Variation of Sputtered WO2.72 Film Thickness in Ag (NPs)/WO2.72/Au (NPs) System for Optimizing Sensing Behaviors to NH3

AbstractGreen fabrication of metal nanoparticles (NPs), using natural reducing and stabilizing agents existed in plants and their derivatives, due to their unique properties, has gained more attention. The present study focuses on the synthesis of gold (Au), silver (Ag) and selenium (Se) NPs using coffee bean extract under hydrothermal conditions (1.5 atm and 121°C, for 15 min). Coffee bean extract obtained in 2 h processing using Clevenger apparatus and Fourier transform-infrared (FT-IR) spectroscopy indicated five highlighted peaks, namely, hydroxyl, amide, aromatic, alkane and ring groups. Dynamic light scattering analysis revealed that among three different NPs formed, fabricated Ag NPs had small particle size (153 nm) and high zeta potential value (16.8 mV). However, synthesized Au NPs had minimum polydispersity index (0.312). Results also indicated that fabricated Au, Se and Ag NPs had low antioxidant activity with values of 9.1, 8.9 and 8.7%, respectively. Morphological and antibacterial activity assessments, demonstrated that synthesized Ag, Au and Se NPs had spherical shape and high bactericidal activity against E. coli and S. aurous. Obtained results indicated that the synthesized NPs, can be utilized in various areas.

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State-of-art of silver and gold nanoparticles synthesis routes, characterization and applications: a review

Zeitschrift für Physikalische Chemie ◽

10.1515/zpch-2021-3084 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Faisal Ali ◽

Muhammad Hamza ◽

Munawar Iqbal ◽

Beriham Basha ◽

Norah Alwadai ◽

...

Keyword(s):

Electron Microscope ◽

X Rays ◽

Ag Nps ◽

Au Nps ◽

Advantages And Disadvantages ◽

Transmission Electron ◽

Synthesis Properties ◽

Synthesis Routes ◽

Synthesis Approach ◽

Comprehensive Study

Abstract To date, the noble metal-based nanoparticles have been used in every field of life. The Au and Ag nanoparticles (NPs) have been fabricated employing different techniques to tune the properties. In this study, the methodologies developed and adopted for the fabrication of Au and Ag have been discussed, which include physical, chemical and biological routes. The Au and Ag characteristics (morphology, size, shape) along with advantages and disadvantages are discussed. The Au and Ag NPs catalytic and biomedical applications are discussed. For the Ag and Au NPs characterization, SEM (scanning electron microscope), TEM (transmission electron microscope), FTIR (Fourier transform infra-red spectroscopy), XRD (X-rays diffraction) and DLS (dynamic light scattering) techniques are employed. The properties of Au and Ag NPs found dependent to synthesis approach, i.e., the size, shape and morphologies, which showed a promising Catalytic, drug delivery and antimicrobial agent applications. The review is a comprehensive study for the comparison of Au and Ag NPs synthesis, properties and applications in different fields.

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Fabrication of periodic microscale stripes of silver by laser interference induced forward transfer and their SERS properties

Nanotechnology ◽

10.1088/1361-6528/ac3e34 ◽

2021 ◽

Author(s):

Huijuan Shen ◽

Yaode Wang ◽

Liang Cao ◽

Ying Xie ◽

Lu Wang ◽

...

Keyword(s):

