Quantum dots as acceptors in FRET-assays containing serum

Michael Beck; Niko Hildebrandt; Hans-Gerd Löhmannsröben

doi:10.1117/12.662722

Translator Disclaimer

14 April 2006 Quantum dots as acceptors in FRET-assays containing serum

Michael Beck, Niko Hildebrandt, Hans-Gerd Löhmannsröben

Author Affiliations +

Proceedings Volume 6191, Biophotonics and New Therapy Frontiers; 61910X (2006) https://doi.org/10.1117/12.662722
Event: SPIE Photonics Europe, 2006, Strasbourg, France

Abstract

Quantum dots (QDs) are common as luminescing markers for imaging in biological applications because their optical properties seem to be inert against their surrounding solvent. This, together with broad and strong absorption bands and intense, sharp tuneable luminescence bands, makes them interesting candidates for methods utilizing Forster Resonance Energy Transfer (FRET), e. g. for sensitive homogeneous fluoroimmunoassays (FIA). In this work we demonstrate energy transfer from Eu³⁺-trisbipyridin (Eu-TBP) donors to CdSe-ZnS-QD acceptors in solutions with and without serum. The QDs are commercially available CdSe-ZnS core-shell particles emitting at 655 nm (QD655). The FRET system was achieved by the binding of the streptavidin conjugated donors with the biotin conjugated acceptors. After excitation of Eu-TBP and as result of the energy transfer, the luminescence of the QD655 acceptors also showed lengthened decay times like the donors. The energy transfer efficiency, as calculated from the decay times of the bound and the unbound components, amounted to 37%. The Forster-radius, estimated from the absorption and emission bands, was ca. 77Å. The effective binding ratio, which not only depends on the ratio of binding pairs but also on unspecific binding, was obtained from the donor emission dependent on the concentration. As serum promotes unspecific binding, the overall FRET efficiency of the assay was reduced. We conclude that QDs are good substitutes for acceptors in FRET if combined with slow decay donors like Europium. The investigation of the influence of the serum provides guidance towards improving binding properties of QD assays.

Citation Download Citation

Michael Beck, Niko Hildebrandt, and Hans-Gerd Löhmannsröben "Quantum dots as acceptors in FRET-assays containing serum", Proc. SPIE 6191, Biophotonics and New Therapy Frontiers, 61910X (14 April 2006); https://doi.org/10.1117/12.662722

ACCESS THE FULL ARTICLE