scholarly journals Optical Nonlinear Refractive Index of Laser-Ablated Gold Nanoparticles Graphene Oxide Composite

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Amir Reza Sadrolhosseini ◽  
A. S. M. Noor ◽  
Nastaran Faraji ◽  
Alireza Kharazmi ◽  
Mohd. Adzir Mahdi
Keyword(s):  
Particle Size ◽  
Gold Nanoparticles ◽  
Refractive Index ◽  
Graphene Oxide ◽  
Gold Nanoparticle ◽  
Spherical Shape ◽  
Refractive Indices ◽  
Hydroxyl Groups ◽  
Uv Visible ◽  
Laser Ablation Technique

Gold nanoparticles were prepared in graphene oxide using laser ablation technique. The ablation times were varied from 10 to 40 minutes, and the particle size was decreased from 16.55 nm to 5.18 nm in spherical shape. The nanoparticles were capped with carboxyl and the hydroxyl groups were obtained from Fourier transform infrared spectroscopy. Furthermore, the UV-visible peak shifted with decreasing of nanoparticles size, appearing from 528 nm to 510 nm. The Z-scan technique was used to measure the nonlinear refractive indices of graphene oxide with different concentrations and a gold nanoparticle graphene oxide nanocomposite. Consequently, the optical nonlinear refractive indices of graphene oxide and gold nanoparticle graphene oxide nanocomposite were shifted from1.63×10-9 cm2/W to4.1×10-9 cm2/W and from1.85×10-9 cm2/W to5.8×10-9 cm2/W, respectively.

scholarly journals A Sensitive Resonance Rayleigh Scattering Method for Na+ Based on Graphene Oxide Nanoribbon Catalysis

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Haidong Wang ◽  
Chongning Li ◽  
Yanghe Luo ◽  
Zhiliang Jiang
Keyword(s):  
Gold Nanoparticles ◽  
Graphene Oxide ◽  
Detection Limit ◽  
Gold Nanoparticle ◽  
Rayleigh Scattering ◽  
Resonance Rayleigh Scattering ◽  
Scattering Method ◽  
Graphene Oxide Nanoribbons ◽  
Potassium Pyroantimonate ◽  
Coordination Reaction

The gold nanoparticle reaction of HAuCl4-H2O2 was very slow under 60°C, and the as-prepared graphene oxide nanoribbons (GONRs) exhibited strong catalysis of the reaction to form gold nanoparticles (AuNP) that appeared a resonance Rayleigh scattering (RRS) peak at 550 nm. Upon addition of potassium pyroantimonate (PA) ligand, it was adsorbed on the GONRs surface to inhibit the catalysis to cause the RRS peak decreasing. When the analyte of Na+ was added, the coordination reaction between PA and Na+ took place to form the stable complexes of [Na2(PA)] to release free GONRs catalyst that resulted in the RRS peak increasing linearly. Accordingly, a new and sensitive RRS method for Na+ was established, with a linear range of 0.69-25.8 nmol/L and a detection limit of 0.35 nmol/L Na+.

scholarly journals Green Nanoparticles for Mosquito Control

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Namita Soni ◽  
Soam Prakash
Keyword(s):  
Gold Nanoparticles ◽  
Mosquito Control ◽  
Spherical Shape ◽  
Probit Analysis ◽  
Bark Extract ◽  
Green Method ◽  
Silver And Gold Nanoparticles ◽  
Transmission Electron ◽  
Uv Visible ◽  
Filariasis Vector

Here, we have used the green method for synthesis of silver and gold nanoparticles. In the present study the silver (Ag) and gold (Au) nanoparticles (NPs) were synthesized by using the aqueous bark extract of Indian spice dalchini (Cinnamomum zeylanicum) (C. zyelanicumorC. verumJ. Presl). Additionally, we have used these synthesized nanoparticles for mosquito control. The larvicidal activity has been tested against the malaria vectorAnopheles stephensiand filariasis vectorCulex quinquefasciatus. The results were obtained using UV-visible spectrophotometer and the images were recorded with a transmission electron microscope (TEM). The efficacy tests were then performed at different concentrations and varying numbers of hours by probit analysis. The synthesized AgNPs were in spherical shape and average sizes (11.77 nm AgNPs and 46.48 nm AuNPs). The larvae ofAn. stephensiwere found highly susceptible to the synthesized AgNPs and AuNPs than theCx. quinquefasciatus. These results suggest that theC. zeylanicumsynthesized silver and gold nanoparticles have the potential to be used as an ideal ecofriendly approach for the control of mosquito.

Optical Properties and Detection Sensitivity of Noble Metal Nanoparticles

2018 ◽  
Vol 10 (3) ◽  
pp. 346-350
Author(s):  
Hongyan Zhao ◽  
Xin Liu ◽  
Shoubao Zhang ◽  
Xiaoli Liu ◽  
Rende Ma ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Silver Nanoparticles ◽  
Refractive Index ◽  
Extinction Spectrum ◽  
Spectral Characteristics ◽  
Resonance Wavelength ◽  
Detection Sensitivity ◽  
Noble Metal Nanoparticles ◽  
Localized Surface Plasmon ◽  
Refractive Indices

By using the finite difference time domain method, the localized surface plasmon extinction spectrum of different sizes of spherical gold and silver nanoparticles were simulated and analyzed in external environments with various refractive indices. It was observed that the changes in the position of the resonance wavelength were linearly proportional to the external refractive index, while the sensitivity increased with nanoparticle size. The sensitivity of the spherical silver nanoparticles with a radius of 40 nm reached 122 nm/RIU. For the silver and gold nanoparticles of the same size, the sensitivity of the silver nanoparticles was greater than that of the gold nanoparticles. In the experiment, the spectral characteristics of the silver nanoparticles with different sizes under various external refractive indices were measured. The experimental results were consistent with the simulation results. The resonance wavelength and the concentration of the solution showed a good linear relationship. By using the sensitive properties of the nanoparticles such as external refractive index, the amount of sucrose in the solution can be measured.

scholarly journals Green Fabrication of Copper Nanoparticles Dispersed in Walnut Oil Using Laser Ablation Technique

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Amir Reza Sadrolhosseini ◽  
Suraya Abdul Rashid ◽  
Azmi Zakaria ◽  
Kamyar Shameli
Keyword(s):  
Particle Size ◽  
Laser Ablation ◽  
Copper Nanoparticles ◽  
Volume Fraction ◽  
Spherical Shape ◽  
Copper Plate ◽  
Refractive Indices ◽  
Walnut Oil ◽  
Laser Ablation Method ◽  
Environmentally Sensitive

Synthesis of copper nanoparticles was achieved by laser irradiation of copper plate in walnut oil. The copper plate was irradiated using Nd:YAG pulse laser at different ablation time from 5 to 50 minutes, and the prepared samples were characterized using analytical methods to find the optical absorption, morphology, particle size, and capping of copper nanoparticles with walnut oil. Consequently, the absorption peak appeared at about 615, 606, 588, 576, and 561 nm; and the nanoparticles formed in spherical shape in walnut oil. The particle size varied from 25 to 4.01 nm, and the tail of the carbonyl band capped the copper nanoparticles through the electron transfer from the carboxylic group to copper nanoparticles. The refractive indices of the nanofluid were measured using a surface plasmon resonance technique and changed from 1.4691 + 0.008i to 1.4682 + 0.043i as the volume fraction increased from 0.0257 × 10−5to 1.26 × 10−5. Consequently, the laser ablation method is environmentally sensitive (i.e., green) and thus is suitable for the fabrication of copper nanoparticles in walnut oil without any agent.

scholarly journals Synthesis of Horseradish Peroxidase-Gold Nanoparticle Conjugate through Green Route

2020 ◽  
Vol 32 (5) ◽  
pp. 1243-1247
Author(s):  
Lovnish Siyal ◽  
Benu Kumar ◽  
Ranjit Kumar ◽  
Rachana Sahney
Keyword(s):  
Gold Nanoparticles ◽  
Enzyme Activity ◽  
Horseradish Peroxidase ◽  
Gold Nanoparticle ◽  
Catalytic Efficiency ◽  
Hydrodynamic Diameter ◽  
Green Route ◽  
Peroxidase Enzyme ◽  
Uv Visible ◽  
Average Hydrodynamic Diameter

