A ThT Derivative as Zn²⁺ Sensor Based on DNA G-quadruplex

In this report, we developed a sensing strategy based on ThT-E (a ThT derivative) and DNA G-quadruplex for the label-free detection of Zn²⁺. In the absence of Zn²⁺, there was a fluorescence enhancement of ThT-E by interaction with human telomere sequence. On the addition of Zn²⁺, Zn²⁺ induced a more compact antiparallel G-quadruplex to release ThT-E, resulting in fluorescence quenching. The detection limit was 0.6996 μM, and the fluorescence intensity showed a good linear relationship with the concentration of Zn²⁺ in the range of 0-10 μM. This sensing strategy which only needs to mix two kinds of materials has the characteristics of label-feel, simple operation, short response time, economical and efficient.