Engineering a flat-lying three-stranded duplex probe for catalytic DNA circuit toward enhanced electrochemical...

Area of Science:

• Biotechnology
• Biosensor Technology
• Nucleic Acid Chemistry

Background:

• Biosensor performance relies heavily on nucleic acid probe design and immobilization.
• Current methods often require complex fabrication and optimization, hindering reliable bioanalysis and efficiency.

Purpose of the Study:

• To develop a facile and effective strategy for constructing electrochemical DNA biosensors.
• To improve probe immobilization and enhance sensing performance through a novel probe design.

Main Methods:

• Engineered a three-stranded duplex (TSD) probe with an internally positioned thiol group for flat-lying immobilization.
• Investigated the impact of flat-lying versus upright immobilization on probe accessibility and assembly density.
• Utilized a catalytic DNA reaction for electrochemical detection of target DNA.

Main Results:

• The flat-lying TSD probe design demonstrated superior sensing performance compared to the upright configuration.
• Achieved a faster reaction rate (1.5 h vs. 2.5 h) and a significantly lower detection limit (244 fM).
• The biosensor exhibited excellent selectivity, reproducibility, and was successfully applied to detect DNA in diluted serum.

Conclusions:

• A novel, facile probe design and immobilization paradigm was presented for electrochemical DNA biosensors.
• The flat-lying immobilization strategy eliminates the need for complex density optimization, offering a robust platform.
• This approach enables highly sensitive and efficient DNA detection, advancing biosensor technology.