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Gold Bulletin
Journal Prestige (SJR): 0.461  Citation Impact (citeScore): 2 Number of Followers: 0  Hybrid journal (It can contain Open Access articles)ISSN (Print) 2364-821X - ISSN (Online) 2190-7579 Published by Springer-Verlag  [2469 journals]
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- Gold nanocluster triggering near-infrared photocatalytic oxidations
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Abstract: Abstract Developing efficient near-infrared photocatalyst for organic transformations is a long but challenging goal. In a recent paper in Journal of the American Chemical Society, Shuxin Wang, Jun Xuan, Manzhou Zhu and co-workers explored the gold nanocluster-triggered near-infrared photocatalytic oxidative functionalization with high efficiency. This work cultivates a new land for the application of metal nanocluster as well as near-infrared photocatalysis.
PubDate: 2022-04-27
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- Phytoremediation ability of Helichrysum arenarium plant for Au and Ag:
case study at Demirören village (Gümüşhane, Turkey)-
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Abstract: Abstract It was investigated ability of Helichrysum arenarium plant, in phytoextraction, phytostabilization, and phytoremediation in this study. Soil and plant samples were collected from the Demirören alteration site which has the potential of gold mineralization and analyzed for gold and silver. When the results of the analysis were evaluated, it was determined that the gold and silver contents in the soil did not show compatibility with the gold and silver contents of the plants grown at the same point. It was concluded that the high gold and silver concentrations in the plants are related to the hydrothermal alteration and weathering at the point where the plants grow. For investigation of phytoremediation ability of the plant, translocation factor (TF), bio-concentration factor (BCF), and bioaccumulation factor (BAF) were calculated. The values of TF, BAF, and BCF for Ag are equal 0.33, 0.043, and 0.13 and for Au are equal 2.04, 0.59, and 0.29, respectively. So, obtained data show that Helichrysum arenarium is not appropriate for phytoextraction and phytostabilization of gold and silver in this case, but H. arenarium can be used in phyto-mining and for biogeochemical exploration of gold. Considering that the gold and silver concentrations in the developed soil in the study area are low concentrations, it is predicted that a similar study will yield satisfactory-interesting results when it is made in plants grown on the gold mineralization/enrichment areas.
PubDate: 2022-04-12
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- Obituary for Masatake Haruta (1947–2022)
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PubDate: 2022-03-19
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- Assessment of microRNA-21 using gold nanoparticle-DNA conjugates based on
colorimetric and fluorescent detection-
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Abstract: Abstract The miR-21 detection is essential for the accurate and early diagnosis or prognosis of most diseases. In the current study, the miR-21 detection method was performed based on the exploitation of the simple colorimetric biosensor due to the unique surface plasmon resonance (SPR) absorption of gold nanoparticles. AuNPs were functionalized with the specific DNA probes on the gold surface by Au-SH bond. Two strategies are proposed to detect the miR-21. In the first strategy, probes (DNA1 and DNA2) were complementary to the sequence of the miR-21. When miR-21 is introduced, the hybridization reaction is triggered between the golden nanoparticles- (GNP)-DNA conjugates and targets, resulting in changes in SPR absorption band and macroscopic color of the AuNPs solution. In the second strategy, we used a fluorescence sequence (DNA3-FAM), which was complimentary of DNA1. The DNA3-FAM was released after hybridization of miR-21 with DNA1 and DNA2. The free DNA3-FAM sequences in plate wells containing 1% agarose gel were assessed by fluorescent microscope. The combination of two strategies and conventional equipment such as UV–Vis spectrometers and fluorescent microscopes could be useful in detecting the desired miRNAs (miR-21).
PubDate: 2022-03-15
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- Formation of gold hollow spheres by rapid heating–cooling process
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Abstract: Abstract Although gold hollow spheres show unique advantages in fields like catalysis, the available synthesis strategies have low atom and economic efficiency. In this paper, Au hollow spheres were produced by combining simple wet chemical method and rapid heating–cooling process, in which rapid temperature rise caused Au evaporation and rapid cooling froze gold “bubbles.” The control experiments confirmed the presence of supports which limit the growth and sintering of Au nanoparticles to some extent, and slower heating rate inhibits the hollowing of gold sphere. This work provides a new strategy for the rapid and facile synthesis of Au hollow spheres, offering a wide range of possibilities for energy storage and biosensing applications.
