Biosensors based on binding-modulated donor–acceptor distances

The promising recognition characteristics exhibited by biomolecules have caused significant interest in biomolecule-based sensor strategies. Here we review several emerging biosensor designs that use modulated electron or energy transfer to a bio-specific ligand as the signaling mechanism. The efficiencies of both electron transfer and energy transfer are strongly dependent on donor–acceptor distance. When coupled with the large conformational changes sometimes associated with biomolecular recognition, these distance-dependant processes provide a robust means for generating optical and electronic signals.