scholarly journals Hydroxyapatite/Silver Nanoparticles Powders as Antimicrobial Agent for Bone Replacements

2019 ◽  
Vol 92 (1) ◽  
pp. 59-68 ◽  
Author(s):  
Agnieszka Sobczak-Kupiec ◽  
Dagmara Malina ◽  
Regina Kijkowska ◽  
Wioletta Florkiewicz ◽  
Klaudia Pluta ◽  
...  
Keyword(s):  
Ag Nanoparticles ◽  
Chemical Reduction ◽  
Absorption Spectrometry ◽  
Bactericidal Effect ◽  
Sem Analysis ◽  
Biological Assessment ◽  
Molar Ratio ◽  
In Situ Deposition ◽  
Morphological Modification ◽  
Xrd Techniques

This paper reports a superficial morphological modification of the hydroxyapatite grains obtained by in situ deposition of Ag nanoparticles on natural origin calcium phosphate powder. Ceramic material was prepared in three stage bone treatment, including hydrolysis with a lactic acid, pre-calcination, and proper calcination. Subsequently, the Ag nanoparticles were synthesized by chemical reduction of Ag+ by sodium borohydride in a solution of polyvinylpyrrolidone and in presence of hydroxyapatite. Such-prepared materials were investigated with X-ray diffraction, Fourier-transformed infrared spectroscopy, atomic absorption spectrometry and scanning electron microscopy with energy dispersive spectroscopy. Furthermore, Ca/P molar ratio was calculated and microbiological tests were performed to investigate materials antimicrobial activity. The appearance of Ag nanoparticles located on phosphate surface was confirmed by SEM analysis, and no chemical bonding with hydroxyapatite was recorded by IR and XRD techniques. Additionally, the biological assessment revealed bactericidal effect on Escherichia coli and Staphylococcus aureus, while slightly affected on Enterococcus faecalis viability.

scholarly journals Synthesis, characterization and evaluation of copper nanoparticles as agrochemicals against Phytophthora spp.

2019 ◽  
Vol 2 (6) ◽  
pp. 48-56
Author(s):  
Hoang Minh Hao ◽  
Cao Van Du ◽  
Duong Thi Ngoc Dung ◽  
Cao Xuan Chuong ◽  
Nguyen Thi Phuong Phong ◽  
...  
Keyword(s):  
Copper Nanoparticles ◽  
Chemical Reduction ◽  
Trisodium Citrate ◽  
Molar Ratio ◽  
In Vitro Test ◽  
Weight Percentage ◽  
Phytophthora Spp ◽  
Transmission Electron ◽  
Xrd Techniques

By using water as a solvent, copper nanoparticles (CuNPs) have been synthesized from copper sulfate via chemical reduction method in the presence of trisodium citrate dispersant and polyvinylpyrrolidone (PVP) as capping agent. The effects of the experimental parameters such as the concentration of reducing agent (NaBH4), reaction temperature, molar ratio of citrate/Cu2+ and weight percentage ratios of Cu2+/PVP on the CuNP sizes were studied. The size of CuNPs in a range of 31 nm was obtained at NaBH4 concentration of 0.2 M, 50oC, citrate/Cu2+ molar ratio of 1.0 and Cu2+/PVP weight percentage of 5%. The colloidal CuNPs were characterized by using UV–Visible spectroscopy, transmission electron microscopy (TEM), and X-ray diffraction (XRD) techniques. The colloidal solution of CuNPs (3±1 nm) was investigated the potential against Phytophthora spp. which cause economically crop diseases. Under in vitro test conditions, the inhibition of Phytophthora spp. mycelia growth at three concentrations of CuNPs (10, 20, 30 ppm) after 48 hours are 90.18%, 91.87% and 100%, respectively. These results provided a simple and economical method to develop the CuNPs-based-fungicide.  

scholarly journals New Antimicrobials Based on the Adarotene Scaffold with Activity against Multi-Drug Resistant Staphylococcus aureus and Vancomycin-Resistant Enterococcus

Antibiotics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 126
Author(s):  
Salvatore Princiotto ◽  
Stefania Mazzini ◽  
Loana Musso ◽  
Fabio Arena ◽  
Sabrina Dallavalle ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Anticancer Activity ◽  
Bactericidal Effect ◽  
Biological Assessment ◽  
Drug Resistant ◽  
Vancomycin Resistant Enterococcus ◽  
Vancomycin Resistant ◽  
Global Increase ◽  
Common Infections

The global increase in infections by multi-drug resistant (MDR) pathogens is severely impacting our ability to successfully treat common infections. Herein, we report the antibacterial activity against S. aureus and E. faecalis (including some MDR strains) of a panel of adarotene-related synthetic retinoids. In many cases, these compounds showed, together with favorable MICs, a detectable bactericidal effect. We found that the pattern of substitution on adarotene could be modulated to obtain selectivity for antibacterial over the known anticancer activity of these compounds. NMR experiments allowed us to define the interaction between adarotene and a model of microorganism membrane. Biological assessment confirmed that the scaffold of adarotene is promising for further developments of non-toxic antimicrobials active on MDR strains.

