Label-free Detection of Zn(2+) Based on G-quadruplex

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Molecular Biology

Background:

• G-quadruplex structures, particularly those from human telomeres, can interact with specific metal ions.
• Fluorescent dyes like thioflavin T can bind to G-quadruplex structures, leading to enhanced fluorescence.
• Existing methods for zinc ion detection often rely on complex or expensive systems.

Purpose of the Study:

• To develop a simple, label-free biosensor for the detection of zinc ions (Zn2+).
• To utilize the structural changes in G-quadruplex induced by Zn2+ for sensing.
• To provide a cost-effective and rapid detection method applicable to real-world samples.

Main Methods:

• A human telomere sequence was used to form G-quadruplex structures.
• Thioflavin T was employed as a fluorescent probe, showing enhanced fluorescence upon binding to the G-quadruplex in the absence of Zn2+.
• The effect of Zn2+ on the G-quadruplex structure and subsequent fluorescence quenching of thioflavin T was investigated.

Main Results:

• The presence of Zn2+ induced a more compact G-quadruplex structure, causing the release of thioflavin T and a decrease in fluorescence.
• The developed biosensor achieved a detection limit of 0.91 μM for Zn2+.
• A linear dynamic range from 0 to 10 μM was observed for Zn2+ detection.

Conclusions:

• The G-quadruplex-based sensing strategy provides a simple, fast, and cost-effective method for label-free Zn2+ detection.
• This method avoids the need for expensive DNAzyme systems or nanomaterial modifications.
• The biosensor demonstrated applicability for detecting Zn2+ in real lake water samples.