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gold nanocluster

Youkun Zheng, Lanmei Lai, Weiwei Liu, Hui Jiang, Xuemei Wang
Fluorescent gold nanoclusters (AuNCs) are emerging as novel fluorescent materials and have attracted more and more attention in the field of biolabeling, biosensing, bioimaging and targeted cancer treatment because of their unusual physicochemical properties, such as long fluorescence lifetime, ultrasmall size, large Stokes shift, strong photoluminescence, as well as excellent biocompatibility and photostability. Recently, significant efforts have been committed to the preparation, functionalization and biomedical application studies of fluorescent AuNCs...
February 16, 2017: Advances in Colloid and Interface Science
Zhen Lei, Xian-Kai Wan, Shang-Fu Yuan, Jia-Qi Wang, Quan-Ming Wang
Ligand-protected metal nanoclusters as unique nanomaterials have attracted great attention. The protecting ligands that directly bind on the cluster surfaces are crucial in dictating the structures and properties of the clusters. In contrast to the extensively studied thiolates, alkynyl ligands have been found recently to be important ligands for passivating gold/silver cluster surfaces. In this Frontier article, recent advances in alkynyl-protected metal nanoclusters are overviewed, and the structures, luminescence and catalytic activities are also discussed...
February 20, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Hongzhi Lu, Shoufang Xu
Construction of ratiometric fluorescent probe often involved in tedious multistep preparation or complicated coupling or chemical modification process. The emergence of dual emission fluorescent nanoparticles would simplify the construction process and avoids the tedious chemical coupling. Herein, we reported a facile strategy to prepare ratiometric fluorescence molecularly imprinted sensor based on dual emission nanoparticles (d-NPs) which comprised of carbon dots and gold nanoclusters for detection of Bisphenol A (BPA)...
February 11, 2017: Biosensors & Bioelectronics
Yan Liu, Ding Ding, Yuanlin Zhen, Rong Guo
Herein, we presented a facile strategy for highly sensitive and selective detection of both Cu(2+) and histidine (His) by combining the peroxidase-like nanozyme activity of gold nanoclusters with amino acid's ambidentate nature. The peroxidase-like catalytic ability of histidine-Au nanoclusters (His-AuNCs) can be inhibited by the addition of Cu(2+). The sensitivity of this probe to Cu(2+) is significant with a linear range of 1-100nM, and a low detection limit of 0.1nM. More interestingly, His-AuNC/Cu(2+) undergoes recovery of the activity upon exposure to free His, because His/Cu(2+) complex is more stable due to the participation of the imidazole ring of His...
January 19, 2017: Biosensors & Bioelectronics
Marija Matulionyte, Dominyka Dapkute, Laima Budenaite, Greta Jarockyte, Ricardas Rotomskis
In recent years, photoluminescent gold nanoclusters have attracted considerable interest in both fundamental biomedical research and practical applications. Due to their ultrasmall size, unique molecule-like optical properties, and facile synthesis gold nanoclusters have been considered very promising photoluminescent agents for biosensing, bioimaging, and targeted therapy. Yet, interaction of such ultra-small nanoclusters with cells and other biological objects remains poorly understood. Therefore, the assessment of the biocompatibility and potential toxicity of gold nanoclusters is of major importance before their clinical application...
February 10, 2017: International Journal of Molecular Sciences
Lu Han, Jun-Mei Xia, Xin Hai, Yang Shu, Xu-Wei Chen, Jian-Hua Wang
A protein-stabilized multifunctional theranostic nanoplatform, gadolinium oxide-gold nanoclusters hybrid (Gd2O3-AuNCs), is constructed for multimodal imaging and drug delivery. The Gd2O3-AuNCs nanohybrid is developed by integrating Gd2O3 nanocrystals and gold nanoclusters into bovine serum albumin scaffold as a stabilizer. The nanohybrid exhibits favorable biocompatibility and is capable of enhancing the contrast in magnetic resonance and X-ray computed tomography imaging. Meanwhile, the integrated AuNCs component not only endows the nanohybrid to produce red fluorescence, but also sensitizes the generation of singlet oxygen ((1)O2) upon near-infrared laser stimulation at 808 nm...
