time

Abstract The presence of nanoparticles on the body of the honeybee Apis dorsata Fabricius, was investigated for the first time to better understand the bee’s behaviour. These have been observed by using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and confirmed by Atomic Force Microscopy (AFM). Our study clearly denotes that the Indian rock honey bee Apis dorsata possess calcium silicate and calcium phosphate nanoparticles on its body surface of 5-50 nm in diameter. In particular, the nanoparticles on the abdomen and thorax of A. dorsata have an average diameter of about 10 nanometers and they are smaller than those found on wings of the same bees which are about 20 nanometers. The nanoparticles found are different of the ones previously observed on honey bees or other insects. The origin and role of these natural nanoparticles on the body of the Indian rock bee need to be to be further investigated; more research in the subject might raise important aspects in relation to the conservation of these unique pollinators.

Properties of Silver Nanoparticles Prepared by the Electric Spark Dispersion Method

2013 ◽  
Vol 872 ◽  
pp. 74-78 ◽  
Author(s):  
S.P. Zhuravkov ◽  
Evgeny Plotnikov ◽  
Dmitry Martemiyanov ◽  
Nikolay A. Yavorovsky ◽  
Ulrich Hasse ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Silver Nanoparticles ◽  
Structural Characteristics ◽  
Silver Particles ◽  
Dispersion Method ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Light Scattering Spectroscopy

The morphological and structural characteristics of nanoscale silver particles obtained by the method of electric spark dispersion of metal granules in the liquid aprotic medium were obtained using atomic force microscopy, transmission electron microscopy, and dynamic light scattering spectroscopy. The specific surface, morphology, structure and the distribution by size of the particles are presented.

scholarly journals Chitosan-based silver nanoparticles: A study of the antibacterial, antileishmanial and cytotoxic effects

2016 ◽  
Vol 32 (4) ◽  
pp. 397-410 ◽  
Author(s):  
Douglas dos Santos Lima ◽  
Beatriz Gullon ◽  
Alejandra Cardelle-Cobas ◽  
Lucas M Brito ◽  
Klinger AF Rodrigues ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Bacterial Strains ◽  
Cytotoxic Effects ◽  
Promising Alternative ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Antibacterial Assay ◽  
Microbial Infections ◽  
Marked Activity

Silver nanoparticles have been studied as an alternative for treatment of microbial infections and leishmaniasis, without promoting induction of microbial or parasite resistance. In this study, chitosan-based silver nanoparticles were synthesized from silver nitrate (AgNO3), sodium borohydride as a reducing agent, and the biopolymer chitosan as a capping agent. The chitosan-based silver nanoparticles were characterized by ultraviolet–visible, Fourier transform infrared, dynamic light scattering, zeta potential, atomic force microscopy, and transmission electron microscope. The antibacterial assay was performed by determination of the minimum inhibitory concentration. The antileishmanial and the cytotoxic effects induced by AgNO3, chitosan, and chitosan-based silver nanoparticles were analyzed by resazurin and MTT colorimetric assays, respectively. AgNO3, chitosan, and chitosan-based silver nanoparticles induced a marked activity against all bacterial strains and promastigote forms of Leishmania amazonensis at minimum inhibitory concentrations ranging from 1.69 to 3.38 µg Ag/mL. Interestingly, the chitosan-based silver nanoparticles presented less cytotoxicity than the AgNO3 alone and were more active against L. amazonensis than solely chitosan. Furthermore, the cytotoxic concentrations (CC50) of both chitosan and chitosan-based silver nanoparticles against macrophages were significantly higher than the IC50 against promastigotes. Thus, the chitosan-based silver nanoparticles represent a promising alternative for the treatment of microbial infections and leishmaniasis.

scholarly journals Structural and optical properties of HDPE implanted with medium fluences silver ions

