A facile approach is proposed for the stabilization of gold nanoparticles within alumina matrix based on fast coprecipitation of colloidal gold and alumina sol in the supercritical carbon dioxide used as antisolvent. Acetylacetone was used as a stabilizer agent for the synthesis of alumina sol. Gold nanoparticles were synthesized from HAuCl4 directly in liquid alumina sol in reaction with acetylacetone

In the past few decades, there have been remarkable advances in our knowledge of gold nanoparticles (AuNPs) and synthesizing methods. AuNPs have become increasingly important in biomedical and industrial applications. As a newly implemented method, AuNPs are being used in nanopackaging industries for their therapeutic and antibacterial characteristics as well as their inert and nontoxic nature. As

Herein, a simple method for etching Aunanorods@SiO2 surface to obtain Aunanorods@B-SiO2 material is reported, which is used for the theoretical study of drug loading and release of composite materials by microcalorimetry. In the presence of surfactant cetyltrime-thylammonium bromide (CTAB), the Aunanorods@SiO2 is etched under the strong acid environment with pH of about 2 to obtain the ideal material

Understanding the various structures of gold clusters and the interaction modes between Au clusters and biomolecules is an important issue in material science such as biosensors and catalysts. The binding of small gold clusters (Aun n = 2–5) with neutral and anionic forms of arginine (Arg) amino acid is investigated in this study using density functional theory (DFT) and B3LYP level. The relative stability

Gold nanorod (AuNR) nanocomposite hydrogels have attracted increasing attention due to the photothermal effect of AuNRs. However, a facile strategy that avoids multi-step surface modification for synthesis of AuNR crosslinkers is still a critical challenge. Here, AuNRs crosslinking PNIPAM hydrogels were prepared by polymerization of NIPAM with N,N′-bis(acryloyl)cystamine (BACA)-modified AuNRs as crosslinkers

Stable solutions of gold nanoparticles with an average diameter of 13 nm and CAu = 5×10–4 M were obtained by the reduction of HAuCl4 with an equivalent amount of sodium sulfite at 80–100 °C in the presence of 2% PEG 6000 as a stabilizer: AuCl4– + 3/2 SO32– + 3/2 H2O → Au0 + 3/2 SO42– + 3 H+ + 4 Cl–. The resulting solutions of nanoparticles do not contain additional components capable of complexation

The paper reports a simple enzyme-free colorimetric sensor for the detection of cardiac marker, Troponin I (cTnI) based on the self-assembly of gold nanorods (AuNRs) on heparin. The sensing system consists of a purple colour solution of Hexadecyltrimethylammonium bromide (CTAB) stabilised AuNRs self-assembled in presence of heparin due to the electrostatic interaction resulting in the reduction of

This article reports a simple one-step method for anisotropic gold nanoparticle synthesis for plasmonic photothermal therapy medical purposes, using 1,4-bis[(2-ethylhexyl) oxy]-1,4-dioxo-2-butanesulfonic acid-sodium (AOT) reverse micelles as nanoreactor, where under specific condition, AOT acts as both a reducing and stabilizing agent. Obtained AuNPs were functionalized by attaching compounds derived

The color of fine gold shows paradoxical variations that have tentatively been explained by metallurgic factors. Measurements and digital photographs show a significantly redder color than predicted by theory. A novel purely optical explanation based on the multiple reflection in grooves is suggested. The analysis in the colorimetric space RGB of the photographs of several fine gold samples and coins

This report provides a method to estimate how much the photocurrents can be increased by adding gold nanoparticles in P3HT:PCBM films, without having to carry out the complex process of fabricate a whole cell. The tuning effect of varying the gold nanoparticle concentration on optical properties of these films was analyzed by measuring optical absorption. To estimate the contribution of the optical

The aim of this research was to describe a facile protocol to obtain biocompatible gold nanoparticles (AuNPs) suitable for microbial optical sensing. For this purpose, polycationic poly-L-lysine (PLL) was employed as both reducing and stabilizing agent in order to obtain an optically active microbial nanotag based on the electrostatic interaction with negatively charged cell envelopes. A one-pot procedure

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One-step laser-assisted fabrication of elongated Au nanoparticles (NPs) and their subsequent fragmentation and agglomeration are experimentally studied. The generation of elongated Au NPs is carried out via laser ablation of a solid Au target in water using an ytterbium-doped fiber laser source with pulse duration of 200 ns and pulse energy of 1 mJ. Extinction spectrum of the resulting particles exhibits

