FRET relies on the non-radiative transfer of energy from an excited donor fluorophore to an acceptor fluorophore. The efficiency of this energy transfer is highly dependent on the distance between the donor and acceptor, typically effective at ranges of 1-10 nanometers. When a toxic compound interacts with a biological target, it may alter the spatial arrangement of the donor and acceptor, thereby affecting the FRET signal. This change can be quantitatively measured, providing valuable information about the toxic interaction.
