| 초록 |
Based on silver ion (Ag+)-mediated formation of C-C mismatched base pairs, a novel fluorescence sensing strategy for Ag+ was constructed. In the presence of Ag+, the single stranded (ss) trigger DNA is hybridized with the first hairpin probe through the formation of C-C mismatched base pairs, consequently opening the hairpin structure. The released ss region of the first hairpin subsequently opens the second hairpin, displacing the Ag+ and ss trigger DNA from the first hairpin probe. Released Ag+ and ss trigger DNA are reused for the next cycle of assembly and produce double stranded (ds) DNA complexes, which would be resistant to the adsorption by graphene oxide (GO) and consequently produce highly enhanced fluorescence signal from ds specific fluorescent dye, SYBR green I. On the other hand, in the absence of Ag+, the ss trigger DNA neither promote the hairpin assembly nor produce ds DNA complexes, resulting in the reduced fluorescence signal. By employing GO as a quencher to significantly reduce the background fluorescence signal from SYBR Green Ⅰ, Ag+ was very reliably detected with high sensitivity and selectivity. |