Gold exchange traded funds help investors to generate the returns based on the movements of underlying commodity. In current scenario, gold ETFs are emerging as one of the best ETFs for the investments. The present study intended to determine the causal relationship between spot prices of gold, SENSEX, and ten selected BSE listed Gold ETFs. The closing prices gold ETFs, SENSEX and spot prices of gold

The purpose of this study was to evaluate the possible synergistic effect of gold nano-therapy (Au-NPs) on Y79 cells treated with ultrasonic hyperthermia. The cells in the presence and absence of gold nanoparticles were subjected to ultrasonic irradiation (3 MHz, 1 W/cm2, 40% pulse mode). Gold nanoparticles with an average diameter of 60 nm were synthesized. The cell viability of the Y79 cells was

The extraction of bimetallic Au-Pt nanoparticles is interesting due to their multiple applications in catalytic processes, electronic devices, photothermal therapies, among others. On the other hand, the tendency of nanoparticles forming agglomerates may modify the behavior of the material, and thus their applications. This study shows a highly reproducible novel synthesis method, which only uses two

Brazing of CoCrFeNi and CoCrFeMnNi equiatomic alloys using 70Au-8Pd-22Ni (AuPdNi) filler foil by infrared and traditional furnaces was investigated. The wettability of AuPdNi filler on both CoCrFeNi and CoCrFeMnNi substrates is excellent at 1050 °C. CoCrFeNi/AuPdNi/CoCrFeNi joints brazed using infrared and traditional furnaces are composed of Au/Ni-rich solid solutions of different sizes. CoCrFeMn

In the present work, sulfur-doped carbon nanotubes (SCNTs) have been prepared using chemical vapor deposition method and various cobalt-containing catalysts. In this line, simple and silica-supported cobalt nanoparticles (Co and Co/SiO2) and 5 cobalt spinels (MCo2O4, M = Ni, Cu, Mn, Fe, Cr, and Mg) were used as the growth catalysts and four different temperatures (600, 650, 700, and 750 °C) were used

Gold oxides with thicknesses of less than 1 nm that were prepared by an oxygen-dc glow discharge over various periods (0.5–10 min) from gold films at room temperature were characterized by X-ray photoelectron spectroscopy (XPS), and a preservation method was developed for these oxides. The O 1s spectra show three oxygen species comprising components I, II, and III in the gold oxides. Components I and

Ligand exchange was triggered at toluene/water emulsion interface between homogeneous gold nanoparticles (Au NPs) with triphenylphosphine (PPh3) and D-penicillamine (D-PA), resulted in amphiphilic Janus Au NPs with both phosphine and thiolate ligands. TEM and XRD analyses indicate that the product is composed of Au nanocrystals in an average diameter of about 3.7 nm. XPS, FTIR, Raman, and 1H NMR analyses

This study reports a new detection process for sensing ultra-low concentrations of tetracycline (TC), using a hot spot surface-enhanced Raman scattering (SERS) sensor. A gold nanoparticles/ macroporous silicon (Au NPs/macroPSi) hot spot SERS sensor was fabricated using a very simple and low cost method. The SERS signal was investigated using Au NPs/macroPSi hot spot SERS sensor for efficient detection

Gold, used for jewelry and ornaments at times, is now considered a safe metal for investment. In addition to buying and selling gold physically, some markets offer electronic trade in gold. Trade volume is on surge in these bullion markets with each passing day. Daily opening and closing gold prices are used for analysis for 7740 days. Data series of daily return on investment in gold is split into

Gold nanoparticle thin films were deposited on copper substrate using electrophoretic deposition (EPD) method. At first, gold nanoparticles were synthesized, using pulsed laser ablation method of a high-purity gold target in distilled water. Ablation was carried out, employing the fundamental wavelength of a Q-switched Nd:YAG laser at 1064 nm and pulse width of 7 ns. Suspension of gold nanoparticle

In this paper, the 24 karat (99.99 wt.% pure) and 22 karat gold (Au-5.8wt.%Cu-2.5wt.%Ag) were grain refined with Au-6wt.%Ti master alloy and the mechanism of grain refinement was studied. The Au-6wt.%Ti master alloy containing Au2Ti and Au4Ti intermetallic particles was added into 24 karat and 22 karat gold at various addition levels of Ti (0.1, 0.2 and 0.3 wt.%) for grain refinement. The intermetallic

