A Lead (II) Ion Sensor Based on Selective Recognition of G‐quadruplex for Ethyl‐substitutive Thioflavin T

Abstract ThT−E (ethyl‐substitutive Thioflavin T), a derivative of Thioflavin T (ThT), is capable of inducing a guanine ‐rich nucleic acid sequence that forms a parallel G‐quadruplex under certain conditions and exhibits significant fluorescence enhancement. In this work, we used Pb 2+ to induce parallel G‐quadruplex into anti‐parallel G‐quadruplex to reduce fluorescence of ThT−E and found a simple Pb 2+ detection method. Through this approach, Pb 2+ in aqueous solutions can be detected at 0. 76 nM with fluorescence spectrometry in a facile way, with high selectivity against other metal ions. These results indicate the method for detecting Pb 2+ is simple, sensitive, specific and label‐free.