The duplex formation mediated by Hg²⁺ in a properly designed ssDNA generates a stable hairpin structure, which greatly alters the translocation profile of the ssDNA through α-hemolysin nanopore. From the 2D-events contour plot, the presence of Hg²⁺ can be confirmed in as little as 30 min at ∼7 nM or higher. The sensor is highly selective to Hg²⁺, without interference from other metal ions. It can be fabricated from readily available materials, without the processes of synthesis, purification, probe-making, and so forth. This sensing strategy opens new possibilities for detecting many types of analytes which have specific interactions with DNA molecules.

 

This research has been online published in J. Am. Chem. Soc. (Shuang Wen, Tao Zeng, Lei Liu, Kai Zhao, Yuliang Zhao, Xianjin Liu, and Hai-Chen Wu. Highly Sensitive and Selective DNA-Based Detection of Mercury(II) with α-Hemolysin Nanopore. J. Am. Chem. Soc., 2011, 133 (45), pp 18312–18317)

This research was supported by 973 program (2010CB-933600), the National Natural Science Foundation of China (No. 20972159) and the “100 Talents” program of the Chinese Academy of Sciences. We are grateful to Prof. H. Bayley (Univ. of Oxford) for the plasmid of αHL.