Unusually large fluorescence quantum yield for a near-infrared emitting DNA-stabilized silver nanocluster

Abstract

Silver nanoclusters stabilized by 5′-CCCGGAGAAG-3′ DNA strands display an unusually high fluorescence quantum yield in the near-infrared region.

Observation of microsecond luminescence while studying two DNA-stabilized silver nanoclusters emitting in the 800–900 nm range

“…28 The high steady-state anisotropy values are in line with previously reported time-resolved anisotropy values that are close to 0.4 at time zero. 10,11,29 Except for the 470 nm transition of the DNA811-AgNC, the other higher energy transitions in DNA841-AgNC and DNA811-AgNC are not aligned with the orientation of the 640 nm transition. Interestingly, for the 470 nm transition of the DNA811-AgNC, a similar excitation anisotropy close to 0.4 is found on the rededge of the transition, while the blue edge has an anisotropy value that drops gradually.…”

“…We have previously shown that the multiexponential nature of DNA-AgNCs can be explained by slow spectral relaxation (relaxation on the time scale of the excited state decay time). [8][9][10] Given the limited sensitivity of the Fluo-time300 detector above 800 nm, we opted to measure timeresolved emission spectra (TRES) only at À196 1C. The results can be found in Fig.…”

“…Purification methods like high-pressure liquid chromatography (HPLC) 4,5 and size exclusion chromatography (SEC) 6 have allowed to collect pure DNA-AgNCs and characterize their composition 4 and photophysical properties. [7][8][9][10][11][12] Recently, it also enabled the crystallization structure determination of several near-infrared (NIR)-emitting DNA-AgNCs by single crystal X-ray diffraction. [13][14][15] NIR emitters are of special interest since these wavelengths have higher tissue penetration depth, reduced light scattering and generate less auto-fluorescence compared to the UV-Vis region.…”

Probing the Fluorescence Behavior of DNA‐Stabilized Silver Nanoclusters in the Presence of Biomolecules

“…[1][2][3][4][5][6][7][8] This devoted attention is due to the peculiar luminescent properties of some DNA-AgNCs such as high fluorescence quantum efficiencies, resistance to photobleaching and wide wavelength tunability. [6,7,[9][10][11] These DNA-AgNCs consist of few silver atoms and cations (up to 30) enclosed in DNA strands, and their luminescence properties are related to the composition, charge and conformation of the AgNC. [6] In the last decade, DNA-AgNCs have emerged in a wide number of bioanalytical and biomedical applications, in particular as probes for the detection of specific analyte molecules, [12,13] since their bright, well-defined luminescence [14] and biocompatibility provides DNA-AgNCs with potential advantageous properties, compared to more traditional chromophores.…”

“…Photoluminescent DNA‐stabilized silver nanoclusters (DNA‐AgNCs) have in recent years attracted significant interest [1–8] . This devoted attention is due to the peculiar luminescent properties of some DNA‐AgNCs such as high fluorescence quantum efficiencies, resistance to photobleaching and wide wavelength tunability [6,7,9–11] . These DNA‐AgNCs consist of few silver atoms and cations (up to 30) enclosed in DNA strands, and their luminescence properties are related to the composition, charge and conformation of the AgNC [6] .…”