Analytical Sciences

Label-free Detection of Zn²⁺ Based on G-quadruplex

Yahui GUO,* Yan SUN,* Xiaoqiang SHEN,* Kunchi ZHANG,* Jiming HU,** and Renjun PEI*

*Key Laboratory of Nano-Bio Interface, Division of Nanobiomedicine, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, P. R. China
**Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry & Molecular Sciences, Wuhan University, Wuhan 430072, P. R. China

Herein, we developed a sensing strategy for the label-free detection of Zn²⁺ based on G-quadruplex. In the absence of Zn²⁺, there was a fluorescence enhancement of thioflavin T by interaction with human telomere sequence. On the addition of Zn²⁺, Zn²⁺ induced a more compact G-quadruplex structure to release thioflavin T, resulting in a fluorescence decrease. This simple “mix-then-detect” method gave the detection limit of 0.91 μM with linear dynamic ranges from 0 to 10 μM. Because it does not require the use of expensive and unstable DNAzyme systems, or need synthesis and modification of nanomaterials, this label-free biosensor is simple, fast, cost-effective and applicable for real samples taken from lake water.

J-STAGE: View this article in J-STAGE