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gold nanocluster

Jingjing Jiang, Pengfei Gao, Yan Zhang, Guomei Zhang, Ying Zhou, Chuan Dong, Shaomin Shuang
Herein, we demonstrate a straightforward synthesis of fluorescent gold nanoclusters (AuNCs), employing 2-Mercapto-4-methyl-5-thiazoleacetic acid (MMTA) as a reducing and protecting agent by a rapid one-pot synthesis method with a short time of 20min. The as-synthesized MMTA-AuNCs exhibited bright blue emission with a strong peak centered at 430nm and the quantum yield (QY) was evaluated to be 4.0%. Based on the fluorescence quenching mechanism of a surface chelating reaction between MMTA and ferric ion (Fe(3+)), the MMTA-AuNCs were exploited as a fluorescence sensor for sensitive and selective detection of Fe(3+)...
November 1, 2017: Talanta
Shuo Zhao, Renxi Jin, Yongbo Song, Hui Zhang, Stephen D House, Judith C Yang, Rongchao Jin
Hydrogen generation via electrocatalytic water splitting holds great promise for future energy revolution. It is desirable to design abundant and efficient catalysts and achieve mechanistic understanding of hydrogen evolution reaction (HER). Here, this paper reports a strategy for improving HER performance of molybdenum disulfide (MoS2 ) via introducing gold nanoclusters as a cocatalyst. Compared to plain MoS2 nanosheets, the Au25 (SR)18 /MoS2 nanocomposite exhibits enhanced HER activity with a small onset potential of -0...
July 24, 2017: Small
B Santiago-Gonzalez, A Monguzzi, M Caputo, C Villa, M Prato, C Santambrogio, Y Torrente, F Meinardi, S Brovelli
Metal nanoclusters featuring tunable luminescence and high biocompatibility are receiving attention as fluorescent markers for cellular imaging. The recently discovered ability of gold clusters to scavenge cytotoxic reactive oxygen species (ROS) from the intracellular environment extends their applicability to biomedical theranostics and provides a novel platform for realizing multifunctional luminescent probes with engineered anti-cytotoxic activity for applications in bio-diagnostics and conceivably cellular therapy...
July 20, 2017: Scientific Reports
Luke F Hartje, Brian E Munsky, Thomas W Ni, Christopher J Ackerson, Christopher D Snow
Large-pore protein crystals (LPCs) are ordered biologically-derived nanoporous materials exhibiting pore diameters greater than 8 nm. These substantial pores distinguish LPCs from typical nanoporous scaffolds; enabling engineered LPC materials to readily uptake, immobilize, and release macromolecular guests. In this study, macromolecular transport within an LPC environment has been experimentally and computationally investigated by studying adsorption-coupled diffusion of Au25(glutathione)18 nanoclusters within a crosslinked LPC scaffold via time-lapse confocal microscopy, bulk equilibrium adsorption, and hindered diffusion simulation...
July 17, 2017: Journal of Physical Chemistry. B
Hsiu-Ying Huang, Kun-Bin Cai, Li-Yun Chang, Po-Wen Chen, Tzu-Neng Lin, Cheng-An Lin, Ji-Lin Shen, Jessa Talite, Wu Ching Chou, Chi-Tsu Yuan
Heavy-metal-containing quantum dots (QDs) with engineered electronic states have been served as luminophores in luminescent solar concentrators (LSCs) with impressive optical efficiency. Unfortunately, those QDs involve toxic elements and need to be synthesized in a hazardous solvent. Recently, biocompatible, eco-friendly gold nanoclusters (AuNCs), which can be directly synthesized in an aqueous solution, have gained much attention for promising applications in "green photonics". Here, we explored the solid-state photophysical properties of aqueous-solution-processed, glutathione-stabilized gold nanoclusters (GSH-AuNCs) with a ligand-to-metal charge-transfer (LMCT) state for developing "green" LSCs...
July 6, 2017: Nanotechnology
Qingfeng Zhai, Huanhuan Xing, Xiaowei Zhang, Jing Li, Erkang Wang
Bimetallic nanoclusters (NCs) with superior performance to that of monometallic nanoclusters have attracted extensive research interest due to the synergetic effect of the two atoms. Inspired from the silver effect on the enhanced fluorescence intensity of Au NCs, a series of bovine serum albumin-protected Au-Ag bimetallic NCs were prepared by regulating the molar ratios of HAuCl4/AgNO3 and their electrochemiluminescence (ECL) property was investigated using triethylamine as co-reactant. Notably, multifold higher efficiency was achieved with Au-Ag bimetallic NCs in reference to the monometallic nanoclusters...
