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DNA silver nanocluster

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https://www.readbyqxmd.com/read/27898376/impedimetric-monitoring-of-apoptosis-using-cytochrome-aptamer-bioconjugated-silver-nanocluster
#1
Mojtaba Shamsipur, Afshin Pashabadi, Fatemeh Molaabasi, Saman Hosseinkhani
It is well known that cytochrome c (Cyt c) is a crucial death regulator that triggers programmed cell death, apoptosis. Here, we report on the successful application of an aptamer bioconjugated nanoclusters for the detection of apoptosis based on release of cytochrome c from mitochondria in lysates human embryonic kidney cells HEK293T. The aptamer-conjugated silver nanoclusters (Apt@AgNCs) were synthesized and immobilized on gold electrode for impedimetric detection of Cyt c over the range of 0.15-375nM. It was found that the presence of Ag(I) ions shell at the surface of prepared NCs could increase their affinity to the donor groups (COO(-) and some amine groups in its deprotonated form, NH2) of cysteine attached on the gold electrode surface...
November 23, 2016: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/27891763/silver-nanoclusters-stabilized-with-denatured-fish-sperm-dna-and-the-application-on-trace-mercury-ions-detection
#2
Yangfang Kuang, Sheng Liang, Fangfang Ma, Shu Chen, Yunfei Long, Rongjin Zeng
In this study, fluorescent silver nanoclusters (Ag NCs) were synthesized using denatured fish sperm DNA as the template. In contrast to other methods, this method did not use artificial DNA as the template. After their reaction with denatured fish sperm DNA, Ag(+) ions were reduced by NaBH4 to form Ag NCs. The Ag NCs showed a strong fluorescence emission at 650 nm when excited at 585 nm. The fluorescence intensity increased fourfold at pH 3.78, controlled with Britton-Robinson buffer solution. The fluorescence of the Ag NCs was quenched in the presence of trace mercury ions (Hg(2)(+) ) in a weakly acidic medium and nitrogen atmosphere...
November 27, 2016: Luminescence: the Journal of Biological and Chemical Luminescence
https://www.readbyqxmd.com/read/27834849/label-free-fluorescent-detection-of-trypsin-activity-based-on-dna-stabilized-silver-nanocluster-peptide-conjugates
#3
Cai-Xia Zhuo, Li-Hui Wang, Jing-Jing Feng, Yao-Dong Zhang
Trypsin is important during the regulation of pancreatic exocrine function. The detection of trypsin activity is currently limited because of the need for the substrate to be labeled with a fluorescent tag. A label-free fluorescent method has been developed to monitor trypsin activity. The designed peptide probe consists of six arginine molecules and a cysteine terminus and can be conjugated to DNA-stabilized silver nanoclusters (DNA-AgNCs) by Ag-S bonding to enhance fluorescence. The peptide probe can also be adsorbed to the surface of graphene oxide (GO), thus resulting in the fluorescence quenching of DNA-AgNCs-peptide conjugate because of Förster resonance energy transfer...
November 9, 2016: Sensors
https://www.readbyqxmd.com/read/27809363/peptide-stabilized-fluorescent-silver-nanoclusters-solid-phase-synthesis-and-screening
#4
Simon Gregersen, Tom Vosch, Knud J Jensen
Few-atom silver nanoclusters (AgNCs) can exhibit strong fluorescence; however, they require ligands to prevent aggregation into larger nanoparticles. Fluorescent AgNCs in biopolymer scaffolds have so far mainly been synthesized in solution, and peptides have only found limited use compared to DNA. Herein, we demonstrate how solid-phase methods can increase throughput dramatically in peptide ligand screening and in initial evaluation of fluorescence intensity and chemical stability of peptide-stabilized AgNCs (P-AgNCs)...
November 3, 2016: Chemistry: a European Journal
https://www.readbyqxmd.com/read/27797508/biostable-l-dna-templated-aptamer-silver-nanoclusters-for-cell-type-specific-imaging-at-physiological-temperature
#5
Gui-Mei Han, Zhen-Zhen Jia, Yan-Jun Zhu, Jia-Jia Jiao, De-Ming Kong, Xi-Zeng Feng
The high susceptibility of the natural D-conformation of DNA (D-DNA) to nucleases greatly limits the application of DNA-templated silver nanoclusters (Ag NCs) in biological matrixes. Here we demonstrate that the L-conformation of DNA (L-DNA), the enantiomer of D-DNA, can also be used for the preparation of aptamer-Ag NCs. The extraordinary resistance of L-DNA to nuclease digestion confers much higher biostability to these NCs than those templated by D-DNA, thus making cell-type-specific imaging possible at physiological temperatures, using at least 100-times lower Ag NC concentration than reported D-DNA-templated ones...