February 17, 2017: ACS Applied Materials & Interfaces
Huijie Meng, Dongqin Yang, Yifeng Tu, Jilin Yan
In this report, a sensitive fluorescent detection of ascorbic acid was developed with protein-stabilized gold nanoclusters. The fluorescence signal from the gold nanoclusters could be effectively quenched by elemental iodine. This kind of quenching could be inhibited by ascorbic acid through a corresponding reduction process, thus a turn-on response toward ascorbic acid was obtained. The validity and performances of the detection scheme were evaluated. The fluorescence responses were linearly related to ascorbic acid in the concentration range 0...
April 1, 2017: Talanta
Tatsuya Higaki, Chong Liu, Yuxiang Chen, Shuo Zhao, Chenjie Zeng, Renxi Jin, Shuxin Wang, Nathaniel L Rosi, Rongchao Jin
Here we report an oxidation-induced transformation of [Au23(S-c-C6H11)16](-)TOA(+) (S-c-C6H11: cyclohexanethiolate; TOA: tetraoctylammonium) to the [Au28(S-c-C6H11)20](0) nanocluster by H2O2 treatment under ambient conditions. This is the first example of oxidation-induced transformation of one stable size to another with atomic precision. The product was crystallized and analyzed by X-ray crystallography. Further insights into the transformation process were obtained by monitoring the process with optical spectroscopy and also by electrochemical analysis...
February 7, 2017: Journal of Physical Chemistry Letters
Sha Yang, Jinsong Chai, Tao Chen, Bo Rao, Yiting Pan, Haizhu Yu, Manzhou Zhu
Herein, we report the synthesis and atomic structures of the cluster-assembled CuxAu25-x(PPh3)10(PhCH2CH2S)5Cl2(2+) and Cu3Au34(PPh3)13((t)BuPhCH2S)6S2(3+) nanoclusters (NCs). The atomic structures of both NCs were precisely determined by single-crystal X-ray crystallography. The CuxAu25-x(PPh3)10(PhC2H4S)5Cl2(2+) NC was assembled by two icosahedral M13 via a vertex-sharing mode. The Cu atom partially occupies the top and waist sites and is monocoordinated with chlorine or thiol ligands. Meanwhile, the Cu3Au34(PPh3)13((t)BuPhCH2S)6S2(3+) NC can be described as three 13-atom icosahedra sharing three vertexes in a cyclic fashion...
February 20, 2017: Inorganic Chemistry
Yuan Tan, Xiao Yan Liu, Leilei Zhang, Aiqin Wang, Lin Li, Xiaoli Pan, Shu Miao, Masatake Haruta, Haisheng Wei, Hua Wang, Fangjun Wang, Xiaodong Wang, Tao Zhang
Chemoselective hydrogenation of 3-nitrostyrene to 3-vinylaniline is quite challenging because of competitive activation of the vinyl group and the nitro group over most supported precious-metal catalysts. A precatalyst comprised of thiolated Au25 nanoclusters supported on ZnAl-hydrotalcite yielded gold catalysts of a well-controlled size (ca. 2.0 nm)-even after calcination at 500 °C. The catalyst showed excellent selectivity (>98 %) with respect to 3-vinylaniline, and complete conversion of 3-nitrostyrene over broad reaction duration and temperature windows...
March 1, 2017: Angewandte Chemie
Brian E Conn, Aydar Atnagulov, Bokwon Yoon, Robert N Barnett, Uzi Landman, Terry P Bigioni
Fathoming the principles underpinning the structures of monolayer-coated molecular metal nanoparticles remains an enduring challenge. Notwithstanding recent x-ray determinations, coveted veritable de novo structural predictions are scarce. Building on recent syntheses and de novo structure predictions of M3Au x Ag17-x (TBBT)12, where M is a countercation, x = 0 or 1, and TBBT is 4-tert-butylbenzenethiol, we report an x-ray-determined structure that authenticates an a priori prediction and, in conjunction with first-principles theoretical analysis, lends force to the underlying forecasting methodology...
