Two-Photon Excitation of Quantum-Dot-Based Fluorescence Resonance Energy Transfer and Its Applications (pages 1921–1926)
A. R. Clapp, T. Pons, I. L. Medintz, J. B. Delehanty, J. S. Melinger, T. Tiefenbrunn, P. E. Dawson, B. R. Fisher, B. O'Rourke and H. Mattoussi
Article first published online: 26 JUN 2007 | DOI: 10.1002/adma.200602036
Nonradiative fluorescence resonance energy transfer (FRET) between a luminescent quantum dot (QD) donor and a proximal dye brought in close proximity of the QD surface via conjugation with a dye-labeled peptide (or a protein) is shown (see figure). The system is excited with near IR irradiation (well below the absorption band of the QD), via a fast two-photon process, which produces a FRET signal with very low background contribution due to a substantially reduced nonlinear direct excitation of the dye.