Gold Bulletin最新文献

Gold nanomaterials have received much attention in sensing due to their unique optical and electronic properties. This article briefly summarized the synthesis, property of gold nanomaterials before focusing on their application to sensing. The synthesis of three major types of gold nanomaterials is discussed: gold nanoclusters, which are synthesized by templated method, and gold nanoparticles, which are synthesized by chemical reduction methods, and gold nanorods, which are synthesized by the seed-mediated method. More methods affecting nano properties are discussed. Properties of these gold nanomaterials are usually connected to their application. Their fluorescent, photoluminescent, chemiluminescent, electrochemiluminescent, and catalytic properties are what give them potential in sensing. For the further application of gold-based nanomaterials in sense, the author suggests that more research needs to be done on understanding their properties and surface functionalization which provide greater selectivity and sensitivity in sense. Moreover, new detection techniques need to be developed to improve detection accuracy and reduce operational complexity.

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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.

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.

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.

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.

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.

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