scholarly journals Study on synthesis of colloidal gold nanoparticles and preparation of antiE. coli O157 monoclonal antibody conjugated nanoparticles

2013 ◽  
Vol 16 (3) ◽  
pp. 75-82
Author(s):  
Thanh Vo Ke Ngo ◽  
Giang Dang Nguyen ◽  
Vinh Quang Lam ◽  
Dat Thanh Huynh
Keyword(s):  
Gold Nanoparticles ◽  
Colloidal Gold ◽  
Chemical Reduction ◽  
Major Effect ◽  
Chloroauric Acid ◽  
Visible Absorption ◽  
E Coli ◽  
Colloidal Gold Nanoparticles ◽  
Transmission Electron ◽  
20 Nm

The present paper describes the preparation of colloidal gold nanoparticles by a chemical reduction method, using some chemical compounds such as sodium citrate (Na3Ct), chloroauric acid (HAuCl4.3H2O) and anti-E. coli O157 monoclonal antibodyconjugated gold nanoparticles. The nanoparticles were characterized by several techniques including Ultraviolet and Visible Absorption Spectroscopy (UV-Vis), Transmission Electron Microscopy (TEM). The UV-Vis confirmed that the concentration of Na3Ct has a major effect on the size of the synthesized gold nanoparticles, and TEM images showed that the size of gold particles is in the range of 10-20 nm. In addition, the binding of the antibody-gold conjugates to E. coli O157 was also investigated using the same characterization means

Inter-band Transition in Citrate Capped Marks Dodecahedral Colloidal Gold Nanoparticles

2020 ◽  
Vol 16 (5) ◽  
pp. 829-836
Author(s):  
Debasish Aich ◽  
Pijus Kanti Samanta ◽  
Satyajit Saha ◽  
Tapanendu Kamilya
Keyword(s):  
Gold Nanoparticles ◽  
Fermi Level ◽  
Colloidal Gold ◽  
Interband Transition ◽  
Visible Absorption ◽  
Colloidal Gold Nanoparticles ◽  
Transmission Electron ◽  
Long Time ◽  
Band Transition ◽  
Absorbance Peak

Background: Optical properties of citrate capped dodecahedral gold nanoparticles have immense applications in a large variety of fields. The interband transition has a role in determining the optical behaviour of gold nanoparticles. Interband transition in citrate capped colloidal gold nanoparticles in the size range above ~5 nm has been left unattended for a long time. Objective: The present work is aimed at studying interband transition in citrate capped colloidal gold nanoparticles of size between ~5 nm and several tens of nanometres. Methods: Turkevich method and modified Brust method were used to prepare citrate capped colloidal gold nanoparticles. Transmission electron microscopy was used to determine their size and shape and their formation was explained with simulated figure obtained by Gnuplot programming. Interband transition was studied with the help of UV-Visible absorption spectroscopy. Results: Dodecahedral citrate capped colloidal gold nanoparticles of mean diameters 31.5 nm, 12.87 nm and 4.69 nm with LSPR peak positions at 528 nm, 524 nm and 509 nm were prepared. The interband peak of nanoparticles of all three sizes was found to be located at about 260 nm. Conclusion: Interband transition between Fermi level and 5d bands of the larger density of states in citrate capped dodecahedral colloidal gold nanoparticles of size above ~5nm leads to absorbance peak at ~260 nm, indicating a gap of ~4.77 eV between the Fermi level and closely spaced 5d bands. For smaller nanoparticles, absorption due to interband transition becomes more prominent relative to surface plasmon resonance absorption.

Effect of Voltage on Colloidal Gold (Au) Nanoparticles Produced Using Electro-Dissolution-Reduction Method

2015 ◽  
Vol 1115 ◽  
pp. 386-389
Author(s):  
Haroon Haiza ◽  
I.I. Yaacob ◽  
Ahmad Zahirani Ahmad Azhar
Keyword(s):  
Gold Nanoparticles ◽  
Electron Microscope ◽  
Colloidal Gold ◽  
Reduction Process ◽  
Chloride Ions ◽  
Complex Ions ◽  
Dc Power ◽  
Colloidal Gold Nanoparticles ◽  
Transmission Electron ◽  
The Mean

