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 Green Synthesis of Novel Jasmine Bud-Shaped Copper Nanoparticles

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Malathi Sampath ◽  
Ramya Vijayan ◽  
Ezhilarasu Tamilarasu ◽  
Abiraman Tamilselvan ◽  
Balasubramanian Sengottuvelan
Keyword(s):  
Copper Nanoparticles ◽  
Isonicotinic Acid ◽  
Chemical Reduction ◽  
Average Particle Size ◽  
Acid Hydrazide ◽  
Reducing Agent ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Atomic Force ◽  
Transmission Electron

Novel jasmine bud-shaped copper nanoparticles were synthesized by a green chemical reduction method using polyvinylpyrrolidone (PVP) as a capping agent, L-ascorbic acid (AA) as a reducing agent as well as antioxidant agent, isonicotinic acid hydrazide (INH) as a reducing agent, and water as a solvent at 60–70°C (pH-7) in the presence of air. The UV-Vis absorption maximum obtained is 573 nm. The crystal lattice (fcc) structure of Cu Nps was confirmed by X-ray diffraction (XRD). The novel jasmine bud shape was visualized in a transmission electron microscope (TEM). The height of single copper nanobud was 6.41 nm as measured by atomic force microscope (AFM). The average particle size 6.95 nm is obtained by XRD results. Antibacterial activity of the Cu nanobuds was evaluated by testing against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria.

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.

INTRAARTERIAL THROMBOLYSIS BY STREPTOKINASE-GLU-PLASMINOGEN

1987 ◽  
Author(s):  
E J Pilger ◽  
J Lammer ◽  
H Bertuch ◽  
H Steiner
Keyword(s):  
Artery Occlusion ◽  
Molar Ratio ◽  
In Vitro Test ◽  
Group Iii ◽  
Fibrinolytic Agent ◽  
Molar Ratios ◽  
Intraarterial Thrombolysis ◽  
Group I

In order to predict usefulness of streptokinase (SK), urokinase (UK) and streptokinase-glutamin-plasminogen (SK-Glu-Plg) for intraarterial fibrinolysis, an in vitro test was designed. Fibrin plates with and without plasminogen were incubated with SK, UK and SK-Glu-Plg (in molar ratios of 1:1, 2:1 and 1:2). On the fibrin plates containing plasminogen the highest fibrinolytic activity was observed with UK; on the fibrin plates without plasminogen, SK-Glu-Plg in a molar ratio of 1:2 was superior. We concluded, that plasmin would be synthesized by SK and Glu-Plg. In order to examine the in vivo efficacy of these different fibrinolytic agents, 120 patients suffering from peripheral artery occlusion were randomized into three treatment groups for local thrombolysis. The technique of Hess and coworkers was used for local thrombolytic therapy. In group I local fibrinolysis was performed with SK (2500 IU/5 min), in group II UK (4000 IU/5 min) was used and in group III the lytic agent consisted of SK-Glu-Plg (2500 IU/5 min). The primary recanalization rate was equal in all groups: 86%, 89% and 83% in group I, II and III respectively. However the duration required for the procedure and thus the total amount of fibrinolytic agent used was significantly different (p < 0,001) between the three groups: 2,3 ± 1,4; 2,1 ± 1,2 and 1,1 ±0,8 hours for groups I,II and III, respectively (mean ± SEM) . We conclude that SK-Glu-Plg or plasmin itself has the highest efficacy as a fibrinolytic agent for intraarterial thrombolysis. Since the intra-thrombotic concentration of Pig is unknown in an individual patient an empirically chosen dose of SK of UK may either be to high or to low for optimal thrombolysis.

scholarly journals Photo-induced chemical reduction of silver bromide to silver nanoparticles

2011 ◽  
Vol 9 (6) ◽  
pp. 982-989 ◽  
Author(s):  
Agnieszka Król-Gracz ◽  
Ewa Michalak ◽  
Piotr Nowak ◽  
Agnieszka Dyonizy
Keyword(s):  
Silver Nanoparticles ◽  
Chemical Reduction ◽  
Silver Bromide ◽  
Molar Ratio ◽  
Efficient Production ◽  
Ag Nps ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Nanoparticle Suspensions ◽  
Actinic Radiation

AbstractThis paper discusses the experimental results of the production of nanocolloidal silver using photoreduction method. Ultrafine crystalline gelatine-stabilised aqueous suspensions of silver bromide were used as a substrate for the synthesis of silver nanoparticles (Ag NPs). The influences of the reductant to substrate molar ratio, the medium’s pH, the type of the source of actinic radiation and the time of exposure to the efficient production of the Ag NPs were studied. A typical reaction was suggested, which involves the photo-induced reduction of silver bromide nanocrystals in the presence of ascorbic acid under specified physicochemical conditions. The properties of resultant silver particles were examined using UV-Vis spectroscopy and Dynamic Light Scattering (DLS). In addition, Transmission Electron Microscopy (TEM) was used for imaging the silver nanoparticle suspensions.

