A Complementary Palette of NanoCluster Beacons

Obliosca, Judy M.; Babin, Mark; Liu, Cong; Liu, Chia‐Jyi; Chen, Yu An; Batson, Robert A.; Ganguly, Mainak; Petty, Jeffrey T.; Yeh, Hsin Chih

doi:10.1021/nn505338e

Cited by 88 publications

(90 citation statements)

References 53 publications

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“…31,38,42 Other emissively silent violet clusters transform into a suite of clusters with strong emission that spans the green to red spectral regions. 42 The diverse spectra of these successor clusters are simply dictated by the sequence of the 5′ cluster domains in the single-stranded sensor (black sequence in Figure 1). Collectively, these studies support the inherent stability of violet clusters with a range of single-stranded DNA hosts.…”

Section: ■ Discussionmentioning

confidence: 99%

Ten-Atom Silver Cluster Signaling and Tempering DNA Hybridization

et al. 2015

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Silver clusters with ∼10 atoms are molecules, and specific species develop within DNA strands. These molecular metals have sparsely organized electronic states with distinctive visible and near-infrared spectra that vary with cluster size, oxidation, and shape. These small molecules also act as DNA adducts and coordinate with their DNA hosts. We investigated these characteristics using a specific cluster-DNA conjugate with the goal of developing a sensitive and selective biosensor. The silver cluster has a single violet absorption band (λ(max) = 400 nm), and its single-stranded DNA host has two domains that stabilize this cluster and hybridize with target oligonucleotides. These target analytes transform the weakly emissive violet cluster to a new chromophore with blue-green absorption (λ(max) = 490 nm) and strong green emission (λ(max) = 550 nm). Our studies consider the synthesis, cluster size, and DNA structure of the precursor violet cluster-DNA complex. This species preferentially forms with relatively low amounts of Ag(+), high concentrations of the oxidizing agent O2, and DNA strands with ≳20 nucleotides. The resulting aqueous and gaseous forms of this chromophore have 10 silvers that coalesce into a single cluster. This molecule is not only a chromophore but also an adduct that coordinates multiple nucleobases. Large-scale DNA conformational changes are manifested in a 20% smaller hydrodynamic radius and disrupted nucleobase stacking. Multidentate coordination also stabilizes the single-stranded DNA and thereby inhibits hybridization with target complements. These observations suggest that the silver cluster-DNA conjugate acts like a molecular beacon but is distinguished because the cluster chromophore not only sensitively signals target analytes but also stringently discriminates against analogous competing analytes.

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Section: ■ Discussionmentioning

confidence: 99%

Ten-Atom Silver Cluster Signaling and Tempering DNA Hybridization

et al. 2015

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“…8,9,[33][34][35][36] Yeh, Martinez, Werner, and co-workers have carried out investigations on DNA detection probes with a greater focus on guanine bases. 12,23,[37][38][39] In addition to the experimental work, theoretical investigations have also been performed on DNA-AgNCs by several groups. Gwinn and coworkers have studied the binding of DNA bases (adenine, cytosine, guanine, and thymine) with neutral silver clusters Ag n (n=1-6) and the absorption spectra of these complexes using density functional theory (DFT).…”

Section: Introductionmentioning

confidence: 99%

Research Update: Density functional theory investigation of the interactions of silver nanoclusters with guanine

2017

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Bare and guanine-complexed silver clusters Ag n z (n = 2-6; z = 0-2) are examined using density functional theory to elucidate the geometries and binding motifs that are present experimentally. Whereas the neutral systems remain planar in this size range, a 2D-3D transition occurs at Ag 5 + for the cationic system and at Ag 4 2+ for the dicationic system. Neutral silver clusters can bind with nitrogen 3 or with the pi system of the base. However, positively charged clusters interact with nitrogen 7 and the neighboring carbonyl group. Thus, the cationic silver-DNA clusters present experimentally may preferentially interact at these sites. © 2017 Author (s)

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“…This could be because AuNCs contract the DNA strand through nucleobase coordination, which results in a condensed and compact structure. Similarly, Obliosca et al 40 used SEC to determine the size of DNA-stabilized silver nanoclusters; they revealed that the retention time of 8 these nanoclusters was slightly slower than that of DNA strands. We also measured the hydrodynamic radius of A30-stabilized AuNCs to determine the impact of AuNC adducts on DNA shape.…”

Section: Resultsmentioning

confidence: 99%

UV-Light-Induced Improvement of Fluorescence Quantum Yield of DNA-Templated Gold Nanoclusters: Application to Ratiometric Fluorescent Sensing of Nucleic Acids

Tseng

2015

ACS Appl. Mater. Interfaces

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The use of DNA as a template has been demonstrated as an effective method for synthesizing different-sized silver nanoclusters. Although DNA-templated silver nanoclusters show outstanding performance as fluorescent probes for chemical sensing and cellular imaging, the synthesis of DNA-stabilized gold nanoclusters (AuNCs) with high fluorescence intensity remains a challenge. Here a facile, reproducible, scalable, NaBH4-free, UV-light-assisted method was developed to prepare AuNCs using repeats of 30 adenosine nucleotides (A30). The maximal fluorescence of A30-stabilized AuNCs appeared at 475 nm with moderate quantum yield, two fluorescence lifetimes, and a small amount of Au(+) on the surface of the Au core. Results of size-exclusion chromatography revealed that A30-stabilized AuNCs were more compact than A30. A series of control experiments showed that UV light played a dual role in the reduction of gold-ion precursors and the decomposition of citrate ions. A30 also acted as a stabilizer to prevent the aggregation of AuNCs. In addition, single-stranded DNA (ssDNA) consisting of an AuNC-nucleation sequence and a hybridization sequence was utilized to develop a AuNC-based ratiometric fluorescent probe in the presence of the double-strand-chelating dye SYBR Green I (SG). Under conditions of single-wavelength excitation, the combination of AuNC/SG-bearing ssDNA and perfectly matched DNA emitted fluorescence at 475 and 525 nm, respectively. The formed AuNC/SG-bearing ssDNA enabled the sensitive, selective, and ratiometric detection of specific nucleic acid targets. Finally, the AuNC-based ratiometric probes were successfully applied to determine specific nucleic acid targets in human serum.

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A Complementary Palette of NanoCluster Beacons

Cited by 88 publications

References 53 publications

Ten-Atom Silver Cluster Signaling and Tempering DNA Hybridization

Ten-Atom Silver Cluster Signaling and Tempering DNA Hybridization

Research Update: Density functional theory investigation of the interactions of silver nanoclusters with guanine

UV-Light-Induced Improvement of Fluorescence Quantum Yield of DNA-Templated Gold Nanoclusters: Application to Ratiometric Fluorescent Sensing of Nucleic Acids

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