Colloidal gold nanoparticles have been successfully prepared using a simple two-electrode cells connected to a DC power supply. During the electro-dissolution-reduction process, the bulk gold at the anode oxidized into gold cations which then reacted with the chloride ions to form aurochloride complex. The complex ions were then reduced by the citrate ion to form colloidal gold nanoparticles. The size and shape of the nanoparticles were modulated by varying the terminal voltages. The colloidal gold nanoparticles obtained were characterized by field-emission scanning electron microscope (FESEM), transmission electron microscope (TEM) and ultraviolet-visible spectrophotometer (UV-Vis). From FESEM analysis, it was found that by increasing the voltage, the size of colloidal gold nanoparticles produced marginally decreased. The mean sizes of gold nanoparticles were roughly about 23.5 nm, 23.2 nm and 19.3 nm for 32 V, 36 V and 40 V, respectively. TEM micrograph showed that the shape of gold nanoparticles obtained is almost spherical. The characteristic peaks of UV-Vis spectra revealed that the suspension was indeed colloidal gold nanoparticles. Keywords: Gold, Nanoparticles, Electro-dissolution-reduction

Effect of Citrate Concentration on Colloidal Gold (Au) Nanoparticles Produced Using Electro-Dissolution-Reduction Method

2016 ◽  
Vol 840 ◽  
pp. 267-270
Author(s):  
Haroon Haiza ◽  
Iskandar Yaacob ◽  
Ahmad Zahirani Ahmad Azhar
Keyword(s):  
Gold Nanoparticles ◽  
Electron Microscope ◽  
Colloidal Gold ◽  
Reduction Process ◽  
Chloride Ions ◽  
Complex Ions ◽  
Citrate Concentration ◽  
Dc Power ◽  
Colloidal Gold Nanoparticles ◽  
Transmission Electron

Colloidal gold nanoparticles have been successfully synthesized using electro-dissolution-reduction process that consists of a simple two-electrode cells connected to a DC power supply. Throughout the process, bulk gold at the anode was oxidized into gold cations which then reacted with the chloride ions to form aurochloride complex. The complex ions were then reduced by the citrate ion to form colloidal gold nanoparticles. The size and shape of the nanoparticles were modulated by varying the citrate concentration. The colloidal gold nanoparticles obtained were characterized by field-emission scanning electron microscope (FESEM), transmission electron microscope (TEM) and ultraviolet-visible spectrophotometer (UV-Vis). From FESEM analysis, it was found that by increasing the citrate concentration, the size of colloidal gold nanoparticles produced marginally increased. The mean sizes of gold nanoparticles were roughly about 18.7 nm, 19.3 nm, 20.5 nm and 21.3 nm for citrate concentrations of 0.05 M, 0.10 M, 0.15 M and 0.20 M, respectively. However, sample prepared without the addition of citrate, remained colorless indicating that aurochloride complex ions were not reduced to colloidal gold nanoparticles. TEM micrographs showed that the shape of gold nanoparticles obtained is almost spherical. The characteristic peaks of UV-Vis spectra revealed that the suspension was indeed colloidal gold nanoparticles.Keywords: Gold, Nanoparticles, Electro-dissolution-reduction

A Simple Method to Self-Assemble Two-dimensional and Three-dimensional Superlattices of Gold Nanoparticles

2007 ◽  
Vol 1056 ◽  
Author(s):  
Tao Fu ◽  
Hai-Yan Qin ◽  
Wen-Jiang Li ◽  
Sailing He
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Gold Nanoparticles ◽  
Particle Dispersion ◽  
Diameter Distribution ◽  
Chloroauric Acid ◽  
Two Dimensional ◽  
Visible Absorption ◽  
Simple Method ◽  
Transmission Electron

ABSTRACTCitrate-capped gold nanoparticles with narrow diameter distribution were prepared by the reduction of chloroauric acid with borohydride. After the gold nanoparticles were transferred to toluene solution through ligand conformation change, close-packed two-dimensional nanocrystal lattices were obtained on transmission electron microscopy (TEM) copper grids by evaporating approximately 10 μL of concentrated particle dispersion. The formation of the thiolate gold nanoparticles was investigated by UV-visible absorption spectroscopy and FTIR spectra. The 2D Fourier transform power spectra of the monolayer confirmed the supperlattices' hexagonal symmetry. Furthermore, long-range-ordered bilayer superlattices, of which the nanoparticles in the top layer piled on the ones in the bottom layer, could also be observed by transmission electron microscopy.

