Oligonucleotide hybridization and free-solution electrokinetic separation in a nanofluidic device

Area of Science:

• Biotechnology
• Nanotechnology
• Analytical Chemistry

Background:

• Lab-on-a-chip systems offer advantages for DNA hybridization assays, but integration with microscale separation remains limited.
• Existing methods often require sample labeling, increasing complexity and cost.

Purpose of the Study:

• To develop a label-free, electrokinetic technique for DNA hybridization detection using nanofluidic separation.
• To quantitatively measure DNA hybridization kinetics and distinguish between complementary and mismatched sequences.

Main Methods:

• Separation of single-stranded and double-stranded oligonucleotides in a nanofluidic device.
• Coupling nanofluidic separation with free-solution hybridization for detection.
• Quantitative measurement of hybridization kinetics by varying sodium ion concentration.

Main Results:

• Demonstrated label-free detection of DNA hybridization.
• Measured the second-order reaction coefficient for complementary 20-mer oligonucleotides across varying sodium concentrations.
• Distinguished between complementary and single-nucleotide mismatched oligonucleotide pairs based on hybridization rates.
• Observed changes in DNA mobility with sodium concentration, indicating potential for biomolecule transport studies.

Conclusions:

• The developed technique provides a simple, efficient method for label-free DNA hybridization detection and kinetic analysis.
• The nanofluidic platform shows promise for studying DNA interactions and biomolecule transport in nanochannels.
• This work advances the integration of separation and hybridization assays on-chip.