November 1, 2016: Analytical Chemistry
https://www.readbyqxmd.com/read/27722695/dna-templated-silver-nanoclusters-structural-correlation-and-fluorescence-modulation
#6
S Y New, S T Lee, X D Su
12 years after the introduction of DNA-templated silver nanoclusters (DNA-AgNCs), exciting progress has been made and yet we are still in the midst of trying to fully understand this nanomaterial. The prominent excellence of DNA-AgNCs is undoubtedly its modulatable emission property, of which how variation in DNA templates causes emission tuning remains elusive. Based on the up-to-date DNA-AgNCs, we aim to establish the correlation between the structure/sequence of DNA templates and emission behaviour of AgNCs...
October 7, 2016: Nanoscale
https://www.readbyqxmd.com/read/27716594/a-label-free-fluorescent-direct-detection-of-live-salmonella-typhimurium-using-cascade-triple-trigger-sequences-regenerated-strand-displacement-amplification-and-hairpin-template-generated-scaffolded-silver-nanoclusters
#7
Peng Zhang, Hui Liu, Xiaocheng Li, Suzhen Ma, Shuai Men, Heng Wei, Jingjing Cui, Hongning Wang
The harm of Salmonella typhimurium (S. typhimurium) to public health mainly by the consumption of contaminated agricultural products or water stresses an urgent need for rapid detection methods to help control the spread of S. typhimurium. In this work, an intelligently designed sensor system took creative advantage of triple trigger sequences-regenerated strand displacement amplification and self-protective hairpin template-generated-scaffolded silver nanoclusters (AgNCs) for the first time. In the presence of live S...
September 12, 2016: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/27713517/implementation-of-arithmetic-and-nonarithmetic-functions-on-a-label-free-and-dna-based-platform
#8
Kun Wang, Mengqi He, Jin Wang, Ronghuan He, Jianhua Wang
A series of complex logic gates were constructed based on graphene oxide and DNA-templated silver nanoclusters to perform both arithmetic and nonarithmetic functions. For the purpose of satisfying the requirements of progressive computational complexity and cost-effectiveness, a label-free and universal platform was developed by integration of various functions, including half adder, half subtractor, multiplexer and demultiplexer. The label-free system avoided laborious modification of biomolecules. The designed DNA-based logic gates can be implemented with readout of near-infrared fluorescence, and exhibit great potential applications in the field of bioimaging as well as disease diagnosis...
October 7, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27589406/the-aptamer-dna-templated-fluorescence-silver-nanoclusters-atp-detection-and-preliminary-mechanism-investigation
#9
Jiaona Xu, Chunying Wei
Two general and reliable fluorescence sensors were proposed in this work utilizing aptamer DNA-templated silver nanoclusters (Ag NCs). Both DNA-AgNCs could be used for label-free detecting of ATP with the limits of detection of 0.44 and 0.65mM. One of them was further applied to monitor the activity of adenosine deaminase (ADA). In our effort to elucidate the light-up mechanism, we studied a total of six Ag NCs prepared by different DNA sequences, and found that they showed different sensitivity to ATP. Both BT3T3- and BT3T3(R)-templated Ag NCs were chose to make particular studies by UV-vis, TEM, fluorescence, and TCSPC methods...
August 25, 2016: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/27570054/a-label-free-fluorescent-assay-for-deoxyribonuclease-i-activity-based-on-dna-templated-silver-nanocluster-graphene-oxide-nanocomposite
#10
Chang Yeol Lee, Ki Soo Park, Yun Kyung Jung, Hyun Gyu Park
A novel label-free system for the sensitive fluorescent detection of deoxyribonuclease I (DNase I) activity has been developed by utilizing DNA-templated silver nanocluster/graphene oxide (DNA-AgNC/GO) nanocomposite. AgNC is first synthesized around C-rich template DNA and the resulting DNA-AgNC binds to GO through the interaction between the extension DNA and GO. The resulting DNA-AgNC/GO would show quite reduced fluorescence signal because the fluorescence from DNA-AgNCs is quenched by GO. In the presence of DNase I, however, it degrades the DNA strand within DNA/RNA hybrid duplex probe employed in this study, consequently releasing RNA which is complementary to the extension DNA...
