| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 867347 | Biosensors and Bioelectronics | 2012 | 4 Pages |
A “turn-on” photoelectrochemical sensor for Hg2+ detection based on thymine-Hg2+-thymine interaction is presented by using a thymine-rich oligonucleotide film and a double-strand DNA intercalator, Ru(bpy)2(dppz)2+ (bpy=2,2′-bipyridine, dppz=dipyrido[3,2-a:2′,3′-c]phenazine) as the photocurrent signal reporter. The presence of Hg2+ induces the formation of a double helical DNA structure which provides binding sites for Ru(bpy)2(dppz)2+. The double helical structure was confirmed by circular dichroism and fluorescence measurements. Under the optimized conditions, a linear relationship between photocurrent and Hg2+ concentration was obtained over the range of 0.1 nM to 10 nM Hg2+, with a detection limit of 20 pM. Interference by 10 other metal ions was negligible. Analytical results of Hg2+ spiked into tap water and lake water by the sensor were in good agreement with mass spectrometry data. With the advantages of high sensitivity and selectivity, simple sensor construction, low instrument cost and low sample volume, this method is potentially suitable for the on-site monitoring of Hg2+ contamination.
► Photoelectrochemical DNA sensor was developed for Hg2+ detection. ► Linear range was 0.1–10 nM, detection limit 20 pM. ► Interference from 10 common metal ions was negligible. ► The sensor was validated with Hg2+ spiked tap and lake water samples.
