Dual-trap optical tweezers with real-time force clamp control

Area of Science:

• Biophysics
• Biochemistry
• Molecular Biology

Background:

• Single molecule force clamp experiments are crucial for understanding molecular mechanisms like enzymes and motors.
• Optical tweezers are a key technology for these studies, allowing precise force application.

Purpose of the Study:

• To develop a dual-trap optical tweezers instrument with real-time force clamp control.
• To present a model for force clamp experiments in dumbbell geometry.
• To validate the instrument's suitability for single molecule biology.

Main Methods:

• Developed a dual-trap optical tweezers instrument with a 200 kHz update rate for force clamp control (0-100 pN).
• Created a theoretical model for force clamp experiments in dumbbell geometry.
• Performed a proof-of-principle experiment using lambda exonuclease on a DNA tether.

Main Results:

• Observed good agreement between predicted and observed power spectra of bead position and force fluctuations.
• The developed model accurately predicts and optimizes instrument dynamics.
• Demonstrated the instrument's capability in a DNA unwinding experiment with lambda exonuclease.

Conclusions:

• The developed dual-trap optical tweezers instrument provides precise real-time force clamp control.
• The accompanying model aids in predicting and optimizing instrument performance.
• The instrument is well-suited for various single molecule biology applications.