DNA-templated NIR-emitting gold nanoclusters with peroxidase-like activity as a multi-signal probe for Hg 2+detection

DNA-templated metal nanoclusters hold great potential in sensing owing to the unique size effect of nanoclusters and the programmability of DNA. However, the single signal readout probes are difficult to satisfy the detection requirements of diversified scenes. Here, we design phosphorothioates-modified oligonucleotides templated gold nanoclusters that possess near-infrared fluorescence and peroxidase-like activity for multi-signal detection of Hg 2 + with high sensitivity, flexibility, and selectivity. In the presence of Hg 2 + , psDNA-AuNCs display a Hg 2 + -stimulated fluorescence quenching ascribes to the electron transfer between psDNA-AuNCs and Hg 2 + by forming T-Hg 2 + -T interactions and Hg 2 + -Au + metallophilic interactions. Simultaneously, the binding of Hg 2 + on gold atoms inhibits the catalytic activity of psDNA-AuNCs, and this phenomenon is used to develop sensitive chemiluminescence assay and colorimetric method. The limit of detection for the detection of Hg 2 + was 28.4 nM in fluorescent mode, 15.3 nM in colorimetric mode, and 8.7 nM in chemiluminescence mode. All of the three sensing platforms show a favorable performance on Hg 2 + detection in real samples. Overall, the multi-signal readout, catalytic activity, and NIR emission enable the development of the psDNA-AuNCs-based functional platform in wide significant fields such as diagnosis, catalysis, and environmental monitoring.

Automated summary

A novel DNA-templated gold nanocluster with high sensitivity and multi-signal detection capability for Hg2+ has been designed in this study, showing great potential in various fields of application.