A lead(II)-driven DNA molecular device for turn-on fluorescence detection of lead(II) ion with high selectivity and sensitivity.

A Pb(2+)-driven DNA molecular device which is constructed based on a DNA duplex-quadruplex exchange is utilized for the highly selective and sensitive detection of Pb(2+). The power of this DNA device originates from the excellent efficiency of Pb(2+) 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 Pb(2+) 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 Pb(2+) detection with high selectivity and sensitivity.