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DNA silver nanocluster

Yasaman-Sadat Borghei, Morteza Hosseini, Mohammad Reza Ganjali, Huangxian Ju
The authors describe a dual (colorimetric and fluorometric) detection scheme for microRNA. The method is based on the use of fluorescent DNA-modified silver nanoclusters (DNA-AgNCs) and gold nanoparticles (AuNPs). The DNA-AgNCs were linked to AuNPs via the interaction of ssDNA-AgNC probes with AuNPs. This led to quenching of the fluorescence of the DNA-AgNCs (best measured at excitation/emission peaks of 370/450 nm) and also prevents salt-induced aggregation of the AuNPs. Upon addition of microRNA, the DNA on the AgNCs hybridizes with microRNA...
May 8, 2018: Mikrochimica Acta
Zhiqiang Chen, Ying Liu, Chen Xin, Jikuan Zhao, Shufeng Liu
Herein, an autocatalytic strand displacement amplification (ASDA) strategy was proposed for the first time, which was further ingeniously coupled with hybridization chain reaction (HCR) event for the isothermal, label-free and multiple amplification toward nucleic acid detection. During the ASDA module, the target recognition opens the immobilized hairpin probe (IP) and initiates the annealing of the auxiliary DNA strand (AS) with the opened IP for the successive polymerization and nicking reaction in the presence of DNA polymerase and nicking endonuclease...
April 23, 2018: Biosensors & Bioelectronics
Congcong Bu, Lixuan Mu, XIngxing Cao, Min Chen, Guangwei She, Wensheng Shi
Linking the fluorescent silver nanoclusters (AgNCs) and guanine-rich(G-rich)DNA chains by the thermal sensitive DNA stem-loop at teminal 5' and 3', DNA nanostructure-based fluorescence thermometers were fabricated. The variations of the temperature alter the distance between AgNCs and G-rich DNA chain, which could affect the interaction between them. As a result, the intensity of fluorescence emission from AgNCs at 636 nm can be sensitively modulated. It was found that such red emission is more sensitive to the temperature comparing with its intrinsic green emission at 543 nm, and sensitivity of -3...
April 27, 2018: Nanotechnology
Chunghyun Lee, Jongback Gang
Restriction endonucleases play an important role in genetic recombination, molecular cloning, clinical diagnosis, and pharmacological application in drug studies. In the present study, DNA-templated Ag+ nanoclusters (DNA-AgNCs) were used to detect NdeI endonuclease activity due to their facile synthesis, outstanding optical properties, and good biocompatibility. This study monitored fluorescence intensity of DNA-AgNCs to detect NdeI endonuclease activity and its inhibition in the presence of 5-fluorouracil under optimal conditions...
September 1, 2018: Journal of Nanoscience and Nanotechnology
Xiaodong Lin, Yaqing Liu, Jiankang Deng, Yanlong Lyu, Pengcheng Qian, Yunfei Li, Shuo Wang
The integration of multiple DNA logic gates on a universal platform to implement advance logic functions is a critical challenge for DNA computing. Herein, a straightforward and powerful strategy in which a guanine-rich DNA sequence lighting up a silver nanocluster and fluorophore was developed to construct a library of logic gates on a simple DNA-templated silver nanoclusters (DNA-AgNCs) platform. This library included basic logic gates, YES, AND, OR, INHIBIT, and XOR, which were further integrated into complex logic circuits to implement diverse advanced arithmetic/non-arithmetic functions including half-adder, half-subtractor, multiplexer, and demultiplexer...
February 21, 2018: Chemical Science
Christian Léon, Darío González-Abradelo, Cristian A Strassert, Jens Müller
Silver nanoclusters (AgNCs) stabilized by double-stranded DNA (dsDNA) are of special interest because the duplex structures provide rigidity and chirality that can be transferred to the metal clusters. We report fluorescent AgNCs obtained from dsDNA templates containing artificial ligand-derived nucleobases. They are compared with fluorescent AgNCs obtained from DNA templates containing C:C mismatches (C, cytosine). Towards this end, the new metal-mediated Im-Ag(I)-C base pair composed of imidazole (Im) and cytosine was introduced into dsDNA and reduced to form AgNCs...
April 17, 2018: Chemistry: a European Journal
Stefan Krause, Miguel R Carro-Temboury, Cecilia Cerretani, Tom Vosch
Measurements on biological samples are often hampered by auto-fluorescence from inherent compounds in tissue or cells, limiting the achievable contrast. Both the signal of interest and the auto-fluorescence are usually detected on the Stokes side of the excitation laser. In this communication, we present two new microscopy modalities, based on the emission of a red-emitting DNA-stabilized silver nanocluster (DNA-AgNC). Its bright fluorescence can be generated on the anti-Stokes side of the readout laser, allowing easy spectral separation of the signal of interest from the Stokes side auto-fluorescence...
