A colorimetric lead (II) ions sensor based on selective recognition of G-quadruplexes by a clip-like cyanine dye.

A probe for colorimetric detecting lead ion (Pb(2+)) has been designed by using a newly synthesized clip-like cyanine dye and G-quadruplex. The unique structure of the clip-like cyanine dye endowed the probe with a high selectivity towards Pb(2+). Significant changes in absorption spectra of the cyanine dye recognizing the Pb(2+)-induced conformational transition of G-quadruplexes made the probe show a high sensitivity towards Pb(2+) with a detection limit of 1nM. The excellent performance enabled the probe to be practically applied in measuring the Pb(2+) pollution in freshwater system.