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gold nanocluster

Chen Fu, Chizhu Ding, Xianchao Sun, Ailing Fu
Nanotechnology plays an important role in the development of drug delivery, imaging, and diagnosis. In this study, nanocapsules containing protein-functionalized gold nanoclusters (AuNCs) as the shell and hydrophobic drug curcumin as the core were prepared as a tumor cell theranostic agent. After the nanocapsules were added into tumor cell media, they entered the cells with high efficiency and exhibited strong fluorescence within the cells. The results indicated that the nanocapsules were broken up in the cells and curcumin was released...
June 1, 2018: Materials Science & Engineering. C, Materials for Biological Applications
Xiaodong Zhang, Xiaokai Chen, Yao-Wen Jiang, Ningning Ma, Liu-Yuan Xia, Xiaotong Cheng, Hao-Ran Jia, Peidang Liu, Ning Gu, Zhan Chen, Fu-Gen Wu
The therapeutic performance of cancer radiotherapy is often limited by the over-expression of glutathione (GSH) in tumor and low radiation sensitivity of cancerous cells. To address these issues, the facilely prepared histidine-capped gold nanoclusters (Au NCs@His) were adopted as a radiosensitizer with a high sensitization enhancement ratio of ~1.54. On one hand, Au NCs@His can inherit the local radiation enhancement property of gold-based materials (external regulation); on the other hand, Au NCs@His can decrease the intracellular GSH level, thus preventing the generated ROS from being consumed by GSH, and arrest the cells at the radiosensitive G2/M phase (internal regulation)...
March 15, 2018: ACS Applied Materials & Interfaces
Daiki Kato, Hayato Sakai, Yasuyuki Araki, Takehiko Wada, Nikolai V Tkachenko, Taku Hasobe
Photophysical control and switching on organic-inorganic hybrid interfaces are of great interest in diverse fundamental and applicative research areas. 6,13-Bis(triisopropylsilylethynyl)pentacene (TP) is well-known to exhibit efficient singlet fission (SF) for generation of high-yield triplet excited states in aggregated forms, whereas perylenediimide (PDI) ensembles show the characteristic excimer formation. Additionally, a combination of pentacene (electron donor: D) and PDI (electron acceptor: A) is expected to undergo an efficient photoinduced electron transfer (PET), and absorption of two chromophores combined covers the entire visible region...
March 14, 2018: Physical Chemistry Chemical Physics: PCCP
Youmei Wang, Minghua Lu, Dianping Tang
A new photoluminescence (PL) enzyme immunoassay was designed for sensitive detection of aflatoxin B1 (AFB1 ) via an innovative enzyme substrate, 6-aza-2-thiothymine-stabilized gold nanocluster (AAT-AuNC) with L-arginine. The enzyme substrate with strong PL intensity was formed through supramolecular host-guest assembly between guanidine group of L-arginine and AAT capped on the surface of AuNC. Upon arginase introduction, the captured L-arginine was hydrolyzed into ornithine and urea, thus resulting in the decreasing PL intensity...
March 5, 2018: Biosensors & Bioelectronics
Yohei Ishida, Akihiro Morita, Tomoharu Tokunaga, Tetsu Yonezawa
We herein present the preparation of short, bulky cationic thiolate (thiocholine) protected fluorescent Au nanoclusters via sputter deposition over a liquid polymer matrix. The obtained Au nanoclusters showed near-infrared fluorescence and had an average core diameter of 1.7 ± 0.6 nm, which is too large compared with that of the reported fluorescent Au nanoclusters prepared via chemical means. We revealed the mechanism of formation of this unique material using single-particle electron microscopy, optical measurements, X-ray photoelectron spectroscopy (XPS), and high-performance liquid chromatography fractionations...
March 12, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Sandor Balog
The dimensions of ultra-small inorganic nanoparticles (US-NPs) is in the heart of the design of diagnostic and therapeutic efficacy; yet its accurate measurement is challenging for most experimental techniques. We show here how to design and analyze Taylor dispersion experiments to characterize the two most sought-after parameters describing size distributions: the number-averaged mean size and polydispersity index. To demonstrate the power of the method, we simulated and analyzed taylograms corresponding to gold US-NPs distributed normally...
March 8, 2018: Analytical Chemistry
Qing Liu, Ning Li, Mengke Wang, Lei Wang, Xingguang Su
Protein kinase (PKA) can regulate many cellular biological processes by phosphorylation substrate peptide or protein. A new fluorescent biosensing method for the detection of PKA activity was developed by using 11-mercaptoundecanoic acid-capped gold nanoclusters (MUA-Au NCs) and graphene oxide (GO) with low background noise. In this strategy, the special designed peptide could be anchored on the surface of MUA-Au NCs by the Au-S bond and also adsorbed on the surface of GO owing to the electrostatic interaction...
