Dielectrophoretic tweezers as a platform for molecular force spectroscopy in a highly parallel format

Area of Science:

• Biophysics
• Nanotechnology
• Molecular Biology

Background:

• Molecular force spectroscopy is crucial for understanding biomolecular mechanics.
• Existing methods often lack high throughput or require complex setups.
• Dielectrophoresis (DEP) offers a label-free method for manipulating micro- and nanoparticles.

Purpose of the Study:

• To develop a simplified and highly parallelizable dielectrophoresis (DEP) system for molecular force spectroscopy.
• To demonstrate the application of DEP tweezers for probing biomolecular interactions.
• To validate the system's performance through simulations and experimental measurements.

Main Methods:

• Utilized a simple electrode geometry with dielectric microstructures to generate uniform dielectrophoretic (DEP) forces.
• Determined DEP crossover frequencies using simplified electrode configurations.
• Employed 2D and 3D electric field simulations to validate experimental geometries.
• Applied DEP tweezers to stretch DNA oligomers and detected extension via total-internal reflection fluorescence microscopy.

Main Results:

• Achieved uniform DEP forces in the hundreds of piconewtons over a macroscopic area.
• Successfully simplified the determination of DEP crossover frequencies.
• Validated experimental DEP tweezers geometries through simulations.
• Demonstrated the ability to stretch DNA and measure its extension using the developed system.

Conclusions:

• The developed DEP tweezers offer a simple, cost-effective, and highly parallelizable platform for molecular force spectroscopy.
• This method is ideal for high-throughput analysis of stretching and unbinding kinetics of biomolecules.
• The combination of facile fabrication, uniform forces, and optical detection advances biomolecular studies.