2021 ◽  
Vol 53 (2) ◽  
pp. 187-198
Author(s):  
Milos Nenadovic ◽  
Danilo Kisic ◽  
Miljana Mirkovic ◽  
Snezana Nenadovic ◽  
Ljiljana Kljajevic
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Surface Composition ◽  
Silver Ions ◽  
Surface Region ◽  
Sample Surface ◽  
Phase Imaging ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron

The implantation of high-density polyethylene (HDPE) has been conducted using Ag+ ions with energy of 60 keV, achieved fluences 1.5 and 10?1015 ions/cm2. Transmission electron microscopy (STEM) and field emission gun - scanning electron microscopy (FEG-SEM) showed the existence of nanoparticle clusters. X ray photoelectron spectroscopy (XPS) revealed the presence of silver in the sample surface region. The surface topography was studied by atomic force microscopy (AFM), while the surface composition uniformity was analyzed using phase imaging AFM. Optical characterization obtained by spectroscopic ellipsometry (SE) showed changes in refractive index, extinction coefficient and the optical band gap with the fluence of implanted ions.

Experimental Study of Interaction of Laser Radiation with Silver Nanoparticles in SiO2 Matrix

2006 ◽  
Vol 6 (3) ◽  
pp. 748-755 ◽  
Author(s):  
M. Sendova ◽  
M. Sendova-Vassileva ◽  
J. C. Pivin ◽  
H. Hofmeister ◽  
K. Coffey ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Photoelectron Spectroscopy ◽  
Chemical Characterization ◽  
Laser Wavelength ◽  
Sio2 Matrix ◽  
Transmission Electron Microscopy Micrographs ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron

Thin films of silica containing silver nanoparticles were deposited by magnetron co-sputtering followed by thermal annealing in air or Ar + 2% H2. Laser fragmentation of the particles was carried out at two different wavelengths. The films were characterized by UV-VIS absorption spectroscopy and plasmon resonance numerical modeling based on the Mie theory, together with Rutherford backscattering elemental analysis, X-ray photoelectron spectroscopy chemical characterization, combined with statistical analysis of the transmission electron microscopy micrographs, and surface topography study by atomic force microscopy. It is demonstrated that the fragmentation is a result of a thermal process and its mechanism does not depend on the laser wavelength as long as the laser light is absorbed by the silver particles. Laser treatment with moderate fluences does not alter the precipitated metal content while fragmenting the particles. TEM study indicates that laser assisted silver particle modification can serve as a method for narrowing the particle size distribution.

scholarly journals Photo-Irradiated Biosynthesis of Silver Nanoparticles Using Edible MushroomPleurotus floridaand Their Antibacterial Activity Studies

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Ravishankar Bhat ◽  
Raghunandan Deshpande ◽  
Sharanabasava V. Ganachari ◽  
Do Sung Huh ◽  
A. Venkataraman
Keyword(s):  
Electron Microscopy ◽  
Silver Nanoparticles ◽  
X Ray Diffraction ◽  
Spectroscopy Analysis ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Synthetic Procedure ◽  
Uv Visible

This is a report on photo-irradiated extracellular synthesis of silver nanoparticles using the aqueous extract of edible oyster mushroom (Pleurotus florida) as a reducing agent. The appearance, size, and shape of the silver nanoparticles are understood by UV-visible spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. The X-ray diffraction studies, energy dispersive X-ray analysis indicate that particles are crystalline in nature. Fourier transform infrared spectroscopy analysis revealed that the nanoparticles are covered with biomoieties on their surface. As can be seen from our studies, the biofunctionalized silver nanoparticles thus produced have shown admirable antimicrobial effects, and the synthetic procedure involved is eco-friendly and simple, and hence high range production of the same can be considered for using them in many pharmaceutical applications.

