Functionalized Glass Micropipettes for Methylated DNA Detection Based on Enzyme-Responsive Signal Switching Effects

Area of Science:

• Epigenetics
• Biomedical Engineering
• Analytical Chemistry

Background:

• DNA methylation is a key epigenetic modification linked to cancer.
• Detecting low-abundance methylated DNA in biological samples is challenging.
• Current methods often lack sensitivity or require complex procedures.

Purpose of the Study:

• To develop a highly sensitive and selective electrochemical sensing strategy for DNA methylation detection.
• To utilize an enzyme-responsive signal switching mechanism for improved detection.
• To establish a simple and effective method for analyzing DNA epigenetic modifications.

Main Methods:

• Functionalized glass micropipette electrochemical sensor utilizing polydopamine nanotubes (PDA-NTs).
• Immobilization of capture probe DNA (cpDNA) for specific target recognition.
• Enzyme-responsive signal switching based on sodium bisulfite conversion and Exo III exonuclease activity.

Main Results:

• Achieved highly sensitive detection of methylated DNA with a linear response from 1 aM to 100 fM.
• Established a low detection limit of 8.5 aM.
• Demonstrated reliable detection in 10% human serum samples, differentiating methylated from unmethylated DNA.

Conclusions:

• The developed sensor provides a sensitive and selective method for DNA methylation analysis.
• The enzyme-responsive signal switching strategy simplifies detection without PCR amplification or complex labeling.
• This approach offers a promising tool for rapid analysis of DNA epigenetic modifications and potential cancer biomarker discovery.