scholarly journals Synthesis of Chloroauric Acid from Gold Electrodes in Alkali Halide Salt Solution by AC Electrolysis and the Sequential Formation of Gold Nanoparticles by Turkevich Method

2021 ◽  
Vol 50 (1) ◽  
pp. 191-194
Author(s):  
Kei Oya ◽  
Kei Aoshika ◽  
Masaki Ageishi ◽  
Hideyuki Magara ◽  
Shuichi Ogawa ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Salt Solution ◽  
Alkali Halide ◽  
Gold Electrodes ◽  
Chloroauric Acid ◽  
Halide Salt ◽  
Sequential Formation

Seed-mediated synthesis and PEG coating of gold nanoparticles for controlling morphology and sizes

MRS Advances ◽  
2020 ◽  
Vol 5 (63) ◽  
pp. 3353-3360
Author(s):  
Susana Helena Arellano Ramírez ◽  
Perla García Casillas ◽  
Christian Chapa González
Keyword(s):  
Gold Nanoparticles ◽  
Polyethylene Glycol ◽  
Room Temperature ◽  
Colloidal Stability ◽  
Infrared Spectrometry ◽  
Ammonium Bromide ◽  
Chloroauric Acid ◽  
Vis Spectroscopy ◽  
Seed Mediated ◽  
Peg Coating

AbstractA significant area of research is biomedical applications of nanoparticles which involves efforts to control the physicochemical properties through simple and scalable processes. Gold nanoparticles have received considerable attention due to their unique properties that they exhibit based on their morphology. Gold nanospheres (AuNSs) and nanorods (AuNRs) were prepared with a seed-mediated method followed of polyethylene glycol (PEG)-coating. The seeds were prepared with 0.1 M cetyltrimethyl-ammonium bromide (CTAB), 0.005 M chloroauric acid (HAuCl4), and 0.01 M sodium borohydride (NaBH4) solution. Gold nanoparticles with spherical morphology was achieved by growth by aggregation at room temperature, while to achieve the rod morphology 0.1 M silver nitrate (AgNO3) and 0.1 M ascorbic acid solution were added. The gold nanoparticles obtained by the seed-mediated synthesis have spherical or rod shapes, depending on the experimental conditions, and a uniform particle size. Surface functionalization was developed using polyethylene glycol. Morphology, and size distribution of AuNPs were evaluated by Field Emission Scanning Electron Microscopy. The average size of AuNSs, and AuNRs was 7.85nm and 7.96 x 31.47nm respectively. Fourier transform infrared spectrometry was performed to corroborate the presence of PEG in the AuNPs surface. Additionally, suspensions of AuNSs and AuNRs were evaluated by UV-Vis spectroscopy. Gold nanoparticles were stored for several days at room temperature and it was observed that the colloidal stability increased once gold nanoparticles were coated with PEG due to the shield formed in the surface of the NPs and the increase in size which were 9.65±1.90 nm of diameter for AuNSs and for AuNRs were 29.03±5.88 and 8.39±1.02 nm for length and transverse axis, respectively.

Optimization of Gold Nanoparticles Synthesis using Design of Experiments Technique

2017 ◽  
Vol 68 (7) ◽  
pp. 1518-1423
Author(s):  
Adina Turcu Stiolica ◽  
Mariana Popescu ◽  
Maria Viorica Bubulica ◽  
Carmen Nicoleta Oancea ◽  
Claudiu Nicolicescu ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Zeta Potential ◽  
Design Of Experiments ◽  
Process Model ◽  
Sodium Citrate ◽  
Drug Carriers ◽  
Chloroauric Acid ◽  
Gold Colloids ◽  
Citrate Concentration ◽  
Vis Spectroscopy

Gold nanoparticles are considered the newest drug carriers for different diseases. Therefore it is appropriate continuous optimization of their preparation. In this study, gold colloids with an average size of 1 - 26 nm were obtained by the reduction of tetrachloroauric acid with trisodium citrate. The nanomaterials were characterized by UV-Vis spectroscopy and dynamic light scattering technique. In addition, zeta potential was measured for samples synthesized in order to determine the stability of the colloids. A Two-level Full Factorial design was chosen to determine the optimum set of process parameters (chloroauric acid concentration and sodium citrate concentration) and their effect on various gold nanoparticles characteristics (size and zeta potential). These effects were quantified using Design of Experiments (DoE) with 5 runs and 1 centerpoint. The selected objective and process model in this investigation are screening and interaction. Findings from this research show that to obtain particles larger than 35 nm, it is recommended to increase sodium citrate concentration, at low chloroauric acid values. These conditions will help to achieve smaller zeta potential, too.

Green synthesis of gold nanoparticles using Tribulus terrestris extract and antibacterial activity against Gram-negative bacteria

2021 ◽  
Vol 7 (2) ◽  
Keyword(s):  
Gold Nanoparticles ◽  
Green Synthesis ◽  
Tribulus Terrestris ◽  
Chloroauric Acid ◽  
X Ray Diffraction ◽  
Inhibitory Effects ◽  
Plant Metabolites ◽  
Sem Images ◽  
Gram Negative ◽  
Human Blood Cells

Aqueous extract of the plant Tribulus terrestris was used to reduce chloroauric acid for synthesizing gold nanoparticles (AuNPs). In this green synthesis, the reaction proceeded to give a red/purple color that was monitored by UV-vis spectrophotometry, where the formed AuNPs had an absorption band with max of 550 nm. In terms of the highest absorbance at 550 nm, reaction conditions were optimized at a temperature of 75°C, at pH 7 and using a reaction time of 4 h. The integrity of the synthesized AuNPs was confirmed and their physical properties were characterized by Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM), which also showed evidence that plant metabolites contributed to capping or stabilization of the AuNPs. XRD spectra suggested a particle size of around 40 nm and SEM images revealed spherical and relatively uniform and disperse particles with a size of less than 0.1 m. In a broth microdilution assay, the AuNPs showed inhibitory effects against Gram-negative Escherichia coli, but not against Gram-positive Enterococcus faecalis. The AuNPs showed no hemagglutination activity or cytotoxic activity against human blood cells, which is important for them to be explored as therapeutic antibacterial agents.

