Laboratoire Matière et Systèmes Complexes

Niko Hildebrandt : Nano Bio Photonics, Institut d’Electronique Fondamentale, Université Paris-Sud

Terbium-to-quantum dot FRET for multiplexed biosensing

K. David Wegnera, Xue Qiua, Stina Lindéna, Zongwen Jina, W. Russ Algarb, Igor L. Medintzc and Niko Hildebrandta a NanoBioPhotonics, Institut d’Electronique Fondamentale, Université Paris-Sud, Orsay, France b Department of Chemistry, University of British Columbia, Vancouver, Canada c Center for Biomolecular Science and Engineering Code 6900, U.S. Naval Research Laboratory, Washington, DC, USA

The combination of terbium complexes (Tbs) and quantum dots (QDs) for time-resolved Förster Resonance Energy Transfer (FRET) offers many advantages for multiplexed diagnostics.1-4 Tbs provide long excited-state lifetimes (up to several milliseconds), which allow efficient FRET to QD acceptors and the suppression of fluorescence background by time-gated detection. Spectral and temporal multiplexing becomes possible using different QD colors and the long Tb luminescence decay times, respectively. Moreover, so-called FRET relays (multistep FRET from Tb-to-QD-to-dye) allow for a highly flexible construction of very versatile biosensors as well as molecular logic devices. In this contribution we will present various Tb- and QD-based FRET-biosensors using a variety of biological recognition molecules, such as antibodies, nanobodies, peptides and oligonucleotides, for multiplexed detection of tumor markers, proteases and DNA. In such bioassays the QDs do not only function as a multicolor fluorophore but also as a nanoscaffold for the attachment of multiple biomolecules. Time- and spectrally-resolved optical analysis of FRET from Tbs-to-dyes, Tbs-to-QDs, or Tbs-to-QDs-to-dyes allows spectro-temporal multiplexing with very high sensitivity in homogeneous non-amplified bioassays. Our results demonstrate the possibility of ultra-sensitive multiplexed detection of several individual biological events or different biomarkers, which are important issues for many biosensing applications using optical fluorescence spectroscopy and fluorescence imaging of in vitro and in vivo biological systems.

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