Oligonucleotide-templated rapid formation of fluorescent gold nanoclusters and its application for Hg2+ ions sensing

• A simple, rapid and mild strategy for synthesis of DNA-templated gold nanoclusters (AuNCs) was developed.
• This process could be completed within 5 min after the reaction beginning under ambient conditions.
• C5 DNA was found as the best template for the formation of fluorescent AuNCs in this system.
• This C5-AuNCs could be applied to detecting Hg2+ ions with excellent selectivity.

In this work, we developed a simple, rapid and mild strategy for synthesis of DNA-templated fluorescent gold nanoclusters (AuNCs) through association of gold ions to DNA templates and reduction with 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES). After systematical investigation on the formation of fluorescent AuNCs by using different DNA templates, C5 DNA was found as the best template for the formation of fluorescent AuNCs in this system. This process could be completed within 5 min after the reaction beginning under ambient conditions. The prepared C5-AuNCs displayed good blue emission and photostability. Furthermore, this C5-AuNCs could be applied to detecting Hg2+ ions specifically based on the specific and strong interaction between Hg2+ and Au+. The C5-AuNCs provided excellent selectivity for Hg2+ ions over other metal ions, and also high sensitivity, with a detection limit of 50 nM. As biocompatible, environmentally-friendly, and synthesis-rapid, this C5-AuNCs probe appears to be promising candidate for biochemical sensing via simple modification of template DNA.

In this work, we developed a simple, rapid and mild strategy for synthesis of DNA-templated fluorescent gold nanoclusters (AuNCs) through association of gold ions to DNA templates and reduction with HEPES. This process could be completed within 5 min after the reaction beginning. Then, this blue fluorescence-emissive DNA-AuNCs was employed as a label-free probe for Hg2+ ions rapid detection based on Hg2+ induced fluorescence quenching.Figure optionsDownload as PowerPoint slide