Quicker than Quick: Correlative Optical Tweezers-Fluorescence Microscopy (CTFM) for the Study of Short-Lived Metabolic Processes

Using optical tweezers in combination with confocal fluorescence microscopy in a controlled microfluidics environment, results in a robust and versatile methodology to study mechanisms occurring at all levels of the cellular metabolism, up to cell membrane interactions and beyond. Both the high temporal and spatial resolutions that correlative optical tweezers-fluorescence microscopy (CTFM) offers represent an asset to investigate processes with short lifetimes. Additionally, by being able to manipulate and exert tensions to selected molecules, we gain access to important structural features. To demonstrate the potential of this hybrid technique, we performed a series of experiments to study the folding/unfolding dynamics of an intracellular signaling protein and the packaging of DNA within a bacteriophage capsid. Both model systems present transient states with fast kinetics, which would be overlooked using other techniques. Our results show that the applications of this single‑molecule technology are not limited to the field of nucleic acids research and quickly advance to new venues.