August 24, 2016: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/27561443/label-free-fluorometric-detection-of-chymotrypsin-activity-using-graphene-oxide-nucleic-acid-stabilized-silver-nanoclusters-hybrid-materials
#11
Shuangqin Li, Yuewei Fu, Xuejuan Ma, Yaodong Zhang
Pancreatic function tests are used to determine the presence of chronic pancreatitis, particularly in the early stage of the disease. Chymotrypsin is an indicator of pancreatic function and is thus related to pancreatic diseases. A new fluorescent biosensing method for assay of chymotrypsin activity was developed using DNA (dC12)-templated silver nanoclusters and graphene oxide (GO). A peptide probe was also designed using chymotrypsin-cleavable amino acid sequence and a cysteine terminus. The peptide probe formed Ag-S bond to dC12-AgNCs to enhance the fluorescence of dC12-AgNCs...
August 12, 2016: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/27545717/copper-mediated-dna-scaffolded-silver-nanocluster-on-off-switch-for-detection-of-pyrophosphate-and-alkaline-phosphatase
#12
Jin-Liang Ma, Bin-Cheng Yin, Xin Wu, Bang-Ce Ye
We present a new copper-mediated on-off switch for detecting either pyrophosphate (PPi) or alkaline phosphatase (ALP) based on DNA-scaffolded silver nanoclusters (DNA/AgNCs) templated by a single-stranded sequence containing a 15-nt polythymine spacer between two different emitters. The switch is based on three favorable properties: the quenching ability of Cu(2+) for DNA/AgNCs with excitation at 550 nm; the strong binding capacity of Cu(2+) and PPi; and the ability of ALP to transform PPi into orthophosphate (Pi)...
September 20, 2016: Analytical Chemistry
https://www.readbyqxmd.com/read/27531578/model-system-for-multifunctional-delivery-nanoplatforms-based-on-dna-polymer-complexes-containing-silver-nanoparticles-and-fluorescent-dye
#13
Nina Kasyanenko, Vladimir Bakulev, Igor Perevyazko, Tatiana Nekrasova, Olga Nazarova, Alexandr Slita, Yulia Zolotova, Euginii Panarin
Creation of multifunctional nanoplatforms is one of the new approaches to complex treatment and diagnosis with the monitoring of the curative process. Inclusion of various components into the drug delivery system may reduce toxicity and enhance or modify the therapeutic effects of medicines. In particular, some properties of metal nanoparticles and nanoclusters provide the ability to create new systems for treatment and diagnosis of diseases, biocatalysis and imaging of objects. For example, the ability of metal nanoparticles to enhance the quantum yield of luminescence can be used in bioimaging and therapy...
October 20, 2016: Journal of Biotechnology
https://www.readbyqxmd.com/read/27497197/electrochemical-dna-probe-for-hg-2-detection-based-on-a-triple-helix-dna-and-multistage-signal-amplification-strategy
#14
Huan Wang, Yihe Zhang, Hongmin Ma, Xiang Ren, Yaoguang Wang, Yong Zhang, Qin Wei
In this work, an ultrasensitive electrochemical sensor was developed for detection of Hg(2+). Gold nanoparticles decorated bovine serum albumin reduction of graphene oxide (AuNP-BSA-rGO) were used as subsurface material for the immobilization of triple-helix DNA. The triple-helix DNA containing a thiol labelled single-stranded DNA (sDNA) and a thymine-rich DNA (T-rich DNA), which could be unwinded in the present of Hg(2+) to form more stable thymine-Hg(2+)-thymine (T-Hg(2+)-T) complex. T-Hg(2+)-T complex was then removed and the sDNA was left on the electrode...
December 15, 2016: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/27494437/antimicrobial-cluster-bombs-silver-nanoclusters-packed-with-daptomycin
#15
Kaiyuan Zheng, Magdiel I Setyawati, Tze-Peng Lim, David Tai Leong, Jianping Xie
Integration of two distinctive bactericides into one entity is a promising platform to improve the efficiency of antimicrobial agents. We report an efficient antimicrobial hybrid formed through conjugating silver nanoclusters (AgNCs) with daptomycin. The as-designed antimicrobial hybrid (D-AgNCs) inherits intrinsic properties of both bactericides with an enhanced synergistic performance. In particular, the chemically integrated D-AgNCs showed improved bacterial killing efficiency over the physically mixed daptomycin and AgNCs (D+AgNCs)...
