A Fluorescence Strategy for Silver Ion Assay via Cation Exchange Reaction and Formation of Poly(thymine)-templated Copper Nanoclusters

The detection of Ag+ ions in the environment and biological systems is important to both environmental monitoring and modern medicine. Herein, a novel and label-free method was developed for Ag+ detection, which utilizes a florescence strategy combining DNA-templated copper nanoclusters (Cu NCs) with cation exchange reactions. The method is primarily based on the effective detection of an Ag+-triggered cation exchange reaction and the release of free Cu2+ from CuS nanoparticles (CuS NPs), while the probe T30 serves as an effective template for the formation of fluorescence-inducing Cu NCs. Under optimal conditions, this sensing system displays high sensitivity with a 50 nM limit of detection and a range from 0 - 100 μM. In addition, the proposed method exhibits high selectivity and, therefore, was successfully applied to the analysis of real samples. Overall, these results demonstrate that our established method has advantages of design and operation simplicity, as well as cost-effectiveness.