High-Resolution Optical Tweezers Combined with Multicolor Single-Molecule Microscopy.

Area of Science:

• Biophysics
• Single-molecule biophysics
• Optical instrumentation

Background:

• Biological macromolecules undergo complex changes during activity.
• Simultaneous multi-parameter analysis of single molecules is crucial for understanding life's machinery.
• Existing techniques often lack the ability to probe multiple degrees of freedom concurrently.

Purpose of the Study:

• To present the latest generation of a high-resolution fleezers instrument.
• To detail the design, construction, and testing of this advanced single-molecule analysis tool.
• To enable simultaneous measurement of molecular motion and multiple fluorescence signals.

Main Methods:

• Integration of high-resolution optical tweezers with multicolor confocal fluorescence spectroscopy.
• Utilizing a single-mode optical fiber for three fluorescence excitation lasers.
• Implementing a timesharing and interlacing laser modulation scheme with acousto-optic modulators (AOM).
• Employing a novel 'random phase' trap AOM control for enhanced precision.

Main Results:

• The instrument achieves pN force resolution and subnanometer distance precision.
• Simultaneous multicolor fluorescence detection allows observation of multiple molecules or degrees of freedom.
• The laser modulation scheme minimizes photobleaching and improves tweezers stability.
• The new control method significantly reduces residual trap positioning and bead position errors.

Conclusions:

• The presented fleezers instrument offers unprecedented capabilities for single-molecule analysis.
• It enables simultaneous probing of molecular motion and multiple fluorescence signals, such as FRET.
• This technology advances the study of complex biological processes at the molecular level.