TY - JOUR A1 - Geißler, Daniel A1 - Linden, S. A1 - Liermann, K. A1 - Wegner, Karl David A1 - Charbonnière, L.J. A1 - Hildebrandt, N. T1 - Lanthanides and quantum dots as Förster resonance energy transfer agents for diagnostics and cellular imaging N2 - Luminescent lanthanide labels (LLLs) and semiconductor quantum dots (QDs) are two very special classes of (at least partially) inorganic fluorophores, which provide unique properties for Förster resonance energy transfer (FRET). FRET is an energy-transfer process between an excited donor fluorophore and a ground-state acceptor fluorophore in close proximity (approximately 1–20 nm), and therefore it is extremely well suited for biosensing applications in optical spectroscopy and microscopy. Within this cogent review, we will outline the main photophysical advantages of LLLs and QDs and their special properties for FRET. We will then focus on some recent applications from the FRET biosensing literature using LLLs as donors and QDs as donors and acceptors in combination with several other fluorophores. Recent examples of combining LLLs and QDs for spectral and temporal multiplexing from single-step to multistep FRET demonstrate the versatile and powerful biosensing capabilities of this unique FRET pair. As this review is published in the Forum on Imaging and Sensing, we will also present some new results of our groups concerning LLL-based time-gated cellular imaging with optically trifunctional antibodies and LLL-to-QD FRET-based homogeneous sandwich immunoassays for the detection of carcinoembryonic antigen. PY - 2014 DO - https://doi.org/10.1021/ic4017883 SN - 0020-1669 SN - 1520-510X VL - 53 IS - 4 SP - 1824 EP - 1838 PB - American Chemical Society CY - Washington, DC AN - OPUS4-31182 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jin, Z. A1 - Geißler, Daniel A1 - Qiu, X. A1 - Wegner, Karl David A1 - Hildebrandt, N. T1 - A rapid, amplification-free, and sensitive diagnostic assay for single-step multiplexed fluorescence detection of microRNA N2 - The importance of microRNA (miRNA) dysregulation for the development and progression of diseases and the discovery of stable miRNAs in peripheral blood have made these short-sequence nucleic acids next-generation biomarkers. Here we present a fully homogeneous multiplexed miRNA FRET assay that combines careful biophotonic design with various RNA hybridization and ligation steps. The single-step, single-temperature, and amplification-free assay provides a unique combination of performance parameters compared to state-of-the-art miRNA detection technologies. Precise multiplexed quantification of miRNA-20a, -20b, and -21 at concentrations between 0.05 and 0.5 nm in a single 150 mL sample and detection limits between 0.2 and 0.9 nm in 7.5 mL serum samples demonstrate the feasibility of both highthroughput and point-of-care clinical diagnostics. KW - Clinical diagnostics KW - FRET KW - MicroRNA KW - Multiplexing KW - Time-gated fluorescence detection PY - 2015 DO - https://doi.org/10.1002/anie.201504887 SN - 1433-7851 SN - 1521-3773 VL - 54 IS - 34 SP - 10024 EP - 10029 PB - Wiley-VCH CY - Weinheim AN - OPUS4-44837 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Geißler, Daniel A1 - Hildebrandt, N. T1 - Recent developments in Förster resonance energy transfer (FRET) diagnostics using quantum dots N2 - The exceptional photophysical properties and the nanometric dimensions of colloidal semiconductor quantum dots (QD) have strongly attracted the bioanalytical community over the last approximately 20 y. In particular, the integration of QDs in the analysis of biological components and interactions, and the related diagnostics using Förster resonance energy transfer (FRET), have allowed researchers to significantly improve and diversify fluorescence-based biosensing. In this TRENDS article, we review some recent developments in QD-FRET biosensing that have implemented this technology in electronic consumer products, multiplexed analysis, and detection without light excitation for diagnostic applications. In selected examples of smartphone-based imaging, single- and multistep FRET, steady-state and time-resolved spectroscopy, and