TY  - JOUR
A1  - Geißler, Daniel
A1  - Charbonnière, Loïc J.
A1  - Ziessel, Raymond F.
A1  - Butlin, Nathaniel G.
A1  - Löhmannsröben, Hans-Gerd
A1  - Hildebrandt, Niko
T1  - Quantum dot biosensors for ultrasensitive multiplexed diagnostics
N2  - Time- and color-resolved detection of Foerster resonance energy transfer (FRET) from luminescent terbium complexes to different semiconductor quantum dots results in a fivefold multiplexed bioassay with sub-picomolar detection limits for all five bioanalytes (see picture). The detection of up to five biomarkers occurs with a sensitivity that is 40-240-fold higher than one of the best-established single-analyte reference assays.
Y1  - 2010
UR  - http://www3.interscience.wiley.com/cgi-bin/jhome/26737/
U6  - https://doi.org/10.1002/anie.200906399
SN  - 1433-7851
ER  - 
TY  - JOUR
A1  - Morgner, Frank
A1  - Stufler, Stefan
A1  - Geissler, Daniel
A1  - Medintz, Igor L.
A1  - Algar, W. Russ
A1  - Susumu, Kimihiro
A1  - Stewart, Michael H.
A1  - Blanco-Canosa, Juan B.
A1  - Dawson, Philip E.
A1  - Hildebrandt, Niko
T1  - Terbium to quantum dot FRET Bioconjugates for clinical diagnostics  influence of human plasma on optical and assembly properties
JF  - Sensors
N2  - Forster 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 Forster 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.
KW  - FRET
KW  - quantum dots
KW  - terbium
KW  - luminescence lifetime
KW  - blood
KW  - plasma
KW  - clinical diagnostics
KW  - biotin
KW  - streptavidin
KW  - histidin
KW  - immunoassay
Y1  - 2011
U6  - https://doi.org/10.3390/s111009667
SN  - 1424-8220
VL  - 11
IS  - 10
SP  - 9667
EP  - 9684
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Sellrie, Frank
A1  - Beck, Michael
A1  - Hildebrandt, Niko
A1  - Micheel, Burkhard
T1  - A homogeneous time-resolved fluoroimmunoassay (TR-FIA) using antibody mediated luminescence quenching
N2  - The determination of low-molecular weight substances (haptens) is demonstrated with a homogeneous time-resolved immunoassay using antibody-induced luminescence quenching. Our novel assay technology uses the newly developed monoclonal antibody (G24-BA9) to quench the luminescence of europium trisbipyridine (EuTBP). We performed a competitive biotin immunoassay including an EuTBP-biotin conjugate, the anti-EuTBP antibody G24-BA9 and streptavidin as assay components. Steric hindrance allows only the binding of either G24-BA9 (to the EuTBP moiety) or streptavidin (to the biotin moiety) to the EuTBP-biotin conjugate. Addition of the analyte biotin resulted in the binding of streptavidin to biotin and a concomitant preferred binding of G24-BA9 to EuTBP-biotin. Since G24-BA9 quenches the luminescence of EuTBP within the conjugate, the luminescence signal could be used to indicate and quantify the presence of free biotin in the system. All experiments were carried out in solution in the presence of 5% serum demonstrating the possibility of using our novel assay for a very fast determination of low molecular weight substances in biological fluids.
Y1  - 2010
UR  - http://www.rsc.org/Publishing/Journals/AY/Index.asp
U6  - https://doi.org/10.1039/C0ay00306a
SN  - 1759-9660
ER  -