Effects of polymorphic DNA on the fluorescent properties of silver nanoclusters.
Silver nanoclusters (Ag NCs) with emission wavelengths from 538 nm to 706 nm were synthesized using a series of G-/C-rich polymorphic DNA templates. Thermodynamic studies on the interactions of Ag(+) with polymorphic DNA indicate that the binding affinities greatly depend on the secondary structures of DNA templates, with a decreasing order: the coiled C-rich strand > the i-motif > the duplex > the G-quadruplex. Fluorescent Ag NCs prepared using these polymorphic DNA templates show that fluorescence stabilities are associated with the binding affinities between DNA templates and Ag(+), e.g., the coiled C-rich strand C4A4C3 with the highest binding constant (40.2 × 10(5) M(-1)) stabilizes Ag NCs for over 300 h, while the G-quadruplex G4T4G4 with the lowest binding constant (0.64 × 10(5) M(-1)) generates Ag NCs with the shortest shelf-life (55 h). The cluster sizes of Ag NCs are associated with the sequence lengths of DNA templates. In addition, the red emitting [C4A4C3]-Ag and the NIR emitting [G4T4G4-C4A4C4]-Ag are successfully used for HeLa cell transfection and exhibit good intracellular emission. These results provide a promising pathway to prepare silver nanomaterials with desirable physicochemical properties through designing suitable DNA templates.
Key Laboratory for Green Chemical Technology MOE, Key Laboratory of Systems Bioengineering MOE, Tianjin University, Tianjin 300072, People's Republic of China. liwei@tju.edu.cn.
Wei
W
Li
Lu
L
Liu
Yan
Y
Fu
Yanhua
Y
Sun
Jinli
J
Zhang
Rongxin
R
Zhang
D002470:Cell Survival / Q000187:drug effects; D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D054856:G-Quadruplexes; D006367:HeLa Cells; D006801:Humans; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000633:toxicity; D018613:Microscopy, Confocal; D010316:Particle Size; D012834:Silver / Q000737:chemistry*; D013816:Thermodynamics; D014162:Transfection
D012834:Silver; D004247:DNA