July 12, 2018: Analytica Chimica Acta
Haiwei Ji, Li Wu, Fang Pu, Jinsong Ren, Xiaogang Qu
The rapid, simple, and reliable identification of the most prevalent pathogens is essential for clinical diagnostics, biology, and food safety. Herein, four protein-encapsulated gold nanoclusters (protein-AuNCs) are designed and prepared as a sensor array for rapid identification of bacteria. The discrimination of six kinds of bacteria, including two kinds of drug-resistant bacteria, is successfully realized by the as-fabricated sensor array. The strategy presented here shows the advantages of easy synthesis and convenient to use...
March 2, 2018: Advanced Healthcare Materials
K L Dimuthu M Weerawardene, Hannu Häkkinen, Christine M Aikens
Ligand-stabilized gold and silver nanoparticles are of tremendous current interest in sensing, catalysis, and energy applications. Experimental and theoretical studies have closely interacted to elucidate properties such as the geometric and electronic structures of these fascinating systems. In this review, the interplay between theory and experiment is described; areas such as optical absorption and doping, where the theory-experiment connections are well established, are discussed in detail; and the current status of these connections in newer fields of study, such as luminescence, transient absorption, and the effects of solvent and the surrounding environment, are highlighted...
February 28, 2018: Annual Review of Physical Chemistry
Shenghao Xu, Yongyin Nie, Liping Jiang, Jun Wang, Guiyun Xu, Wei Wang, Xiliang Luo
A novel fluorescence resonance energy transfer (FRET)-based platform using polydopamine nanospheres (PDANSs) as energy acceptors and dual colored Au NCs as energy donors for simultaneous detection of multiple tumor-related microRNAs with DNase-I-assisted target recycling amplification was developed for the first time. On the basis of monitoring the change of the recovered fluorescence intensity at 445 and 575 nm upon the addition of targets miRNA-21 and let-7a, these two microRNAs (miRNAs) can be simultaneously quantitatively detected, with detection limits of 4...
March 2, 2018: Analytical Chemistry
Jigna R Bhamore, Sanjay Jha, Hirakendu Basu, Rakesh Kumar Singhal, Z V P Murthy, Suresh Kumar Kailasa
Herein, fluorescent gold nanoclusters (Au NCs) were obtained by one-pot synthetic method using bovine serum albumin (BSA) and bromelain as templates. As-synthesized fluorescent Au NCs were stable and showed bright red fluorescence under UV lamp at 365 nm. The fluorescent Au NCs exhibit the emission intensity at 648 nm when excited at 498 nm. Various techniques were used such as spectroscopy (UV-visible, fluorescence, and Fourier-transform infrared), high-resolution transmission electron microscopy, and dynamic light scattering for the characterization of fluorescent Au NCs...
February 26, 2018: Analytical and Bioanalytical Chemistry
Ying Yang, Shuxin Wang, Changzhi Xu, Anjian Xie, Yuhua Shen, Manzhou Zhu
A novel integrated system composed of hydrosoluble gold nanoclusters (AuNCs), two-level mesoporous canal silica, gelatin and folic acid was for the first time designed and synthesized, which could conquer poor stability of AuNCs and shows aggregation-enhanced fluorescence imaging, cancer cell-specific targeting, and synergistic photothermal/photodynamic therapies for the goal of personalized nanotheranostics.
February 26, 2018: Chemical Communications: Chem Comm
Yan Peng, Maomao Wang, Xiaoxia Wu, Fu Wang, Lang Liu
Gold nanoclusters (Au NCs) have been considered as novel heavy metal ions sensors due to their ultrafine size, photo-stability and excellent fluorescent properties. In this study, a green and facile method was developed for the preparation of fluorescent water-soluble gold nanoclusters with methionine as a stabilizer. The nanoclusters emit orange fluorescence with excitation/emission peaks at 420/565 nm and a quantum yield of about 1.46%. The fluorescence of the Au NCs is selectively and sensitively enhanced by addition of Cd(II) ions attributed to the Cd(II) ion-induced aggregation of nanoclusters...
February 23, 2018: Sensors
Zhikun Wu
Anti-galvanic reaction (AGR) not only defies classic galvanic theory but also is a promising method for tuning noble metal nanoparticles' compositions, structures and properties. In particular, employing AGR for the preparation of alloy nanoparticles has recently received extensive interest. Herein, we report on a unprecedented alloying mode by way of AGR, in which the foreign atoms induce the structural transformation of the mother nanoparticles and enter the novel nanoparticles in a non-replacement fashion...
