Silver Nanomaterials Regulated by Structural Competition of G-/C-Rich Oligonucleotides

Abstract

Silver nanomaterials with distinct fluorescent properties are synthesized with a series of G-rich/C-rich DNA templates, and the influence of DNA conformational structures on the size and the fluorescence of silver nanomaterials was investigated through varying the sequence composition and the ratio of complementary sequences, using CD, UV–vis, fluorescence spectroscopy, and TEM. It is intriguing to find out that G-rich templates at acidic conditions are capable of generating red emitters that are susceptible to the G-quadruplex structures associated with the number of 5′-terminal guanines. C-rich sequences can produce red silver clusters at either acidic or neutral conditions, and the emission is dramatically regulated by the number of 3′-end cytosines. It is the first time to report that double-stranded DNA templates can generate distinct fluorescent nanosilver modulated by the predominance among the structural competition of the Watson–Crick duplex, G-quadruplex, and i-motif. These results provide a promising pathway to prepare silver nanomaterials with desirable physicochemical properties through designing suitable DNA templates.

Control of the Fluorescence of DNA-templated Silver Nanoclusters by Adenosine Triphosphate and Mercury(II)

“…A slight red shift occurs at pH 3.0, which is mainly due to the change in the secondary structures of the two DNA templates. Because of the protonation of the cytosine bases, C–Ag + –C coordination becomes weaker upon decreasing pH value . The fluorescence intensities of T 0 ‐DNA–Ag and T 15 ‐DNA–Ag NCs reach their maxima at pH 3.0 and 7.0, respectively (Figure (a)).…”

Establishing empirical design rules of nucleic acid templates for the synthesis of silver nanoclusters with tunable photoluminescence and functionalities towards targeted bioimaging applications

“…1F, dashed line), indicating the parallel-stranded G-quadruplex structures where the individual oligo-guanine strands formed tetrameric structures via Hoogsteen base pairing in solution. [69][70][71][72] When Ag + was added, the characteristic peaks of the G-quadruplex structure disappeared, accompanied with the appearance of a new prominent peak at a negative ellipticity of 275 nm (Fig. 1F, dotted line).…”

The spatial organization of trace silver atoms on a DNA template

“…Aer adding the complementary sequence for hybridizing with the recognition site, the absorption of the formed AgNCs 64 (B) G-quadruplex, 65 and the (C) length-dependent intra-stand and inter-strand folding of the DNA template in the synthesis of AgNCs. (D) Triplex, and (E) the reorganization of the template structure via the proximity of two identical or different emitters upon hybridization.…”