Enhanced acceptor fluorescence-resonance energy transfer

K. Ukonaho, T Loevgren, T Soukka, T. Tandem dye acceptor used to enhance upconversion fluorescence resonance energy transfer in homogeneous assays. Anal. Chem. 2007, 79, 6312-6318. 

Nonradiative relaxation from states can be effected via fluorescence resonance energy transfer. The rate of energy transfer in donor-acceptor pairs is directly related to their distance, which can of course be affected by analyte complexation. Excitation energy transfer leads to quenching of the donor, but also to enhancement of the acceptor fluorescence therefore, the ratio of fluorescence intensities at donor and acceptor emission wavelengths provides information on complexation via changes in donor-acceptor distance. The chapters by Valeur, Bouas-Laurent, and Krafft describe uses of the energy transfer mechanism. 

Figure 14. FRET (fluorescence resonance energy transfer) experiment between a surface-attached donor dye-labeled probe strand and an acceptor dye-labeled target strand from solution, Shown are the angular scans of the reflectivities and of the fluorescence emission of the donor dye before and after hybridization, as well as, after denaturing the hybrid. While the reflectivities are virtually identical the fluorescence shows a strong enhancement at surface plasmon resonance (—) which is completely quenched after hybridization (—), however, can be fully recovered upon the dissociation of the hybrid (..).

---