scholarly journals Synthesis and Antibacterial Activity of (AgCl, Ag)NPs/Diatomite Hybrid Composite

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3409
Author(s):  
Zhanar Kubasheva ◽  
Myroslav Sprynskyy ◽  
Viorica Railean-Plugaru ◽  
Paweł Pomastowski ◽  
Aliya Ospanova ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Silver Chloride ◽  
Silver Ions ◽  
Metallic Silver ◽  
Ag Nps ◽  
Concentration Method ◽  
Transmission Electron ◽  
Mineral Impurity ◽  
Cytotoxic Studies ◽  
Antibacterial Potential

In the present research, hybrid (AgCl, Ag)NPs/diatomite composites were synthesized by direct impregnation with aqueous silver nitrate solutions. The silver chloride nanoparticles (AgCl-NPs) were formed as an effect of the exchange reaction when silver interacted with the diatomite mineral impurity halite. Nanoparticles of metallic silver (AgNPs) were created by the reduction of silver ions under the influence of hydrogen peroxide. The content of silver chloride nanoparticles in the (AgCl, Ag)NPs/diatomite composite was limited by the content of the halite in the used diatomite. Samples of natural diatomite and synthesized (AgCl, Ag)NPs/diatomite composites were examined by using scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, infrared spectroscopy and thermogravimetric analysis. Moreover, the antibacterial potential of synthesized composites was also studied using the MIC (minimal inhibitory concentration) method against the most common drug-resistant microorganisms in the medical field: Gram-positive Staphylococcus aureus and Gram-negative Klebsiella pneumoniae. The obtained hybrid (AgCl, AgNPs)/diatomite composites were shown to have antimicrobial potential. However, widespread use requires further study by using various microorganisms and additional cytotoxic studies on eukaryotic systems, e.g., cell lines and animal models.

Biosynthesis of Silver Nanoparticles

2003 ◽  
Vol 774 ◽  
Author(s):  
Rajesh R. Naik ◽  
Sarah J. Stringer ◽  
Jay M. Johnson ◽  
Morley O. Stone
Keyword(s):  
Electron Microscopy ◽  
Silver Nanoparticles ◽  
Silver Ions ◽  
Nucleation And Growth ◽  
Inorganic Nanoparticles ◽  
Inorganic Materials ◽  
Synthetic Methods ◽  
Metallic Silver ◽  
Transmission Electron ◽  
Binding Peptides

AbstractThe use of biomolecules in the creation of inorganic materials offers an alternative to conventional synthetic methods. Biomolecules are currently used to control nucleation and growth of inorganic nanoparticles. Here we demonstrate the formation of silver nanoparticles in the presence of silver-binding peptides. Examination of the silver nanoparticles by transmission electron microscopy revealed a variety of crystal morphologies such as hexagons, triangles and spheres. The peptides serve to reduce the silver ions in the aqueous solution to metallic silver as well as control crystal growth. The nucleation property of peptides can be used as tool for bottom-up fabrication.

Effect of pH on the Green Synthesis of Silver Nanoparticles through Reduction with Pistiastratiotes L. Extract

2015 ◽  
Vol 1131 ◽  
pp. 223-226 ◽  
Author(s):  
Pranlekha Traiwatcharanon ◽  
Kriengkri Timsorn ◽  
Chatchawal Wongchoosuk
Keyword(s):  
Silver Nanoparticles ◽  
Green Synthesis ◽  
Spherical Shape ◽  
Silver Ions ◽  
Basic Medium ◽  
Metallic Silver ◽  
Visible Spectroscopy ◽  
Ag Nps ◽  
Transmission Electron ◽  
Effects Of Ph

In this work, we have presented the green synthesis of silver nanoparticles (Ag-NPs) using extracts of Pistiastratiotes L. as reducing agent. The silver nitrate (AgNO3) solutions were used as precursor. The experiments were performed under irradiation with a light that can help to increase the activation for reduction of silver ions (Ag+) to metallic silver (Ag0). The effects of pH on the nature of Ag-NPs have been systematically studied by using ultraviolet-visible spectroscopy (UV-Vis) and transmission electron microscopy (TEM). The results show that the synthesis of Ag-NPs in acidic medium gives smaller size than that in basic medium. A number of synthesized Ag-NPs increase with increasing the concentrations of acidic/basic medium. All synthesized Ag-NPs have spherical shape.

scholarly journals Bacteria-Mediated Synthesis of Silver and Silver Chloride Nanoparticles and Their Antimicrobial Activity

