How G-quadruplex topology and loop sequences affect optical properties of DNA-templated silver nanoclusters

• Published in: Nano research 2018-04, Vol.11 (4), p.2237-2247
• Main Authors: Tao, Guangyu, Chen, Yang, Lin, Ruoyun, Zhou, Jiang, Pei, Xiaojing, Liu, Feng, Li, Na
• Format: Article
• Language: English
• Subjects: Adenine; Atomic/Molecular Structure and Spectra; Biomedicine; Biotechnology; Chemistry and Materials Science; Circular dichroism; Condensed Matter Physics; Correlation analysis; Deoxyribonucleic acid; Dichroism; DNA; Emission spectroscopy; Fabrication; Fluorescence; Gene sequencing; Materials Science; Nanoclusters; Nanotechnology; Nucleotide sequence; Optical properties; Research Article; Silver; Spectroscopy; Tetrads; Thymine; Topology
• ISSN: 1998-0124; 1998-0000
• DOI: 10.1007/s12274-017-1844-4

In the study of the fabrication of DNA-templated silver nanoclusters (DNA-Ag NCs), how templates affect the fluorescence of the nanoclusters remains unclear, and it has been a challenge to understand the correlation between the properties of the DNA template and the Ag NCs. In this respect, based on the rational design of a series of structurally defined intramolecular G-quadruplexes, we prepared G-quadruplex-templated Ag NCs with a defined G-tetrad-to-silver ratio of 1:2. We evaluated the effect of G-quadruplex topology and loop sequences on the fluorescence of DNA-Ag NCs using circular dichroism, and extinction and emission spectroscopy. G-quadruplex templates with an anti-parallel topology were found to produce Ag NCs with stronger fluorescence compared with parallel and hybrid configurations. Loop bases adjacent to G-tetrads have a more significant impact on the fluorescence of Ag NCs compared with those in the middle of the loop, with adenine largely exhibiting an enhancement effect and thymine being detrimental. Generally, G-quadruplexes having an anti-parallel topology with adenine in the loop adjacent to the G-tetrad would be good templates for producing highly fluorescent Ag NCs. This is the first study to focus on the correlation between G-quadruplex topology/sequence and the optical properties of Ag NCs. We hope that the results of this study will facilitate a more in-depth understanding of correlation between G-quadruplex templates and Ag NCs, and help to understand and utilize their unique attributes.