scholarly journals Controlled Synthesis of Gold Nanoparticles UsingAspergillus terreusIF0 and Its Antibacterial Potential against Gram Negative Pathogenic Bacteria

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Eepsita Priyadarshini ◽  
Nilotpala Pradhan ◽  
Lala B. Sukla ◽  
Prasanna K. Panda
Keyword(s):  
Gold Nanoparticles ◽  
Pathogenic Bacteria ◽  
Particle Diameter ◽  
Weight Fraction ◽  
Xrd Analysis ◽  
Controlled Synthesis ◽  
Chloroauric Acid ◽  
Gram Negative ◽  
Fungal Extract ◽  
Vis Spectroscopy

Biosynthesis of monodispersed nanoparticles, along with determination of potential responsible biomolecules, is the major bottleneck in the area of bionanotechnology research. The present study focuses on an ecofriendly, ambient temperature protocol for size controlled synthesis of gold nanoparticles, using the fungusAspergillus terreusIF0. Gold nanoparticles were formed immediately, with the addition of chloroauric acid to the aqueous fungal extract. Synthesized nanoparticles were characterized by UV-Vis spectroscopy, TEM-EDX, and XRD analysis. Particle diameter and dispersity of nanoparticles were controlled by varying the pH of the fungal extract. At pH 10, the average size of the synthesized particles was in the range of 10–19 nm. Dialysis to obtain high and low molecular weight fraction followed by FTIR analysis revealed that biomolecules larger than 12 kDa and having –CH, –NH, and –SH functional groups were responsible for bioreduction and stabilization. In addition, the synthesized gold nanoparticles were found to be selectively bactericidal against the pathogenic gram negative bacteria,Escherichia coli.

In Situ Stepwise Synthesis of Functional Multijunction Molecular Wires on Gold Electrodes and Gold Nanoparticles

2010 ◽  
Vol 49 (20) ◽  
pp. 3508-3512 ◽  
Author(s):  
Geoffrey J. Ashwell ◽  
Barbara Urasinska-Wojcik ◽  
Laurie J. Phillips
Keyword(s):  
Gold Nanoparticles ◽  
Molecular Wires ◽  
Gold Electrodes ◽  
Stepwise Synthesis

scholarly journals Tunability and stability of gold nanoparticles obtained from chloroauric acid and sodium thiosulfate reaction

2012 ◽  
Vol 7 (1) ◽  
pp. 337 ◽  
Author(s):  
Guandong Zhang ◽  
Jacek B Jasinski ◽  
Justin Howell ◽  
Dhruvinkumar Patel ◽  
Dennis P Stephens ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Sodium Thiosulfate ◽  
Chloroauric Acid

Near Infrared Tunable Gold Nanoparticles for Low Power Laser Ablation of Esophageal Adenocarcinoma

2012 ◽  
Vol 1416 ◽  
Author(s):  
Guandong Zhang ◽  
Jacek Jasinski ◽  
Dhruvinkumar Patel ◽  
Kurtis James ◽  
Xinghua Sun ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Low Power ◽  
Esophageal Adenocarcinoma ◽  
Near Infrared ◽  
Average Particle Size ◽  
Sodium Thiosulfate ◽  
Molar Ratio ◽  
Average Particle ◽  
Chloroauric Acid ◽  
Nir Absorption

ABSTRACTGold nanoparticles (GNPs) with precisely controlled near infrared (NIR) absorption were synthesized by one-step reaction of chloroauric acid and sodium thiosulfate. The NIR absorption wavelengths and average particle size increase with increasing molar ratio of HAuCl4/Na2S2O3. The as-synthesized GNPs consist of different shape and size, including small spherical gold colloids and larger non-spherical gold crystals. The GNPs with good chemical and optical stability only form in a suitable range of the HAuCl4/Na2S2O3 molar ratio. High molar ratio of HAuCl4/Na2S2O3 reduces GNPs stability due to Ostwald ripening. Chitosan coating improves particle stability and allows these GNPs effective ablation for esophageal adenocarcinoma under low power NIR laser radiation.

scholarly journals Biosynthesis of Gold Nanoparticles (Green-gold) Using Leaf Extract ofTerminalia Catappa

2010 ◽  
Vol 7 (4) ◽  
pp. 1334-1339 ◽  
Author(s):  
Balaprasad Ankamwar
Keyword(s):  
Gold Nanoparticles ◽  
Leaf Extract ◽  
Biomedical Application ◽  
Low Cost ◽  
Attractive Potential ◽  
Chloroauric Acid ◽  
Rapid Reduction ◽  
Tem Analysis ◽  
Terminalia Catappa ◽  
Average Size

The synthesis of eco-friendly nanoparticles is evergreen branch of nanoscience for biomedical application. Low cost of synthesis and non toxicity are main features make it more attractive potential option for biomedical field and elsewhere. Here, we report the synthesis of gold nanoparticles in aqueous medium usingTerminalia catappa(Almond) leaf extract as the reducing and stabilizing agent. On treating chloroauric acid solutions withTerminalia catappa(TC) leaf extract rapid reduction of chloroaurate ions is observed leading to the formation of highly stable gold nanoparticles in solution. TEM analysis of the gold nanoparticles indicated that they ranged in size from 10 to 35 nm with average size of 21.9 nm.

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