scholarly journals Synthesis and Characterization of about 20nm Gold Nanoparticles

2021 ◽  
Vol 37 (5) ◽  
pp. 1187-1191
Author(s):  
Arpita Biswas
Keyword(s):  
Gold Nanoparticles ◽  
Electron Diffraction ◽  
Chemical Reduction ◽  
Reduction Process ◽  
Trisodium Citrate ◽  
Average Diameter ◽  
Chloroauric Acid ◽  
X Ray ◽  
Vis Spectroscopy

The synthesis of spherical gold nanoparticles (AuNPs) by the chemical reduction process and the characterization of the synthesized nanoparticles is the main aim of this article. Reduction of Chloroauric acid by trisodium citrate salt was performed to get AuNPs of average diameter 20nm. Trisodium citrate is not only the reducing reagent but also the stabilizer of the synthesized AuNPs. Some important modern techniques like UV-VIS spectroscopy, diffraction light scattering (DLS), X-ray diffraction (XRD), transmission electron microscopy (TEM), Selected area electron diffraction (SAED) and electron diffraction X-ray (EDX) were involved for the characterization of synthesized AuNPs. Chemical reduction and Size-controlled growth of spherical AuNPs were followed for this particular synthesis of AuNPs.

scholarly journals Synthesis and characterization of Fe, Co, and Ni colloids in 2-mercaptoethanol

2020 ◽  
Vol 10 ◽  
pp. 184798042096688
Author(s):  
Galo Cárdenas-Triviño ◽  
Sergio Triviño-Matus
Keyword(s):  
Electron Microscopy ◽  
Electron Diffraction ◽  
Colloidal Dispersions ◽  
Synthesis And Characterization ◽  
X Ray ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Chemical Liquid Deposition ◽  
Liquid Deposition

Metal colloids in 2-mercaptoethanol using nanoparticles (NPs) of iron (Fe), cobalt (Co), and nickel (Ni) were prepared by chemical liquid deposition method. Transmission electron microscopy, electron diffraction, UV-VIS spectroscopy, and scanning electron microscopy with electron dispersive X-ray spectroscopy characterized the resulting colloidal dispersions. The NPs exhibited sizes with ranges from 9.8 nm for Fe, 3.7 nm for Co, and 7.2 nm for Ni. The electron diffraction shows the presence of the metals in its elemental state Fe (0), Co (0), and Ni (0) and also some compounds FeO (OH), CoCo2S4, and NiNi2S4.

Study on the Radiosensitizing Applications of Gold Nanoparticles

2016 ◽  
Vol 851 ◽  
pp. 26-30 ◽  
Author(s):  
Chang Shu Tsai ◽  
Jou Kang Hsiao
Keyword(s):  
Gold Nanoparticles ◽  
Ph Value ◽  
Trisodium Citrate ◽  
Molar Ratio ◽  
Human Breast ◽  
X Ray ◽  
Vis Spectroscopy ◽  
M Phase ◽  
Redox Method ◽  
20 Nm

Citrate-coated gold nanoparticles (AuNPs) were prepared by using redox method and its characterization was studied thoroughly. In the preparation process, the varieties of factors were examined by TEM morphology, DLS zetasizer, XPS analysis and UV-Vis spectroscopy for evaluating their qualities and stability. The experimental results obtained under optimal condition, which are 100±5°C of reaction temperature, 4.5-6.4 of the pH value, 2-10 of molar ratio between trisodium citrate and tetrachloroauric acid, respectively. The fluorescent intensities of DCFDA-stain indicate the amount of generated ROS (reactive oxygen species) by AuNPs. The cell cycle for MDA-MB-231 human breast cancer cells exhibits S-phase arrest which can prevent mitosis. The radiosensitizing effect of AuNPs with 20 nm diameter in MDA-MB-231 was investigated by RCGG values (ratio of cell numbers in the G2/M phase to the G0/G1 phase, RCGG) and its radiosensitizing efficiency was ca. 2.29 to 3.75 fold. In this study, it was found that the radiosensitizing efficiency is related to the cytotoxicity by AuNPs. After the irradiation by x-ray to cells, the enhancement value in the presence of 20 nm diameter AuNPs were 17.2% for 3 Gy and 18.9% for 7 Gy respectively. Compared to the irradiated group alone, the enhancements values were 21.8% and 19.7, respectively.