August 23, 2016: ACS Nano
https://www.readbyqxmd.com/read/27417153/nanostructured-luminescently-labeled-nucleic-acids
#16
Larry J Kricka, Paolo Fortina, Jason Y Park
Important and emerging trends at the interface of luminescence, nucleic acids and nanotechnology are: (i) the conventional luminescence labeling of nucleic acid nanostructures (e.g. DNA tetrahedron); (ii) the labeling of bulk nucleic acids (e.g. single-stranded DNA, double-stranded DNA) with nanostructured luminescent labels (e.g. copper nanoclusters); and (iii) the labeling of nucleic acid nanostructures (e.g. origami DNA) with nanostructured luminescent labels (e.g. silver nanoclusters). This review surveys recent advances in these three different approaches to the generation of nanostructured luminescently labeled nucleic acids, and includes both direct and indirect labeling methods...
July 15, 2016: Luminescence: the Journal of Biological and Chemical Luminescence
https://www.readbyqxmd.com/read/27406901/a-universal-design-for-a-dna-probe-providing-ratiometric-fluorescence-detection-by-generation-of-silver-nanoclusters
#17
Jackson Travis Del Bonis-O'Donnell, Daniel Vong, Sumita Pennathur, Deborah Kuchnir Fygenson
DNA-stabilized silver nanoclusters (AgNCs), the fluorescence emission of which can rival that of typical organic fluorophores, have made possible a new class of label-free molecular beacons for the detection of single-stranded DNA. Like fluorophore-quencher molecular beacons (FQ-MBs) AgNC-based molecular beacons (AgNC-MBs) are based on a single-stranded DNA that undergoes a conformational change upon binding a target sequence. The new conformation exposes a stretch of single-stranded DNA capable of hosting a fluorescent AgNC upon reduction in the presence of Ag(+) ions...
August 14, 2016: Nanoscale
https://www.readbyqxmd.com/read/27349801/synthesis-and-assessment-of-dna-silver-nanoclusters-probes-for-optimal-and-selective-detection-of-tristeza-virus-mild-strains
#18
Ehsan Shokri, Morteza Hosseini, Farnoush Faridbod, Mahdi Rahaie
Citrus Tristeza virus (CTV) is one of the most destructive pathogens worldwide that exist as a mixture of malicious (Sever) and tolerable (Mild) strains. Mild strains of CTV can be used to immunize healthy plants from more Severe strains damage. Recently, innovative methods based on the fluorescent properties of DNA/silver nanoclusters have been developed for molecular detection purposes. In this study, a simple procedure was followed to create more active DNA/AgNCs probe for accurate and selective detection of Tristeza Mild-RNA...
September 2016: Journal of Fluorescence
https://www.readbyqxmd.com/read/27304093/effect-of-compartmentalization-of-donor-and-acceptor-on-the-ultrafast-resonance-energy-transfer-from-dapi-to-silver-nanoclusters
#19
Roopali Prajapati, Surajit Chatterjee, Krishna K Kannaujiya, Tushar Kanti Mukherjee
The mechanism and dynamics of excitation energy transfer (EET) from photo-excited 4',6-diamidino-2-phenylindole (DAPI) to silver nanoclusters (Ag NCs) and its subsequent modulation in the presence of cationic polymer poly(diallyldimethylammonium chloride) (PDADMAC) and Calf Thymus DNA (CT-DNA) have been demonstrated using steady-state fluorescence and femtosecond fluorescence upconversion techniques. The synthesized Ag NCs were characterized using FTIR, mass spectrometry, XPS, HRTEM, DLS, UV-Vis and PL spectroscopy...
July 14, 2016: Nanoscale
https://www.readbyqxmd.com/read/27295571/dna-stabilized-silver-nanoclusters-and-carbon-nanoparticles-oxide-a-sensitive-platform-for-label-free-fluorescence-turn-on-detection-of-hiv-dna-sequences
#20
Yu-Dan Ye, Li Xia, Dang-Dang Xu, Xiao-Jing Xing, Dai-Wen Pang, Hong-Wu Tang
Based on the remarkable difference between the interactions of carbon nanoparticles (CNPs) oxide with single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA), and the fact that fluorescence of DNA-stabilized silver nanoclusters (AgNCs) can be quenched by CNPs oxide, DNA-functionalized AgNCs were applied as label-free fluorescence probes and a novel fluorescence resonance energy transfer (FRET) sensor was successfully constructed for the detection of human immunodeficiency virus (HIV) DNA sequences. CNPs oxide were prepared with the oxidation of candle soot, hence it is simple, time-saving and low-cost...
November 15, 2016: Biosensors & Bioelectronics
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