@article{MorgnerStuflerGeissleretal.2011,
  author    = {Morgner, Frank and Stufler, Stefan and Geissler, Daniel and Medintz, Igor L. and Algar, W. Russ and Susumu, Kimihiro and Stewart, Michael H. and Blanco-Canosa, Juan B. and Dawson, Philip E. and Hildebrandt, Niko},
  title     = {Terbium to quantum dot FRET Bioconjugates for clinical diagnostics influence of human plasma on optical and assembly properties},
  series = {Sensors},
  volume    = {11},
  journal   = {Sensors},
  number    = {10},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {1424-8220},
  doi       = {10.3390/s111009667},
  pages     = {9667 -- 9684},
  year      = {2011},
  abstract  = {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.},
  language  = {en}
}
@article{GeisslerStuflerLoehmannsroebenetal.2013,
  author    = {Geissler, Daniel and Stufler, Stefan and L{\"o}hmannsr{\"o}ben, Hans-Gerd and Hildebrandt, Niko},
  title     = {Six-color time-resolved forster resonance energy transfer for ultrasensitive multiplexed biosensing},
  series = {Journal of the American Chemical Society},
  volume    = {135},
  journal   = {Journal of the American Chemical Society},
  number    = {3},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {0002-7863},
  doi       = {10.1021/ja310317n},
  pages     = {1102 -- 1109},
  year      = {2013},
  abstract  = {Simultaneous monitoring of multiple molecular interactions and multiplexed detection of several diagnostic biomarkers at very low concentrations have become important issues in advanced biological and chemical sensing. Here we present an optically multiplexed six-color Forster resonance energy transfer (FRET) biosensor for simultaneous monitoring of five different individual binding events. We combined simultaneous FRET from one Tb complex to five different organic dyes measured in a filter-based time-resolved detection format with a sophisticated spectral crosstalk correction, which results in very efficient background suppression. The advantages and robustness of the multiplexed FRET sensor were exemplified by analyzing a 15-component lung cancer immunoassay involving 10 different antibodies and five different tumor markers in a single 50 mu L human serum sample. The multiplexed biosensor offers clinically relevant detection limits in the low picomolar (ng/mL) concentration range for all five markers, thus providing an effective early screening tool for lung cancer with the possibility of distinguishing small-cell from non-small-cell lung carcinoma. This novel technology will open new doors for multiple biomarker diagnostics as well as multiplexed real-time imaging and spectroscopy.},
  language  = {en}
}
@article{HildebrandtGeissler2012,
  author    = {Hildebrandt, Niko and Geissler, Daniel},
  title     = {Semiconductor quantum dots as FRET acceptors for multiplexed diagnostics and molecular ruler application},
  series = {Advances in Experimental Medicine and Biology},
  volume    = {733},
  journal   = {Advances in Experimental Medicine and Biology},
  editor    = {Zahavy, E and Ordentlich, A and Yitzhaki, S and Shafferman, A},
  publisher = {Springer},
  address   = {Dordrecht},
  isbn      = {978-94-007-2554-6},
  issn      = {0065-2598},
  doi       = {10.1007/978-94-007-2555-3_8},
  pages     = {75 -- 86},
  year      = {2012},
  abstract  = {Applications based on Forster resonance energy transfer (FRET) play an important role for the determination of concentrations and distances within nanometer-scale systems in vitro and in vivo in many fields of biotechnology. Semiconductor nanocrystals (Quantum dots - QDs) possess ideal properties for their application as FRET acceptors when the donors have long excited state lifetimes and when direct excitation of QDs can be efficiently suppressed. Therefore, luminescent terbium complexes (LTCs) with excited state lifetimes of more than 2 ms are ideal FRET donor candidates for QD-acceptors. This chapter will give a short overview of theoretical and practical background of FRET, QDs and LTCs, and present some recent applications of LTC-QD FRET pairs for multiplexed ultra-sensitive in vitro diagnostics and nanometer-resolution molecular distance measurements.},
  language  = {en}
}