Highly selective DNA-based sensor for lead(II) and mercury(II) ions

Area of Science:

• Environmental Science
• Analytical Chemistry
• Biotechnology

Background:

• Heavy metal contamination by lead (Pb2+) and mercury (Hg2+) poses significant environmental and health risks.
• Accurate and sensitive detection methods are crucial for monitoring these pollutants.

Purpose of the Study:

• To develop a novel, highly selective, and sensitive DNA-based sensor for the simultaneous detection of Pb(2+) and Hg(2+).
• To demonstrate the sensor's effectiveness in real-world environmental samples.

Main Methods:

• Utilized a thrombin-binding aptamer (TBA) probe labeled with a fluorophore (FAM) and quencher (DABCYL).
• Exploited structural changes in TBA upon binding Pb(2+) and Hg(2+) ions, leading to fluorescence quenching via FRET.
• Quantified heavy metal ions based on changes in fluorescence intensity.

Main Results:

• Achieved highly selective and sensitive detection of Pb(2+) down to 300 pM and Hg(2+) down to 5.0 nM.
• Established linear correlations between fluorescence intensity and heavy metal concentrations (R(2) = 0.98).
• Successfully applied the sensor to detect Pb(2+) in soil and Hg(2+) in pond water samples.

Conclusions:

• Developed the first single DNA-based sensor capable of detecting both Hg(2+) and Pb(2+) ions.
• The developed sensor is simple, cost-effective, and suitable for environmental monitoring applications.