Synthesis of horseradish peroxidase-gold nanoparticle conjugates (HRP-AuNPs) has been studied for the development of biofunctionalized gold nanoparticles (AuNPs) through biogenic route. Herein, horseradish peroxidase enzyme has been used to synthesize gold nanoparticles at room temperature in tricine buffer. The morphology and size distribution of HRP-AuNPs conjugates were obtained by different techniques including dynamic light scattering (DLS), UV-visible (UV-vis) spectrophotometry, scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). The enzyme activity of HRP-AuNP conjugate was compared with free enzyme to determine their catalytic efficiency. The results suggests that HRP-AuNP conjugates are monodisperse particles with average hydrodynamic diameter of 83.93 ± 2.1 nm, zeta potential of about -18.4 ± 1.1 mV and higher enzyme activity towards H2O2 as compared to free horseradish peroxidase. These biofunctionalized gold nanoparticles could act as tag or labeling agent for various applications.

scholarly journals Continuous flow synthesis of citrate capped gold nanoparticles using UV induced nucleation

RSC Advances ◽  
2017 ◽  
Vol 7 (16) ◽  
pp. 9632-9638 ◽  
Author(s):  
H. du Toit ◽  
T. J. Macdonald ◽  
H. Huang ◽  
I. P. Parkin ◽  
A. Gavriilidis
Keyword(s):  
Particle Size ◽  
Gold Nanoparticles ◽  
Gold Nanoparticle ◽  
Continuous Flow ◽  
Nanoparticle Synthesis ◽  
Nucleation And Growth ◽  
Reactor System ◽  
Growth Phases ◽  
Flow Synthesis ◽  
Gold Nanoparticle Synthesis

A novel multimodal reactor system for separating the nucleation and growth phases of gold nanoparticle synthesis to control particle size.

scholarly journals XRD-HTA, UV Visible, FTIR and SEM Interpretation of Reduced Graphene Oxide Synthesized from High Purity Vein Graphite

2017 ◽  
Vol 14 (1) ◽  
pp. 19-30 ◽  
Author(s):  
C. H Manoratne ◽  
S. R. D. Rosa ◽  
I. R. M. Kottegoda
Keyword(s):  
Particle Size ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Reduction Process ◽  
Bet Surface Area ◽  
High Quality ◽  
Graphene Layers ◽  
Reduced Graphene ◽  
Uv Visible ◽  
Vein Graphite

Attempts were made to synthesize high quality graphite oxide (GO) and reduced graphene oxide (rGO) by using successive oxidation-reduction process of high quality vein graphite from Sri Lanka. We report the lowest optimum reduction temperature for converting GO to rGO which has been systematically studied using X-ray diffraction spectroscope (XRD) with the high temperature heating attachment (HTA) for the first time. The effect of particle size of graphite on properties of GO and rGO is also compared using commercially available graphite of particle size of ~111 mm and ball-milled graphite of particle size ~37 mm. The GO and rGO were characterized using XRD, UV-Visible spectroscopy, Fourier Transform Infrared spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). The GO and rGO synthesized from ball-milled graphite showed higher oxidation and reduction properties as verified through the UV-Vis and FTIR analysis. The SEM analysis revealed that the splitting of graphene layers is efficiently taken place in GO from ball-milled graphite. The lowest optimum temperature for thermal reduction of GO to rGO was found to be at 475 °C. FTIR confirmed the removal of most of the functional groups in rGO and according to the BET surface area analysis few layers, supposed to be 2-6 is formed. The efficient oxidation and reduction process of smaller particle size graphite has led to yield highly oxidized GO and high quality rGO which can be used to prepare high quality graphene for future applications.

scholarly journals A thio-β-cyclodextrin functionalized graphene/gold nanoparticle electrochemical sensor: a study of the size effect of the gold nanoparticles and the determination of tetrabromobisphenol A

RSC Advances ◽  
2019 ◽  
Vol 9 (31) ◽  
pp. 17897-17904
Author(s):  
Suxing Luo ◽  
Yuanhui Wu ◽  
Qingsong Mou ◽  
Jinhai Li ◽  
Xiaoxue Luo
Keyword(s):  
Gold Nanoparticles ◽  
Graphene Oxide ◽  
Size Effect ◽  
Gold Nanoparticle ◽  
Glassy Carbon ◽  
Tetrabromobisphenol A ◽  
Carbon Electrode ◽  
Functionalized Graphene ◽  
Modified Glassy Carbon Electrode

