Electrochemical aptamer biosensor for DNA detection based on label-free aptamers

Area of Science:

• Electrochemistry
• Biosensing
• Nucleic Acid Detection

Background:

• Electrochemical aptasensors are advanced for nucleic acid detection but often lack specificity, flexibility, and simplicity.
• Traditional aptasensor assembly relies on Au-S bonds, which can be less stable.
• Improving hybridization stability and signal amplification are key challenges.

Purpose of the Study:

• To develop a highly specific, flexible, and simple electrochemical aptasensor for nucleic acid detection.
• To utilize a triblock DNA probe strategy for enhanced aptasensor performance.
• To establish a robust method for DNA detection in complex biological samples.

Main Methods:

• A triblock DNA probe (probe-polyA-probe) was designed, leveraging polyA's affinity for gold electrode surfaces.
• Assembly on the gold electrode surface was achieved via polyA-DNA interactions, avoiding traditional Au-S bonds.
• Target DNA hybridization with two capture probes enhanced stability via base stacking.
• [Ru(NH3)6]3+ was used as an electrostatic signal probe adsorbed onto the DNA backbone.

Main Results:

• The aptasensor demonstrated a wide linear detection range from 10 pM to 10 μM.
• A low detection limit of 2.9 pM was achieved.
• The sensor exhibited excellent repeatability, stability, and specificity.
• Successful detection of DNA in human serum samples confirmed its practical applicability.

Conclusions:

• The developed triblock DNA probe strategy offers a simple and effective method for constructing electrochemical aptasensors.
• The aptasensor exhibits superior performance characteristics, including high sensitivity and specificity.
• This approach holds significant potential for real-world applications in complex biological environments, such as clinical diagnostics.