2021 ◽  
Vol 11 (7) ◽  
pp. 3134
Author(s):  
Ioana Ghiuta ◽  
Catalin Croitoru ◽  
Joseph Kost ◽  
Rodica Wenkert ◽  
Daniel Munteanu
Keyword(s):  
Electron Microscopy ◽  
Antimicrobial Activity ◽  
Silver Chloride ◽  
X Ray Diffraction ◽  
Ag Nps ◽  
Cubic Crystal ◽  
X Ray ◽  
Microbial Drug Resistance ◽  
Transmission Electron ◽  
Nitrate Precursor

Within the frame of this work, the synthesis of silver nanoparticles (Ag NPs) and silver chloride nanoparticles (AgCl NPs) as mediated by microbes has been investigated. The nanoparticles were reduced from a silver nitrate precursor by the presence of bacteria, like Raoultella planticola and Pantoea agglomerans. The results show that the characteristic surface plasmon resonance absorption band occurs at about 440 nm. Nanoparticles were also characterized with the help of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), and X-ray diffraction (XRD), which showed the formation of spherical Ag/AgCl NPs with a centered cubic crystal structure and a mean particle size of around 10–50 nm. Assays for antimicrobial activity of the biosynthesized nanoparticles demonstrated meaningful results against microorganisms such as Staphylococcus aureus, Streptococcus pyogenes, Salmonella, and Bacillus amyloliquefaciens. Furthermore, this study shows that the combination of the obtained nanoparticles with standard antibiotics may be useful in the fight against emerging microbial drug resistance.

scholarly journals Zinc Oxide and Silver Nanoparticle Effects on Intestinal Bacteria

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2489
Author(s):  
Ami Yoo ◽  
Mengshi Lin ◽  
Azlin Mustapha
Keyword(s):  
Electron Microscopy ◽  
Zinc Oxide ◽  
Morphological Changes ◽  
Intestinal Bacteria ◽  
Bacterial Cells ◽  
Ag Nps ◽  
Zno Nps ◽  
Bifidobacterium Animalis ◽  
Transmission Electron

The application of nanoparticles (NPs) for food safety is increasingly being explored. Zinc oxide (ZnO) and silver (Ag) NPs are inorganic chemicals with antimicrobial and bioactive characteristics and have been widely used in the food industry. However, not much is known about the behavior of these NPs upon ingestion and whether they inhibit natural gut microflora. The objective of this study was to investigate the effects of ZnO and Ag NPs on the intestinal bacteria, namely Escherichia coli, Lactobacillus acidophilus, and Bifidobacterium animalis. Cells were inoculated into tryptic soy broth or Lactobacilli MRS broth containing 1% of NP-free solution, 0, 12, 16, 20 mM of ZnO NPs or 0, 1.8, 2.7, 4.6 mM Ag NPs, and incubated at 37 °C for 24 h. The presence and characterization of the NPs on bacterial cells were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDS). Membrane leakage and cell viability were assessed using a UV-visible spectrophotometer and confocal electron microscope, respectively. Numbers of treated cells were within 1 log CFU/mL less than those of the controls for up to 12 h of incubation. Cellular morphological changes were observed, but many cells remained in normal shapes. Only a small amount of internal cellular contents was leaked due to the NP treatments, and more live than dead cells were observed after exposure to the NPs. Based on these results, we conclude that ZnO and Ag NPs have mild inhibitory effects on intestinal bacteria.

scholarly journals Interaction of storage medium and silver diamine fluoride on demineralized dentin

2021 ◽  
Vol 49 (2) ◽  
pp. 030006052098533
Author(s):  
Jing-Yuan Peng ◽  
Michael George Botelho ◽  
Jukka Pekka Matinlinna ◽  
Hao-Bo Pan ◽  
Edwin Kukk ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Silver Chloride ◽  
Metallic Silver ◽  
Storage Medium ◽  
Silver Diamine Fluoride ◽  
X Ray ◽  
Whole Saliva ◽  
Demineralized Dentin ◽  
Scanning Electron