PubDate: 2022-03-08
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- Development of gold, silver, and iron nanoparticles using isolated
berberine: its characterization and antimicrobial and cytotoxic activities
against COLO320DM and Hela cells-
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Abstract: Abstract The current report discloses the development of gold, silver, and iron nanoparticles using berberine by green synthesis and its evaluation for antimicrobial activity and in vitro cytotoxicity against colon cancer and human cervical cancer cells. The prepared nanoparticles were characterized by Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction analysis. The characterization of results of the prepared nanoparticles satisfied the distinctive properties of the potent nanodrug. The antimicrobial potential was exhibited by all the prepared nanoparticles against the selected microbial strains. The zone of inhibition (mm) exhibited by gold nanoparticles biosynthesized using berberine (BAuNPs) was 15.66 ± 0.47 mm against Pseudomonas aeruginosa, 15.0 ± 1.41 against Escherichia coli, and 15.33 ± 1.24 mm against Staphylococcus aureus. The cytotoxicity study exhibited promising results as compared to pure berberine. The results of the MTT assay of gold nanoparticles against COLO320DM exhibited 92.27 ± 0.14% inhibition, whereas in the case of the SRB assay, it revealed 89.72 ± 0.29% inhibition as compared to other nanoparticles and pure berberine. For Hela cell lines, in the case of the MTT assay, BAuNPs exhibited 92.13 ± 0.64% inhibition while in the SRB assay, it revealed 85.56 ± 0.39% inhibition. The results of the Trypan blue assay revealed that BAuNPs showed 76.54 ± 1.00% inhibition against the COLO320DM cell line, whereas in the case of Hela cell lines, 78.03 ± 1.47% inhibition was observed. The effect exhibited by BAuNPs may be attributed to increased production of reactive oxygen species by treated carcinoma cells that results in oxidation of vital constituents which ultimately causes death of the cell. Thus, these in vitro results demonstrate the promising therapeutic applications of the BAuNPs in nanomedicine.
PubDate: 2022-02-18
DOI: 10.1007/s13404-022-00309-9
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- Comparison of polyampholyte derivative of chitosan with bisphthalimides of
low molecular weight in the green synthesis of Au nanoparticles-
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Abstract: Abstract This work reports the chemical modification of chitosan with phthalimide moieties and the synthesis of two bisphthalimides (BPIs) with low molecular weight useful in the green synthesis of Au nanoparticles. The polyampholyte derivative of chitosan was obtained in water while the two BPIs, N,N´-(1,3-phenylene)bis(phthalimide-5-carboxylic acid) (BPI-1) and N,N´-(1,4-phenylene)bis(phthalimide-5-carboxylic acid) (BPI-2) were obtained by solid state reaction without the use of organic solvents. The polyampholyte and two BPIs were soluble in water; therefore, they were used in the green synthesis of Au nanoparticles. The characterization of three compounds was made by FTIR and 1H NMR. TEM and UV–Vis results revealed that the compounds can reduce gold ions and stabilize Au nanoparticles in the colloidal solutions. The shape of the Au nanoparticles was quasi-spherical, while the average size of Au nanoparticles stabilized with the compounds BPI-1 and BPI-2 was 3 and 12 nm, respectively. Thus, with BPI-1 was obtained Au nanoparticles with lower size than BPI-2. Finally, the average size of nanoparticles stabilized with the polyampholyte was 10 nm. However, the faster reaction to obtain nanoparticles was with the polyampholyte derivative of chitosan (5 min), due to high quantity of oxidizable groups found in the polymer structure by its high molecular weight.
PubDate: 2022-02-15
DOI: 10.1007/s13404-022-00310-2
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- Synergic effect of paclitaxel and cisplatin associated with gold
nanoparticles on HeLa cervical cells-
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Abstract: The combination of two or more chemotherapy drugs and nanotechnology has emerged as an effective strategy in the fight against cancer. Paclitaxel (PTX) and cisplatin show improved cytotoxic effects on being used together in the chemotherapy of various cancer types, than when used individually. However, these chemotherapy drugs have been shown to have numerous toxic effects in cancer patients. Therefore, the aim of this study was to evaluate the cytotoxicity of PTX and cisplatin associated with gold nanoparticles (AuNps) on HeLa cells containing multiple copies of human papillomavirus 18. AuNps were successfully synthesized with a mean size of 20 to 61 nm, polydispersity index ≥ 0.3, and negative surface charge. Together, PTX and cisplatin associated with AuNps showed a higher cytotoxic effect on HeLa cells than free drugs. The combination of PTX and cisplatin with AuNps potentiated their cytotoxic effects, inducing synergism between the treatments, resulting in HeLa cell death by apoptosis. Graphical abstract
PubDate: 2022-01-22
DOI: 10.1007/s13404-021-00305-5
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- Organo-gold(III) complexes via mechanochemistry in a ball mill
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Abstract: Abstract Owing to their highly interesting applications in medicine, catalysis, and their luminescence properties, over the past decade, increasing efforts have been devoted to the synthesis of organo-gold(III) complexes. Therefore, the design of mild, practical, and modular protocols for their synthesis is a highly active field of research. In a recent paper in Angewandte Chemie, Hashmi and co-workers developed an efficient and solvent-free method for the mechanochemical synthesis of differently organo-gold(III) complexes; this method opens up a new perspective for the field.