Film Thickness ◽

Laser Fluence ◽

Nano Particles ◽

Good Resolution ◽

Laser Interference ◽

Ag Nps ◽

Wide Range ◽

Forward Transfer ◽

Stripe Structure ◽

Average Size

Abstract The micro-stripe structure was prepared by laser interference induced forward transfer (LIIFT) technique, composed of Ag nano-particles (NPs). The effects of the film thickness with the carbon nano-particles mixed polyimide (CNPs@PI), Ag film thickness, and laser fluence were studied on the transferred micro-stripe structure. The periodic Ag micro-stripe with good resolution was obtained in a wide range of CNPs@PI film thickness from ~ 0.5 μm to ~ 1.0 μm for the Ag thin film ~ 20 nm. The distribution of the Ag NPs composing the micro-stripe was compact. Nevertheless, the average size of the transferred Ag NPs was increased from ~ 41 nm to ~ 197 nm with the change of the Ag donor film from ~ 10 nm to ~ 40 nm. With the increase of the laser fluence from 102 mJ•cm-2 to 306 mJ•cm-2 per-beam, the transferred Ag NPs became aggregative, improving the resolution of the corresponding micro-stripe. Finally, the transferred Ag micro-stripe exhibited the significant surface enhanced Raman scattering (SERS) property for rhodamine B (RhB). While the concentration of the RhB reached 10-10 mol•L-1, the Raman characteristic peaks of the RhB were still observed clearly at 622 cm-1, 1359 cm-1, and 1649 cm-1. These results indicate that the transferred Ag micro-stripe has potential application as a SERS chip in drug and food detection.

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Au-on-Ag nanostructure for in-situ SERS monitoring of catalytic reactions

Nanotechnology ◽

10.1088/1361-6528/ac47d2 ◽

2022 ◽

Author(s):

Shuyue He ◽

Di Wu ◽

Siwei Chen ◽

Kai Liu ◽

Eui-Hyeok Yang ◽

...

Keyword(s):

Catalytic Activity ◽

Thermal Evaporation ◽

Reduction Process ◽

Ag Nps ◽

Au Nps ◽

Surface Enhanced ◽

Surface Enhanced Raman ◽

Enhanced Raman Scattering ◽

Raman Probe

Abstract Dual-functionality Au-on-Ag nanostructures (AOA) were fabricated on a silicon substrate by first immobilizing citrate-reduced Ag nanoparticles (Ag NPs, ~43 nm in diameter), followed by depositing ~7 nm Au nanofilms (Au NFs) via thermal evaporation. Au NFs were introduced for their catalytic activity in concave-convex nano-configuration. Ag NPs underneath were used for their significant enhancement factor (EF) in surface-enhanced Raman scattering (SERS)-based measurements of analytes of interest. Rhodamine 6G (R6G) was utilized as the Raman-probe to evaluate the SERS sensitivity of AOA. The SERS EF of AOA is ~37 times than that of Au NPs. Using reduction of 4-nitrothiophenol (4-NTP) by sodium borohydride (NaBH4) as a model reaction, we demonstrated the robust catalytic activity of AOA as well as its capacity to continuously monitor via SERS the disappearance of reactant 4-NTP, emergence and disappearance of intermediate 4, 4’-DMAB, and the appearance of product 4-ATP throughout the reduction process in real-time and in situ.

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Marine Bacterial Exopolymers-Mediated Green Synthesis of Noble Metal Nanoparticles with Antimicrobial Properties

Polymers ◽

10.3390/polym11071157 ◽

2019 ◽

Vol 11 (7) ◽

pp. 1157 ◽

Cited By ~ 7

Author(s):

Angela Scala ◽

Anna Piperno ◽

Alexandru Hada ◽

Simion Astilean ◽

Adriana Vulpoi ◽

...

Keyword(s):

Hydrothermal Vents ◽

Thermophilic Bacteria ◽

Silver Chloride ◽

Antimicrobial Properties ◽

Biological Evaluation ◽

Noble Metal Nanoparticles ◽

Ag Nps ◽

Au Nps ◽

Minimum Fungicidal Concentration ◽

Gold Silver

A straightforward and green method for the synthesis of gold, silver, and silver chloride nanoparticles (Au NPs and Ag/AgCl NPs) was developed using three different microbial exopolymers (EP) as reducing and stabilizing agents. The exopolysaccharides EPS B3-15 and EPS T14 and the poly-γ-glutamic acid γ-PGA-APA were produced by thermophilic bacteria isolated from shallow hydrothermal vents off the Eolian Islands (Italy) in the Mediterranean Sea. The production of metal NPs was monitored by UV−Vis measurements by the typical plasmon resonance absorption peak and their antimicrobial activity towards Gram-positive and Gram- negative bacteria (Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa), as well as fungi (Candida albicans) was investigated. The biological evaluation showed no activity for EP-Au NPs, except against E. coli, whereas EP-Ag NPs exhibited a broad-spectrum of activity. The chemical composition, morphology, and size of EP-Ag NPs were investigated by UV–Vis, zeta potential (ζ), dynamic light scattering (DLS) measurements and transmission electron microscopy (TEM). The best antimicrobial results were obtained for EPS B3-15-Ag NPs and EPS T14-Ag NPs (Minimum Inhibitory Concentration, MIC: 9.37–45 µg/mL; Minimum Bactericidal Concentration/Minimum Fungicidal Concentration, MBC/MFC: 11.25–75 µg/mL).

