Detecting Force‐Induced Molecular Transitions with Fluorescence Resonant Energy Transfer

Don't FRET: The first successful combination of optical-tweezers force microscopy and single-molecule fluorescence resonant energy transfer (FRET) is demonstrated with a force sensor based on a DNA hairpin (see picture). As the hairpin is opened and closed by the optical tweezers, the structural change is simultaneously monitored by the FRET emission from fluorescence labels.