Hairpin DNA probe based electrochemical biosensor using methylene blue as hybridization indicator

Area of Science:

• Electrochemistry
• Molecular Biology
• Biosensors

Background:

• Studying DNA hybridization specificity is crucial for molecular diagnostics.
• Existing methods can be complex or lack sensitivity.
• Development of rapid, label-free detection methods is needed.

Purpose of the Study:

• To propose a label-free, rapid, and simple method for assessing hairpin DNA probe hybridization specificity.
• To utilize methylene blue (MB) as a hybridization indicator for electrochemical detection.
• To investigate the influence of target DNA mismatch position and concentration on hybridization.

Main Methods:

• Immobilization of thiolated hairpin DNA probes on a gold electrode via self-assembly.
• Electrochemical detection using cyclic voltammetry (CV) to measure methylene blue (MB) signals.
• Discrimination of complementary, single-base mutated, and random oligonucleotides.

Main Results:

• The method successfully discriminated between complementary target DNA and single-base mutated or random oligonucleotides.
• Mutations in the center of the target DNA had the most significant impact on hybridization.
• A decrease in MB reduction current correlated with increasing target DNA concentration.

Conclusions:

• Methylene blue serves as an effective hybridization indicator for label-free DNA detection.
• The developed electrochemical method offers high specificity and sensitivity for target DNA measurement.
• This approach holds significant promise for rapid and specific DNA analysis.