July 5, 2017: Analytical Chemistry
Malamatenia A Koklioti, Theodosis Skaltsas, Yuta Sato, Kazu Suenaga, Anastasios Stergiou, Nikos Tagmatarchis
Metal nanoclusters (MNCs) based on silver and gold, abbreviated as AgNCs and AuNCs, respectively, were synthesized and combined with functionalized graphene, abbreviated as f-G, forming novel MNC/f-G ensembles. The preparation of MNCs/f-G was achieved by employing attractive electrostatic interactions developed between negatively charged MNCs, attributed to the presence of carboxylates due to α-lipoic acid employed as a stabilizer, and positively charged f-G, attributed to the presence of ammonium units as addends...
July 13, 2017: Nanoscale
Sumei Cao, Shushu Ding, Yingzi Liu, Anwei Zhu, Guoyue Shi
Hurdles of nanopore modification and characterization restrain the development of glass capillary-based nanopore sensing platforms. In this article, a simple but effective biomimetic mineralization method was developed to decorate glass nanopore with a thin film of bovine serum albumin-protected Au nanocluster (BSA-Au NC). The BSA-Au NC film emitted a strong red fluorescence whereby nondestructive characterization of Au film decorated at the inner surface of glass nanopore can be facilely achieved by a fluorescence microscopy...
July 13, 2017: Analytical Chemistry
Haodong Cui, Dehong Hu, Jingnan Zhang, Guanhui Gao, Ze Chen, Wenjun Li, Ping Gong, Zonghai Sheng, Lintao Cai
A well-designed gold nanoclusters-indocyanine green nanoprobes (Au NCs-INPs) have been developed by the conjugation of Au NCs assemblies with indocyanine green (ICG) for the therapeutic real-time monitoring based on fluorescence resonance energy transfer (FRET). The synthesized Au NCs-INPs demonstrated the improved cellular uptake and effective tumor targeting due to the enhanced permeability and retention (EPR) effect and the gp60-mediated SPARC combined transport pathway, suggesting excellent dual-modal near-infrared fluorescent (NIRF) and photoacoustic (PA) imaging...
July 4, 2017: ACS Applied Materials & Interfaces
Tatsuya Higaki, Chong Liu, Meng Zhou, Tian-Yi Luo, Nathaniel L Rosi, Rongchao Jin
We report the synthesis and crystal structure determination of a gold nanocluster with 103 gold atoms protected by 2 sulfidos and 41 thiolates (i.e., 2-naphthalenethiolates, S-Nap), denoted as Au103S2(S-Nap)41. The crystallographic analysis reveals that the thiolate ligands on the nanocluster form local tetramers by intracluster interactions of C-H···π and π···π stacking. The herringbone pattern formation via intercluster interactions is also observed, which leads to a linearly connected zigzag pattern in the single crystal...
July 11, 2017: Journal of the American Chemical Society
Chenjie Zeng, Rongchao Jin
Chiral nanomaterials have received wide interest in many areas, but the exact origin of chirality at the atomic level remains elusive in many cases. With recent significant progress in atomically precise gold nanoclusters (e.g., thiolate-protected Aun (SR)m ), several origins of chirality have been unveiled based upon atomic structures determined by using single-crystal X-ray crystallography. The reported chiral Aun (SR)m structures explicitly reveal a predominant origin of chirality that arises from the Au-S chiral patterns at the metal-ligand interface, as opposed to the chiral arrangement of metal atoms in the inner core (i...
June 27, 2017: Chemistry, An Asian Journal
Qi Li, Michael G Taylor, Kristin Kirschbaum, Kelly J Lambright, Xiaofan Zhu, Giannis Mpourmpakis, Rongchao Jin
The synthesis and structure determination of atomically precise alloy nanoclusters have attracted much attention in recent research. Herein, we report a new alloy nanocluster Au24-xAgx(TBBM)20 (x∼1) synthesized via a ligand-exchange-induced size/structure transformation method. Its X-ray structure is obtained successfully and the dopant Ag is found to occupy three special positions in the kernel, rather than equivalently over all the kernel sites. This selective occupancy is interesting and DFT calculation results suggest that the relative oxidation state (rationalized as difference in the charge) of the Ag when doped into the cluster is likely determining the most favorable doping positions...
June 16, 2017: Journal of Colloid and Interface Science
Wen Wu Xu, Xiao Cheng Zeng, Yi Gao
An understanding of the structural stability and formation mechanism of ligated gold nanoclusters with triply coordinated μ3-sulfido (μ3-S) motifs is important not only for gold chemistry but also for the design of more effective catalysts or drug carriers for various applications. In this article, a new elementary block Au3(μ3-S) with zero valence electrons [referred to as Au3(μ3-S)(0e)] has been identified, which describes all crystallized ligated gold clusters with μ3-S motifs, in conjunction with the previously reported Au3(2e) and Au4(2e) elementary blocks, in a grand unified model (GUM)...
