Endonuclease-driven DNA walking for constructing a novel colorimetric and electrochemical dual-mode biosensing method

Area of Science:

• Environmental Science
• Analytical Chemistry
• Biotechnology

Background:

• Antibiotic pollution poses risks to food safety and environmental health.
• On-site detection methods are crucial for effective monitoring and quality control.
• Existing methods may lack convenience, sensitivity, or require complex instrumentation.

Purpose of the Study:

• To develop a novel dual-mode (colorimetric and electrochemical) biosensing method for kanamycin detection.
• To utilize a magnetic bead-based DNA walker for amplified signal transduction.
• To enable convenient and sensitive on-site analysis of antibiotic residues.

Main Methods:

• Design of a magnetic bead (MB)-based DNA walker for target-triggered, endonuclease-driven walking reactions.
• Colorimetric detection via telomerase extension of released primers into G-quadruplex/hemin DNAzymes.
• Electrochemical detection using the MB complex as a walker to trigger further DNA walking and release ferrocene labels.

Main Results:

• Colorimetric strategy achieved a linear range of 0.1 pg mL⁻¹ to 1 ng mL⁻¹ with a 22 fg mL⁻¹ detection limit.
• Electrochemical strategy demonstrated a wide linear range (0.01 pg mL⁻¹ to 1 ng mL⁻¹) and an ultralow detection limit of 8.4 fg mL⁻¹.
• Both strategies exhibited dual signal amplification, high sensitivity, and simplicity without expensive equipment.

Conclusions:

• The developed dual-mode biosensor provides a convenient and highly sensitive platform for on-site kanamycin detection.
• The method is valuable for food quality control and environmental monitoring of antibiotic residues.
• The DNA walker-based approach offers a promising strategy for developing advanced biosensing systems.