Optical Tweezers

An introductory explanation of the logic behind optical trapping experiments

To decipher complex molecular interactions, scientists need the ability to observe the same biological process from multiple points of view. The combination of optical tweezers with fluorescence microscopy enables the simultaneous and in real-time visualization of individual molecules and measurement of the mechanical properties of biomolecular complexes to reveal greater detail.

Working Principle

Correlative Optical Tweezers – Fluorescence Microscopy (CTFM) is a  single-molecule technique that combines optical tweezers, fluorescence microscopy, and microfluidics into a fully integrated platform. It can be used to apply and measure forces while simultaneously visualizing individual molecules in real-time. CTFM enables scientists to correlate mechanical properties to the number, location and conformational state biomolecules

With this technology it is possible to perform simultaneous manipulation, force measurements and visualization of these complexes — for example proteins interacting with DNA. This means that scientists can now correlate mechanical properties to the number, location and conformational state of the proteins bound to DNA. This revolutionary single-molecule visualization technology enables the understanding of life to the smallest detail, which is critical for life science research and drug development.

Optical Tweezers – Fluorescence Microscopy

The figure shows a typical CTFM experimental setup, where optical tweezers are used to trap beads and catch a biomolecule such as DNA in between. Fluorescently labeled proteins are then visualized with confocal or STED fluorescence microscopy. Simultaneous force and extension measurements allow correlating the protein activity and binding kinetics with the mechanical properties of the DNA.

The importance of this technique is it provides the ability to observe the same biological process from multiple points of view. With this new ability to perform simultaneous manipulation, force measurements, and visualization
of these complexes—for example proteins interacting with DNA— scientists can correlate mechanical properties to the number, location and conformational state of the proteins bound to DNA.

 

Working principle_Illustration_C-Trap

Force extension, manipulation, and visualization

Polymers and filaments can be manipulated with the high-resolution optical tweezers while simultaneously measuring force, extension and fluorescence microscopy data. Combining global mechanistic information with local activity provides essential insights into the dynamic function of the substrate under study.

Constant force measurements

Equilibrium dynamics of biomolecular states can be measured by performing constant force measurements. By keeping the traps in a fixed position while measuring tension fluctuations caused by intramolecular conformational transitions with ultra-high sensitivity it is possible to detect the smallest, rarest and most transient states.

C-Trap Protein Folding Equilibrium Dynamics Small

Real-time single-molecule visualization

The kymograph gives unique insights into the dynamic interactions between proteins and filament substrates, such as DNA, and protein–protein interactions. Simultaneous force and extension measurements allow for correlating the protein activity and binding kinetics with the mechanical properties of the protein substrate complex.

As an example, in the kymograph below we can distinguish:

  • single fluorescent protein on DNA
  • single protein unbinds from DNA,
  • fast binding & unbinding event (<10ms).
Kymograph DNA-protein Interactions Explanation

Available Products

C-Trap Optical Tweezers Fluorescence Microscopy

C-Trap™

Optical Tweezers – Fluorescence Microscopy

The C-Trap™ is the world’s first instrument that allows simultaneous manipulation and visualization of molecular interactions in real-time. It combines high-resolution optical tweezers, confocal microscopy or STED nanoscopy, with an advanced microfluidics system in a truly integrated and correlated solution.

m-Trap system optical tweezers

m-Trap™

Dedicated High-resolution Optical Tweezers

The m-Trap™ is the first dedicated optical tweezers instrument specifically developed for high-resolution single-molecule force spectroscopy research. Ultra-high force resolution and stability, with incredible throughput and ease-of-use, all at an unprecedented price level.

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