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Silver nanoclusters (AgNCs) are the next-generation nanomaterials representing supra-atomic structures where silver atoms are organized in a particular geometry. DNA can effectively template and stabilize these novel fluorescent AgNCs. Only a few atoms in size – the properties of nanoclusters can be tuned using only single nucleobase replacement of C-rich templating DNA sequences. A high degree of control over the structure of AgNC could greatly contribute to the ability to fine-tune the properties of silver nanoclusters. In this study, we explore the properties of AgNCs formed on a short DNA sequence with a C 12 hairpin loop structure (AgNC@hpC 12 ). We identify three types of cytosines based on their involvement in the stabilization of AgNCs. Computational and experimental results suggest an elongated cluster shape with 10 silver atoms. We found that the properties of the AgNCs depend on the overall structure and relative position of the silver atoms. The emission pattern of the AgNCs depends strongly on the charge distribution, while all silver atoms and some DNA bases are involved in optical transitions based on molecular orbital (MO) visualization. We also characterize the antibacterial properties of silver nanoclusters and propose a possible mechanism of action based on the interactions of AgNCs with molecular oxygen.
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Detection of cancer‐associated miRNA using a fluorescence switch of AgNC@NA and guanine‐rich overhang sequences
Abstract DNA‐templated silver nanoclusters (AgNC@DNA) are a novel type of nanomaterial with advantageous optical properties. Only a few atoms in size, the fluorescence of nanoclusters can be tuned using DNA overhangs. In this study, we explored the properties of AgNCs manufactured on a short single‐stranded (dC)12when adjacent G‐rich sequences (dGN, withN = 3–15) were added. The ‘red’ emission of AgNC@dC12with λMAX = 660 nm dramatically changed upon the addition of a G‐rich overhang with NG = 15. The pattern of the emission–excitation matrix (EEM) suggested the emergence of two new emissive states at λMAX = 575 nm and λMAX = 710 nm. The appearance of these peaks provides an effective way to design biosensors capable of detecting specific nucleic acid sequences with low fluorescence backgrounds. We used this property to construct an NA‐based switch that brings AgNC and the G overhang near one another, turning ‘ON’ the new fluorescence peaks only when a specific miRNA sequence is present. Next, we tested this detection switch on miR‐371, which is overexpressed in prostate cancer. The results presented provide evidence that this novel fluorescent switch is both sensitive and specific with a limit of detection close to 22 picomoles of the target miR‐371 molecule.
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- Award ID(s):
- 2204027
- PAR ID:
- 10418782
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Luminescence
- Volume:
- 38
- Issue:
- 7
- ISSN:
- 1522-7235
- Format(s):
- Medium: X Size: p. 1385-1392
- Size(s):
- p. 1385-1392
- Sponsoring Org:
- National Science Foundation
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