Constructing a Robust Fluorescent DNA-Stabilized Silver Nanocluster Probe Module by Attaching a Duplex Moiety.

Fluorescent DNA-templated silver nanoclusters (DNA-Ag NCs) have served as excellent luminescent probes and operation units in various applications. However, the fluorescence property of DNA-Ag NCs is very sensitive to elongation or modification of the DNA template, limiting the breadth of applications. In this work, we propose a strategy for constructing a robust fluorescent DNA-Ag NCs probe module by attaching a duplex moiety to the nanocluster-bearing sequence. The fluorescence intensity of the DNA-Ag NCs can be enhanced 90-fold upon hybridization of the elongated moiety. Adenine in the linker sequence has a further enhancing effect on the fluorescence intensity, whereas thymine has a quenching effect. The transformation from a non-fluorescent species to fluorescent nanoclusters is responsible for the fluorescence enhancement with duplex formation of the elongated moiety. We hope that this design will aid future diversification of experimental designs to facilitate more applications that are currently limited by the aforementioned problems.