PubDate: 2022-01-21
DOI: 10.1007/s13404-021-00302-8
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- Effect of plasmonic coupling in different assembly of gold nanorods
studied by FDTD-
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Abstract: Abstract The influence of the orientation of gold nanorods in different assemblies has been investigated using the finite difference time domain (FDTD) simulation method. To understand the relative orientation, we vary the size and angle in dimer geometries. Significant effects of plasmon coupling emerged in longitudinal resonances having end-to-end configurations of gold nanorods. The effect of orientational plasmon coupling in dimers gives rise to both bonding and anti-bonding plasmon modes. Effects of various geometries like primary monomer, dimer, trimer, and tetramer structures have been explored and compared with their higher nanorod ensembles. The asymmetric spectral response in a 4 × 4 gold nanorods array indicates a Fano-like resonance. The variation of gap distance in ordered arrays allowed modulation of the Fano resonance mode. The plasmon modes’ resonance wavelength and field enhancement have been tuned by varying the gap distance, angular orientation, size irregularity between the nanorods, and nanorod numbers in an array. The integrated nanostructures studied here are not only significant for fundamental research but also applications in plasmon-based devices.
PubDate: 2022-01-16
DOI: 10.1007/s13404-022-00307-x
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- The potential of marine-based gold nanomaterials in cancer therapy: a
mini-review-
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Abstract: Abstract Cancer is still one of the most common causes of death today despite advances in its detection and treatment. The present article reviews the application of marine-based gold nanoparticles in the diagnosis and treatment of cancer. The main data were collected from original research articles on the application of different marine-based gold nanoparticles in detecting and imaging cancer cells as well as in drug delivery systems and treatment of cancer. The results show the excellent anticancer potential of both gold nanoparticles and natural marine products. The most studied marine-based gold nanomaterial was chitosan-based ones, in which the role of chitosan is a stabilizer not an anticancer agent. Despite the excellent anticancer potential of different marine natural products, limited studies have been conducted using gold nanoparticles in their composition in cancer therapy. Moreover, most of these studies are related to their application as a drug delivery system not an anticancer drug. Although there are serious challenges in the application of nanoparticles in medicine, marine-based gold nanomaterials may promise an interesting novel strategy in the oncology field.
PubDate: 2022-01-14
DOI: 10.1007/s13404-021-00304-6
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- The effect of chitosan-modified gold nanoparticles in Lemna valdiviana and
Daphnia pulex-
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Abstract: Abstract Gold nanoparticles (AuNPs) are nowadays used in many areas of science, particularly in medicine as drug release and gene carriers. The extensive use of these materials makes imperative the study of their effects on the environment after their disposal, that mostly affects the aquatic media. The present work explores the bioaccumulation and toxicity of chitosan-functionalized and non-functionalized gold nanoparticles, with primary producers (Lemna valdiviana) and primary consumers (Daphnia pulex) aquatic organisms. Bioaccumulation of 27.4 nm AuNPs and 43.1 nm chitosan-gold nanoparticles (CO-AuNPs) was evaluated in both microorganisms, finding accumulation of AuNPs and inhomogeneous aggregation of CO-AuNPs in Daphnia pulex gut, and internalization of both types of nanoparticles in Lemna valdiviana cell walls. The effective concentration of nanomaterial for 50% survival (LC50) of Daphnia pulex organisms was 1.13 mg/L for AuNPs and 0.96 mg/L for CO-AuNPs in the acute test. In Lemna valdiviana 7-day test, the EC50 for area and frond number were 1.19 mg/L and 1.26 mg/L, respectively, for AuNPs, 1.53 mg/L and 1.44 mg/L, respectively, for CO-AuNPs, finding higher toxicity of CO-AuNPs to Daphnia pulex, and AuNPs to Lemna valdiviana. The obtained results suggest that the effects of nanomaterials on the growth and survival of key organisms deserve further study, as this may lead to the development of appropriate environmental regulations.