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Green Plasmonic Nanoparticles and Bio-Inspired Stimuli-Responsive Vesicles in Cancer Therapy Application

Nanomaterials ◽

10.3390/nano10061083 ◽

2020 ◽

Vol 10 (6) ◽

pp. 1083 ◽

Cited By ~ 1

Author(s):

Valeria De Matteis ◽

Loris Rizzello ◽

Mariafrancesca Cascione ◽

Eva Liatsi-Douvitsa ◽

Azzurra Apriceno ◽

...

Keyword(s):

Cancer Therapy ◽

Anticancer Agents ◽

Chemical Properties ◽

Dark Side ◽

Stimuli Responsive ◽

Ag Nps ◽

Au Nps ◽

Physico Chemical ◽

Living Organisms ◽

Biological Entities

In the last years, there is a growing interest in the application of nanoscaled materials in cancer therapy because of their unique physico-chemical properties. However, the dark side of their usability is limited by their possible toxic behaviour and accumulation in living organisms. Starting from this assumption, the search for a green alternative to produce nanoparticles (NPs) or the discovery of green molecules, is a challenge in order to obtain safe materials. In particular, gold (Au NPs) and silver (Ag NPs) NPs are particularly suitable because of their unique physico-chemical properties, in particular plasmonic behaviour that makes them useful as active anticancer agents. These NPs can be obtained by green approaches, alternative to conventional chemical methods, owing to the use of phytochemicals, carbohydrates, and other biomolecules present in plants, fungi, and bacteria, reducing toxic effects. In addition, we analysed the use of green and stimuli-responsive polymeric bio-inspired nanovesicles, mainly used in drug delivery applications that have revolutionised the way of drugs supply. Finally, we reported the last examples on the use of metallic and Au NPs as self-propelling systems as new concept of nanorobot, which are able to respond and move towards specific physical or chemical stimuli in biological entities.

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Gelatin as an ecofriendly natural polymer for preparing colloidal silver@gold nanobranches

Green Processing and Synthesis ◽

10.1515/gps-2016-0036 ◽

2016 ◽

Vol 5 (5) ◽

Cited By ~ 4

Author(s):

Phuong Phong Nguyen Thi ◽

Dai Hai Nguyen

Keyword(s):

Ph Value ◽

Component Ratio ◽

X Ray Diffraction ◽

Ag Nps ◽

Au Nps ◽

X Ray ◽

Transmission Electron ◽

Uv Visible ◽

The Stability ◽

Maximum Absorption Wavelength

AbstractWe report star-shaped silver@gold (Ag@Au) nanoparticles (NPs) in gelatin suspensions for the purpose of enhancing the stability of Ag@Au NPs. In this case, Ag NPs were designed as nucleating agents, whereas gelatin was used as a protecting agent for Au development. Especially, variable gelatin concentrations were also prepared to explore its ability to increase the stability of Ag@Au NPs. The obtained samples were then characterized by UV-visible spectroscopy, transmission electron spectroscopy (TEM), X-ray diffraction, and Fourier transform infrared spectroscopy. The maximum absorption wavelength of all samples (566–580 nm) indicated that branched Ag@Au@gelatin NPs were successfully synthesized. In addition, our TEM results revealed that the size of branched Ag@Au@gelatin NPs was found to be between 20 and 45 nm as influenced by the component ratio and the pH value. These results can provide valuable insights into the improvement of Ag@Au NP stability in the presence of gelatin.

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