scholarly journals Glycerol Valorization over ZrO2-Supported Copper Nanoparticles Catalysts Prepared by Chemical Reduction Method

Catalysts ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1040
Author(s):  
Juan Garcés ◽  
Ramón Arrué ◽  
Néstor Novoa ◽  
Andreia F. Peixoto ◽  
Ricardo J. Chimentão
Keyword(s):  
Copper Nanoparticles ◽  
Reduction Method ◽  
Chemical Reduction ◽  
X Ray Diffraction ◽  
Chemical Reduction Method ◽  
X Ray ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Region I ◽  
Temperature Programmed

Copper nanoparticles (NPs) and ZrO2-supported copper NPs (Cu NPs/ZrO2) were synthesized via a chemical reduction method applying different pH (4, 7 and 9) and evaluated in a glycerol dehydration reaction. Copper NPs were characterized with transmission electron microscopy (TEM) and UV–vis spectroscopy. Transmission electron microcopy (TEM) results revealed a homogeneous distribution of copper NPs. A hypsochromic shift was identified with UV–vis spectroscopy as the pH of the synthesis increased from pH = 4 to pH = 9. Zirconia-supported copper NPs catalysts were characterized using N2 physisorption, X-ray diffraction (XRD), TEM, X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (TPR), temperature-programmed desorption of ammonia (NH3-TPD) and N2O chemisorption. The presence of ZrO2 in the chemical reduction method confirmed the dispersion of the copper nanoparticles. X-ray diffraction indicated only the presence of tetragonal zirconia patterns in the catalysts. XPS identified the Cu/Zr surface atomic ratio of the catalysts. TPR patterns showed two main peaks for the Cu NPS/ZrO2 pH = 9 catalyst; the first peak between 125 and 180 °C (region I) was ascribed to more dispersed copper species, and the second one between 180 and 250 °C (region II) was assigned to bulk CuO. The catalysts prepared at pH = 4 and pH = 7 only revealed reduction at lower temperatures (region I). Copper dispersion was determined by N2O chemisorption. With NH3-TPD it was found that Cu NPs/ZrO2 pH = 9 exhibited the highest total quantity of acidic sites and the highest apparent kinetic constant, with a value of 0.004 min−1. The different pH applied to the synthesis media of the copper nanoparticles determined the resultant copper dispersion on the ZrO2 support, providing active domains for glycerol conversion.

Synthesis of Copper Nanoparticles by Chemical Reduction Method and its Influential Factors

2012 ◽  
Vol 627 ◽  
pp. 804-808 ◽  
Author(s):  
Li Na Wang ◽  
Ming Yu Li ◽  
Qing Xuan Zeng
Keyword(s):  
Copper Nanoparticles ◽  
Chemical Reduction ◽  
Sulfate Solution ◽  
Xrd Analysis ◽  
Influential Factors ◽  
Sodium Hypophosphite ◽  
Copper Sulfate Solution ◽  
Different Shapes ◽  
Xrd Techniques ◽  
20 Nm

Synthesis of copper nanoparticles was achieved by reduction of copper sulfate solution using sodium hypophosphite (NaH2PO2). The nanoparticles are characterized by using SEM and XRD techniques. The XRD analysis and theoretic calculation indicate that the products have a fcc structure, and the size of crystallite is about 20 nm. Different solvents have been used to produce copper particles with different shapes, and the size of the particles can be controlled by varying reaction condition.

scholarly journals Design of Nanosystems for the Delivery of Quorum Sensing Inhibitors: A Preliminary Study

Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5655
Author(s):  
Supandeep Singh Hallan ◽  
Paolo Marchetti ◽  
Daria Bortolotti ◽  
Maddalena Sguizzato ◽  
Elisabetta Esposito ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
High Performance ◽  
Correlation Spectroscopy ◽  
Molar Ratio ◽  
In Vitro Test ◽  
Dimethyl Benzyl ◽  
Capacity Evaluation ◽  
Size And Morphology ◽  
Dicetyl Phosphate

Biofilm production is regulated by the Quorum Sensing system. Nowadays, Quorum Sensing represents an appealing target to design new compounds to increase antibiotics effects and avoid development of antibiotics multiresistance. In this research the use of liposomes to target two novel synthetic biofilm inhibitors is presented, focusing on a preformulation study to select a liposome composition for in vitro test. Five different liposome (LP) formulations, composed of phosphatidyl choline, cholesterol and charged surfactant (2:1:1, molar ratio) have been prepared by direct hydration and extrusion. As charged surfactants dicetyl phosphate didecyldimethylammonium chloride, di isobutyl phenoxy ethyl dimethyl benzyl ammonium chloride and stearylamine (SA) and have been used. Liposome charge, size and morphology were investigated by zeta potential, photon correlation spectroscopy, small angle x-ray spectroscopy and electron microscopy. LP-SA was selected for the loading of biofilm inhibitors and subjected to high performance liquid chromatography for entrapment capacity evaluation. LP-SA loaded inhibitors showed a higher diameter (223.6 nm) as compared to unloaded ones (205.7 nm) and a dose-dependent anti-biofilm effect mainly after 48 h of treatment, while free biofilm inhibitors loose activity. In conclusion, our data supported the use of liposomes as a strategy to enhance biofilm inhibitors effect.

