DNA Hybridization Kinetics Observed at the Single-Molecule Level Using Graphene Near-Field Effects.

Area of Science:

• Nanotechnology
• Biophysics
• Molecular Biology

Background:

• Graphene's unique photonic properties enable sensitive detection of molecular interactions.
• Understanding DNA hairpin hybridization kinetics is crucial for molecular diagnostics and nanotechnology.

Purpose of the Study:

• To develop an advanced sensing platform for real-time kinetic analysis of single DNA hairpins.
• To utilize graphene's near-field effects for enhanced optical signal detection.
• To investigate the nanoscale unfolding mechanisms and intermediate states of DNA hairpins.

Main Methods:

• Functionalization of graphene with fluorophore-labeled DNA hairpins.
• Utilizing Total Internal Reflection Fluorescence (TIRF) microscopy with an EM-CCD camera.
• Applying super-resolution reconstruction techniques based on the Point Spread Function (PSF).
• Developing a semiempirical model to correlate optical signals with fluorophore-graphene distances.

Main Results:

• Successful detection and kinetic assessment of individual DNA hairpins at low concentrations.
• Observation of intermediate, partially hybridized states, doubling hairpin unfolding time.
• Determination of fluorophore-graphene distances at the nanometer scale.
• Identification of step-like unfolding processes with intermittent metastates and potential nucleation events.

Conclusions:

• The developed graphene-based sensing platform provides a novel method for studying biomolecular kinetics at the single-molecule level.
• The findings offer insights into the complex unfolding pathways of DNA hairpins.
• This approach is adaptable for investigating the kinetics of various biomolecules in different environments.