single-molecule FRET (Förster Resonance Energy Transfer)

Single-molecule FRET is a technique that observes energy transfer between two tiny molecules called fluorophores, attached to a single biological molecule like a protein or DNA. When the donor fluorophore is excited by light, it can transfer energy to the acceptor fluorophore if they are very close—usually within 1-10 nanometers. This transfer causes the acceptor to emit light, which is detected and measured. By monitoring the changes in light signals, scientists can see how molecules move or change shape in real-time, providing detailed insights into their dynamics and interactions at the single-molecule level.