Correlative Tweezers-Fluorescence Microscopy (CTFM) for single-molecule research


The C-Trap is a CTFM system combining single-molecule scanning confocal microscopy with high-resolution dual-trap optical tweezers.

The instrument enables a simple and fast workflow for bead trapping, DNA tethering, subsequent DNA manipulation and controlled triggering of the biochemical reaction by incubating the DNA with different proteins of interest. The whole workflow can be executed within 1 minute.

The confocal approach provides effective background rejection, allowing the live imaging of fluorescently labeled proteins binding to nucleic acids with single-molecule sensitivity, in real time and at concentrations up to 100 nM. The one-dimensional configuration of the optically stretched nucleic acid dramatically reduces image acquisition times, allowing visualization of DNA-proteins interaction at the millisecond timescale.


The C-Trap™ CTFM can strongly impact the field of structural biology, where models of protein function require improvement and validation. Current state of the art techniques for protein analysis like XRD, NMR and Cryo-EM have become very powerful in resolving the structure of proteins and protein complexes. Based on the protein structure one can derive models for its function in vivo. The next step is to improve and validate these models through live observation of these processes in real-time at the single-molecule level. CTFM makes this possible for the first time.

Key differentiators:

  • Live observation of Protein – DNA interaction
  • Physiologically relevant conditions;
  • DNA suspended in solution
  • Up to 100nM protein concentrations
  • Room temperature
  • Fast (200Hz) imaging at diffraction limited-resolution (250-300nm).
  • Protein localization accuracy: 10 nm
  • Best in class force resolution: <0.2 pN @ 100 Hz on 48kb DNA