bio/chemiluminescence detection of QDs used as both FRET donors and acceptors, we highlight the advantages of QD-based FRET biosensing for multiplexed and sensitive diagnostics. KW - Fluorescence spectroscopy and imaging KW - Multiplexing immunoassay KW - Nanoparticle KW - DNA/RNA KW - BRET/CRET PY - 2016 DO - https://doi.org/10.1007/s00216-016-9434-y SN - 1618-2642 SN - 1618-2650 VL - 408 IS - 17 SP - 4475 EP - 4483 PB - Springer-Verlag CY - Berlin, Heidelberg AN - OPUS4-36546 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bhuckory, S. A1 - Wegner, Karl David A1 - Qiu, X. A1 - Wu, Y.T. A1 - Jennings, T. L. A1 - Incamps, A. A1 - Hildebrandt, N. T1 - Triplexed CEA-NSE-PSA Immunoassay Using Time-Gated Terbium-to-Quantum Dot FRET N2 - Time-gated Förster resonance energy transfer (TG-FRET) between Tb complexes and luminescent semiconductor quantum dots (QDs) provides highly advantageous photophysical properties for multiplexed biosensing. Multiplexed Tb-to-QD FRET immunoassays possess a large potential for in vitro diagnostics, but their performance is often insufficient for their application under clinical conditions. Here, we developed a homogeneous TG-FRET immunoassay for the quantification of carcinoembryonic antigen (CEA), neuron-specific enolase (NSE), and prostatespecific antigen (PSA) from a single serum sample by multiplexed Tb-to-QD FRET. Tb–IgG antibody donor conjugates were combined with compact QD-F(ab’)2 antibody acceptor conjugates with three different QDs emitting at 605, 650, and 705 nm. Upon antibody–antigen–antibody Sandwich complex formation, the QD acceptors were sensitized via FRET from Tb, and the FRET ratios of QD and Tb TG luminescence intensities increased specifically with increasing antigen concentrations. Although limits of detection (LoDs: 3.6 ng/mL CEA, 3.5 ng/mL NSE, and 0.3 ng/mL PSA) for the triplexed assay were slightly higher compared to the single-antigen assays, they were still in a clinically relevant concentration range and could be quantified in 50 μL serum samples on a B·R·A·H·M·S KRYPTOR Compact PLUS clinical immunoassay plate reader. The simultaneous quantification of CEA, NSE, and PSA at different concentrations from the same serum sample demonstrated actual multiplexing Tb-to-QD FRET immunoassays and the potential of this technology for translation into clinical diagnostics. KW - Lanthanides KW - Nanoparticles KW - Biosensing KW - Multiplexing KW - FRET KW - Fluorescence KW - PSA KW - NSE KW - CEA PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512290 DO - https://doi.org/10.3390/molecules25163679 VL - 25 IS - 16 SP - 3679 PB - MDPI AN - OPUS4-51229 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wegner, Karl David A1 - Hildebrandt, N. T1 - Near infrared quantum dots for biosensing and bioimaging N2 - Quantum dots (QDs) possess unique optoelectronic properties, which make them very attractive to be used as optical probes in biosensing and bioimaging applications. The strong absorbance and light scattering of biological compounds like tissue and blood in the visible range pose a problem. However, if optical probes emitting in the near-infrared (NIR) range are used, scattering, absorption, and autofluorescence of biological components are strongly reduced. This allows for an increased light penetration depth and higher spatial and temporal resolution for the investigation of biological processes. The synthesis and application of NIR emitting QDs is a fast-growing research field and the benefits of using QDs were demonstrated for a variety of applications, such as photoelectrochemical biosensor, in vivo vascular imaging, and fluorescence-guided surgery. This article reviews the state-of-the-art developments in the preparation of NIR/IR QDs and highlights the latest research about their utilization in biosensing and bioimaging applications. KW - Quantum dots KW - Near-infrared KW - Biosensing KW - Bioimaging KW - NIR-II / SWIR KW - Advanced nanomaterials PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-609708 SN - 0165-9936 DO - https://doi.org/10.1016/j.trac.2024.117922 VL - 180 SP - 1 EP - 19 PB - Elsevier B.V. AN - OPUS4-60970 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -