scholarly journals Novelty Au Nanoparticles with Different Nano Sizes as an Acidity Sensor

2021 ◽  
Vol 31 (3) ◽  
pp. 167-173
Author(s):  
Zehraa Najim Abdul-Ameer
Keyword(s):  
Particle Size ◽  
Gold Nanoparticles ◽  
Au Nanoparticles ◽  
Energy Gap ◽  
Uv Spectroscopy ◽  
Ph Sensor ◽  
Spherical Shape ◽  
Optical Energy Gap ◽  
Covalent Bonds ◽  
Wide Range

The amazing wide range, applications of gold nanoparticles corresponding to excellent optical and electronic properties enhance utilization of Au NP as PH sensor. Gold nanoparticles were synthesized in simple and rapid Turkevich method to accomplish optical sensing technologies covalent or non-covalent, bonds formation causes, aggregation of the nanoparticles in the target substance. Au nanoparticles characterization was studied using XRD, UV-spectroscopy and SEM. XRD indicate polycrystalline. Nanoparticles with two different sizes according to reducing agent amount to obtain 20 30 nm. Optical energy gap was calculated for both particle size to find it (2.13) eV for 30nm particle size and (2.33) eV for 20nm.Scanning Electron Microscope showed spherical shape particles. PH test were performed to investigate efficiency of Au Np’s for PH sensor and that is found to be excellent results for both sizes with more efficiency for 30 nm due to its rough surface. Which is a fantastic tool and measurement device to test the pH of soil, food, and other puncture-worthy applications.

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 new strategy for the green synthesis of chondroitin sulfate-reduced gold nanoparticles; in vitro evaluation of synthesized nanoparticles

Bioimpacts ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 217-226
Author(s):  
Maryam Asariha ◽  
Azam Chahardoli ◽  
Farshad Qalekhani ◽  
Mahnaz Ghowsi ◽  
Mehdi Fouladi ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Antibacterial Activity ◽  
Green Synthesis ◽  
Chondroitin Sulfate ◽  
Blood Compatibility ◽  
Spherical Shape ◽  
Hemolysis Assay ◽  
Wide Range ◽  
New Strategy

introduction: The application of gold nanoparticles (GNPs) in medicine is expanding as an effective therapeutic and diagnostic compound. Different polysaccharides with high biocompatibility and hydrophilic properties have been used for synthesis and capping of GNPs. Chondroitin sulfate (CHS) as a polysaccharide possesses a wide range of biological functions e.g. anti-oxidant, anti-inflammation, anti-coagulation, anti-atherosclerosis, anti-thrombosis with insignificant immunogenicity and has not been used for the green synthesis of GNPs. Methods: GNPs were synthesized using CHS, and their physicochemical properties were evaluated. The antibacterial activity of CHS-GNPs was estimated against both gram-positive and gram-negative bacteria. The cytotoxicity of CHS and CHS-GNPs was obtained by MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) test, and the electrocatalytic activity of CHS-GNPs was investigated. The blood compatibility was evaluated by the in vitro hemolysis assay. Results: The absorption band at 527 nm reveals the reduction of Au3+ into GNPs. The transmission electron microscopy (TEM) image displays the spherical shape of GNPs in the range of 5.8–31.4 nm. The CHS and CHS-GNPs at 300 µg/mL revealed a maximum DPPH (1, 1-diphenyl-2-picrylhydrazyl) scavenging activity of 73% and 65%, respectively. CHS-GNPs showed antibacterial activity against Bacillus subtilis, while CHS has no antibacterial activity. CHS-GNPs exhibited a cytotoxicity effect against MDA-MB-468 and βTC3 cancer cell lines, and the electrochemical study indicated a significant increase in electrocatalytic properties of CHS-GNPs coated electrode compared by the bare electrode. The hemolysis test proved the blood compatibility of CHS-GNPs. Conclusion: The results indicate the advantages of using CHS to produce blood-compatible GNPs with antioxidant, cytotoxic, and electrochemical properties.

scholarly journals Thermal Atomic Layer Deposition of Gold Nanoparticles: Controlled Growth and Size Selection for Photocatalysis

2019 ◽  
Author(s):  
Fatemeh Sadat Minaye Hashemi ◽  
Fabio Grillo ◽  
Vikram Ravikumar ◽  
dominik Benz ◽  
Ankit Shekhar ◽  
...  
Keyword(s):  
Particle Size ◽  
Gold Nanoparticles ◽  
Atomic Layer Deposition ◽  
Au Nanoparticles ◽  
Atomic Layer ◽  
Structure Property ◽  
Structure Property Relationships ◽  
Layer Deposition ◽  
Catalytically Active ◽  
Au Particle Size

Gold nanoparticles have been extensively studied for their applications in catalysis. For Au nanoparticles to be catalytically active, controlling the particle size is crucial. Here we present a low temperature (105 °C) thermal atomic layer deposition approach for depositing gold nanoparticles on TiO<sub>2</sub> with controlled size and loading using trimethylphosphino-trimethylgold (III) and two co-reactants (ozone and water) in a fluidized bed reactor. We show that the exposure time of the precursors is a variable that can be used to decouple the Au particle size from the Au loading. Longer exposures of ozone narrow the particle size distribution while longer exposures of water broaden it. By studying the photocatalytic activity of Au/TiO<sub>2</sub> nanocomposites we show how the ability to control particle size and loading independently can be used not only to enhance performance but also to investigate structure-property relationships. This study provides insights into the mechanism underlying formation and evolution of Au nanoparticles via a vapor phase technique which eliminates the shortcomings of conventional liquid-base processes.

Spectroscopic Studies of Polypyrrole - PVA Reinforced Iraqi Bentonite Clay Composites

2021 ◽  
Vol 19 (11) ◽  
pp. 151-157
Author(s):  
Shaymaa Hadi Al-Rubaye ◽  
Eman Hammod Abdullah ◽  
Amar Al-Keisy
Keyword(s):  
Particle Size ◽  
Energy Gap ◽  
Wave Length ◽  
Bentonite Clay ◽  
Spectroscopic Studies ◽  
Optical Energy Gap ◽  
Weight Percentage ◽  
Length Increase ◽  
Vis Spectroscopy ◽  
Composite Samples

The mixture of Polypyrrole solution with polyvinyl alcohol reinforced Iraqi Bentonite clay are used for preparing a composite that investigated in this study. The weight percentage of bentonite used is 5, 10, 15, and 20 and the particle size selected is less than 75 μm. Composite samples prepared has a thickness of 0.15mm and dimensions of 2.6×2.8 cm2. The optical properties of polymer composites were studied using UV-Vis spectroscopy. The values of optical energy gap decreased from 5.44, 5.41, 5.38 and 5.28 eV for the 5, 10, 15, and 20 wt% of bentonite respectively, and the absorption coefficient increased. The extinction coefficient increases with increasing additive bentonite and decreases as the incident wave length increase. The present work is very important for tailoring the optical response of Polypyrrole – bentonite composites according to specific requirements.

Effect of TiO2-In2O3 and TiO2-Al2O3 Sol-Gel Supports on the Morphology of Gold Nanoparticles

2009 ◽  
Vol 5 ◽  
pp. 1-12 ◽  
Author(s):  
Vicente Rodríguez-González ◽  
S. Castillo ◽  
F.M. Morán-Pineda ◽  
R. Zanella ◽  
Ricardo Gómez
Keyword(s):  
Particle Size ◽  
Gold Nanoparticles ◽  
Au Nanoparticles ◽  
Sol Gel ◽  
Precipitation Method ◽  
Al2o3 Support ◽  
Different Shapes ◽  
The Mean ◽  
Effect Of Support

We report the findings concerning the preparation and characterization of Au nanoparticles deposited on sol-gel derived TiO2, TiO2-Al2O3 and TiO2-In2O3 semiconductors. The gold nanoparticles were obtained by the deposition-precipitation method using urea. The mean particle size was determined by HAADF-STEM. The gold nanoparticles ranged form 2.4 to 4.4 nm, and the smallest corresponding to the TiO2-Al2O3 support was 2.4 nm. The effect of support on the growth of the gold nanoparticles was analyzed by HRTEM. The gold nanoparticles showed different shapes depending on the semiconductor supports. Truncated cuboctahedral gold nanoparticles were identified and analyzed.

scholarly journals Optical properties of annealed As30Te67Ga3 thin films grown by thermal evaporation