November 2016: Science Advances
Catherine Ghosh, Tridib Mondal, Kankan Bhattacharyya
Effect of gold nanoclusters (Au-NCs) on the circular dichroism (CD) spectra and enzymatic activity of α-chymotrypsin (ChT) (towards hydrolysis of a substrate, N-succinyl-l-phenylalanine p-nitroanilide) are studied. The CD spectra indicate that on binding to Au-NC, ChT is completely unfolded, resulting in nearly zero ellipticity. α-chymotrypsin (ChT) coated gold nano-clusters exhibit almost no enzymatic activity. Addition of glutathione (GSH) or oxidized glutathione (GSSG) restore the enzyme activity of α-chymotrypsin by 30-45%...
May 15, 2017: Journal of Colloid and Interface Science
Hongwei Dong, Lingwen Liao, Shengli Zhuang, Chuanhao Yao, Jishi Chen, Shubo Tian, Min Zhu, Xu Liu, Lingling Li, Zhikun Wu
Studying the kernel evolution pattern of gold nanoclusters is intriguing but challenging due to the difficulty of precise size control and structure resolution. Herein, we successfully synthesized two novel gold nanoclusters, Au34(S-c-C6H11)22 and Au42(S-c-C6H11)26 (S-c-C6H11: cyclohexanethiolate), and resolved their structures. Interestingly, it was found that the kernel evolves from Au28(S-c-C6H11)20 to Au34(S-c-C6H11)22 and Au42(S-c-C6H11)26 in a novel fashion: alternate single-stranded evolution at both ends, which is remarkably different from the reported double-stranded growth at the bottom for the 4-tert-butylbenzenethiolate (TBBT)-protected nanocluster series...
January 30, 2017: Nanoscale
Yanyan Liu, Hongchang Li, Bin Guo, Lijuan Wei, Bo Chen, Youyu Zhang
Herein we report a novel switch-off fluorescent probe for highly selective determination of uric acid (UA) based on the inner filter effect (IFE), by using poly-(vinylpyrrolidone)-protected gold nanoparticles (PVP-AuNPs) and chondroitin sulfate-stabilized gold nanoclusters (CS-AuNCs) as the IFE absorber/fluorophore pair. In this IFE-based fluorometric assay, the newly designed CS-AuNCs were explored as an original fluorophore and the hydrogen peroxide (H2O2) -driven formed PVP-AuNPs can be a powerful absorber to influence the excitation of the fluorophore, due to the complementary overlap between the absorption band of PVP-AuNPs and the emission band of CS-AuNCs...
May 15, 2017: Biosensors & Bioelectronics
Di Wu, Wenjing Qi, Chun Liu, Qing Zhang
A "turn-on" fluorescent sensor for ozone using bovine serum albumin-directed gold nanoclusters (BSA-Au NCs) via energy transfer was developed. The spectral overlap of fluorescent spectrum of BSA-Au NCs with absorption spectrum of indigo carmine (IDS) was utilized. Ozone cleaves C = C bond of IDS and suppresses energy transfer from BSA-Au NCs to IDS. Therefore, this proposed fluorescent sensor is a "turn-on" detection motif. It is the first application of fluorescent nanoclusters in sensitively detecting ozone from 0...
