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gold nanocluster

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https://www.readbyqxmd.com/read/28444989/water-soluble-naked-gold-nanoclusters-are-not-luminescent
#1
Julia Perez-Prieto, Pablo Londoño-Larrea, Julie P Vanegas, Daniel Cuaran, Elena Zaballos-García
We report here the synthesis of water-dispersible naked gold nanoclusters (AuNCnaked) by a simple reduction of HAuCl4 with NaOH at room temperature and show that they are non-luminescent. They were then easily passivated with different thiols and adenosine monophosphate to lead to luminescent NCs. This is an important finding as the photoluminescence of the passivated NCs can now be clearly attributed to the ligand-AuNC surface interaction. These results are also highly relevant from the point of view of the preparation of luminescent NCs from the same NC batch...
April 26, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28443925/the-effect-of-ligand-ligand-interactions-on-the-formation-of-photoluminescent-gold-nanoclusters-embedded-in-au-i-thiolate-supramolecules
#2
Hsiang-Yu Chang, Yu-Ting Tseng, Zhiqin Yuan, Hung-Lung Chou, Ching-Hsiang Chen, Bing-Joe Hwang, Meng-Che Tsai, Huan-Tsung Chang, Chih-Ching Huang
In this study, we prepared photoluminescent l-cysteine (Cys)-capped gold nanoclusters (Cys-Au NCs) via NaBH4-mediated reduction of aggregated coordination polymers (supramolecules) of -[Cys-Au(i)]n-. The -[Cys-Au(i)]n- supramolecules with interesting chiral properties were formed through simple reactions of chloroauric acid (HAuCl4) with Cys at certain pH values (pH 3-7). The -[Cys-Au(i)]n- polymers could self-assemble into -[Cys-Au(i)]n- supramolecules with irregular morphologies and diameters larger than 500 nm through stacked hydrogen bonding and zwitterionic interactions between Cys ligands and through Au(i)Au(i) aurophilic interactions in solutions with pH values ≤7...
April 26, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28440296/gold-nanoclusters-assisted-delivery-of-ngf-sirna-for-effective-treatment-of-pancreatic-cancer
#3
Yifeng Lei, Lixue Tang, Yangzhouyun Xie, Yunlei Xianyu, Lingmin Zhang, Peng Wang, Yoh Hamada, Kai Jiang, Wenfu Zheng, Xingyu Jiang
Pancreatic cancer is one of the deadliest human cancers, whose progression is highly dependent on the nervous microenvironment. The suppression of gene expression of nerve growth factor (NGF) may have great potential in pancreatic cancer treatment. Here we show that gold nanocluster-assisted delivery of siRNA of NGF (GNC-siRNA) allows efficient NGF gene silencing and pancreatic cancer treatment. The GNC-siRNA complex increases the stability of siRNA in serum, prolongs the circulation lifetime of siRNA in blood and enhances the cellular uptake and tumour accumulation of siRNA...
April 25, 2017: Nature Communications
https://www.readbyqxmd.com/read/28419942/nucleotide-directed-syntheses-of-gold-nanohybrid-systems-with-structure-dependent-optical-features-selective-fluorescence-sensing-of-fe-3-ions
#4
Ditta Ungor, Edit Csapó, Barbara Kismárton, Ádám Juhász, Imre Dékány
This study demonstrates a one-step synthesis for the preparation of both adenosine monophosphate (AMP)-stabilized colloidal gold nanoparticles (AMP-Au NPs) and fluorescent gold nanoclusters (AMP-Au NCs). The dominant role of AMP:AuCl4(-) molar ratios in the formation of diverse nanosized Au products was proved. The size, the structure and the unique structure-dependent optical properties of the NPs and NCs were determined based on the results of numerous spectroscopic (UV-vis, fluorescence, infrared, x-ray photoelectron), high resolution electron microscopy (HRTEM) and dynamic light scattering (DLS) techniques...
April 9, 2017: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/28411590/effects-of-ordered-islands-on-surface-resistivity-ni-on-au-111
#5
Joshua I Cohen, R G Tobin
The change in surface resistivity due to the formation of nickel islands on gold(111) was studied by measuring the resistance of a thin film of Au as a function of Ni coverage, θ. Previous studies showed that the Au(111) herringbone reconstruction provides a template for the periodic growth of ordered islands. Ni islands grow radially until θ ≈ 0.3 ML, after which subsequent Ni atoms contribute primarily to a second layer. Since Ni atoms on Au(111) grow in ordered nanoclusters, a nonlinear dependence of resistance on θ might be anticipated...
