A Highly Charged Ag<sub>6</sub><sup>4+</sup> Core in a DNA‐Encapsulated Silver Nanocluster

Koszinowski, Konrad; Ballweg, Korbinian

doi:10.1002/chem.200902743

Cited by 67 publications

(78 citation statements)

References 35 publications

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“…83,84 However, a wide range of these compounds has been synthesized with diverse ligands such as halides, oxides, thiols, peptides, and oligonucleotides. 56,85–90 The first reported example, Ag 2 F, and related compounds mimic bulk silver because they have high electrical conductivities at temperatures as low as 20 K. 91–93 Such metallic characteristics may develop because low-lying 5 s /5p states lie near the Fermi level and can accommodate excess electrons. 92,94 These complexes have relatively short silver–silver bond distances of 2.75–2.85 Å, as does the violet cluster.…”

Section: Discussionmentioning

confidence: 99%

A Segregated, Partially Oxidized, and Compact Ag₁₀ Cluster within an Encapsulating DNA Host

et al. 2016

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Silver clusters develop within DNA strands and become optical chromophores with diverse electronic spectra and wide-ranging emission intensities. These studies consider a specific cluster that absorbs at 400 nm, has low emission, and exclusively develops with single-stranded oligonucleotides. It is also a chameleon-like chromophore that can be transformed into different highly emissive fluorophores. We describe four characteristics of this species and conclude that it is highly oxidized yet also metallic. One, the cluster size was determined via electrospray ionization mass spectrometry. A common silver mass is measured with different oligonucleotides and thereby supports a Ag10 cluster. Two, the cluster charge was determined by mass spectrometry and Ag L3-edge X-ray absorption near-edge structure spectroscopy. Respectively, the conjugate mass and the integrated white-line intensity support a partially oxidized cluster with a +6 and +6.5 charge, respectively. Three, the cluster chirality was gauged by circular dichroism spectroscopy. This chirality changes with the length and sequence of its DNA hosts, and these studies identified a dispersed binding site with ~20 nucleobases. Four, the structure of this complex was investigated via Ag K-edge extended X-ray absorption fine structure spectroscopy. A multishell fitting analysis identified three unique scattering environments with corresponding bond lengths, coordination numbers, and Debye–Waller factors for each. Collectively, these findings support the following conclusion: a Ag10+6 cluster develops within a 20-nucleobase DNA binding site, and this complex segregates into a compact, metal-like silver core that weakly links to an encapsulating silver–DNA shell. We consider different models that account for silver–silver coordination within the core.

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Section: Discussionmentioning

confidence: 99%

A Segregated, Partially Oxidized, and Compact Ag₁₀ Cluster within an Encapsulating DNA Host

et al. 2016

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“…1–5 Though bare silver nanodots have been prepared within rare gas 6, 7 or zeolite matrices, 8–10 their utility as fluorescent labels at ambient conditions has only become possible upon encapsulation in water-soluble molecular scaffolds. Although successfully encapsulated in dendrimers, 11 microgels, 12 and peptides, 13 the single stranded DNA (ssDNA) scaffolds with varying sequences 1–4, 14–17 have, to date, produced the widest variety of and most robust nanodot emitters. Encapsulated within ss-DNA, few-atom Ag nanoclusters (“nanodots”) exhibit excellent brightness with typical fluorescence quantum yields of ~30% and extinction coefficients exceeding 2 × 10 5 M −1 cm −1 .…”

Section: Introductionmentioning

confidence: 99%

Tailoring silver nanodots for intracellular staining

Choi

Patel

et al. 2011

Photochem Photobiol Sci

127

148

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Through tailored oligonucleotide scaffolds, Ag nanocluster syntheses have yielded thermally and cell culture stable silver cluster-based emitters. Optimizing ssDNA stability has enabled creation of highly concentrated and spectrally pure nanocluster emitters with strong intracellular emission. Both fixed and live-cell staining become possible, and intracellular delivery is demonstrated both through conjugation to cell penetrating peptides and via microinjection.

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“…In addition, covalent attachment of multiple DNA on a benzene ring allows for much stronger fluorescence than that afforded by a single-stranded DNA of the same sequence [49]. Usually, the length of DNA is around 12-mer or longer, and it has been documented that 6-mer DNA cannot support fluorescent AgNCs [50]. On the other hand, the cytosine DNA monomer (i.e.…”

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confidence: 99%

DNA-stabilized, fluorescent, metal nanoclusters for biosensor development

Liu

2014

TrAC Trends in Analytical Chemistry

198

141

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In the past decade, fluorescent silver, gold and copper nanoclusters (Ag, Au and CuNCs) have emerged as a new class of signaling moiety for biosensor development. Compared to semiconductor quantum dots, metal NCs have less toxicity concerns and can be more easily conjugated to biopolymers. Due to their extremely small size, these NCs need a stabilizing ligand. Many polymers, proteins and nucleic acids have been reported to stabilize NCs. In particular, many DNA sequences produce highly fluorescence NCs. Coupling these DNA stabilizers with other sequences such as aptamers has generated a large number of biosensors. In this review, the synthesis of DNA and nucleotide-templated NCs is first summarized; their chemical interactions are also discussed. In the second part, the properties of NCs such as fluorescence quantum yield, emission wavelength and lifetime, structure and photostability are briefly reviewed. In the last part, various sensor design strategies using these NCs are categorized into the following four classes: 1) fluorescence de-quenching; 2) generation of templating DNA sequences to produce NCs; 3) change of nearby environment; and 4) reacting with heavy metal ions or other quenchers. Finally, the future trends in this field are discussed.

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A Highly Charged Ag₆⁴⁺ Core in a DNA‐Encapsulated Silver Nanocluster

Cited by 67 publications

References 35 publications

A Segregated, Partially Oxidized, and Compact Ag₁₀ Cluster within an Encapsulating DNA Host

A Segregated, Partially Oxidized, and Compact Ag₁₀ Cluster within an Encapsulating DNA Host

Tailoring silver nanodots for intracellular staining

DNA-stabilized, fluorescent, metal nanoclusters for biosensor development

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A Highly Charged Ag64+ Core in a DNA‐Encapsulated Silver Nanocluster

Cited by 67 publications

References 35 publications

A Segregated, Partially Oxidized, and Compact Ag10 Cluster within an Encapsulating DNA Host

A Segregated, Partially Oxidized, and Compact Ag10 Cluster within an Encapsulating DNA Host

Tailoring silver nanodots for intracellular staining

DNA-stabilized, fluorescent, metal nanoclusters for biosensor development

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A Highly Charged Ag₆⁴⁺ Core in a DNA‐Encapsulated Silver Nanocluster

A Segregated, Partially Oxidized, and Compact Ag₁₀ Cluster within an Encapsulating DNA Host

A Segregated, Partially Oxidized, and Compact Ag₁₀ Cluster within an Encapsulating DNA Host