Globally, continuous R & D efforts are being made to recuperate precious metals from wastes in order to conserve the natural resources as well as minimize environmental pollution. Keeping in view of the above, a process has been developed to recover gold from industrial effluent using hydrometallurgical route. Initially, the effluent was pre-treated using precipitation and solvent extraction techniques

Au nanorods were prepared through seed growth method. Their lengths and diameters were controlled by adjusting Ag+ content in the growth solution. Ethyl orthosilicate were hydrolyzed in alkali solutions to obtain SiO2-coated Au nanostructures. Au nanorods with ideal morphologies and sizes could only be obtained under the presence of a certain Ag+ concentration in the growth solution. Without Ag+, only

The green synthesis of gold nanoparticles has attracted tremendous interest owing to their unique physicochemical properties and widespread applications which are primarily size-dependent. The stability, less reaction time, and use of biological resources as novel nanofactories as an alternative to conventional synthesis strategies are the main objectives of green synthesis approaches. However, to

Herein, we report a simple one-pot synthesis of water-dispersible gold nanoparticles (AuNPs) by using meso-tetra(methyl) meso-tetra hydrazide-functionalized calix[4]pyrrole (ECPTH) as both reducing and stabilizing template. The characterization of ECPTH-AuNPs has been carried out by UV-Vis spectroscopy, transmission electron microscope, X-ray diffraction (XRD), dynamic light scattering (DLS), and zeta

The electrochemical corrosion behaviour of 22k gold (Au-5.8wt.%Cu-2.5wt.%Ag) and Ti containing 22k (Ti-22k) gold (Au-5.8wt.%Cu-2.0wt.%Ag-0.5wt.%Ti) was studied. Elemental Ti was added as the quaternary element to 22k gold by replacing Ag, resulting in the formation of secondary phase precipitates during age hardening treatment, thereby improving the hardness of the alloy. Anodic polarization tests

A new nanocomposite material based on gold nanorods and polyurethane foam was obtained, and a method for the determination of catecholamines with the use of this nanocomposite modified with silver nitrate was developed. The determination is based on the measuring hypsochromic shift of a short-wave surface plasmon resonance band in a diffuse reflection spectrum of the nanocomposite. This shift is caused

This work introduces an innovative new method to transport gold nanoparticles (Au-NPs) toward specific organs using as transporter the M13 filamentous phage. The aim is to improve the radiotherapy efficiency by injecting gold nanoparticles in the tumor tissues in order to increase the effective atomic number and, consequently, to produce higher locally deposited doses. The biocompatible Au-NPs can

The transport of gold(III) across a supported liquid membrane containing the ionic liquid Cyphos IL102 (trihexyl(tetradecyl)phosphonium bromide) in Solvesso 100 has been investigated. The investigation was carried out under various experimental variables affecting to the transport process: stirring speed in the aqueous feed solution, HCl and gold(III) concentrations in this same phase, and carrier

Nanotechnology has the impending ability to improve the therapeutic potential of drugs and radiation-based treatment approaches for reducing cancerous cell death while curtailing collateral toxicity to non-cancerous cells. Among all metal nanomaterials, gold nanoparticles (AuNPs) are establishing themselves as an excellent radiosensitizer and serve as a multimodal modality due to their unique physicochemical

In this study, gold nanoparticles were supported at graphene derivatives (AuNPs@GDs) from chloroauric acid and graphene oxide (GO) by using sodium citrate, L-ascorbic acid, and 4-(2-hydroxyethyl)-1-piperazineethane-sulfonic acid (HEPES) as green reductants to evaluate the catalytic activity in the 4-nitrophenol (4-NP) reduction system. Among the three reductants, HEPES which derived AuNP@GD (3) exhibited

In this study, we report on the influence of support and gas atmosphere on the thermal stability of Au nanoparticles on oxidic supports. All samples were prepared with a modified impregnation method and have initial Au particle sizes in the range of 3–4 nm. We observed that in air, Au nanoparticles on SiO2 and Al2O3 are thermally much more stable than Au nanoparticles on TiO2. For instance, upon treatment