Electrooxidation of Methanol on Carbon Supported Gold Nanoparticles

2013 ◽  
Vol 313-314 ◽  
pp. 232-236
Author(s):  
Dan Zhang
Keyword(s):  
Gold Nanoparticles ◽  
Catalytic Activity ◽  
Competitive Adsorption ◽  
Chemical Reduction ◽  
Reduction Process ◽  
Carbon Support ◽  
Transmission Electron ◽  
Supported Gold Nanoparticles ◽  
Supported Gold

Activated carbon supported gold nanoparticles (Au/C) were prepared by a chemical reduction process using NaBH4as a reducing agent. The characterization of transmission electron microscope indicated that the Au nanoparticles (AuNPs) in the Au/C catalyst were highly well dispersed on the carbon support. The catalytic activity of the Au/C catalyst for the methanol electrooxidation (MEO) was investigated by the cyclic voltammetry (CV). The results displayed that the Au/C catalyst exhibited a favorable catalytic activity towards the MEO in alkaline solution. Moreover, the competitive adsorption between OH-and CH3OH on the surface of the AuNPs in the Au/C catalyst existed in the course of the MEO. Based on this competitive adsorption, the mechanism of the MEO on the Au/C catalyst was further investigated.

scholarly journals Exploration of the Antimicrobial and Catalytic Properties of Gold Nanoparticles Greenly Synthesized by Cryptolepis buchanani Roem. and Schult Extract

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Kamonpan Wongyai ◽  
Phitchayapak Wintachai ◽  
Rasimate Maungchang ◽  
Parawee Rattanakit
Keyword(s):  
Staphylococcus Aureus ◽  
Gold Nanoparticles ◽  
Analytical Techniques ◽  
Average Diameter ◽  
Face Centered Cubic ◽  
Tem Analysis ◽  
X Ray ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Face Centered

A green, simple, and rapid synthesis of gold nanoparticles using plant extract, Cryptolepis buchanani Roem. and Schult, and their applications are first described in this paper. The formation of gold nanoparticles was visually observed by the appearance of a ruby red color, which was further indicated by an absorption peak at 530 nm in UV-Vis spectroscopy. Optimization of reaction parameters for the gold nanoparticles was also investigated. Various analytical techniques were employed as part of the process of characterizing the resulting gold nanoparticles. Fourier transform infrared (FTIR) analysis revealed that the phenol compounds present in the extract were responsible for gold(III) reduction and stabilization of gold nanoparticles. Transmission electron microscopy (TEM) analysis showed that the gold nanoparticles were spherical in shape with an average diameter of 11 nm. Powder X-ray diffraction (XRD) pattern indicated that the green synthesis approach produced highly crystalline, face-centered cubic gold nanoparticles. Energy-dispersive X-ray spectroscopy (EDS) measurements confirmed the presence of elemental gold in the prepared nanoparticles. The negative zeta potential value of gold nanoparticles was found to be -30.28 mV. The green synthesized gold nanoparticles expressed effective antibacterial activity against Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, and Acinetobacter baumannii and exhibited an excellent catalytic property in terms of its reduction ability of methylene blue.

scholarly journals Characterization of Ni-Cd Nanostructured System Obtained by Chemical Reduction of Salts

2016 ◽  
Vol 17 (4) ◽  
pp. 275 ◽  
Author(s):  
V.M. Pugachev ◽  
Yu.A. Zaharov ◽  
A.S. Valnyukova ◽  
V.G. Dodonov
Keyword(s):  
Chemical Reduction ◽  
Structural Parameters ◽  
Reduction Process ◽  
Metal Powders ◽  
X Ray Diffraction ◽  
X Ray ◽  
Initial Stage ◽  
Fcc Lattice ◽  
High Alkalinity