February 21, 2018: Angewandte Chemie
Tsai-Mu Cheng, Hsueh-Liang Chu, Yi-Cheng Lee, Di-Yan Wang, Che-Chang Chang, Kuan-Lan Chung, Hung-Chi Yen, Chu-Wen Hsiao, Xi-Yu Pan, Tsung-Rong Kuo, Chia-Chun Chen
The glucose metabolism rate in cancer cells is a crucial piece of information for the cancer aggressiveness. A feasible method to monitor processes of oncogenic mutations has been demonstrated in this work. The fluorescent gold nanoclusters conjugated with glucose (glucose-AuNCs) were successfully synthesized as a cancer-targeting probe for glucose transporters (Gluts) overexpressed by U-87 MG cancer cells, which can be observed under confocal microscopy. The structural and optical characterizations of fluorescent glucose-AuNCs were confirmed by transmission electron microscope (TEM) and Fourier transform infrared spectroscopy (FTIR)...
February 21, 2018: Analytical Chemistry
Caifeng Ding, Yujuan Xu, Yanan Zhao, Hua Zhong, Xiliang Luo
Drug delivery which can offer efficient and localized drug transportation together with imaging capabilities is highly demanded in the development of cancer theranostic approaches. Herein, we report the construction of bovine serum albumin (BSA) gold nanoclusters (BSA@AuNCs) for cell fluoresce imaging and target drug delivery. BSA@AuNCs were modified with cyclic arginine-glycine-aspartate (cRGD) with the product RGD-BSA@AuNCs to enhance the cell internalization of the nanoclusters. Furthermore, doxorubicin (DOX), a widely used a chemotherapy drug, was also used to modify RGD-BSA@AuNCs...
February 19, 2018: ACS Applied Materials & Interfaces
Seong-Rok Kim, Seongyeon Cho, Moon Il Kim
Although Fe3O4 magnetic nanoparticles (MNPs) have gathered particular interest as potent peroxidase mimetics, their practical utility has been critically limited by their low catalytic activity. Here, we have developed a nanohybrid material to significantly enhance the catalytic activity of MNPs by incorporating other enzyme mimetics, gold nanoclusters (AuNCs), through electrostatic attraction. Owing to the synergistic effect of MNPs and AuNCs, the constructed nanohybrid yielded highly enhanced peroxidase-like activity and higher resolution in electrochemical detection of H2O2 than bare MNPs...
February 1, 2018: Journal of Nanoscience and Nanotechnology
Fei Qu, Zeqiu Chen, Jinmao You, Cuihua Song
Human telomere DNA plays a vital role in genome integrity control and carcinogenesis as an indication for extensive cell proliferation. Herein, silver nanoclusters (Ag NCs) templated by polymer and unmodified gold nanoparticles (Au NPs) are designed as a new colorimetric platform for sensitively differentiating telomere DNA with different lengths, monitoring G-quadruplex and dsDNA. Ag NCs can produce the aggregation of Au NPs, so the color of Au NPs changes to blue and the absorption peak moves to 700nm. While the telomere DNA can protect Au NPs from aggregation, the color turns to red again and the absorption band blue shift...
February 7, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Siwen Wang, Noushin Omidvar, Emily Marx, Hongliang Xin
Geometry-based reactivity descriptors, e.g., regular, generalized, and orbitalwise coordination numbers, were used for unraveling intrinsic size effects of Au nanocatalysts towards CO oxidation. For an ensemble of Au nanoparticles with varying sizes and shapes, s-orbital coordination numbers (CNs) linearly correlate with *CO and *O adsorption energies at the on-top and hollow sites, respectively, outperforming their regular (CN) and generalized (C[combining macron]N[combining macron]) counterparts attributed to an explicit consideration of interatomic interactions...
February 13, 2018: Physical Chemistry Chemical Physics: PCCP
Tuğba Köker, Nathalie Tang, Chao Tian, Wei Zhang, Xueding Wang, Richard Martel, Fabien Pinaud
The in cellulo assembly of plasmonic nanomaterials into photo-responsive probes is of great interest for many bioimaging and nanophotonic applications but remains challenging with traditional nucleic acid scaffolds-based bottom-up methods. Here, we address this quandary using split-fluorescent protein (FP) fragments as molecular glue and switchable Raman reporters to assemble gold or silver plasmonic nanoparticles (NPs) into photonic clusters directly in live cells. When targeted to diffusing surface biomarkers in cancer cells, the NPs self-assemble into surface-enhanced Raman-scattering (SERS) nanoclusters having hot spots homogenously seeded by the reconstruction of full-length FPs...
February 9, 2018: Nature Communications
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