2018 ◽  
Vol 12 (3) ◽  
pp. 209-217 ◽  
Author(s):  
Alaa Abd-Elnaiem ◽  
Samar Moustafa
Keyword(s):  
Optical Properties ◽  
Glass Transition ◽  
Chalcogenide Glasses ◽  
Annealing Temperature ◽  
Thermal Evaporation ◽  
Energy Gap ◽  
Dielectric Constants ◽  
Heating Rates ◽  
Optical Energy Gap ◽  
Wide Range

Chalcogenide glasses have received lots of attention because of their superior optical properties. To optimize these properties and expand areas of applications, more studies are required to establish the extent to which the parameters can be tuned over a wide range of annealing temperatures and heating rates. To do this, bulk and thin ?150 nm As30Te67Ga3 films were prepared by melt-quenching and thermal evaporation techniques, respectively. The phase transition was investigated using differential scanning calorimeter (DSC) while the crystal structures were studied by X-ray diffraction (XRD). Characteristic temperatures such as the glass transition, crystallization and melting temperature of the bulk glass were found to depend on the heating rate. The activation energy of glass transition was 167.29 kJ/mol while the energy of crystallization was 103.98 kJ/mol. XRD results indicated that the annealed films showed more crystallinity, larger average crystallite size, lower dislocation density and lower strain as annealing temperature increased. According to the Avrami exponent, a combination of two and three-dimensional crystal growth with heterogeneous nucleation are possible mechanisms for the crystallization process. Moreover, optical constants such as the optical band gap, refractive index, extinction coefficient, high-frequency dielectric constants, real and imaginary parts of dielectric constants were found to strongly depend on the annealing temperature. The optical energy gap decreased from 1.1 to 0.89 eV as the annealing temperature increased from 373 to 433K. These results indicate that thermal annealing is a major factor that can be used to tune the crystal structure, and hence the optical properties of As30Te67Ga3 system.

scholarly journals BIOSYNTHESIS AND CHARACTERIZATION OF GOLD NANOPARTICLES AND THEIR INTERACTION STUDY WITH METFORMIN

2020 ◽  
Vol 21 (2) ◽  
pp. 56
Author(s):  
Dian Anggraini ◽  
Siti Suhartati ◽  
Iwan Syahjoko Saputra ◽  
Sudirman Sudirman
Keyword(s):  
Particle Size ◽  
Gold Nanoparticles ◽  
Leaf Extract ◽  
Average Particle Size ◽  
Synthesis Method ◽  
Spherical Shape ◽  
Imperata Cylindrica ◽  
Average Particle ◽  
Interaction Study

BIOSYNTHESIS AND CHARACTERIZATION OF GOLD NANOPARTICLES AND THEIR INTERACTION STUDY WITH METFORMIN. Synthesis of gold nanoparticles successfully carried using Imperata cylindrica L leaf extract. In this study, the approach used through green synthesis method is a reaction betwen of the HAuCl4 solution (concentration variation as 3; 5; 7 x 10-4 M) with Imperata cylindrica L leaf extract. Results of UV-Vis showed of gold nanoparticles has a maximum wavelength at 530 nm with absorbance value of 1.4. Results of FTIR shows a shift the absorption peak at wavenumber of 3392 cm-1 to 3404 cm-1. PSA and PZC showed the distribution of gold nanoparticles was 48.84 nm with a charge of 20.5 mV. Gold nanoparticles has a spherical shape and an average particle size of 20 nm which can be seen from the results of the characterization using TEM. XRD showed crystalize size average of gold nanoparticles as 20.47 nm. The interaction between of gold nanoparticles with metformin can be seen in the absorbance decrease of 0.38 at a wavelength of 531 nm and the results of PSA shows an average particle size of AuNPs@metformin is 122 nm. From the characterization data can be concluded the gold nanoparticles were successfully synthesized using natural bioreductors by utilizing secondary metabolites from Imperata cylindrica L leaf extract.

scholarly journals Green Synthesis and the Study of Some Physical Properties of MgO Nanoparticles and Their Antibacterial Activity

2020 ◽  
pp. 266-276
Author(s):  
Rand Ali ◽  
Zainab Jassim ◽  
Ghada Muhammad Saleh ◽  
Quraysh Abass
Keyword(s):  
Particle Size ◽  
Antibacterial Activity ◽  
Energy Gap ◽  
Average Particle Size ◽  
Spherical Shape ◽  
Magnesium Nitrate ◽  
Average Particle ◽  
Force Microscopy ◽  
Atomic Force ◽  
The Impact

