Double strand DNA-templated copper nanoclusters as a novel fluorescent probe for label-free detection of rutin

In this study, we developed a simple, sensitive, low-cost and label-free method to detect rutin by using double-strand DNA-templated copper nanoclusters (dsDNA-CuNCs) as fluorescent probe. The dsDNA-template can facilitate the formation of highly fluorescent CuNCs with a maximum emission wavelength at 575 nm. In the dsDNA-CuNCs fluorescent probe, rutin was intercalated into the structure of dsDNA via hydrogen bond and electrostatic interaction. The fluorescence of dsDNA-CuNCs was quenched considerably due to the electron transfer from CuNCs to rutin. This decrease in fluorescence intensity of dsDNA-CuNCs can be used to monitor the concentration of rutin from 0.6 to 400 µM with a detection limit of 0.12 µM (S/N = 3). Compared with the previous reports, this method does not require complex DNA sequence design, fluorescence dye label and sophisticated experimental techniques. Moreover, the proposed sensing system could be applicable for the detection of rutin in pharmaceutical samples.