Synthesis of fluorescent AuNCs with RNA as template

Although nucleic acids have been widely used as templates for the synthesis of nanomaterials, the synthesis of RNA-templated gold nanoclusters (AuNCs) has not been explored. In this work, we developed a simple strategy for synthesis of RNA-templated fluorescent AuNCs. We first evaluated the adsorption of different nucleoside monophosphates (NMP) on gold atoms. Our density function theory simulation and isothermal titration calorimetry measurements demonstrated that adenosine monophosphate (AMP) is a superior gold binder than other NMPs or deoxyadenosine monophosphate. Afterwards, NMP-templated synthesis of AuNCs was conducted in various pH environments, and our results indicated that bright green light-emitting AMP-templated AuNCs can be obtained at pH similar to 6.0. In order to study the synthesis mechanism of AuNCs, we investigated the effects of reducing agent type and addition time, and the negative charge carried by template nucleotides on the fluorescence of AuNCs. Finally, we extended the template AMP into RNA hairpin structure, the fluorescence intensity was the highest when the cyclic bases were poly 16 A. This study opens new routes to synthesize fluorescent AuNCs using RNA templates.