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

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.