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Time-resolved and steady-state FRET spectroscopy on commercial biocompatible quantum dots

: Wegner, D.; Geißler, D.; Stufler, S.; Löhmannsröben, H.-G.; Hildebrandt, N.


Parak, W.J. ; Society of Photo-Optical Instrumentation Engineers -SPIE-, Bellingham/Wash.:
Colloidal quantum dots/nanocrystals for biomedical applications VI : 22 - 24 January 2011, San Francisco, California
Bellingham, WA: SPIE, 2011 (Proceedings of SPIE 7909)
ISBN: 978-0-8194-8446-8
ISSN: 1605-7422
Paper 79090D
Conference "Colloidal Quantum Dots/Nanocrystals for Biomedical Applications" <6, 2011, San Francisco/Calif.>
Fraunhofer IAP ()

Semiconductor nanocrystals (quantum dots - QDs) possess unique photophysical properties that make them highly interesting for many biochemical applications. Besides their common use as fluorophores in conventional spectroscopy and microscopy, QDs are well-suited for studying Förster resonance energy transfer (FRET). Size-dependent broadband absorption and narrow emission bands offer several advantages for the use of QDs both as FRET donors and acceptors. QD-based FRET pairs can be efficiently used as biological and chemical sensors for highly sensitive multiplexed detection. In this contribution we present the use of several commercially available QDs (Qdot® Nanocrystals - Invitrogen) as FRET donors in combination with commercial organic dyes as FRET acceptors. In order to investigate the FRET process within our donor-acceptor pairs, we used biotinylated QDs and streptavidin-labeled dyes. The well-known biotinstreptavidin molecular recognition enables effective FRET fro m QDs to dye molecules and provides defined distances between donor and acceptor. Steady-state and time-resolved fluorescence measurements were performed in order to investigate QD-to-dye FRET. Despite a thick polymer shell around the QDs, our results demonstrate the potential of these QDs as efficient donors both for steady-state and time-resolved FRET applications in nano-biotechnology.