January 26, 2017: Analytical and Bioanalytical Chemistry
Shahad K Alsaiari, Mohammed A Hammami, Jonas G Croissant, Haneen W Omar, Pradeep Neelakanda, Tahir Yapici, Klaus-Viktor Peinemann, Niveen M Khashab
Healthcare-associated infections (HAIs) are the infections that patients get while receiving medical treatment in a medical facility with bacterial HAIs being the most common. Silver and gold nanoparticles (NPs) have been successfully employed as antibacterial motifs; however, NPs leaching in addition to poor dispersion and overall reproducibility are major hurdles to further product development. In this study, the authors design and fabricate a smart antibacterial mixed-matrix membrane coating comprising colloidal lysozyme-templated gold nanoclusters as nanofillers in poly(ethylene oxide)/poly(butylene terephthalate) amphiphilic polymer matrix...
January 25, 2017: Advanced Healthcare Materials
Xin Chen, Huanhuan Zhu, Xin Huang, Peisong Wang, Fulei Zhang, Wei Li, Guang Chen, Bingdi Chen
As the most common endocrine malignancy with a high incidence, thyroid cancer lacks a dual-modal imaging method for precise diagnosis. An accurate and multimodal imaging system is pivotal to solve this problem. Herein, dual-modality fluorescence/Computed Tomography (CT) iodinated gold nanoclusters for malignant thyroid cancer visualization have been recently fabricated. In this study, innovative iodinated gold nanoclusters (AuNCs@BSA-I) were synthesized via Bovine serum albumin (BSA) and chloramine-T. AuNCs@BSA-I not only possess an ultra-small size and brilliant biocompatibility but also exhibit excellent fluorescence/CT imaging properties...
January 25, 2017: Nanoscale
Mukesh Kumar Kumawat, Mukeshchand Thakur, Jaya R Lakkakula, Deepika Divakaran, Rohit Srivastava
We report in situ transformation of glutathione-capped red-fluorescent gold nanoclusters (AuNCs) into larger gold nanoparticles (AuNPs) embedded on a copper grid under high energy electron beam of Field Emission Gun Transmission Electron Microscope (FEG-TEM). Electron beam irradiation causes coalescing of individual finer AuNCs into bigger discrete AuNPs as a function of electron dose rate and time. The coalescence was closely studied over time and the mechanism is discussed. The study will help to understand the structural and morphological changes that occur in AuNCs inside FEG-TEM due to prolonged electron beam exposure...
January 15, 2017: Micron: the International Research and Review Journal for Microscopy
Maria Godoy-Gallardo, Cedric Labay, Vasileios Trikalitis, Paul Kempen, Jannik B Larsen, Thomas Lars Andresen, Leticia Hosta-Rigau
Cell organelles are subcellular structures entrapping a set of enzymes to achieve a specific functionality. The incorporation of artificial organelles into cells is a novel medical paradigm which might contribute to the treatment of various cell disorders by replacing malfunctioning organelles. In particular, artificial organelles are expected to be a powerful solution in the context of enzyme replacement therapy since enzymatic malfunction is the primary cause of organelle dysfunction. Although several attempts have been made to encapsulate enzymes within a carrier vehicle, only few intracellularly active artificial organelles have been reported to date and they all consist of single-compartment carriers...
January 24, 2017: ACS Applied Materials & Interfaces
Shenghao Xu, Xiuying Feng, Teng Gao, Ruizhi Wang, Yaning Mao, Jiehua Lin, Xijuan Yu, Xiliang Luo
A novel ultrasensitive dual-functional biosensor for highly sensitive detection of inorganic pyrophosphate (PPi) and pyrophosphatase (PPase) activity was developed based on the fluorescent variation of globulin protected gold nanoclusters (Glo@Au NCs) with the assistance of Cu(2+). Glo@Au NCs and PPi were used as the fluorescent indicator and substrate for PPase activity evaluation, respectively. In the presence of Cu(2+), the fluorescence of the Glo@Au NCs will be quenched owing to the formation of Cu(2+)-Glo@Au NCs complex, while PPi can restore the fluorescence of the Cu(2+)-Glo@Au NCs complex because of its higher binding affinity with Cu(2+)...
March 15, 2017: Analytica Chimica Acta
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