Interfacial Disorder of Graphene Grown at High Temperatures on 4H-SiC(000-1)

2016 ◽  
Vol 858 ◽  
pp. 1129-1132
Author(s):  
Filippo Giannazzo ◽  
Giuseppe Nicotra ◽  
Ioannis Deretzis ◽  
Aurora Piazza ◽  
Gabriele Fisichella ◽  
...  
Keyword(s):  
High Temperatures ◽  
Amorphous Layer ◽  
Force Microscopy ◽  
Annealing Conditions ◽  
Atomic Force ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Disordered Layer ◽  
Electron Energy Loss

This paper presents an investigation of the morphological and structural properties of graphene (Gr) grown on SiC(000-1) by thermal treatments at high temperatures (from 1850 to 1950 °C) in Ar at atmospheric pressure. Atomic force microscopy and micro-Raman spectroscopy showed that the grown Gr films are laterally inhomogeneous in the number of layers, and that regions with different stacking-type (coupled or decoupled Gr films) can coexist in the same sample. Scanning transmission electron microscopy and electron energy loss spectroscopy shoed that a nm-thick C-Si-O amorphous layer is present at the interface between Gr and SiC. Basing on these structural results, the mechanisms of Gr growth on the C-face of SiC under these annealing conditions and the role of this disordered layer in the suppression of epitaxy between Gr and the substrate have been discussed.

scholarly journals Growth of Ag-Nanoparticles: Shape-Directing Role of Silver Ions and Stabilizer in Aqueous Solutions

2010 ◽  
Vol 6 (3) ◽  
pp. 1049-1058
Author(s):  
Zoya Zaheer ◽  
Rafiuddin Rafiuddin
Keyword(s):  
Silver Nanoparticles ◽  
Optical Properties ◽  
Ag Nanoparticles ◽  
Cetyltrimethylammonium Bromide ◽  
Silver Ions ◽  
Average Diameter ◽  
Capping Agent ◽  
Transmission Electron ◽  
Uv Visible

Silver nanoparticles were synthesized using Tulsi leaves extract as reducing as well as a capping agent to reduce the steps and parameters involved in the synthesis. The morphology, stability and optical properties of Ag-nanoparticles depend on reactants and stabilizer, cetyltrimethylammonium bromide (CTAB) concentrations. The silver nanoparticles were characterized by UV-visible spectrophotometer, and transmission electron microscope (TEM). Spherical morphology of the silver nanoparticles with an average diameter of  25 nm. Morphology changed markedly from spherical aggregated to highly polydispersed in presence of CTAB.

scholarly journals Green Synthesis of Silver Nanoparticles from several NTFP Plants

2016 ◽  
Vol 8 (1) ◽  
pp. 106-111
Author(s):  
Somnath BHOWMIK ◽  
Badal Kumar DATTA ◽  
Ajay Krishna SAHA ◽  
Pradyut CHAKMA ◽  
Narayan Chandra MANDAL
Keyword(s):  
Silver Nanoparticles ◽  
Plant Extract ◽  
Silver Ions ◽  
Biological Synthesis ◽  
Synthesis Of Nanoparticles ◽  
Force Microscopy ◽  
Atomic Force ◽  
One Step ◽  
Aqueous Leaf Extract ◽  
Uv Visible

The biological synthesis of nanoparticles using plant extracts plays an important role in the field of nanotechnology. In this study, rapid, simple approach was applied for synthesis of silver nanoparticles using , Clerodendrum infortunatum, Mucuna interrupta, Phlogancanthus thyrsiflorus and Sansevieria trifasciata aqueous leaf extract. The plant extract acts both as reducing agent as well as capping agent. To identify the compounds responsible for reduction of silver ions, the functional groups present in plant extract were investigated by FTIR. Various techniques used to characterize synthesized nanoparticles are Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and UV–Visible spectrophotometer. Results confirmed that this protocol was simple, rapid, one step, eco-friendly, non-toxic and might be an alternative conventional physical/chemical methods. Conversion of silver nanoparticles takes place at room temperature without the involvement of any hazardous chemicals.

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