Detecting topological variations of DNA at single-molecule level

Area of Science:

• Biophysics
• Nanotechnology
• Molecular Biology

Background:

• Ultrathin nanopore membranes are used in DNA sequencing.
• Nanopores can detect topological variations in DNA by analyzing ionic flow modulation during translocation.
• Existing methods lack precision in identifying specific topological changes.

Purpose of the Study:

• To develop and validate new barcoding methods for detecting topological variations in DNA using nanopore technology.
• To improve the accuracy and reliability of signal detection for DNA topology analysis.
• To enable unambiguous determination of barcode positions for enhanced sequence information.

Main Methods:

• Utilized two programmable base-pairing barcoding methods: dsDNA gapping and ssDNA protrusion site creation.
• Generated hybrid DNA complexes for translocation through nanopores.
• Integrated discriminative noise analysis for double-stranded (ds) and single-stranded (ss) DNA topologies.
• Employed threshold detection for multi-level signal analysis.

Main Results:

• Achieved improved multi-level signal detection through discriminative noise analysis.
• Successfully extracted reliable information about DNA topological variations.
• Demonstrated unambiguous determination of barcode positional information along the DNA sequence.
• Showcased potential for modification to detect DNA nicks, damage, and repair sites.

Conclusions:

• The developed barcoding and noise analysis methods significantly enhance the detection of DNA topological variations via nanopore translocation.
• These techniques offer precise positional information and hold promise for DNA damage and repair site detection.
• This approach advances nanopore-based DNA analysis beyond sequencing applications.