scholarly journals Synthesis of Silver and Gold Nanoparticles: Chemical and Green Synthesis Method and Its Toxicity Evaluation against Pathogenic Bacteria Using the ToxTrak Test

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Pankaj Kumar Tyagi ◽  
Cristina Quispe ◽  
Jesús Herrera-Bravo ◽  
Shruti Tyagi ◽  
D. Barbhai Mrunal ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Antibacterial Activity ◽  
Pathogenic Bacteria ◽  
The Other ◽  
X Ray ◽  
E Coli ◽  
Plasmon Peak ◽  
Transmission Electron ◽  
Silver Nps ◽  
Gold Nps

In the current investigation, silver/gold nanoparticles (NPs) were synthesized using two methods: chemical and biological, and then characterized colloidal solutions of both NPs using UV-Vis, transmission electron microscopy (TEM) and zeta potential analyzers, X-ray powder diffraction (XRD), and energy dispersive X-ray (EDX) as well as the ToxTrak test for in vitro toxicity and antibacterial activity against Gram-positive bacteria (B. subtilis) and Gram-negative bacteria (E. coli). The plasmon peak of chemical synthesized silver NPs (CH-AgNPs) and gold NPs (CH-AuNPs) was observed at 414 and 530 nm, respectively, while the sharp plasmon peak of biological synthesized silver NPs (Bio-AgNPs) and gold NPs (Bio-AuNPs) was observed at 410 and 525 nm. Under transmission electron microscopy (TEM), the average sizes of CH-AgNPs and CH-AuNPs were 50.56 and 25.98 nm, respectively. Bio-AgNPs and Bio-AuNPs, on the other hand, had average sizes of 25.25 and 16.65 nm, respectively. The stability of NPs was also investigated using the zeta potential. The crystalline structure of AgNPs was confirmed through XRD, and EDX results confirm the element compositions. In the ToxTrak test, the toxic effect value/percentage inhibition (TEV/PI) was calculated. The results showed that CH-AgNPs have the highest TEV/PI value (85.45% for B. subtilis and 83.77% for E. coli) when compared to Bio-AgNPs (55.75% for B. subtilis and 54.42% for E. coli). CH-AuNPs, on the other hand, were 33.51% toxic to B. subtilis and 36.85% toxic to E. coli, compared to Bio-AuNPs, which were 23.36% toxic to B. subtilis and 24.46% toxic to E. coli. The antibacterial activity of Ag/Au NPs was tested and monitored; zone of inhibition (mm in diameter) against B. subtilis and E. coli, with the following pattern emerging: CH-AgNPs (24.80) had the highest antibacterial activity followed by Bio-AgNPs (22.80) < CH-AuNPs (10.60) < Bio-AuNPs (09.00), whereas the control sample (tetracycline antibiotic) revealed a 25.08 mm, zone of inhabitation. Overall, Bio-AgNPs and Bio-AuNPs are the most effective pathogen-killing materials with the lowest toxicity. Our suggestion is that such materials instead of chemical synthesized NPs can be used to coat antibiotic drugs and could be a game-changer for the pharmaceutical industry in terms of effectively controlling the pathogenic bacteria.

A Facile Method for the Synthesis of Silver Nanoparticles in the Presence of Sodium Phosphate

2011 ◽  
Vol 109 ◽  
pp. 174-177 ◽  
Author(s):  
Yu Li Shi ◽  
Qi Zhou ◽  
Li Yun Lv ◽  
Wang Hong
Keyword(s):  
Electron Microscopy ◽  
Silver Nanoparticles ◽  
Sodium Phosphate ◽  
X Ray Diffraction ◽  
Visible Spectroscopy ◽  
X Ray ◽  
Stabilizing Agents ◽  
Transmission Electron ◽  
Silver Nps ◽  
Uv Visible

