DNA-templated silver nanoclusters-graphene oxide nanohybrid materials: a platform for label-free and sensitive fluorescence turn-on detection of multiple nucleic acid targets

In this study, we develop an efficient method for multiple DNA detection by exploring silver nanoclusters (AgNCs)-graphene oxide (GO) nanohybrid materials. Because of the extraordinarily high quenching efficiency of GO, the ssDNA-AgNCs probe exhibits minimal background fluorescence, while strong emission is observed when it forms a double helix with the specific target DNA, leading to a high signal-to-background ratio. Therefore the AgNCs-GO nanohybrid materials can be successfully applied for DNA detection. The system described here exhibits not only high sensitivity with a detection limit of 1 nM, but also an excellent differentiation ability for single-base mismatched sequences. In addition, by exploring AgNCs as signal reporters and GO as the nanoquencher, this approach avoids labeling the probe DNA or target DNA, which offers the advantages of simplicity and cost efficiency. Moreover, the large planar surface of GO allows adsorption of different DNA-AgNCs probes, each with a distinct emission, leading to a multicolor sensor for the detection of multiple DNA targets in the same solution.