April 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28402112/self-assembled-upconversion-nanoparticle-clusters-for-nir-controlled-drug-release-and-synergistic-therapy-after-conjugation-with-gold-nanoparticles
#6
Huijuan Cai, Tingting Shen, Alexander M Kirillov, Yu Zhang, Changfu Shan, Xiang Li, Weisheng Liu, Yu Tang
Fabricated three-dimensional (3D) upconversion nanoclusters (abbreviated as EBSUCNPs) are obtained via an emulsion-based bottom-up self-assembly of NaGdF4:Yb/Er@NaGdF4 nanoparticles (abbreviated as UCNPs), which comprise a NaGdF4:Yb/Er core and a NaGdF4 shell. The EBSUCNPs were then coated with a thin mesoporous amino-functionalized SiO2 shell (resulting in EBSUCNPs@SiO2 precursor) and further conjugated with gold nanoparticles to give the novel EBSUCNPs@SiO2@Au material. Finally, EBSUCNPs@SiO2@Au was applied as a biocompatible and efficient drug carrier for doxorubicin (DOX), thus giving rise to a multifunctional EBSUCNPs@SiO2-DOX@Au nanocomposite...
April 12, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28401408/fluorescence-immunosensing-of-insulin-via-protein-functionalized-gold-nanoclusters
#7
Shalini Menon, K Girish Kumar
A novel fluorescent immunosensor for the determination of insulin, an important peptide hormone, has been fabricated in homogeneous solution. Bovine serum albumin (BSA) capped gold nanoclusters (AuNCs), being highly biocompatible, were used to label the insulin antibody (Ab). In presence of the target antigen, insulin (Ag), specific immunoreaction between Ab and Ag takes place leading to the fluorescence recovery of AuNCs that provided signal readout for the immunosensing process. A linear relationship between the fluorescence signal and concentration of insulin was obtained in the range of 4...
April 11, 2017: Journal of Fluorescence
https://www.readbyqxmd.com/read/28399445/sensitive-detection-of-alkaline-phosphatase-by-switching-on-gold-nanoclusters-fluorescence-quenched-by-pyridoxal-phosphate
#8
Mohamed Ibrahim Halawa, Wenyue Gao, Muhammad Saqib, Shimeles Addisu Kitte, Fengxia Wu, Guobao Xu
In this work, we designed highly sensitive and selective luminescent detection method for alkaline phosphatase using bovine serum albumin functionalized gold nanoclusters (BSA-AuNCs) as the nanosensor probe and pyridoxal phosphate as the substrate of alkaline phosphatase. We found that pyridoxal phosphate can quench the fluorescence of BSA-AuNCs and pyridoxal has little effect on the fluorescence of BSA-AuNCs. The proposed mechanism of fluorescence quenching by PLP was explored on the basis of data obtained from high-resolution transmission electron microscopy (HRTEM), dynamic light scattering (DLS), UV-vis spectrophotometry, fluorescence spectroscopy, fluorescence decay time measurements and circular dichroism (CD) spectroscopy...
April 6, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28398738/au10-sg-10-a-chiral-gold-catenane-nanocluster-with-zero-confined-electrons-optical-properties-and-first-principles-theoretical-analysis
#9
Franck Bertorelle, Isabelle Russier-Antoine, Nathalie Calin, Clothilde Comby-Zerbino, Amina Bensalah, Stephan Guy, Philippe Dugourd, Pierre-Francois Brevet, Zeljka Sanader, Marjan Krstic, Vlasta Bonacic-Koutecky, Rodolphe Antoine
We report a facile synthesis of the Au10(SG)10 nanoclusters, where SG stands for glutathione, found to be promising as a new class of radiosensitizers for cancer radiotherapy.The homoleptic catenane structure with two Au5SG5 interconnected rings cluster, among different isomer structures, gives the best agreement between theoretical and experimental optical spectra and XRD patterns. This catenane structure exhibits a centrosymmetry-broken structure, resulting in enhanced second harmonic response and new characteristic circular dichroism (CD) signals in the spectral region of 250-400 nm...
April 11, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28398723/valence-states-effect-on-electrogenerated-chemiluminescence-of-gold-nanocluster
#10
Huaping Peng, Meili Jian, Haohua Deng, Wenjun Wang, Zhongnan Huang, Kaiyuan Huang, Ailin Liu, Wei Chen
This work elucidated the valence states effect on the electrogenerated chemiluminescence (ECL) performance of gold nanocluster (AuNC). The N-acetyl-l-cysteine-AuNCs (NAC-AuNCs) and the electrochemical reduction method for reducing the AuNCs were first employed to this study. Results demonstrate that the electrochemical reduction degree of the AuNCs depended on the reduction potential, and the enhancement of the ECL signals was positively correlated with the reduction degree of AuNCs, which indicated that the valence state of Au plays a vital role in the ECL performance of AuNCs...