Aggregation Characteristics of Cu and Ag Nanoparticles in Presence of Starch as the Polymer Stabilizer

2010 ◽  
Vol 123-125 ◽  
pp. 615-618 ◽  
Author(s):  
Indrajit Sinha ◽  
Manjeet Singh ◽  
Rajiv Kumar Mandal
Keyword(s):  
Small Molecule ◽  
Ag Nanoparticles ◽  
Growth Models ◽  
Chemical Reduction ◽  
Cluster Aggregation ◽  
Diffusion Limited ◽  
X Ray Scattering ◽  
Polymer Stabilizer ◽  
Aqueous Conditions ◽  
Diffusion Limited Cluster Aggregation

This presentation deals with the aggregation characteristics of Cu and Ag nanoparticles in presence of starch as the polymer stabilizer. Uncontrolled aggregation of the destabilized nanoparticles offers problem for applications based on surface plasmon activity. Polymer or small molecule surfactants are used to control nature of aggregation of nanoparticles produced by chemical reduction synthesis routes. Different growth models such as diffusion limited cluster aggregation (DLCA), reaction limited cluster aggregation (RLCA) proposed to explain the formation of fractal colloidal aggregates do not account for aggregate formation in presence of polymer or small molecule surfactants. We shall be discussing the role of starch on the aggregation characteristics of copper and silver nanoparticles formed by chemical reduction in aqueous conditions. The effect of NaOH concentration and consequently the pH on such aggregation kinetics during such synthesis is delineated. We use small angle x-ray scattering (SAXS) to quantitatively understand different aspects of aggregation behavior.

Facile Synthesis of Silver Nanoparticles by Chemical Reduction Route

2013 ◽  
Vol 756 ◽  
pp. 99-105
Author(s):  
Rajasingam Ratnamalar ◽  
Mustapha Mariatti ◽  
Zulkifli Ahmad ◽  
Sharif Zein Sharif Hussein
Keyword(s):  
Silver Nanoparticles ◽  
Ag Nanoparticles ◽  
Chemical Reduction ◽  
Facile Synthesis ◽  
Cubic Lattice ◽  
Vis Spectroscopy ◽  
Simple Chemical ◽  
The Face ◽  
Fine Control ◽  
Xrd Patterns

This work reports a simple chemical reduction route for the preparation of uniformed Ag nanoparticles whereby a fine control over the sizes of the Ag nanoparticles was studied by varying the concentrations of the reducing agents used. In characterization, UV-Vis spectroscopy showed the changes in optical properties of the Ag nanoparticles with regards to their sizes, where as the XRD patterns of the synthesized Ag nanoparticles confirmed the distinct peaks approximately at 2θ = 38.1°, 44.3°, 64.4°, 77.4°, and 81.5 representing Bragg’s reflections from (111), (200), (220), (311), and (222) planes of the face centred cubic lattice phase. This route of synthesis is feasible to produce Ag nanoparticles with diameters in the range of 30-45 nm.

Growth of Ag Nanoparticles by Spin Coating

2013 ◽  
Vol 24 ◽  
pp. 163-167 ◽  
Author(s):  
S.D. Sartale ◽  
A.A. Ansari
Keyword(s):  
Ag Nanoparticles ◽  
Spin Coating ◽  
Chemical Reduction ◽  
Reduction Process ◽  
Thermal Reduction ◽  
Environment Effects ◽  
Uv Visible ◽  
Absorbance Spectra ◽  
Scanning Electron ◽  
Better Than

Ag nanoparticles were grown on glass substrate by spin coating of Ag ions (AgNO3) solution followed by either chemical reduction, in aqueous hydrazine or NaBH4 solution, or by thermal reduction in H2 environment. Effects of different reducing agent have been explained. Morphology and absorbance spectra ofAg nanoparticles films, measured by using Scanning Electron Microscopy (SEM) and UV-visible Spectrophotometer techniques, are used to understand effect of reduction process on growth of Ag nanoparticles. To grow uniformly size distributed Ag nanoparticles thermal reduction in H2 is better than chemical reduction by aqueous either NaBH4 orhydrazine hydrate solutions.

