A facile and sensitive electrochemiluminescence biosensor for Hg2+ analysis based on a dual-function oligonucleotide...

Area of Science:

• Electrochemistry
• Nanotechnology
• Biomedical Engineering

Background:

• Mercury ion (Hg2+) contamination poses significant environmental and health risks.
• Sensitive and selective detection methods for Hg2+ are crucial for environmental monitoring and public health.
• Existing detection methods can be complex or lack sufficient sensitivity.

Purpose of the Study:

• To develop a sensitive and easily prepared electrochemiluminescent (ECL) biosensor for Hg2+ detection.
• To utilize a self-assembled, mercury-specific oligonucleotide on gold nanoparticles (AuNPs) for enhanced detection.
• To achieve a low detection limit and high selectivity against interfering metal ions.

Main Methods:

• Fabrication of an indium tin oxide (ITO) electrode modified with gold nanoparticles (AuNPs).
• Self-assembly of a mercury-specific oligonucleotide probe onto the AuNPs-modified ITO electrode.
• Utilizing the conformational change of the oligonucleotide upon Hg2+ binding to trigger an ECL signal generated by [Ru(bpy)2(dppz)](BF4)2.
• Quantification of Hg2+ using the ECL signal intensity.

Main Results:

• The biosensor demonstrated a highly sensitive detection limit of 5.1 pM for Hg2+.
• The sensor showed excellent selectivity, with minimal interference from ten other common metal ions.
• The oligonucleotide probe effectively carried multiple ECL signal-generating molecules without complex labeling.
• The performance was validated using spiked water samples, showing good agreement with atomic fluorescent spectrometry.

Conclusions:

• A simple yet effective ECL biosensor for Hg2+ detection was successfully developed.
• The self-assembly approach and dual-function oligonucleotide probe offer a streamlined and efficient detection strategy.
• This biosensor shows great promise for practical applications in environmental water quality monitoring.