Since ionic lead is a major environmental pollutant, the sensitive and selective detection of aqueous Pb²⁺ is of particular interest. In their recent study, LI Tao, a PhD candidate of Changchun Institute of Applied Chemistry (CIAC), CIAC Prof. DONG Shaojun and Prof. WANG Erkang report a Pb²⁺ -driven DNA molecular device as a conceptually new fluorescent Pb²⁺ sensor, which integrates high sensitivity and selectivity with good reusability.

The device is constructed based on a DNA duplex-quadruplex exchange, and is utilized for the highly selective and sensitive detection of Pb²⁺. The power of this DNA device originates from the excellent efficiency of Pb²⁺ for stabilizing G-quadruplexes, which makes the DNA duplex unwind thereby driving the device. This device can be reset to the original state by addition of a strong Pb²⁺ chelator DOTA, endowing the device with good reusability. In the whole process, the signal readout is modulated via a fluorescent probe binding to and being released from the G-quadruplex. Such a DNA device can serve as a novel turn-on fluorescent sensor for Pb²⁺ detection with high selectivity and sensitivity. This DNA device has great promise in environmental monitoring.

The study has been published in the Journal of the American Chemical Society (2010, 132, 13156-13157). This project is supported by the National Natural Science Foundation of China (20735003 and 20890020), 973 Program (also called National Program on Key Basic Research Project of China, 2009CB930100 and 2010CB933600), and the Chinese Academy of Sciences (KJCX2.YW.H11).