July 6, 2017: Nanoscale
Jeong-Hwan Kim, Haruki Eguchi, Yoshihiro Ishikawa
Ultrafine Au quantum clusters (QCs) were synthesized by etching host Au nanoparticles in the presence of ethylenediamine (en) and exhibited both strong photoluminescence (PL) and specific anticancer activity. The cutting-edge feature of this QC compound comprises subnanometer-size rhombohedral Au8, which consists of 8 units of the anticancer motif, namely, an Au(+)(en) complex (Au(en)QCs), which contributes to photo- and physicochemical stability as well as subcellular theranostic activity in intracellular PL imaging and in situ targeting...
July 6, 2017: Nanoscale
Alvaro Rafael Muñoz-Castro, Franck Gam, Dayan Paez-Hernandez, Ramiro Arratia-Perez, C W Liu, Samia Kahlal, Jean-Yves Saillard
Coinage-metal atomically precise nanoclusters are made of a well-defined metallic core embedded in a ligand-protecting outer shell. Whereas gold derivatives are particularly well documented, examples of silver nanoclusters are somewhat limited and copper species remain particularly scare. Our DFT relativistic calculations on superatomic metallic cores indicate that copper species are almost as stable as gold clusters and more stable than their silver counterparts. Thus, for silver superatomic cores, the role of the stabilizing ligands is more crucial in the stabilization of the overall structure, in comparison to copper and gold...
June 19, 2017: Chemistry: a European Journal
Jose M Carnerero, Aila Jimenez-Ruiz, Elia M Grueso, Rafael Prado-Gotor
It is well known that single-stranded DNA (ssDNA) is easily able to adsorb on citrate-capped, non-functionalized gold nanoparticles (AuNPs). However, the affinity of double-stranded DNA (dsDNA) for them is much more limited. The present work demonstrates that long dsDNA suffers from a bending conformational change when anionic nanoparticles are present in solution. A striking decrease in the persistence length of the double helix in the absence of salt is observed through dynamic light scattering (DLS), viscometric, and atomic force microscopy (AFM) methods...
June 21, 2017: Physical Chemistry Chemical Physics: PCCP
Xing-Juan Li, Jian Ling, Cai-Ling Han, Li-Qiang Chen, Qiu-E Cao, Zhong-Tao Ding
In this paper, chicken egg white purchased from a local market without further purification was directly used to prepare fluorescent gold nanoclusters through a one-step, simple, fast and green synthesis approach for analytical purposes. The as-prepared chicken egg white stabilized gold nanocluster probe has strong red fluorescence emission, which can be quenched by mercury ions and copper ions sensitively. By using an ethylenediaminetetraacetate (EDTA) masking method, mercury ions in the range from 0.60 to 10 μM can be linearly detected with the limit of detection (LOD, 3σ) of 0...
2017: Analytical Sciences: the International Journal of the Japan Society for Analytical Chemistry
Kaiyuan Zheng, Magdiel I Setyawati, David Tai Leong, Jianping Xie
Bulk gold (Au) is known to be chemically inactive. However, when the size of Au nanoparticles (Au NPs) decreases to close to 1 nm or sub-nanometer dimensions, these ultrasmall Au nanoclusters (Au NCs) begin to possess interesting physical and chemical properties and likewise spawn different applications when working with bulk Au or even Au NPs. In this study, we found that it is possible to confer antimicrobial activity to Au NPs through precise control of their size down to NC dimension (typically less than 2 nm)...
June 13, 2017: ACS Nano
Hui Li, Ping Wang, Yunxiang Deng, Meiying Zeng, Yan Tang, Wei-Hong Zhu, Yingsheng Cheng
Pancreatic ductal adenocarcinoma (PDAC) is one of the most devastating malignancies in patients, and there is an urgent need for an effective treatment method. Herein, we report a novel gold nanocluster-based platform for confocal laser endomicroscopy-guided photothermal therapy (PTT)/photodynamic therapy (PDT) for PDAC, which consists of four components: the PTT-carrier gold nanocluster, an active targeting ligand U11 peptide, a Cathepsin E (CTSE)-sensitive PDT therapy prodrug, and a CTSE-sensitive imaging agent (cyanine dye Cy5...
September 2017: Biomaterials
Shweta Jindal, Siva Chiriki, Satya S Bulusu
We propose a highly efficient method for fitting the potential energy surface of a nanocluster using a spherical harmonics based descriptor integrated with an artificial neural network. Our method achieves the accuracy of quantum mechanics and speed of empirical potentials. For large sized gold clusters (Au147), the computational time for accurate calculation of energy and forces is about 1.7 s, which is faster by several orders of magnitude compared to density functional theory (DFT). This method is used to perform the global minimum optimizations and molecular dynamics simulations for Au147, and it is found that its global minimum is not an icosahedron...
May 28, 2017: Journal of Chemical Physics
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