In this study, a novel tetrabromobisphenol A (TBBPA) sensor was fabricated based on a CTAB-capped gold nanoparticle (AuNP)-thio-β-cyclodextrin (SH-β-CD)/graphene oxide modified glassy carbon electrode (GCE).

scholarly journals Excess Molar Quantities of Binary Mixture of Dipropyl amine with Aliphatic Alcohols at 298.15 K

2018 ◽  
Vol 34 (4) ◽  
pp. 2074-2082 ◽  
Author(s):  
Zainab A. H. Al-Dulaimy ◽  
Dhafir T. A. Al-Heetimi ◽  
Husam Saleem Khalaf ◽  
Ahmed Mohammed Abbas
Keyword(s):  
Free Energy ◽  
Refractive Index ◽  
Binary Mixture ◽  
Excess Molar Volumes ◽  
Standard Errors ◽  
Refractive Indices ◽  
Hydroxyl Groups ◽  
Molar Gibbs Free Energy ◽  
Viscosity Deviations ◽  
Refractive Index Deviations

Refractive indices (nD), viscosities (η) and densities (ρ) were deliberated for the binary mixtures created by dipropyl amine with 1-octanol, 1-heptanol, 1-hexanol, 1-pentanol and tert-pentyl alcohol at temperature 298.15 K over the perfect installation extent. The function of Redlich-Kister were used to calculate and renovated of the refractive index deviations (∆nD), viscosity deviations (ηE), excess molar Gibbs free energy (∆G*E) and excess molar volumes (VmE) The standard errors and coefficients were respected by this function. The values of ∆nD, ηE, VmE and ∆G*E were plotted against mole fraction of dipropyl amine. In all cases the obtained ηE, ∆G*E, VmE and ∆nD values were negative at 298.15K. Effect of carbon atoms number in the chain of alcohol and hydroxyl groups' position on molecular interactions in these mixtures has also been discussed.

scholarly journals Characterization and biodistribution of trans resveratrol-PEG-folic acid-gold nanoparticle conjugates

2022 ◽  
Vol 20 (2) ◽  
pp. 223-230
Author(s):  
Azhoma Gumala ◽  
Sutriyo ◽  
Fadlina Chany Saputri
Keyword(s):  
Particle Size ◽  
Folic Acid ◽  
Zeta Potential ◽  
Gold Nanoparticle ◽  
High Performance ◽  
Spherical Shape ◽  
Systemic Circulation ◽  
Sprague Dawley ◽  
Biodistribution Data ◽  
Sprague Dawley Rats

Purpose: To evaluate the characteristics and biodistribution of trans resveratrol-PEG-folic acid-gold nanoparticle conjugates (rsv-PEG-FA-AuNP). Methods: Gold nanoparticles were produced by citric reduction followed by conjugation of PEG-folic acid and resveratrol. Characterization of rsv-PEG-FA-AuNP conjugates including their particle size, zeta potential, and by Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM) was carried out. Biodistribution study of rsv-PEG-FA-AuNP was carried out using female Sprague Dawley rats. Biodistribution data were obtained from high performance liquid chromatography (HPLC) analysis. Results: The mean particle size and zeta potential of rsv-PEG-FA-AuNP were 249.03 ± 10.31 and - 36.33 ± 3.12 mV, respectively. TEM images showed rsv-PEG-FA-AuNP conjugates formed spherical shape. Rsv-PEG-FA-AuNP conjugates found in plasma, kidney (1.90 ± 0.20 μg/g), spleen (2.65 ± 1.18 μg/g), liver (1.74 ± 0.03 μg/g), and lung (1.82 ± 0.12 μg/g), after 90 minutes intravenous administration (i.v.) in female Sprague Dawley rats. No free resveratrol was found in plasma, kidney, or spleen after i.v administration in female dawdle Sprague Dawley rats. Conclusion: Resveratrol-PEG-FA-AuNP conjugates appear to be a potential chemotherapy delivery system for active targeting purposes because of its longer systemic circulation and its accumulation in the kidney.

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