Detection of mercury(II) by DNA templated gold nanoclusters based on forming thymidine-Hg(2+)-thymidine duplexes

We have successfully synthesized gold nanoclusters (AuNCs) templated with DNA (5'-CCCCCCCCCCCCTTTTTT-3'), and subsequently employed the fluorescent DNA-AuNCs as a novel probe for sensitive detections of mercury ions (Hg(2+)). Basically, the procedure is due to the formation of thymidine-Hg(2+)-thymidine duplexes between DNA-AuNCs and Hg(2+), thus leading to aggregations of DNA-AuNCs described here occurring, and facilitating their fluorescence decrease. Significantly, this decrease of fluorescent signals permitted sensitive detection of Hg(2+) in a linear range of 0.1-100 µmol L(-1), with a detection limit of 0.083 µmol L(-1) at a signal-to-noise ratio of 3. Additionally, the practicality of this probe for assaying Hg(2+) in human urine and lake water samples was further validated, and showed various advantages including simplicity, selectivity, sensitivity and low cost, demonstrating its potential to broaden ways for assaying Hg(2+) in real samples.