Highly sensitive and selective detection of Hg2+ using mismatched DNA and a molecular light switch complex in aqueous solution.

Xiaoru Zhang, Ying Li, Haoran Su, Shusheng Zhang

Key Laboratory of Eco-chemical Engineering, Ministry of Education, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao, China.

Biosensors & bioelectronics 2010 Feb 15

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A novel "signal-on" assay for sensitive and selective detection of Hg(2+) in aqueous solution based on mismatched DNA and a molecular light switch complex, [Ru(phen)(2)(dppz)](2+), was reported in the present work. This Hg(2+) specific sensor system composed of two label-free DNA probes with eight T-T mismatches, which could form stable DNA duplexes by thymine-Hg(2+)-thymine (T-Hg(2+)-T) in the presence of Hg(2+). The luminescence of [Ru(phen)(2)(dppz)](2+) is very weak in aqueous solution, and significant luminescence can be observed when intercalating into DNA duplexes. By monitoring Hg(2+)-dependent luminescence intensity enhancement, highly sensitive and selective determination of Hg(2+) has been achieved. Under the optimum conditions, the luminescence intensity was proportional to the concentration of Hg(2+) in the range of 1.0x10(-9)-1.5x10(-7) M. A detection limit of 3.5x10(-10) M Hg(2+) was achieved using 3sigma. The presence of other metal ions did not interfere with the detection of Hg(2+) even at high concentrations. This approach is simple and rapid, which can be used to monitor the Hg(2+) concentration in drinking water and natural media within 30 min. Copyright 2009 Elsevier B.V. All rights reserved.

Citation

Xiaoru Zhang, Ying Li, Haoran Su, Shusheng Zhang. Highly sensitive and selective detection of Hg2+ using mismatched DNA and a molecular light switch complex in aqueous solution. Biosensors & bioelectronics. 2010 Feb 15;25(6):1338-43