PubDate: 2022-01-13
DOI: 10.1007/s13404-021-00306-4
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- Fibers covered with 3D interconnected network of Au nanostructures and
their application in SERS detection-
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Abstract: Abstract A simple template-free method was developed for the fabrication of fibers whose surfaces were covered by a three-dimensional interconnected network of Au nanostructures (3D-NW AuNSs) without additional stabilizer. The EDS and XPS measurements confirmed the metallic nature of the formed 3D gold nanowire networks on the fiber surface. The morphology of these 3D-NW AuNSs can be controlled by the experimental parameters, such as reaction time, roughness of the glass fiber surface, HAuCl4, and sodium citrate concentration. The 3D gold nanowire networks showed excellent uniformity. Additionally, the nanofiber was used to accurately and reliably detect methyl red (MR), crystal violet (CV), and acridine orange (AO), which can be detected as low as 1, 10, and 5 μg/L, respectively. Since the proposed strategy is simple, cost-effective, and reproducible for the mass production of network-like gold film–covered nanofiber, it is expected to play an important role in the development of trace analytical devices.
PubDate: 2022-01-04
DOI: 10.1007/s13404-021-00303-7
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- Gold carbene complexes and beyond: new avenues in gold(I)-carbon
coordination chemistry-
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Abstract: Abstract The different coordination modes in carbon-gold(I) complexes are spotlighted with a focus on gold(I). The emergence of gold carbene complexes and their critical discussion in the community is presented, and an overview of their bonding fundamentals and synthetic procedures is given. Several intriguing and sometimes highly reactive gold-carbon coordination complexes that were recently synthesised and isolated are reviewed and a critical outlook into their potential applications is provided. This includes vinylidene and higher cumulenylidene complexes, free carbenes with gold substituents, carbodicarbene complexes, and non-Fischer/Schrock sesquicarbene complexes.
PubDate: 2022-01-03
DOI: 10.1007/s13404-021-00298-1
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- Study on the growth kinetics of Au nanorods based on local surface plasmon
resonance-
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Abstract: Abstract Gold nanorods are of great significance in biomedical and sensing applications due to their local surface plasmon resonance absorption. The silver-mediated seeding method was used to prepare gold nanorods, the longitudinal local surface plasmon resonance (LSPR) absorption of the prepared gold nanorods was monitored, and the growth kinetics of the gold nanorods were discussed. The results show that the growth process of gold nanorods is characterized by a first-order reaction, and its activation energy is about 54.4 kJ/mol. This experimental conclusion provides a good theoretical guide for the preparation of gold nanorods during application research.
PubDate: 2021-10-29
DOI: 10.1007/s13404-021-00299-0
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- The age hardenability of 22 karat gold (Au-5.8wt.%Cu-2.5wt.%Ag) alloyed
with titanium-
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Abstract: Abstract The age hardenability of 22 karat gold (Au-5.8wt.%Cu-2.5wt.%Ag) alloyed with Ti at various concentrations (0.5, 0.75, and 1 wt.%) was studied. The addition level of Ti is compensated with Ag to maintain the purity of gold in 22 karat, i.e., 91.75 wt.%. The Ti containing 22 karat gold was prepared by melting Au, Cu, and Ag and adding Ti via Au-6wt.%Ti master alloy. The castings obtained were cold-rolled into thin sheet (90% reduction). Both the cast and cold-rolled sheets were subjected to age hardening treatment (solutionizing and artificial aging). Artificial aging was performed as a function of time at 550 °C to identify the peak aging. At all addition level of Ti, the 22 karat gold responded well to the age hardening treatment. The cold-worked sheet samples showed faster peak aging within 30 min. and higher peak hardness than their cast counterpart. Increasing the Ti concentration increases the peak hardness of both cold-rolled sheet and casting samples. Transmission electron microscopic analysis of the peak aged cold-rolled sheet samples shows uniformly distributed coherent Au4Ti precipitates in Au matrix which contribute to the higher hardness.
PubDate: 2021-10-27
DOI: 10.1007/s13404-021-00301-9
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- Do LBMA gold price follow random-walk'
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Abstract: Abstract The present study attempted to analyse the random-walk characteristics of the gold spot price of the London Bullion Market Association (LBMA) by using several linear and nonlinear models. The research collects two decades of daily data from 3rd February 2000 to 2nd October 2020. Econometric tests such as serial correlation test, unit-root tests, multiple variance ratio (MVR), and the BDS test were applied to examine the linear and nonlinear dependence of return series. Further, we employed all the tests from ARCH family to examine the volatility clustering of the gold return series. The results of serial correlation and the unit-root test suggest that the gold return is stationary, therefore does not follow the random-walk benchmark, and hence the gold market is inefficient. EGARCH results indicate that the positive news has a more significant impact on the gold return than the negative news. The findings have important implications for the efficient portfolio investments, and better hedging opportunities for the investors.