<p>The process of obtaining of highly dispersed metal powders of Ni-Cd system by reduction of their salts by hydrazine in aqueous medium at high alkalinity was investigated. The possibility of production metal powders containing up to 50 mol% of cadmium is established and conditions for their synthesis are optimized. Phase composition, structural parameters, dispersity of solid products during the reduction process were studied by X-ray diffraction (XRD) and SAXS. The formation of metal solid solutions with FCC lattice contradicts to the known phase diagram for Ni-Cd and may be explained by increasing the energy of the particles in the nanostate. The formation of intermetallide NiCd<sub>5</sub> in the studied compositions area is caused by sequential character of reduction process; as a result the metal product on the initial stage of reduction is significantly enriched with cadmium.</p>

scholarly journals Green Synthesis and Characterization of Gold Nanoparticles using Ethanolic Turmeric Crude Extract At Neutral Ph

2020 ◽  
Vol 8 (6) ◽  
pp. 1535-1539
Keyword(s):  
Gold Nanoparticles ◽  
Crude Extract ◽  
Fourier Transforms ◽  
Cost Effective ◽  
Green Method ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Effective Synthesis ◽  
Average Size

There is a great interest in the development of green protocols to avoid environmental and health hazards. In this research, the eco-friendly and cost-effective synthesis of gold nanoparticles (GNPs) has been achieved by the green method using ethanolic turmeric crude extract at pH 7. The bioac-tive compounds of turmeric crude extract are responsible for the reduction, capping and sta-bility of the GNPs. The characterization of GNPs was carried out by ultraviolet-visible (UV-vis) spectroscopy, Fourier transforms infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM) and energy dispersive X-ray (EDX) spectroscopy. The UV-vis spectral study indicated the formation of GNPs with a surface plasmon resonance (SPR) band at 547 nm. FTIR analysis of turmeric crude extract and GNPs showed that phenolic groups reduced the gold ions. The FESEM analysis showed the polydisperse morphology of GNPs with average size of 26.6 nm±7.4 nm. The elemental composition determined by EDX re-vealed the presence of gold. The synthesized GNPs can be useful in a variety of applications involving medicine, cosmetics, environment and nutraceutical.

Preparation and characterization of silver nanoparticle-porphyrazine composites

2013 ◽  
Vol 17 (10) ◽  
pp. 928-933
Author(s):  
Altuğ Mert Sevim ◽  
Ayşe Selda Keskin ◽  
Ahmet Gül
Keyword(s):  
Silver Nanoparticles ◽  
Chemical Reduction ◽  
Reduction Process ◽  
Silver Ions ◽  
Organic Medium ◽  
Nano Particles ◽  
Effective Manner ◽  
Vis Spectroscopy ◽  
One Step

A one step chemical reduction process was used for the preparation of hydrophilic silver nanoparticles ( AgNP ) using silver nitrate, sodiumborohydride and polyvinylpyrolidone as stabilizer. In the case of hydrophobic silver nanoparticles reduced silver ions were stabilized with cetyl trimethylammonium bromide (CTAB). The resultant nano particles were characterized by absoption spectra and their interactions with cationic cobalt (QCoPz) and neutral magnesium (MgPz) porphyrazines in water and in organic medium were investigated by using UV-vis spectroscopy and zeta potential techniques. It is confirmed that both metalloporphyrazine molecules interact with silver nanoparticles in an effective manner. The possible arrangement of the porphyrazines on the surfaces of the hydrophilic and hydrophobic AgNPs has been also discussed according to obtained spectroscopic results. These well-characterized novel AgNP -metalloporphyrazine composites are expected to be useful in optical and catalytic applications.