April 19, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28391081/glucose-decorated-gold-nanoclusters-a-membrane-potential-independent-fluorescence-probe-for-rapid-identification-of-cancer-cells-expressing-glut-receptors
#11
Sanjay Singh
The effective nanomedicines require nanoparticles to attach or adhere to the cell surface, which is dictated by several parameters of nanoparticles such as shape, size, charge, and composition. However, these parameters lead to the membrane potential dependent non-specific delivery of therapeutic or imaging nanosystems into cancer cells. This leads to significant complications and results into the serious impediment to effective treatment of cancer. Cancer cells are known to metabolize high amount of glucose in order to support their rapid proliferation and expansion...
April 1, 2017: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/28390487/colorimetric-detection-of-glutathione-in-cells-based-on-peroxidase-like-activity-of-gold-nanoclusters-a-promising-powerful-tool-for-identifying-cancer-cells
#12
Jiayu Feng, Pengcheng Huang, Shuizhen Shi, Ke-Yu Deng, Fang-Ying Wu
Glutathione (GSH), the most abundant biothiol in cells, not only plays a pivotal role in protective and detoxifying functions of the cell, but also serves as a very important mediator in many cellular functions. Especially, the difference of GSH level between cancer cells and normal cells is regarded as one of most important physiological parameters for cancer diagnosis. It is thereby extremely necessary to develop a simple, sensitive, and reliable analytical method for detection of GSH in cells. On the basis of the inhibition effect of GSH on the peroxidase-like activity of GSH stabilized gold nanoclusters, here a novel and facile strategy for colorimetric detection of cellular GSH level was well established...
May 15, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28383080/fluorescent-au-nanoclusters-stabilized-by-silane-facile-synthesis-color-tunability-and-photocatalytic-properties
#13
Shaochen Zhou, Yanyan Duan, Fu Wang, Chuanyi Wang
Synthesis of tunable, luminescent metal nanoclusters remains challenging due to their tendency to aggregate. Herein, we report a simple photoreduction method to synthesize fluorescent silane-stabilized Au nanoclusters. By altering the molar ratio of stabilizer and Au precursor, emissions of the as-prepared Au nanoclusters can be tuned in the wavelength range of 538-580 nm. High resolution transmission electron microscopy results showed that the variation in the size of the as-formed nanoclusters (1.2-2.0 nm) might be responsible for this emission shift...
April 6, 2017: Nanoscale
https://www.readbyqxmd.com/read/28382162/incorporating-gold-nanoclusters-and-target-directed-liposomes-as-a-synergistic-amplified-colorimetric-sensor-for-her2-positive-breast-cancer-cell-detection
#14
Yu Tao, Mingqiang Li, Bumjun Kim, Debra T Auguste
Breast cancer is the second leading cause of cancer-related mortality in women. Successful development of sensitive nanoprobes for breast cancer cell detection is of great importance for breast cancer diagnosis and symptomatic treatment. Herein, inspired by the intrinsic peroxidase property of gold nanoclusters, high loading, and targeting ability of ErbB2/Her2 antibody functionalized liposomes, we report that gold nanoclusters-loaded, target-directed, functionalized liposomes can serve as a robust sensing platform for amplified colorimetric detection of HER2-positive breast cancer cells...
2017: Theranostics
https://www.readbyqxmd.com/read/28372359/reversible-luminescent-nanoswitches-based-on-aggregation-induced-emission-enhancement-of-silver-nanoclusters-for-luminescence-turn-on-assay-of-inorganic-pyrophosphatase-activity
#15
Cong Tang, Hui Feng, Yuanyuan Huang, Zhaosheng Qian
Unique aggregation-induced emission (AIE) property has been found and widely applied in chemo/biosensors for thiolated gold nanoclusters and copper nanoclusters; however, little is known about this property of thiolate-protected silver nanoclusters. In this work, specific aggregation-induced emission enhancement (AIEE) of glutathione-capped silver nanoclusters (AgNCs) was verified via its solid-state luminescence and enhanced emission in poor solvent, three stimuli responsive nanoswitches were constructed based on its AIEE property, and a reliable and sensitive PPase assay was developed via ion-triggered luminescence switch...
April 12, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28371383/determination-of-fluvoxamine-maleate-in-human-urine-and-human-serum-using-alkaline-kmno4-rhodamine-b-chemiluminescence
#16
Dongqin Yang, Yanyan He, Funan Chen
The flow-injection chemiluminescence (FI-CL) behavior of a gold nanocluster (Au NC)-enhanced rhodamine B-KMnO4 system was studied under alkaline conditions for the first time. In the present study, the as-prepared bovine serum albumin-stabilized Au NCs showed excellent stability and reproducibility. The addition of trace levels of fluvoxamine maleate (Flu) led to an obvious decline in CL intensity in the rhodamine B-KMnO4 -Au NCs system, which could be used for quantitative detection of Flu. Under optimized conditions, the proposed CL system exhibited a favorable analytical performance for Flu determination in the range 2 to 100 μg ml(-1) ...
