Ultra-Sensitive Detection of Mercury by Using Field-Effect Transistor Biosensors Based on Single-Walled Carbon...

Area of Science:

• Environmental Science
• Nanotechnology
• Analytical Chemistry

Background:

• Mercury ion (Hg²⁺) contamination from human activities poses significant health risks due to its toxicity and bioaccumulation.
• Current Hg²⁺ detection methods often lack the required sensitivity and selectivity for practical environmental monitoring.
• Developing rapid, accurate, and cost-effective Hg²⁺ detection is crucial for public health and environmental safety.

Purpose of the Study:

• To develop a highly sensitive and selective biosensor for detecting mercury ions (Hg²⁺) in practical environments.
• To leverage DNA and single-walled carbon nanotubes (SWNTs) for direct conversion of Hg²⁺ interaction into electrical signals.
• To enhance biosensor performance using a phase-locked amplifier for improved anti-noise capability and detection speed.

Main Methods:

• Fabrication of a field-effect transistor (FET) biosensor by adsorbing DNA onto single-walled carbon nanotubes (SWNTs) using 1,5-diaminonaphthalene (DAN).
• Utilizing the interaction between DNA and Hg²⁺ to generate measurable electrical signals.
• Implementing a phase-locked amplifier to improve detection sensitivity and reduce noise.

Main Results:

• The SWNTs-based FET biosensor achieved a limit of detection (LOD) of 42.6 pM for Hg²⁺ without a phase-locked amplifier.
• Incorporating a phase-locked amplifier significantly enhanced sensitivity, achieving an LOD of 5.14 pM.
• The biosensor demonstrated excellent selectivity and successful practical detection of Hg²⁺ in tap water samples.

Conclusions:

• The developed DNA-SWNTs FET biosensor offers a promising, high-performance, and low-cost platform for Hg²⁺ detection.
• The integration of a phase-locked amplifier is key to achieving superior sensitivity and anti-noise performance.
• This method presents a viable solution for sensitive and selective environmental monitoring of mercury ion contamination.