A Multicolor Chameleon DNA‐templated Silver Nanocluster and Its Application for Ratiometric Fluorescence Target Detection with Exponential Signal Response

• Published in: Advanced functional materials 2017-12, Vol.27 (46), p.n/a
• Main Authors: Zhou, Weijun, Zhu, Jinbo, Fan, Daoqing, Teng, Ye, Zhu, Xiaoqing, Dong, Shaojun
• Format: Article
• Language: English
• Subjects: chameleon; Color; Deoxyribonucleic acid; DNA; DNA‐templated AgNC; exponential signal response; Fluorescence; Materials science; Nanoclusters; ratiometric fluorescence detection; Sensitivity analysis; Target detection
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.201704092

For the first time, a novel type of chameleon DNA‐templated silver nanocluster (AgNC) is found whose fluorescence color can be switched among yellow, orange, and red by the regulation of complementary DNA, nonfluorescent assistant AgNC as well as Mg2+. AgNC templated by A20‐C55 (A20‐C55‐NC) possesses strong yellow fluorescence (Y signal) in phosphate buffer solution. When approaching to the nonfluorescent assistant AgNC through template hybridization, Y signal decreases while a new red emission (R signal) rises, leading to a dramatic color change of AgNC solution from yellow to red. On the other hand, hybridization of A20‐C55‐NC with complementary DNA (T20) largely enhances the Y signal while A20‐C55‐NC shows R and Y signal with equal intensity simultaneously in the presence of Mg2+. Therefore, the chameleon AgNC achieves controllable multicolor fluorescence variation. Based on above mechanism, a series of ratiometric analysis platforms are constructed for DNA target detection. Surprisingly, the ratiometric probes demonstrate an exponential growth of signal response with nanomolar sensitivity whether in double‐stranded or hairpin‐shaped structure. Accordingly, this universal ratiometric analysis platform possesses low background, large signal variation in a narrow concentration range, which presents obvious advantages over most of previous DNA detection strategies that are based on DNA‐templated AgNC. Herein, a novel type of chameleon DNA‐templated AgNC whose fluorescence color can be switched among yellow, orange and red by the regulation of complementary DNA, nonfluorescent assistant AgNC as well as Mg2+ is found. Therefore, ratiometric analysis platforms that possess low background and large signal variation in a narrow concentration range have been constructed for DNA target detection.