Gold nanostructures (AuNP) are important as strong platforms for targeted therapeutic and diagnostic applications. Tireless effort has been devoted nowadays to explore the multifunctionality of AuNP in multicomponent biostructures. Herein, we report the fabrication of horseradish peroxidase enzyme (HRP)-AuNP/ZnAlLDH heterostructure by the facile synthesis of AuNP on the biocompatible matrices of layered

Metallic gold is not completely inert towards biological tissues and cells. Cytotoxicity and immunotoxicity are concerns in various gold applications. This study shows that treating the surface of gold with OH• radicals renders the gold surface non-cytotoxic, as well as prevents any biocorrosion of gold implants by an immune reaction. The detoxification is discussed as resulting from the selective

Synthesis of gold nanoparticles (Au-NPs) was performed using method of an inorganic chemical reduction. The synthesized Au-NPs showed an intensive surface plasmon resonance band at 525 nm that is typical for corresponding Au-NPs reported in literature. The structural and morphology characterizations of the obtained Au-NPs were carried out using SEM, AFM, TEM, and X-ray spectral analysis. The possibility

In order to recover gold and silver from anode slimes containing Cu, Ni, Sn, and Zn, an integrated hydrometallurgical process consisting of leaching, solvent extraction, and cementation was developed. All the metals together with 10% of Ag(I) were dissolved by the mixture of HCl and H2O2 at the optimum conditions. Separation of Au (III) together with Sn (II) was performed by Cyanex 272 from the leaching

The adsorption of hydrogen on the surface of gold nanoparticles deposited on a graphite support was studied in the presence of an external electric field by means of scanning tunneling microscopy (STM) and spectroscopy (STS). Hydrogen was adsorbed from the gas phase onto the surface of gold nanoparticles synthesized by impregnation-precipitation method. During the adsorption process, the STM tip was

Although antimicrobial photothermal inactivation of naked gold nanostructures using powerful pulsed lasers has been previously studied, there are little reports about their photodynamic antimicrobial properties under the irradiation of low-power density continuous wave lasers. Therefore, this paper attempts to fill this gap. In this paper, we studied the effects of a 40-mW/cm2 continuous Nd:Yag laser

The Au(CN)2− ion and its metal-ligand compounds have recently gained considerable interest in industrial applications such as optical diagnostics systems as well as pharmacology with antirheumatic and antitumor activity. Here, [Ni2(N-bishydeten)2][Au(μ-CN)2]3[Au(CN)2]·H2O (C1), [Cu2(N-bishydeten)2][Au(μ-CN)2]3[Au(CN)2]·H2O (C2), and [Zn2(μ-N-bishydetenH)(N-bishydeten)(NC)2Au][Au(CN)2] (C3) were synthesized

The construction of porous organic polymer from 5,10,15,20-tetraphenylporphyrin (TPP) was described using one-pot Friedel-Crafts alkylation reaction. Au was simultaneously loaded on the porphyrin-based polymer denoted as Au/KAPs(DCM-TPP). This polymer-supported Au was fully characterized by many physicochemical methods. It was found to possess BET surface area of 796 m2 g−1, good thermal stability

In this study, at first, gold nanorods (GNRs) were synthesized and then they were coated with a layer of hydrogel composed of poly(N-isopropylacrylamide) (PNIPAM) grafted onto carboxymethyl cellulose (CMC) as a backbone. The chemical structure of GNRs/PNIPAM-g-CMC hydrogel was characterized by Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), atomic-force microscopy (AFM), transmission

We confirm that the unusual purple color of the intermetallic compound AuAl2 is of a plasmonic origin by launching surface plasmons (SPs) in thin AuAl2 films. We measure the SP dispersion relation and also use the films to measure the index of refraction of sucrose solutions using standard SP resonance sensing. We find that the SP energy in planar AuAl2 is approximately 2.1 eV, about 0.4 eV lower than

Photoelectrochemical cell composed of solution-processed nanoflower heterostructure of Au core and eight CdSe petals was investigated for enhanced photocurrent generation. The electrode of CdSe nanorods displayed photocurrent density of 2.1 mA/cm2 whereas the Au core CdSe nanoflower exhibited 4.6 mA/cm2 corresponding to a 119% increase during photoelectrochemical cell performance. Both electrodes showed

The color of ternary Au-Ag-Cu alloys is investigated; a simple and efficient model relying only on the reflectance of gold, silver, and copper is suggested. The alloy color diagram (a⋆,b⋆) based on the alloy proportion (u, v) has the shape of a “wizard’s hat” with special properties. Leuser’s classical triangle can be improved upon these results.