Objective The effects of saliva on demineralized dentin and silver diamine fluoride (SDF) were investigated in vitro. Methods Dentin samples stored in deionized water (DIW), buffer solution (BS), basal medium mucin (BMM), and unstimulated whole saliva (UWS) were demineralized for 3 days and immersed in the same storage media. SDF as a 38 mass% solution was applied to the dentin samples for 3 minutes after they had been replaced in their respective medium. Surfaces were analyzed by scanning electron microscopy, energy-dispersive X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). Results Scanning electron microscopy showed various surface deposits and coatings, including occlusion of dentinal tubules. DIW resulted in the thinnest coating, whereas BMM resulted in the thickest. EDX and XPS showed the formation of metallic silver and silver compounds in all four media, with the greatest formation in BS. XRD indicated that the main product was silver chloride except in DIW. Sulphur was found in BMM and UWS. EDX and XPS detected fluoride and XRD detected calcium fluoride and fluorohydroxyapatite in BS, BMM, and UWS. Conclusion The interaction between SDF and demineralized dentin was dependent upon the storage medium. BMM provided an outcome most similar to human saliva.

Preparation of Triangular Silver Nanoparticles Using Polyvinyl Pyrrolidone with Different Concentration

2013 ◽  
Vol 873 ◽  
pp. 206-210
Author(s):  
Kai Li ◽  
Rao Fu ◽  
Qing Ran Gao ◽  
Ai Wei Tang ◽  
Ying Feng Wang
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Silver Nanoparticles ◽  
Driving Force ◽  
Ostwald Ripening ◽  
Polyvinyl Pyrrolidone ◽  
Protective Agent ◽  
Ag Nps ◽  
Transmission Electron ◽  
Uv Visible

This paper continues our previous work on preparation of triangular silver nanoparticles. The method proceeds with reaction of silver nitrate with hydrazine hydrate in the presence of polyvinyl pyrrolidone in aqueous solution. Effects of the concentration of PVP on the morphologies of Ag NPs were systematically investigated. The obtained Ag NPs were characterized by transmission electron microscopy and UV-visible spectrophotometer. The results showed that, triangular Ag NPs with edge lengths in the range of 50-200 nm were obtained using PVP as protective agent with lower concentration. As the concentration of PVP increased, spherical Ag NPs with their sizes about 6.2 nm were prepared and triangular Ag NPs were not obtained. The formation mechanism of triangular Ag NPs has been studied. Ostwald ripening is the driving force on the conversion of spherical Ag NPs to triangular Ag NPs in the presence of PVP.

scholarly journals On the Operational Aspects of Measuring Nanoparticle Sizes

Nanomaterials ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 18 ◽  
Author(s):  
Jean-Marie Teulon ◽  
Christian Godon ◽  
Louis Chantalat ◽  
Christine Moriscot ◽  
Julien Cambedouzou ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ag Nps ◽  
Force Microscopy ◽  
Average Value ◽  
Atomic Force ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Experimental Protocols ◽  
Operational Aspects

Nanoparticles are defined as elementary particles with a size between 1 and 100 nm for at least 50% (in number). They can be made from natural materials, or manufactured. Due to their small sizes, novel toxicological issues are raised and thus determining the accurate size of these nanoparticles is a major challenge. In this study, we performed an intercomparison experiment with the goal to measure sizes of several nanoparticles, in a first step, calibrated beads and monodispersed SiO2 Ludox®, and, in a second step, nanoparticles (NPs) of toxicological interest, such as Silver NM-300 K and PVP-coated Ag NPs, Titanium dioxide A12, P25(Degussa), and E171(A), using commonly available laboratory techniques such as transmission electron microscopy, scanning electron microscopy, small-angle X-ray scattering, dynamic light scattering, wet scanning transmission electron microscopy (and its dry state, STEM) and atomic force microscopy. With monomodal distributed NPs (polystyrene beads and SiO2 Ludox®), all tested techniques provide a global size value amplitude within 25% from each other, whereas on multimodal distributed NPs (Ag and TiO2) the inter-technique variation in size values reaches 300%. Our results highlight several pitfalls of NP size measurements such as operational aspects, which are unexpected consequences in the choice of experimental protocols. It reinforces the idea that averaging the NP size from different biophysical techniques (and experimental protocols) is more robust than focusing on repetitions of a single technique. Besides, when characterizing a heterogeneous NP in size, a size distribution is more informative than a simple average value. This work emphasizes the need for nanotoxicologists (and regulatory agencies) to test a large panel of different techniques before making a choice for the most appropriate technique(s)/protocol(s) to characterize a peculiar NP.

scholarly journals Functionalized β-Cyclodextrin Immobilized on Ag-Embedded Silica Nanoparticles as a Drug Carrier