April 17, 2018: Chemical Communications: Chem Comm
Yang Zhao, Lu Tan, Xiaoshan Gao, Guifen Jie, Tingyu Huang
Herein, we successfully devised a novel photoelectrochemical (PEC) platform for ultrasensitive detection of adenosine by target-triggering cascade multiple cycle amplification based on the silver nanoparticles-assisted ion-exchange reaction with CdTe quantum dots (QDs). In the presence of target adenosine, DNA s1 is released from the aptamer and then hybridizes with hairpin DNA (HP1), which could initiate the cycling cleavage process under the reaction of nicking endonuclease. Then the product (DNA b) of cycle I could act as the "DNA trigger" of cycle II to further generate a large number of DNA s1, which again go back to cycle I, thus a cascade multiple DNA cycle amplification was carried out to produce abundant DNA c...
March 30, 2018: Biosensors & Bioelectronics
Seyeon Kim, Jongback Gang
Fluorescence assays have been developed to detect biomolecules using DNA-templated silver nanoclusters (DNA-AgNCs) utilizing their unique physical and optical properties. This study was designed to detect single-mismatched DNA by the hybridization of target DNA to template DNA either before or after DNA-AgNCs synthesis. The results showed that the detection specificity of a single-mismatched DNA was clearly enhanced when the target DNA (cDNA) was hybridized to template DNA prior to DNA-AgNCs synthesis compared with cDNA hybridization subsequent to DNA-AgNCs synthesis...
March 30, 2018: Analytical Biochemistry
Amrita Chakraborty, Ann Candice Fernandez, Anirban Som, Biswajit Mondal, Ganapati Natarajan, Ganesan Paramasivam, Tanja Lahtinen, Hannu Häkkinen, Nonappa Nonappa, Thalappil Pradeep
We present the self-assembled structures of atomically precise, ligand-protected noble metal nanoclusters leading to encapsulation of plasmonic gold nanorods (GNRs). Unlike highly sophisticated DNA nanotechnology, our approach demonstrates a strategically simple hydrogen bonding-directed self-assembly of nanoclusters leading to octahedral nanocrystals encapsulating GNRs. Specifically, we use the p-mercaptobenzoic acid (pMBA) protected atomically precise nanocluster, Na4[Ag44(pMBA)30] and pMBA functionalized GNRs...
April 1, 2018: Angewandte Chemie
Xueqi Leng, Yu Wang, Rongguo Li, Su Liu, Jianzhuang Yao, Qianqian Pei, Xuejun Cui, Yuqin Tu, Dan Tang, Jiadong Huang
The authors describe a fluorometric strategy for the detection of pathogenic bacteria with ultrasensitivity and high specificity. This strategy relies on the combination of target-modulated photoinduced electron transfer (PET) between G-quadruplex DNAzyme and DNA (labeled with silver nanoclusters) along with hairpin probe-based circular exponential amplification. The reaction system involves three hairpin probes (H1, H2 and H3). Probe H1 contains an aptamer against S. Typhimurium and the recognition sequence for nicking endonuclease...
February 10, 2018: Mikrochimica Acta
Lu Yang, Chi Yao, Feng Li, Yuhang Dong, Zhikun Zhang, Dayong Yang
Metal nanoclusters (NCs) possess unique optical properties, and exhibit a wide variety of potential applications. DNA with robust molecular programmability is demonstrated as an ideal scaffold to regulate the formation of NCs, offering a rational approach to precisely tune the spatial structures of NCs. Herein, the first use of branched DNA as scaffold to regulate the formation of silver nanoclusters (super-AgNC) is reported, in which the spatial structures are precisely designed and constructed. Super-AgNC with tunable shapes and arm-lengths including Y-, X-, and (Y-X)- shaped super-AgNC is achieved...
March 25, 2018: Small
Bi-Yun Fang, Cheng Li, Jie An, Sun-Duo Zhao, Zhi-Yong Zhuang, Yuan-Di Zhao, Yue-Xuan Zhang
In this paper, DNA containing six cytosines as the formation site for silver nanoclusters (Ag NCs) was adopted as a template for preparing fluorescent DNA-Ag NCs. For the first time, it was found that the fluorescence of DNA-Ag NCs could be quenched after hybridization with their complementary sequence. On the basis of this new phenomenon, we designed a sequence C1 that was completely complementary to human immunodeficiency virus (HIV) DNA, and probe DNA which was partially complementary to C1 for the synthesis of DNA-Ag NCs...