Gold nanoparticles (AuNPs) are successfully used as an adjuvant in the design of effective vaccines and in the preparation of high-affinity antibodies to haptens and complete antigens. Here, we assessed the adjuvant properties of AuNPs conjugated to a synthetic M2e peptide of the influenza A virus capsid. The resulting conjugate, a commercial influenza vaccine, and M2e in combination with different

The paper presents an investigation of the synthesis of gold particles on liquid–liquid interfaces using room temperature ionic liquids (RTIL) and ethylene glycol at temperatures up to 180 °C. The results show that depending on the RTIL used, the resulting gold particles are of different shape like trigonal and hexagonal plates, single fibers as well as bundles of fibers, and polyhedral and globular

Bimetallic Ag–Au alloy nanoparticles with a tunable size and composition were synthesized by laser beam power density. A set of Psi substrates with different morphologies fabricated by laser-assisted etching process with laser power density from 10 to 40 mW/cm2 was explored as a substrate for materialization bimetallic Ag–Au alloy nanoparticles by a simple immersion plating process of Psi in a mixture

Nanoparticle (NP) trophic transfer is reported as an important exposure route for organisms in aquatic ecosystems. This study focused on gold nanoparticle (AuNP, PEG-coated, 10 nm diameter) transfer using an experimental benthic food chain which included two trophic levels: natural river biofilm and grazer fish Hypostomus plecostomus. AuNP biofilm accumulation was assessed via water AuNP concentrations

One percent gold supported on three different metal oxides (TiO2, ZnO and Al2O3) has been evaluated as a catalyst, to reduce sulphur dioxide with carbon monoxide at different reaction temperatures. During the reaction, no carbonyl sulphide was formed and the only sulphur-containing product that was detected was elemental sulphur which condensed as S8 at the reactor exit. High-resolution transmission

We report five effective fluorescence resonance energy transfer (FRET) systems based on gold nanoparticles (AuNPs) and organic fluorescent dyes, including ionic [fluorescein sodium (FS) and Eosin B (EB)] and cationic [rhodamine 6G (Rh6G), acridine orange (AO), and safranine T (ST)] fluorescent dyes. The fluorescence intensity of the five FRET systems demonstrates that efficient quenching is possible

In this work, we present the application of the uranium, thorium–helium (U,Th–He) dating method to two different types of gold objects: geologic gold deposits and archeological gold objects. Direct dating of geologic gold deposits is difficult without assuming contemporaneity between gold and datable hydrothermal minerals. We show that our results indicate that the applied dating method opens a new

Uniformly sized and shaped gold nanoparticles (AuNP) were produced by microwave irradiation using Euphorbia tirucalli latex. The AuNPs were characterized by ultraviolet visible spectroscopy (UV–Vis), Fourier transform infrared spectroscopy (FTIR), dynamic light scattering, zeta potential, and transmission electron microscopy (TEM). UV–Vis analysis was employed to detect the characteristic surface plasmon

Gold nanoparticles are more and more used in bio-medical field for their advantages to be employed as contrast medium for diagnostic images and as targets of disease cells in which thermal-therapy or radiotherapy must be applied. In this contest, a suitable concentration of nanoparticles was added to human blood to study in vitro some physical properties of the treated liquid which is prepared to transport

Phytomining involves bioharvesting of metals from high biomass crops grown in soil substrates. This process has the potential for economic exploitation of low-grade mineralized soils (e.g., gold), which are too poor for conventional mining of metals. There is a lot of evidence that supports the synthesis of gold nanoparticles in living plants. In this study, the bioreduction of Au ions to Au nanoparticles

Supported Au nanoparticles (NPs) have attracted much attention in catalytic field because of their high activity and selectivity. However, its activity was affected by its dispersion. In this work, a controlled impregnation method was used to prepare Au/Zn-hydrotalcites (Au/Zn-HTs). The role of lattice Zn2+ in controlling Au NPs was studied. The size, structure, and composition of Au NPs were characterized

Most traditional ceramic glazes employ high amounts of transition metal colorants that are toxic to the environment and can cause health issues in humans through surface leaching. Gold nanoparticles (Au-NPs) have been found to be environmentally friendly and non-toxic alternative metal colorant in ceramic glazes. The plasmon band observed with Au-NPs can result in vibrant solutions by manipulating