How does enzymatic FRET biosensor work?

In this biosensor, the donor and acceptor molecules are usually positioned close to one another. When the target biomolecule interacts with the biosensor, it alters the distance between these fluorescent molecules. This change influences the energy transfer between them, affecting the intensity of fluorescence emitted by the acceptor molecule. By measuring this fluorescence change, researchers can detect and measure the presence or activity of the target biomolecule.