     Magnesium oxide nanoparticles (MgO NPs) were synthesized by a green method using the peels of Persimmon extract as the reducing agent , magnesium nitrate, and NaOH. This method is eco-friendly and non-toxic. In this study, an ultrasound device was used to reduce the particle size, with the impact on the energy gap was set at the beginning at 5.39 eV and then turned to 4.10 eV. The morphological analysis using atomic force microscopy (AFM)  showed that the grain size for MgO NPs was 67.70 nm which became 42.33 nm after the use of the ultrasound. The shape of the particles was almost spherical and became cylindrical.  In addition the Field-Emission Scanning Electron Microscopy (FESEM) analysis showed that the average particle size was reduced and the spherical shape was changed into cylindrical flakes. The antibacterial activity of MgO Nps was measured against both gram positive and negative bacteria (Staphylococcus aureus and Escherichia coli, respectively) for both the synthesized and the scaled-down particles by the ultrasonic. MgO NPs showed an efficacy at a minimum inhibitory concentration (MIC) of 500 μg/ml, with the better effect being observed after the ultrasonic treatment of the MgO NPs.

MODIFICATION INDUCED BY PROTON IRRADIATION IN BAYFOL UV1 7-2 NUCLEAR TRACK DETECTOR

2018 ◽  
Vol 183 (4) ◽  
pp. 450-459 ◽  
Author(s):  
S A Nouh ◽  
N Gaballah ◽  
A Abou Elfadl ◽  
S A Alsharif
Keyword(s):  
Proton Irradiation ◽  
Dynamic Range ◽  
Energy Gap ◽  
Uv Spectroscopy ◽  
Ion Beam ◽  
Radiation Detection ◽  
Track Detector ◽  
Optical Energy Gap ◽  
Nuclear Track Detector ◽  
Polymeric Solid

Abstract Bayfol is a class of polymeric solid state nuclear track detector which has many applications in various radiation detection fields. It is a Makrofol polycarbonate/polyester blend. Samples from Bayfol film have been irradiated with different fluences (1011−1014 p/cm2) of 1 MeV protons at the University of Surrey Ion Beam Center, UK. The resultant effect of proton irradiation on the structural and optical properties of the Bayfol samples has been investigated using X-ray diffraction, Fourier Transform Infrared and UV spectroscopy. The optical energy gap was decreased from 4.24 to 4.03 eV with increasing the proton fluence from 1011 to 1013 p/cm2, and was accompanied by an increase in the Urbach energy from 0.79 to 1.29 eV. This could be correlated to the results obtained from XRD and FTIR spectroscopy. Further, the non-irradiated Bayfol is nearly colorless. It showed significant sensitivity to color by proton irradiation, associated with an increase in the red and yellow color components. The variation of optical and color parameters with the proton fluence indicate that the dynamic range of Bayfol UV1 7-2 is in the fluence range from 1011 to 1013 p/cm2.

Synthesis of Chitosan-Gold Nanoparticles for Drug Delivery

2014 ◽  
Vol 896 ◽  
pp. 280-283 ◽  
Author(s):  
Hanani Yazid ◽  
Amirah Mohd Yassin ◽  
Ahmad Zahid Ruslan ◽  
Siti Hajar Alias ◽  
Rohana Adnan ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Particle Size ◽  
Gold Nanoparticles ◽  
Environmental Remediation ◽  
Gold Salt ◽  
Au Nps ◽  
Chitosan Concentration ◽  
Wide Range ◽  
Potential Applications ◽  
Au Particle Size

Gold nanoparticles (Au NPs) have potential applications in catalysis, drug delivery, sensors and environmental remediation. This wide range application is due to its amenability of synthesis and functionalization, less toxicity and ease of detection. The present work focuses on functionalization of Au NPs with chitosan for further application in biomedical research. Gold nanoparticles (Au NPs) functionalized chitosan were prepared by reducing gold salt solution at various pH medium in the presence of sodium borohydride. The effect of pH and chitosan concentration on the Au particle size and distribution are studied. The results revealed the dependence of Au particle size on the pH of the solution. The smallest Au particle size is found to form in a range of 10.22 ± 2.96 nm at 0.2% chitosan concentration. In this study, we anticipate the Au NPs functionalized chitosan can be used for drug delivery applications.

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