A facile method for the synthesis of silver nanoparticles (NPs) has been developed by using sodium phosphate (Na3PO4) as stabilizing agents and glucose the reducing agent, respectively. The obtained silver NPs have been characterized by X-ray diffraction (XRD), UV-visible spectroscopy (UV-vis) and transmission electron microscopy (TEM). It was found that in the presence of sodium phosphate, silver NPs with different morphologies and sizes were obtained. The formation mechanism of diverse silver NPs was studied preliminarily.

scholarly journals Structural Characterization and Antibacterial Activity of Antibiotic Streptomycin Immobilized on Zeolite Synthesized from Natural Kaolinite

2021 ◽  
Vol 11 (5) ◽  
pp. 13573-13586
Keyword(s):  
Electron Microscopy ◽  
Antibacterial Activity ◽  
Hydrothermal Process ◽  
Antibacterial Activities ◽  
Good Prospect ◽  
X Ray ◽  
Gram Positive Bacteria ◽  
Transmission Electron ◽  
Inhibition Concentration ◽  
Diffusion Technique

This study evaluated the efficacy of antibacterial activities for a zeolite A (ZEO) sample loaded with streptomycin (STR). The ZEO was synthesized from kaolinite (KAO) via the alkaline hydrothermal process and verified with various techniques, such as X-ray Diffraction, Fourier-Transform Infrared spectroscopy, Field Emission Scanning Electron Microscopy with Energy Dispersive X-ray, Transmission Electron Microscopy, and dispersion behavior to confirm the production of ZEO with high purity and reproducibility. The cubic framework of ZEO was maintained after the immobilization of STR, indicating STR molecules' adsorption on the ZEO surface. The STR-loaded ZEO (ZS) samples were prepared in three STR concentrations (50, 100, and 200 mg/L). The samples' antibacterial activity was determined using the disc diffusion technique and minimum inhibition concentration against Gram-negative bacteria (Escherichia coli ATCC 11229) and Gram-positive bacteria (Staphylococcus aureus ATCC 6538). Both bacteria were susceptible to ZS, which showed an antibacterial effect directly proportional to the STR concentration. Thus, the synthesized ZEO synthesized from natural KAO had a good prospect as a carrier system for STR for generating a broad spectrum of antibacterial activity.

Combined Plasma-Microincineration, Electron Microscopy And Electron Probe Microanalysis For Fine Localization of Biological Mineral Substances

1973 ◽  
Vol 31 ◽  
pp. 334-335 ◽  
Author(s):  
Richard S. Thomas ◽  
Mabel I. Corlett
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Electron Probe ◽  
Oxygen Plasma ◽  
Chemical Nature ◽  
The Other ◽  
X Ray ◽  
Transmission Electron ◽  
Mineral Substances ◽  
Fine Localization

Ash patterns produced by oxygen plasma microincineration(OPM) of thin-sectioned biological materials and examined with the transmission electron microscope (TEM) can show unambiguously the distribution of mineral substances in the specimen with resolutions down to 100 Å. The chemical nature of the mineral is not demonstrated, however. Electron-probe X-ray microanalysis (EXM), on the other hand, can determine precisely the nature of the mineral in ashgd or unashed sections but its spatial resolution is limited to 1000-10,000 A at best. Also its sensitivity of analysis on unashed specimens is limited by intolerance of the specimen to high beam intensities. Using both TEM and EXM together on ash patterns of suitable specimens can overcome their independent spatial and chemical limitations. Furthermore, use of OPM produces a highly stable mineral specimen for EXM, thereby improving sensitivity.

scholarly journals Structure-Function Relationship of Antibacterial Synthetic Peptides Homologous to a Helical Surface Region on Human Lactoferrin against Escherichia coli Serotype O111

1998 ◽  
Vol 66 (6) ◽  
pp. 2434-2440 ◽  
Author(s):  
Daniel S. Chapple ◽  
David J. Mason ◽  
Christopher L. Joannou ◽  
Edward W. Odell ◽  
Vanya Gant ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Transmission Electron Microscopy ◽  
Flow Cytometry ◽  
Antibacterial Activity ◽  
Synthetic Peptides ◽  
Membrane Integrity ◽  
E Coli ◽  
Transmission Electron ◽  
Helical Region

