Electromagnetic tweezers with independent force and torque control

Area of Science:

• Biophysics
• Molecular Mechanics
• Nanotechnology

Background:

• Magnetic tweezers are essential for studying biological molecule mechanics.
• Existing setups often lack independent control over applied force and torque.
• Precise manipulation is crucial for understanding molecular behavior.

Purpose of the Study:

• To present a novel electromagnetic tweezer (EMT) setup.
• To enable independent control of force and torque applied to biological molecules.
• To demonstrate the EMT's capability in studying DNA mechanics.

Main Methods:

• Implemented an EMT combining a single solenoid for force (f-EMT) and four solenoids for torque (τ-EMT).
• Utilized optically asymmetric Janus beads attached to single, tethered DNA molecules.
• Applied forces in the piconewton range and torques in the piconewton-nanometer range.

Main Results:

• Demonstrated independent control of force and torque on DNA molecules.
• Showcased the ability to apply piconewton forces and piconewton-nanometer torques simultaneously.
• Verified that torsional stiffness can be continuously tuned by adjusting torque-generating currents at various force levels.

Conclusions:

• The novel EMT provides flexible and independent control of both force and torque.
• This capability makes the EMT an ideal tool for simultaneous tensional and torsional studies.
• Facilitates advanced research in molecular and cellular mechanics.