scholarly journals Growth-controlled synthesis of polymer-coated colloidal-gold nanoparticles using electrospray-based chemical reduction

Particuology ◽  
2021 ◽  
Vol 57 ◽  
pp. 72-81
Author(s):  
Mohamed Hasaan Hussain ◽  
Noor Fitrah Abu Bakar ◽  
Kim-Fatt Low ◽  
Ana Najwa Mustapa ◽  
Fatmawati Adam ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Colloidal Gold ◽  
Chemical Reduction ◽  
Controlled Synthesis ◽  
Colloidal Gold Nanoparticles

scholarly journals Synthesis and Optical Properties of Colloidal Gold Nanoparticles for Biomedical Applications

2011 ◽  
Vol 21 (1) ◽  
pp. 63 ◽  
Author(s):  
Nghiem Thi Ha Lien ◽  
Vu Xuan Hoa ◽  
Vu Thi Thuy Duong ◽  
Nguyen Van Tinh ◽  
Tran Hong Nhung
Keyword(s):  
Gold Nanoparticles ◽  
Colloidal Gold ◽  
Biomedical Applications ◽  
Strong Dependence ◽  
Trisodium Citrate ◽  
Visible Range ◽  
Chloroauric Acid ◽  
Stabilizing Agents ◽  
Colloidal Gold Nanoparticles ◽  
The Stability

The gold nanoparticle solutions are well known as an extremely sensitive biomedical analytical tool due to the strong dependence of their absorption in the visible range on the environment. In this work, the colloidal nano golds were synthesized from metal precursor chloroauric acid (HAuCl4) using trisodium citrate dehydrate (C6H5O7Na3) as reducing and stabilizing agents. The optical characterization - absorption of colloidal gold solution have been investigated under the different synthetic conditions such as: reducing agent concentration, concentration of auric ion, pH, duration of reaction and aging time. The results show that the absorption and the stability of the colloidal gold nanoparticles depend robustly on the synthetic conditions and pH of environment.

scholarly journals Semi-Biosynthesis of Magnetite-Gold Composite Nanoparticles Using an Ethanol Extract ofEucalyptus camaldulensisand Study of the Surface Chemistry

2009 ◽  
Vol 2009 ◽  
pp. 1-5 ◽  
Author(s):  
Emad al din Haratifar ◽  
Hamid Reza Shahverdi ◽  
Mojtaba Shakibaie ◽  
Kamyar Mollazadeh Moghaddam ◽  
Mohsen Amini ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Surface Chemistry ◽  
Eucalyptus Camaldulensis ◽  
Ethanol Extract ◽  
Uv Spectra ◽  
Composite Nanoparticles ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
Transmission Electron ◽  
20 Nm

Green synthesis of metal nanoparticles, such as silver or gold nanoparticles, has been attracting increasing attention in recent years. Functionalized magnetite nanoparticles have many uses in various applications, including nanoelectronic devices, molecular recognition, biomedical applications, drug delivery targeting, and optical devices. In this investigation, magnetic cores (Fe3O4) were synthesized using a fabrication method involving coprecipitation ofFe2+andFe3+. In the next step, magnetite-gold composite nanoparticles were synthesized with size ranging from 6–20 nm, using an ethanol extract ofEucalyptus camaldulensisas a natural reducing agent. Transmission electron microscopy, energy-dispersive spectroscopy, X-ray diffraction spectroscopy, and visible absorption spectroscopy confirmed the fabrication of magnetite-gold composite nanoparticles. In the UV spectra diagram, a red-shift of the surface plasmon of the Au was evidence that contact between gold andFe3O4had occurred. The surface chemistry of the as-prepared magnetite-gold nanoparticles was studied using infrared spectroscopy. The presence of organic compounds with a carboxyl moiety was confirmed on the surface of the magnetite-gold nanoparticles fabricated by this combined chemical and biological reducing process, which we have designated as a semi-biosynthesis method.

Dense aqueous colloidal gold nanoparticles prepared from highly concentrated precursor solution

2011 ◽  
Vol 362 (2) ◽  
pp. 325-329 ◽  
Author(s):  
Tetsuro Soejima ◽  
Seisaku Oshiro ◽  
Yasuji Nakatsuji ◽  
Seishiro Ito
Keyword(s):  
Gold Nanoparticles ◽  
Colloidal Gold ◽  
Precursor Solution ◽  
Colloidal Gold Nanoparticles
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