PubDate: 2021-09-15
DOI: 10.1007/s13404-021-00300-w
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- Anglo-Saxon bling — a warrior king’s Golden Helmet
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Abstract: Abstract In 2009, a metal detectorist discovered a hoard of Anglo-Saxon gold and silver in a field in Staffordshire. Hence, it quickly became known as ‘The Staffordshire Hoard’. It was, and remains, the biggest collection of Anglo-Saxon gold (4 kg) and silver (1.7 kg) ever discovered and comprised of more than 4000 fragments that equated to over 600 discrete objects and larger pieces. The Staffordshire Hoard is co-owned by Birmingham and Stoke-on-Trent City Councils and is cared for on behalf of the nation by Birmingham Museums Trust and The Potteries Museum & Art Gallery. Over the intervening years, most of the larger and recognisably important pieces have now been identified and catalogued. We now also know an exceptional amount about their probable methods of manufacture, artistic styles, date, and function. This paper focuses on what is now known to be one of the most fragmented yet magnificent of its objects, a Helmet that has been declared as being ‘fit for a king’, but which was found scattered into well over 1000 disparate fragments. Fragments that are now considered to make up around one-third of the Hoard’s total of finds and compose this single high-status Golden Helmet. Too damaged and incomplete to be re-joined or displayed in a form that delivers to the casual observer a true sense of the majesty of the original. Thus, the museums responsible for the collection commissioned an experimental reconstruction project to create two of the helmets for display in their shared Hoard collections.
PubDate: 2021-06-11
DOI: 10.1007/s13404-021-00297-2
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- Size-dependent optical and electrochemical properties of gold
nanoparticles to L-cysteine-
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Abstract: Abstract A series of gold nanoparticles were synthesized by stepwise growth method under the condition of citrate as a reducing agent and stabilizer. The optical properties with the maximum absorption wavelength (λmax) and electrochemical properties of the oxidation potential (Ep) dependence on the particle size were analyzed. The method of calculating the particle size from the UV-visible spectrum and the electrochemical oxidation peak was deduced, following the theoretical prediction trend and consistent with previous observations. Furthermore, we investigated the application performance based on the electrochemical catalytic activity and the aggregation of the spherical gold nanoparticles using L-cysteine as a target. The results indicated that the optical and electrochemical properties of the gold nanoparticles to L-cysteine were closely related to the particle size of gold nanoparticles. With the increased size of the nanoparticles, the full width at half maximum in the UV-visible absorption spectrum increased and the electrochemical oxidation potential was positively shifted.
PubDate: 2021-04-28
DOI: 10.1007/s13404-021-00296-3
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- Synthesis, characterization, and in vitro drug release properties of
AuNPs/p(AETAC-co-VI)/Q nanocomposite hydrogels-
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Abstract: In this study, the cationic monomer [2-(acryloyloxy)ethyl]trimethylammonium chloride solution (AETAC) and vinyl imidazole (VI) were used with the free radical polymerization technique, which is a simple and rapid synthesis method, to synthesize p(AETAC-co-VI) hydrogels. To increase the density of cationic charge on the hydrogel, it underwent the protonation process with HCl. The obtained p(AETAC-co-VI)/Q hydrogel was modified with Au nanoparticles to increase bactericidal effect to obtain the AuNPs/p(AETAC-co-VI)/Q nanocomposite hydrogel. The morphology and chemical structure of the hydrogels were characterized with SEM and FTIR. Additionally, the swelling capabilities were tested in different pH media. XRD and TEM confirmed the formation of the nanocomposite hydrogel. The antibacterial activity of the hydrogels was tested against E. coli and S. aureus, and controlled release implementations were completed with sodium diclofenac (NaDc) drug. The NaDc drug release profiles of the hydrogels were researched using the Korsmeyer–Peppas model at 37 °C in different simulated buffer (pH 6.0, 7.2, and 8.0) solutions. It was found that both the hydrogel and nanocomposite hydrogel followed non-Fickian diffusion mechanisms as free release mechanism. Here, the maximum drug release efficacy was found to be 97%, and drug release was more rapid in basic media when release media were compared. The AuNPs/p(AETAC-co-VI)/Q nanocomposite hydrogels produced in this study with advanced antibacterial features were suitable for recommendation as good carriers for in vitro release of NaDc drugs in areas like the biomedical and pharmaceutical industries. Graphical abstract
PubDate: 2021-04-14
DOI: 10.1007/s13404-021-00295-4
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