scholarly journals Sol-gel bioactive glass-ceramics Part II: Glass-ceramics in the CaO-SiO2-P2O5-MgO system

2009 ◽  
Vol 7 (3) ◽  
pp. 322-327 ◽  
Author(s):  
Lachezar Radev ◽  
Vladimir Hristov ◽  
Irena Michailova ◽  
Bisserka Samuneva
Keyword(s):  
Sol Gel ◽  
Glass Ceramics ◽  
Static Condition ◽  
Ceramic Materials ◽  
Molar Ratio ◽  
In Vitro Test ◽  
X Ray Diffraction ◽  
Vitro Test ◽  
Good Agreement

AbstractCeramics, with basic composition based on the CaO-SiO2-P2O5-MgO system with different Ca+ Mg/P+Si molar ratio (R), were prepared via polystep sol-gel technique. The structure of the obtained ceramic materials has been studied by XRD, FTIR spectroscopy, and SEM. X-ray diffraction showed the presence of akermanite and HA for the sample with R = 1.68 and Mg substituted β-TCP and silicocarnotite for the sample with R = 2.16, after thermal treatment at 1200°C/2 h. The obtained results are in good agreement with FTIR. In vitro test for bioactivity in static condition proved that the carbonate containing hydroxyapatite (CO3HA) can be formed on the surface of the synthesized samples. CO3HA consisted of both A- and B-type CO 32− ions. SEM micrographs depicted different forms of HA particles, precipitated on the surface after soaking in 1.5 simulated body fluid (SBF).

scholarly journals Nanofibrillated Cellulose and Copper Nanoparticles Embedded in Polyvinyl Alcohol Films for Antimicrobial Applications

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Tuhua Zhong ◽  
Gloria S. Oporto ◽  
Jacek Jaczynski ◽  
Changle Jiang
Keyword(s):  
Polyvinyl Alcohol ◽  
Copper Nanoparticles ◽  
Chemical Reduction ◽  
Antimicrobial Properties ◽  
Nanofibrillated Cellulose ◽  
Microbial Reduction ◽  
Nanocomposite Films ◽  
Transmission Electron ◽  
Average Size ◽  
Thermoplastic Resins

Our long-term goal is to develop a hybrid cellulose-copper nanoparticle material as a functional nanofiller to be incorporated in thermoplastic resins for efficiently improving their antimicrobial properties. In this study, copper nanoparticles were first synthesized through chemical reduction of cupric ions on TEMPO nanofibrillated cellulose (TNFC) template using borohydride as a copper reducing agent. The resulting hybrid material was embedded into a polyvinyl alcohol (PVA) matrix using a solvent casting method. The morphology of TNFC-copper nanoparticles was analyzed by transmission electron microscopy (TEM); spherical copper nanoparticles with average size of 9.2 ± 2.0 nm were determined. Thermogravimetric analysis and antimicrobial performance of the films were evaluated. Slight variations in thermal properties between the nanocomposite films and PVA resin were observed. Antimicrobial analysis demonstrated that one-week exposure of nonpathogenicEscherichia coliDH5αto the nanocomposite films results in up to 5-log microbial reduction.

Synthesis and Properties of Au Nanoparticles with Various Sizes

2013 ◽  
Vol 710 ◽  
pp. 117-121 ◽  
Author(s):  
Yuan Na Zhu ◽  
Yong Qiang Cao ◽  
Ai Yu Zhang ◽  
Ping Yang
Keyword(s):  
Raman Scattering ◽  
Au Nanoparticles ◽  
Particle Diameter ◽  
Trisodium Citrate ◽  
Reducing Agent ◽  
Molar Ratio ◽  
Chloroauric Acid ◽  
Au Nps ◽  
Transmission Electron ◽  
Nir Absorption

Properties of Au nanoparticles (NPs) caused by various sizes (5-12 nm) were studied in this article. Au NPs capped with citrate of various sizes were synthesized by two methods including trisodium citrate dihydrate reduction of chloroauric acid tetrahydrate and sodium borohydride reducion of chloroauric acid tetrahydrate. Au NPs were characterized and measured by using transmission electron microscope (TEM), UV-vis-NIR absorption spectroscopy, and surface Raman scattering. The results of experiment indicated that the size of Au NPs was related to the type of reducing agent and molar ratio of reducing agent and chloroauric acid. The weaker the reducing capacity of the reducing agent or the lower the molar ratio, the bigger the size of Au NPs is. The max wavelength of absorption peak for the citrate-capped Au NPs is red-shifted with the increase of particle diameter. Raman scattering observed from Au NPs of various sizes is found to be NP size-dependent. It is clear that the bigger Au NPs are more apparent in the Raman scattering determination. Size-tunable Au NPs should be crucial for biosensors, particularly as Raman-tag particles.

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