Synthesis and Characterization of Gold Nanoparticles Grafted on Nanoporous Anodic Aluminum Oxide (AAO) Membrane

2015 ◽  
Vol 752-753 ◽  
pp. 77-80 ◽  
Author(s):  
Hanani Yazid ◽  
Nek Zamzila Nekhia ◽  
Rohana Adnan ◽  
Abdul Mutalib Md Jani
Keyword(s):  
Gold Nanoparticles ◽  
Anodic Aluminum Oxide ◽  
Diffuse Reflectance ◽  
Au Nps ◽  
X Ray ◽  
Anodic Aluminum ◽  
Vis Spectroscopy ◽  
Anionic Exchange ◽  
Nanoporous Anodic Aluminum Oxide

Gold nanoparticles (Au NPs) supported on nanoporous anodic aluminium oxide (AAO) membrane has been successfully prepared by direct anionic exchange for further application in catalysis. The nanoporous AAO membrane is immersed in HAuCl4 solution at different pH to achieve gold nanoparticles grafted on AAO (Au-AAO). It was found that the pH of the HAuCl4 solution played an important role for controlling the size of Au NPs as well as the amount of Au depositing on the surface of AAO membrane. The prepared Au-AAO membranes were characterized by diffuse reflectance UV-Vis spectroscopy, high-resolution scanning electron microscopy (SEM) and energy dispersive x-ray (EDX) spectroscopy.

scholarly journals The Effect of PEI and PVP-Stabilized Gold Nanoparticles on Equine Platelets Activation: Potential Application in Equine Regenerative Medicine

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Mateusz Hecold ◽  
Roma Buczkowska ◽  
Aleksandra Mucha ◽  
Jakub Grzesiak ◽  
Olga Rac-Rumijowska ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Growth Factors ◽  
Growth Factor ◽  
Regenerative Medicine ◽  
Chemical Reduction ◽  
Interleukin 1 ◽  
Mrna Level ◽  
Bone Morphogenetic Protein 2 ◽  
Chloroauric Acid ◽  
Vis Spectroscopy

The aim of this work was to assess the effect of different stabilizing agents, for example, polyethylenimine (PEI) and polyvinylpyrrolidone (PVP), on gold nanoparticles (AuNPs) and their influence on equine platelet activation and release of particular growth factors. The gold nanoparticles were produced by chemical reduction of chloroauric acid. UV-Vis spectroscopy confirmed the presence of gold nanoparticles in investigated solutions. The AuNPs were incubated with whole blood at various concentrations. The morphology of platelets in PRP prepared from the blood incubated with AuNPs was characterized by scanning transmission electron microscopy, whereas the concentrations of growth factors and cytokines were evaluated by ELISA assays. The most promising results were obtained with equine platelets incubated with 5% AuNPs stabilized by PEI, which lead to secretion of bone morphogenetic protein 2 (BMP-2), vascular endothelial growth factor (VEGF), and fibroblast growth factor 1 (FGF-1) and simultaneously cause decrease in concentration of interleukin-1 alpha (IL-1α). The qRT-PCR confirmed ELISA test results. The incubation with 5% AuNPs stabilized by PEI leads to upregulation of BMP-2 and VEGF transcripts of mRNA level and to downregulating expression of interleukin-6 (IL-6). Obtained data shed a promising light on gold nanoparticle application for future regenerative medicine application.

scholarly journals Synthesis and Characterization of Zincoxide Nanoparticles of Average Diameter 10nm in Aqueous Medium

2021 ◽  
Vol 37 (6) ◽  
pp. 1447-1451
Author(s):  
Arpita Biswas
Keyword(s):  
Electron Microscopy ◽  
Electron Diffraction ◽  
Aqueous Medium ◽  
Zinc Acetate Dihydrate ◽  
Ultra Violet ◽  
Average Diameter ◽  
Precipitation Method ◽  
Zno Nps ◽  
X Ray ◽  
Vis Spectroscopy

Synthesis of Zincoxide nanoparticles (ZnO NPs) with definite size and shape and their morphological characterization rationally is really a challenging aspect at present due to the ongoing demand of these nanosize particles for their divergent use in different field of science and technology. Reduction of Zinc acetate dihydrate by sodium hydroxide was performed to produce ZnO NPs by following precipitation method. Here the whole reaction was completed in aqueous medium in low temperature. To characterize the synthesized ZnO NPs some recent techniques like X-Ray diffraction study (XRD), Ultra-Violet Visible (UV-Vis) spectroscopy, Field emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM), Selected area electron diffraction (SAED) and Electron diffraction X-ray (EDX) were used systematically.

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