Multicolor Three-Dimensional Tracking for Single-Molecule Fluorescence Resonance Energy Transfer Measurements

Area of Science:

• Biophysics
• Biochemistry
• Microscopy

Background:

• Single-molecule fluorescence resonance energy transfer (smFRET) is crucial for studying biomolecular interactions and dynamics.
• Traditional smFRET methods face limitations in observation time (burst confocal) or temporal resolution (surface immobilization).

Purpose of the Study:

• To develop a novel smFRET 3D tracking microscope.
• To enable extended observation times and high temporal resolution for single biomolecules in solution.

Main Methods:

• A confocal tracking microscope utilizing closed-loop feedback to follow particles in solution.
• Utilizes two overlapping tetrahedral detection elements for donor and acceptor channels.
• Demonstrated multicolor tracking and quantification of fluorescent beads and DNA molecules.

Main Results:

• Successfully demonstrated multicolor tracking of fluorescent beads with varying smFRET efficiencies (0.45-0.69).
• Quantified intramolecular smFRET of double-stranded DNA in viscous glycerol solution.
• Achieved high temporal resolution for single-particle tracking in solution.

Conclusions:

• The developed smFRET 3D tracking microscope overcomes limitations of existing methods.
• This technology provides a powerful new tool for studying biomolecular dynamics in solution.
• Future applications include studying protein dynamics in native biological environments.