March 28, 2018: Nanoscale
Baozhu Zhang, Chunying Wei
A novel turn-on fluorescent biosensor has been constructed using C-PS2.M-DNA-templated silver nanoclusters (Ag NCs) with an average diameter of about 1 nm. The proposed approach presents a low-toxic, simple, sensitive, and selective detection for Pb2+ . The fluorescence intensity of C-PS2.M-DNA-Ag NCs enhances significantly in the presence of Pb2+ , which is attributed to the special interaction between Pb2+ and its aptamer DNA PS2.M. Pb2+ induces the aptamer to form G-quadruplex and makes two darkish DNA/Ag NCs located at the 3' and 5' terminus close, resulting in the fluorescence light-up...
May 15, 2018: Talanta
Taotao Li, Huan Yi, Yuan Liu, Zunliang Wang, Shiquan Liu, Nongyue He, Hongna Liu, Yan Deng
DNA strands have been used as templates to form different sized silver nanoclusters. Although DNA templated silver nanoclusters (NCs) probes which show outstanding fluorescence properties have been widely applied in chemical sensing and cellular imaging, synthesis of DNA template Au-Ag bimetallic nanoclusters remains a challenge. A facile one-step synthesis method was thus developed in this study to form Au-Ag NCs using C4-ATAT-C4 as template. C4-ATAT-C4 acted as a stabilizer for preventing aggregation of the Au-Ag NCs...
January 1, 2018: Journal of Biomedical Nanotechnology
Shi Ting Lee, David Beaumont, Xiao Di Su, Kasturi Muthoosamy, Siu Yee New
Single strand DNA (ssDNA) chimeras consisting of a silver nanoclusters-nucleating sequence (NC) and an aptamer are widely employed to synthesize functional silver nanoclusters (AgNCs) for sensing purpose. Despite its simplicity, this chimeric-templated AgNCs often leads to undesirable turn-off effect, which may suffer from false positive signals caused by interference. In our effort to elucidate how the relative position of NC and aptamer affects the fluorescence behavior and sensing performance, we systematically formulated these NC and aptamer regions at different position in a DNA chimera...
June 20, 2018: Analytica Chimica Acta
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...
May 5, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Dan Han, Chunying Wei
In this work, we develop a fluorescent molecular beacon based on the DNA-templated silver nanoclusters (DNA-Ag NCs). The skillfully designed molecular beacon can be conveniently used for detection of diverse virulence genes as long as the corresponding recognition sequences are embedded. Importantly, the constructed detection system allows simultaneous detection of multiple nucleic acids, which is attributed to non-overlapping emission spectra of the as-synthesized silver nanoclusters. Based on the target-induced fluorescence enhancement, three infectious disease-related genes HIV, H1N1, and H5N1 are detected, and the corresponding detection limits are 3...
May 1, 2018: Talanta
Sidsel Ammitzbøll Bogh, Miguel R Carro-Temboury, Cecilia Cerretani, Steven M Swasey, Stacy M Copp, Elisabeth G Gwinn, Tom Vosch
In this paper we present a new near-IR emitting silver nanocluster (NIR-DNA-AgNC) with an unusually large Stokes shift between absorption and emission maximum (211 nm or 5600 cm-1 ). We studied the effect of viscosity and temperature on the steady state and time-resolved emission. The time-resolved results on NIR-DNA-AgNC show that the relaxation dynamics slow down significantly with increasing viscosity of the solvent. In high viscosity solution, the spectral relaxation stretches well into the nanosecond scale...
February 9, 2018: Methods and Applications in Fluorescence
Yasaman-Sadat Borghei, Morteza Hosseini, Mohammad Reza Ganjali, Saman Hosseinkhani
BRCA1 (breast cancer 1) genomic deletions are the most important founder mutations in breast cancer patients and can be passed to you from your mother or father. Herein, we report a silver nanoclusters-based (AgNCs-based) fluorescence resonance energy transfer (FRET) method for detection of BRCA1 gene deletion. The method relies on the specific hybridization of DNA-AgNCs fluorescent probe to deleted genes and interaction between double stranded DNA-AgNCs and QD, and the signal amplification through energy transfer from fluorescent AgNCs to QDs during FRET...
April 15, 2018: Journal of Pharmaceutical and Biomedical Analysis
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