Quantum dots as acceptors in FRET-assays containing serum

  • 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 Förster Resonance Energy Transfer (FRET), e. g. for sensitive homogeneous fluoroimmunoassays (FIA). In this work we demonstrate energy transfer from Eu<SUP>3+</SUP>-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 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 Förster Resonance Energy Transfer (FRET), e. g. for sensitive homogeneous fluoroimmunoassays (FIA). In this work we demonstrate energy transfer from Eu<SUP>3+</SUP>-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 Förster-radius, estimated from the absorption and emission bands, was ca. 77 Å. 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.show moreshow less

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Metadaten
Author:Michael Beck, Niko Hildebrandt, Hans-Gerd Löhmannsröben
URN:urn:nbn:de:kobv:517-opus-9504
Series (Serial Number):Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe, ISSN 1866-8372 (paper 019)
Document Type:Postprint
Language:English
Date of Publication (online):2006/09/29
Year of Completion:2006
Publishing Institution:Universität Potsdam
Release Date:2006/09/29
Tag:Förster-Resonanz-Energie-Transfer
Energy Transfer; Europium; FRET; Immunoassay; Luminescence; Quantum Dot; Serum
GND Keyword:Energietransfer; Europium; Fluoreszenz-Resonanz-Energie-Transfer; Immunoassay; Lumineszenz; Quantenpunkt; Serum
Source:Proceedings of SPIE, Vol. 6191 (2006), 61910X , pp. 234-241
RVK - Regensburg Classification:VE 9908
Organizational units:Mathematisch-Naturwissenschaftliche Fakultät / Institut für Chemie
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 54 Chemie / 540 Chemie und zugeordnete Wissenschaften
Collections:Universität Potsdam / Aufsätze (Pre- und Postprints) / Mathematisch-Naturwissenschaftliche Fakultät / Institut für Chemie / Physikalische Chemie
Notes extern:
© 2006 Society of photo-Optical Instrumentation Engineers

This paper was published in:
Biophotonics and New Therapy Frontiers / Romualda Grzymala, Olivier Haeberle (eds.). - S. 234 - 241. - (Proceedings of SPIE ; 6191)
ISBN: 9780819462473
doi: 10.1117/12.662722

It is made available as an electronic reprint with permission of SPIE. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.