scholarly journals Bactericidal effect of hydrogen peroxide is prevented by the lactoperoxidase-thiocyanate system under anaerobic conditions

1980 ◽  
Vol 29 (3) ◽  
pp. 1190-1192
Author(s):  
J Carlsson
Keyword(s):  
Hydrogen Peroxide ◽  
Bactericidal Effect ◽  
Molar Ratio ◽  
Anaerobic Conditions ◽  
Streptococcus Sanguis

Streptococcus sanguis and Peptostreptococcus anaerobius were exposed to various combinations of the components of the lactoperoxidase-thiocyanate-hydrogen peroxide system. The bactericidal effect of hydrogen peroxide was prevented under anaerobic conditions by lactoperoxidase together with thiocyanate, but not by lactoperoxidase or thiocyanate alone. Thiocyanate was effective already at a molar ratio to hydrogen peroxide of 1:100.

Chemical reduction of Ag+ to Ag employing organic electron donors: evaluation of the effect of Ag+-mediated cytosine–cytosine base pairing on the aggregation of Ag nanoparticles

2021 ◽  
Author(s):  
Takenori Dairaku ◽  
Rika Kawai ◽  
Kanako Nozawa-Kumada ◽  
Kentaro Yoshida ◽  
Tetsuya Ono ◽  
...  
Keyword(s):  
Ag Nanoparticles ◽  
Chemical Reduction ◽  
Total Concentration ◽  
Electron Donors ◽  
Base Pairing ◽  
Reduction Activity ◽  
Organic Electron

The formation of C–Ag+–C base pairing inhibits the aggregation of AgNPs in solution. The total concentration of the obtained AgNP solution can be controlled by the degree of the reduction activity of the organic electron donors.

scholarly journals Organic Molecule Detection Based on SERS in Microfluidics

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Xin Zhang ◽  
Haiyan Zhang ◽  
Sheng Yan ◽  
Zugang Zeng ◽  
Anshou Huang ◽  
...  
Keyword(s):  
Environmental Monitoring ◽  
Ag Nanoparticles ◽  
Organic Molecule ◽  
Organic Molecules ◽  
Chemical Reduction ◽  
Fdtd Method ◽  
Great Influence ◽  
High Sensitivity ◽  
Surface Enhanced Raman Spectroscopy ◽  
Sers Substrate

AbstractSensitive in situ detection of organic molecules is highly demanded in environmental monitoring. In this work, the surface enhanced Raman spectroscopy (SERS) is adopted in microfluidics to detect the organic molecules with high accuracy and high sensitivity. Here the SERS substrate in microchannel consists of Ag nanoparticles synthesized by chemical reduction. The data indicates the fabrication conditions have great influence on the sizes and distributions of Ag nanoparticles, which play an important role on the SERS enhancement. This result is further confirmed by the simulation of electromagnetic field distributions based on finite difference time domain (FDTD) method. Furthermore, the SERS spectra of organic molecule (methylene blue) obtained in this plasmonic microfluidic system exhibit good reproducibility with high sensitivity. By a combination of SERS and microfluidics, our work not only explores the research field of plasmonics but also has broad application prospects in environmental monitoring.

Synthesis of Ag Nanoparticles-Clinoptilolite Composite by Homogeneous and Heterogeneous Nucleation

2013 ◽  
Vol 755 ◽  
pp. 97-103 ◽  
Author(s):  
A. Ruíz-Baltazar ◽  
R. Esparza ◽  
R. Pérez ◽  
G. Rosas
Keyword(s):  
Silver Nitrate ◽  
Sodium Borohydride ◽  
Heterogeneous Nucleation ◽  
Ag Nanoparticles ◽  
Natural Zeolite ◽  
Colloidal Solution ◽  
Chemical Reduction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

In this study, a natural zeolite clinoptilolite-type was impregnated through homogeneous and heterogeneous nucleation with silver nanoparticles. The synthesis of Ag nanoparticles was carried out by chemical reduction of silver nitrate (AgNO3) with sodium borohydride (NaBH4). In the case of homogeneous nucleation, colloidal solution of Ag nanoparticles at concentrations of 1, 2 and 4 parts per million was added and magnetically mixed with the porous material. With respect to heterogeneous nucleation, a solution of clinoptilolite and silver nitrate (0.01 M) was prepared and stirred; subsequently, the reduction of Ag was possible due to the addition of an aqueous solution of sodium borohydride. For the structural characterization, transmission electron microscopy (TEM), X-ray diffraction (XRD) and infrared spectroscopy (IR) techniques were carried out. The results were compared and discussed in both types of nucleation.

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