ABSTRACT Lactoferricin includes an 11-amino-acid amphipathic alpha-helical region which is exhibited on the outer surface of the amino-terminal lobe of lactoferrin. Synthetic peptides homologous to this region exhibited potent antibacterial activity against a selected range of both gram-negative and gram-positive bacteria. An analog synthesized with methionine substituted for proline at position 26, which is predicted to disrupt the helical region, abolished antibacterial activity against Escherichia coli and considerably reduced antibacterial activity against Staphylococcus aureus and anAcinetobacter strain. The mode of action of human lactoferrin peptide (HLP) 2 against E. coli serotype O111 (NCTC 8007) was established by using flow cytometry, surface plasmon resonance, and transmission electron microscopy. Flow cytometry was used to monitor membrane potential, membrane integrity, and metabolic processes by using the fluorescent probes bis-1,3-(dibutylbarbituric acid)-trimethine oxonol, propidium iodide, and carbonyl cyanide m-chlorophenylhydrazone, respectively. HLP 2 was found to act at the cell membrane, causing complete loss of membrane potential after 10 min and of membrane integrity within 30 min, with irreversible damage to the cell as shown by rapid loss of viability. The number of particles, measured by light scatter on the flow cytometer, dropped significantly, showing that bacterial lysis resulted. The peptide was shown to bind toE. coli O111 lipopolysaccharide by using surface plasmon resonance. Transmission electron microscopy revealed bacterial distortion, with the outer membrane becoming detached from the inner cytoplasmic membrane. We conclude that HLP 2 causes membrane disruption of the outer membrane, resulting in lysis, and that structural considerations are important for antibacterial activity.

Preparation of Antibacterial Silk and Analysis of Interface Formation Mechanism

2014 ◽  
Vol 9 (3) ◽  
pp. 155892501400900 ◽  
Author(s):  
Xiaoli Chen ◽  
Liqiao Wei
Keyword(s):  
Electron Microscopy ◽  
Antibacterial Activity ◽  
Chemical Structure ◽  
Chemical Reduction ◽  
Valence Bond ◽  
Chemical Reduction Method ◽  
E Coli ◽  
Antibacterial Performance ◽  
Transmission Electron ◽  
Long Acting

Nano-Ag-loaded SiO2 antibacterial agent (Ag/SiO2) was prepared by a chemical reduction method and served as a modifier to endow silk fabric with antibacterial activity. Impregnated antibacterial silk (I-silk) and grafted antibacterial silk (G-silk) were obtained by dipping method and grafting with coupling agent KH550, respectively. The morphologies and valence-bond structures were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FTIR). The washing fastness and antibacterial performance of G-silk were detected by the washing test and oscillation flask method. The results show that the chemical structure of G-silk changed in comparison with that of natural silk. The antibacterial rates of G-silk against E. coli and S. aureus were 96.5% and 92.8%, respectively. And it was still over 80% even after being washed for 30 times, suggesting good wash fastness and long-acting antibacterial activity.

scholarly journals Controlling the Antimicrobial Action of Surface Modified Magnesium Hydroxide Nanoparticles

Biomimetics ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 41 ◽  
Author(s):  
Ahmed F. Halbus ◽  
Tommy S. Horozov ◽  
Vesselin N. Paunov
Keyword(s):  
Electron Microscopy ◽  
Antimicrobial Activity ◽  
Magnesium Hydroxide ◽  
Inorganic Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray ◽  
E Coli ◽  
Transmission Electron ◽  
Surface Modified ◽  
Magnesium Hydroxide Nanoparticles

