DNA-based biosensors for Hg(2+) determination by polythymine-methylene blue modified electrodes

Area of Science:

• Electrochemistry
• Biosensors
• Environmental Science

Background:

• Mercury ions (Hg2+) pose significant environmental and health risks.
• Accurate and sensitive detection methods for Hg2+ are crucial for environmental monitoring.
• Existing methods for Hg2+ detection can be complex and costly.

Purpose of the Study:

• To develop a novel electrochemical DNA-based biosensor for selective Hg2+ determination.
• To investigate the use of polythymine-modified electrodes with methylene blue as a redox probe.
• To evaluate the performance of the biosensor using different electrode configurations (Au and Au SPE).

Main Methods:

• Electrochemical DNA-based biosensor development.
• Modification of gold (Au) and screen-printed gold (Au SPE) electrodes with polythymine and methylene blue.
• Square wave voltammetry (SWV) for signal detection.
• Analysis of real samples (water and fish).

Main Results:

• The biosensor demonstrated selective detection of Hg2+ through Thymine-Hg-Thymine (T-Hg-T) complex formation.
• Detection limits (LOD) as low as 0.1 nM were achieved.
• High sensitivity and reproducibility were observed for both Au and Au SPE configurations.
• Accurate mercury detection in real water and fish samples with high recovery rates (92-107%).

Conclusions:

• The developed electrochemical DNA biosensor offers a selective, fast, and cost-effective method for Hg2+ detection.
• The biosensor shows great potential for environmental monitoring and analysis of mercury in real-world samples.
• The use of polythymine-modified electrodes provides an efficient platform for electrochemical sensing applications.