March 29, 2017: Luminescence: the Journal of Biological and Chemical Luminescence
https://www.readbyqxmd.com/read/28371113/simulated-sunlight-mediated-photodynamic-therapy-for-melanoma-skin-cancer-by-titanium-dioxide-nanoparticle-gold-nanocluster-graphene-heterogeneous-nanocomposites
#17
Yan Cheng, Yun Chang, Yanlin Feng, Ning Liu, Xiujuan Sun, Yuqing Feng, Xi Li, Haiyuan Zhang
Simulated sunlight has promise as a light source able to alleviate the severe pain associated with patients during photodynamic therapy (PDT); however, low sunlight utilization efficiency of traditional photosensitizers dramatically limits its application. Titanium-dioxide-nanoparticle-gold-nanocluster-graphene (TAG) heterogeneous nanocomposites are designed to efficiently utilize simulated sunlight for melanoma skin cancer PDT. The narrow band gap in gold nanoclusters (Au NCs), and staggered energy bands between Au NCs, titanium dioxide nanoparticles (TiO2 NPs), and graphene can result in efficient utilization of simulated sunlight and separation of electron-hole pairs, facilitating the production of abundant hydroxyl and superoxide radicals...
March 31, 2017: Small
https://www.readbyqxmd.com/read/28351146/carborane-derivative-conjugated-with-gold-nanoclusters-for-target-cancer-cell-imaging
#18
Jianling Wang, Leifeng Chen, Jing Ye, Zhiyong Li, Hui Jiang, Hong Yan, Marina Yu Stogniy, Igor B Sivaev, Vladimir Iosifovich Bregadze, Xuemei Wang
Polyhedral borane derivatives has been utilized in the treatment of Boron Neuron Capture Therapy (BNCT) for brain glioma, and much attention has been paid to search good biocompatible boron-rich composites for the effective cancer BNCT therapy. In this study, we have exploited the possibility of the self-assembly of the gold nanoclusters with carborane amino derivatives (GNCs-CB) for the precise bioimaging of cancer cells and targeted delivery of the relevant carborane to the tumors. Our observations demonstrate that the GNCs-CB can readily realize the accurate tumor imaging and long-term accumulation in tumor sites by EPR effect and nanometer size effect, and thus efficiently implement tumor targeting delivery of carborane derivatives and facilitate the real-time fluorescent visualization monitoring of carborane targeted delivery process...
March 28, 2017: Biomacromolecules
https://www.readbyqxmd.com/read/28345880/detecting-proteins-glycosylation-by-a-homogeneous-reaction-system-with-zwitterionic-gold-nanoclusters
#19
Jinan Li, Jing Liu, Zheyi Liu, Yuan Tan, Xiaoyan Liu, Fangjun Wang
Homogeneous gold nanoclusters (Au NCs) have been widely utilized in drug delivery, chemical sensing, bioassays, and biolabeling due to their unique physical and chemical properties. However, little attention has been paid to their application in detecting protein post-translational modifications. Herein, we describe the development of a homogeneous reaction system with water-soluble zwitterionic Au NCs to capture glycopeptides from complex biological samples. The unique characteristics of Au NCs, such as their molecular-like properties, the excellent homogeneity in aqueous solution, the organic solvent responsive precipitation, and the easy preparation in only 4...
March 28, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28337982/the-fourth-crystallographic-closest-packing-unveiled-in-the-gold-nanocluster-crystal
#20
Zibao Gan, Jishi Chen, Juan Wang, Chengming Wang, Man-Bo Li, Chuanhao Yao, Shengli Zhuang, An Xu, Lingling Li, Zhikun Wu
Metal nanoclusters have recently attracted extensive interest not only for fundamental scientific research, but also for practical applications. For fundamental scientific research, it is of major importance to explore the internal structure and crystallographic arrangement. Herein, we synthesize a gold nanocluster whose composition is determined to be Au60S6(SCH2Ph)36 by using electrospray ionization mass spectrometry and single crystal X-ray crystallography (SCXC). SCXC also reveals that Au60S6(SCH2Ph)36 consists of a fcc-like Au20 kernel protected by a pair of giant Au20S3(SCH2Ph)18 staple motifs, which contain 6 tetrahedral-coordinate μ4-S atoms not previously reported in the Au-S interface...
March 24, 2017: Nature Communications
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