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Terbium to Quantum Dot FRET Bioconjugates for Clinical Diagnostics: Influence of Human Plasma on Optical and Assembly Properties
NanoPolyPhotonik, Fraunhofer Institut für Angewandte Polymerforschung, D-14476 Potsdam, Germany
Physikalische Chemie, Universität Potsdam, D-14476 Potsdam, Germany
Center for Bio/Molecular Science and Engineering, Code 6900, US Naval Research Laboratory, Washington, DC 20375, USA
College of Science, George Mason University, 4400 University Dr., Fairfax, VA 22030, USA
Optical Sciences Division, Code 5611, US Naval Research Laboratory, Washington, DC 20375, USA
Departments of Cell Biology and Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA
Institut d’Electronique Fondamentale, Université Paris-Sud 11, Orsay Cedex 91405, France
* Author to whom correspondence should be addressed.
Received: 1 September 2011; in revised form: 29 September 2011 / Accepted: 30 September 2011 / Published: 12 October 2011
Abstract: Förster resonance energy transfer (FRET) from luminescent terbium complexes (LTC) as donors to semiconductor quantum dots (QDs) as acceptors allows extraordinary large FRET efficiencies due to the long Förster distances afforded. Moreover, time-gated detection permits an efficient suppression of autofluorescent background leading to sub-picomolar detection limits even within multiplexed detection formats. These characteristics make FRET-systems with LTC and QDs excellent candidates for clinical diagnostics. So far, such proofs of principle for highly sensitive multiplexed biosensing have only been performed under optimized buffer conditions and interactions between real-life clinical media such as human serum or plasma and LTC-QD-FRET-systems have not yet been taken into account. Here we present an extensive spectroscopic analysis of absorption, excitation and emission spectra along with the luminescence decay times of both the single components as well as the assembled FRET-systems in TRIS-buffer, TRIS-buffer with 2% bovine serum albumin, and fresh human plasma. Moreover, we evaluated homogeneous LTC-QD FRET assays in QD conjugates assembled with either the well-known, specific biotin-streptavidin biological interaction or, alternatively, the metal-affinity coordination of histidine to zinc. In the case of conjugates assembled with biotin-streptavidin no significant interference with the optical and binding properties occurs whereas the histidine-zinc system appears to be affected by human plasma.
Keywords: FRET; quantum dots; terbium; luminescence lifetime; blood; plasma; clinical diagnostics; biotin; streptavidin; histidin; immunoassay
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Morgner, F.; Stufler, S.; Geißler, D.; Medintz, I.L.; Algar, W.R.; Susumu, K.; Stewart, M.H.; Blanco-Canosa, J.B.; Dawson, P.E.; Hildebrandt, N. Terbium to Quantum Dot FRET Bioconjugates for Clinical Diagnostics: Influence of Human Plasma on Optical and Assembly Properties. Sensors 2011, 11, 9667-9684.
Morgner F, Stufler S, Geißler D, Medintz IL, Algar WR, Susumu K, Stewart MH, Blanco-Canosa JB, Dawson PE, Hildebrandt N. Terbium to Quantum Dot FRET Bioconjugates for Clinical Diagnostics: Influence of Human Plasma on Optical and Assembly Properties. Sensors. 2011; 11(10):9667-9684.
Morgner, Frank; Stufler, Stefan; Geißler, Daniel; Medintz, Igor L.; Algar, W. Russ; Susumu, Kimihiro; Stewart, Michael H.; Blanco-Canosa, Juan B.; Dawson, Philip E.; Hildebrandt, Niko. 2011. "Terbium to Quantum Dot FRET Bioconjugates for Clinical Diagnostics: Influence of Human Plasma on Optical and Assembly Properties." Sensors 11, no. 10: 9667-9684.