2019 ◽  
Vol 20 (2) ◽  
pp. 315 ◽  
Author(s):  
Eun Kang ◽  
Yu Baek ◽  
Eunil Hahm ◽  
Sang Lee ◽  
Xuan-Hung Pham ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Drug Delivery ◽  
Drug Carrier ◽  
Silica Nanoparticle ◽  
Surface Modifications ◽  
Ag Nps ◽  
Drug Delivery Vehicles ◽  
Transmission Electron ◽  
Delivery Vehicles ◽  
Simple Surface

Cyclodextrins (CDs) have beneficial characteristics for drug delivery, including hydrophobic interior surfaces. Nanocarriers with β-CD ligands have been prepared with simple surface modifications as drug delivery vehicles. In this study, we synthesized β-CD derivatives on an Ag-embedded silica nanoparticle (NP) (SiO2@Ag NP) structure to load and release doxorubicin (DOX). Cysteinyl-β-CD and ethylenediamine-β-CD (EDA-β-CD) were immobilized on the surface of SiO2@Ag NPs, as confirmed by transmission electron microscopy (TEM), ultraviolet-visible (UV-Vis) spectrophotometry, and Fourier transform infrared (FTIR) spectroscopy. DOX was introduced into the β-CD on the SiO2@Ag NPs and then successfully released. Neither cysteinyl-β-CD and EDA-β-CD showed cytotoxicity, while DOX-loaded cysteinyl-β-CD and EDA-β-CD showed a significant decrease in cell viability in cancer cells. The SiO2@Ag NPs with β-CD provide a strategy for designing a nanocarrier that can deliver a drug with controlled release from modified chemical types.

scholarly journals Carbene modification and reversible crosslinking of silver nanoparticles for controlled antibacterial activity

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Liling Jing ◽  
Mark G. Moloney ◽  
Hao Xu ◽  
Lian Liu ◽  
Wenqiang Sun ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Silver Nanoparticles ◽  
Antibacterial Activity ◽  
Photoelectron Spectroscopy ◽  
Inhibition Zone ◽  
Insertion Reaction ◽  
Ag Nps ◽  
Zone Method ◽  
Transmission Electron

Abstract Silver nanoparticles (Ag NPs) system capable of exhibiting different particle size at different temperature was developed, which depended on the extent of Diels–Alder (DA) reaction of bismaleimide with furan. Thus, Ag NPs were functionalized on the surface by a furyl-substituted carbene through an insertion reaction. Subsequent reversible DA crosslinking achieved a controlled aggregation with different particle size, which gives a series of different antibacterial activity. These Ag NPs were characterized by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), and Nanoparticle Size Analyzer. The aggregation of the Ag NPs could be reliably adjusted by varying the temperature of DA/reverse-DA reaction. The antibacterial activity was assessed using the inhibition zone method against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), which decreased first and then increased in agreement with the size evolution of Ag NPs. This approach opens a new horizon for the carbene chemistry to modify silver nanoparticles with variable size and give controlled antibacterial activity.

Fabrication and Characterization of Cellulose Acetate Ultrafine Fiber Containing Silver Nanoparticles by Electrospinning

2011 ◽  
Vol 337 ◽  
pp. 116-119 ◽  
Author(s):  
Dong Mei Zhao ◽  
Qing Mao Feng ◽  
Li Li Lv ◽  
Jian Li
Keyword(s):  
Electron Microscopy ◽  
Silver Nanoparticles ◽  
Cellulose Acetate ◽  
Average Diameter ◽  
Xrd Analysis ◽  
Water Soluble ◽  
Ag Nps ◽  
Ultrafine Fibers ◽  
Transmission Electron ◽  
Electrospinning Method

Silver nanoparticles (Ag NPs)/cellulose acetate (CA) composite ultrafine fibers were successfully prepared by the electrospinning method. Water-soluble Ag NPs were directly mixed into CA polymer fibers to form organic–inorganic composite ultrafine fibers. The optical property of Ag NPs was measured by ultraviolet-visble spectrometer (UV-vis). The presence and identification of crystalline of Ag NPs were confirmed by XRD analysis. Transmission electron microscopy (TEM) images showed that silver nanoparticles (Ag NPs) with an average diameter of 5–15 nm were obtained and were well distributed in the CA ultrafine fibers. The morphologies of the as-prepared electrospun Ag NPs/CA composite ultrafine fibers were characterized by scanning electron microscopy (SEM) and TEM. The composition of fibers was characterized by FTIR spectrometer.

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