Magnesium hydroxide nanoparticles (Mg(OH)2NPs) have recently attracted significant attention due to their wide applications as environmentally friendly antimicrobial nanomaterials, with potentially low toxicity and low fabrication cost. Here, we describe the synthesis and characterisation of a range of surface modified Mg(OH)2NPs, including particle size distribution, crystallite size, zeta potential, isoelectric point, X-ray diffraction (XRD), dynamic light scattering (DLS), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), energy dispersive X-ray analysis (EDX), Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM). We explored the antimicrobial activity of the modified Mg(OH)2NPs on the microalgae (C. reinhardtii), yeast (S. cerevisiae) and Escherichia coli (E. coli). The viability of these cells was evaluated for various concentrations and exposure times with Mg(OH)2NPs. It was discovered that the antimicrobial activity of the uncoated Mg(OH)2NPs on the viability of C. reinhardtii occurred at considerably lower particle concentrations than for S. cerevisiae and E. coli. Our results indicate that the antimicrobial activity of polyelectrolyte-coated Mg(OH)2NPs alternates with their surface charge. The anionic nanoparticles (Mg(OH)2NPs/PSS) have much lower antibacterial activity than the cationic ones (Mg(OH)2NPs/PSS/PAH and uncoated Mg(OH)2NPs). These findings could be explained by the lower adhesion of the Mg(OH)2NPs/PSS to the cell wall, because of electrostatic repulsion and the enhanced particle-cell adhesion due to electrostatic attraction in the case of cationic Mg(OH)2NPs. The results can be potentially applied to control the cytotoxicity and the antimicrobial activity of other inorganic nanoparticles.

scholarly journals Synthesis and Antibacterial Aspects of Graphitic C3N4@Polyaniline Composites

Coatings ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 950
Author(s):  
Mohammad Oves ◽  
Mohammad Omaish Ansari ◽  
Reem Darwesh ◽  
Afzal Hussian ◽  
Mohamed F. Alajmi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Morphological Analysis ◽  
Oxidative Polymerization ◽  
X Ray Diffraction ◽  
X Ray ◽  
E Coli ◽  
Transmission Electron ◽  
Aging Conditions ◽  
Polyaniline Composites

In this work, Pani and Pani@g-C3N4 was synthesized by in situ oxidative polymerization methodology of aniline, in the presence of g-C3N4. The as prepared Pani@g-C3N4 was characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction (XRD). The morphological analysis showed well dispersed Pani in g-C3N4, as well as the coating of Pani on g-C3N4. The XRD further revealed this, and peaks of Pani as well as g-C3N4 was observed, thereby suggesting successful synthesis of the composite. The DC electrical conductivity studies under isothermal and cyclic aging conditions showed high stability of composites over 100 °C. Further, the synthesized composite material proved to be an excellent antimicrobial agent against both type i.e., gram positive Streptococcus pneumoniae and negative bacteria Escherichia coli. In the zone inhibition assay 18 ± 0.5, 16 ± 0.75 and 20 ± 0.5, 22 ± 0.5 mm zone diameter were found against E. coli and S. pneumoniae in presence of pure g-C3N4 and Pani@g-C3N4 at 50 µg concentrations, respectively. Further antimicrobial activity in the presence of sunlight in aqueous medium showed that Pani@g-C3N4 is more potent than pure g-C3N4.

scholarly journals Synthesis and Antibacterial Testing of Silver/Poly (Ether Amide) Composite Nanofibers with Ultralow Silver Content

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Shuai Liang ◽  
Geng Zhang ◽  
Jianzhong Min ◽  
Junqiao Ding ◽  
Xingmao Jiang
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Antimicrobial Properties ◽  
Scanning Calorimetry ◽  
X Ray ◽  
E Coli ◽  
Antimicrobial Materials ◽  
Transmission Electron ◽  
Antimicrobial Material ◽  
Testing Standards

Antimicrobial materials have attracted much attention all over the world. Herein, a new kind of antimicrobial material, poly (ether amide) (PebaxⓇ) nanofibers containing Ag nanoparticles, was prepared by electrospinning method. The Ag/PebaxⓇcomposites were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC), and thermogravimetric analyzer (TGA) measurements. The antimicrobial properties of Ag/PebaxⓇcomposites againstEscherichia coli(E. coli; ATCC25922 and avirulent) andStaphylococcus aureus(S. aureus; ATCC6538 and avirulent) were evaluated by membrane adhering method. It was found that the Ag content played an important part in the antimicrobial ability of Ag/PebaxⓇcomposites. When the mass ratio of AgNO3to PebaxⓇin the precursor was 0.15‰, the inhibition rate can reach >99.9% and antimicrobial activity againstE. coliandS. aureuswas 5.8 and 5.6, respectively, exceeding the antimicrobial testing standards JIS Z 2801. The above results indicated that the Ag/PebaxⓇcomposite was a promising antimicrobial material that can be used in many applications.

scholarly journals Cerium doped hydroxyapatite nanoparticles synthesized by coprecipitation method

2016 ◽  
Vol 81 (4) ◽  
pp. 433-446 ◽  
Author(s):  
Carmen Ciobanu ◽  
Cristina Popa ◽  
Daniela Predoi
Keyword(s):  
Electron Microscopy ◽  
Progressive Increase ◽  
Morphological Properties ◽  
Bacterial Strains ◽  
X Ray Diffraction ◽  
X Ray ◽  
E Coli ◽  
Transmission Electron ◽  
Ft Raman Spectroscopy ◽  
Xrd Studies

The present work reports a simple coprecipitation adapted method for the synthesis of stable Ce substituted to Ca hydroxyapatite (HAp) nanoparticles. The structural and morphological properties of Ce doped hydroxyapatite (Ce:HAp) were characterized by X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray analysis (EDAX). The optical properties of Ce doped hydroxyapatite were also investigated using Fourier Transform Infrared (FTIR) spectroscopy, FT Raman spectroscopy and photoluminescence analysis. The results of the XRD studies revealed the progressive increase in the a- and c-axes with increasing of Ce concentrations. In the FTIR studies of Ce:HAp powders a similar structure to hydroxyapatite was observed. IR and Raman wavenumbers and the peak strength of the bands associated to the P-O and O-H bonds decreases progressively with the increase of Ce concentration. All the emission maxima could be attributed to the 5d-4f transitions of Ce ions. The displacement of maximum emission bands with the increase of Cerium in the samples is in agreement with the results obtained by XRD studies. The Ce:HAp samples with xCe =0.03 and 0.05 exhibited significant antibacterial activity against Staphylococcus aureus ATCC 6538 and E. coli 714 bacterial strains compared to Ce:HAp samples with xCe =0 (pure HAp) and 0.01.

scholarly journals In Vitro Antibacterial Activity and Mechanism of Silver Nanoparticles against Foodborne Pathogens

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
S. Rajeshkumar ◽  
C. Malarkodi
Keyword(s):  
Electron Microscopy ◽  
Silver Nanoparticles ◽  
Antibacterial Activity ◽  
Food Safety ◽  
Pathogenic Bacteria ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
X Ray ◽  
Food Borne ◽  
Uv Visible

Biosynthesis of silver nanoparticles usingPlanomicrobiumsp. and to explore the antibacterial activity against food borne pathogenic bacteriaBacillus subtilis, (3053)Klebsiella planticola(2727)Klebsiella pneumoniae(MAA)Serratia nematodiphila(CAA) andEscherichia coli. In the current studies, 1 mM of silver nitrate was added into 100 mL ofPlanomicrobiumsp. culture supernatant. The bioreduction of pure AgNO3was characterized by UV-visible spectroscopy, X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), energy-dispersive analysis (EDS), transmission electron microscopy (TEM), and Fourier transform infrared (FT-IR) analysis. The formation of silver nanoparticles was confirmed by the presence of an absorption peak at 400 nm using UV-visible spectrophotometry. The morphology and size of the silver nanoparticles was monitored by TEM and SEM. Crystal structure was obtained by carrying out X-ray diffraction studies and it showed face centered cubic (FCC) structure. The bactericidal effect of silver nanoparticles was compared based on diameter of inhibition zone in well method. Bacterial sensitivity to nanoparticles a key factor in manufacture the suitable for long life application in food packaging and food safety. Food safety is a worldwide health goal and the food borne diseases get a main disaster on health. Therefore, controlling of bacterial pathogens in food is credit of harms associated to health and safety.

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