TY - CONF A1 - Hoffmann, Katrin A1 - Kage, Daniel A1 - Ameskamp, J. A1 - Wittkamp, M. A1 - Thiele, T. A1 - Borcherding, H. A1 - Göhde, W. A1 - Schedler, U. A1 - Resch-Genger, Ute T1 - Time-resolved flow cytometry N2 - The fast identification of a large number of analytes or events is increasingly required in bioanalytical, diagnostic, and security applications. The versatility and straightforward use make multiparametric fluorescence techniques particularly interesting as detection techniques. An established method for high-throughput single-cell and single-particle measurements is flow cytometry (FCM). Using only spectral encoding without further intensity information, state-of-the-art instruments equipped with several light sources and detectors can resolve almost 20 different color codes. However, this is not sufficient to answer complex research questions, e.g. in cell biology and immunology. In contrast, routine applications demand low-cost and sometimes even portable instruments and thus a minimum number of instrument components. Thus, there are currently two main research directions in FCM: the development of methods that can either address increasingly complex analytical challenges or provide low-cost and robust approaches for routine multiplex analyses. Common spectral multiplexing approaches face limitations in both directions. On the one hand, spectral overlap of labels restricts the number of codes and makes elaborate correction schemes necessary. On the other hand, even for lower degrees of multiplexing often a sophisticated optical setup is needed. An alternative to spectral multiplexing and intensity encoding is to exploit the luminescence lifetime (LT) as an encoding parameter. This can allow for extending the parameter space in combination with spectral encoding or result in more simple and compact devices due to fewer optical components. The availability of fast electronics enables miniaturized and portable lifetime measurement setups at relatively low cost. LT-FCM requires to master LT determination with a limited number of detected photons due to the short interaction time of the encoded objects with the laser spot. In this study, we address this issue for time-domain cytometry and present a novel lifetime flow cytometry (LT-FCM) platform based on a compact setup and straightforward time-domain measurements utilizing LT-encoded luminescent beads. Moreover, we present the realization of a first bioanalytical assay with LT-encoded beads. T2 - ANAKON 2019 CY - Münster, Germany DA - 25.03.2019 KW - Fluorescence KW - Time-resolved KW - Flow cytometry KW - Lifetime-encoding KW - Bead-based assays PY - 2019 AN - OPUS4-47708 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hoffmann, Katrin A1 - Resch-Genger, Ute A1 - Engel, A. A1 - Bäumle, M. T1 - Reference standards for the performance validation of fluorescence measurement systems T2 - 11th International Conference on Methods and Applications of Fluorescence: Spectroscopy, Imaging and Probes CY - Budapest, Hungary DA - 2009-09-06 PY - 2009 AN - OPUS4-20424 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hoffmann, Katrin A1 - Hoffmann, Angelika A1 - Spieles, Monika A1 - Resch-Genger, Ute T1 - Reference Standard for the performance validation of fluroescence measuring systems T2 - Life Science Day 2011 CY - Berlin, Germany DA - 2011-08-26 PY - 2011 AN - OPUS4-24520 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hoffmann, Katrin A1 - Hoffmann, Angelika A1 - Pauli, Jutta A1 - Spieles, Monika A1 - Brunner, Claudia A1 - Resch-Genger, Ute T1 - Reference Materials for Standardization of Fluorescence-based Measurements N2 - Here, we summerize our efforts concerning new design concepts and examples for fluorescence standards that can provide traceability to radiometric units and present a first step towards a toolbox of fluorescence standards, currently consisting of: i) A first set of liquid fluorescence standards enables the determination of a broad variety of fluorescence parameters was developed and certified by BAM and is distributed by Sigma-Aldrich. ii) Ready-to-use, glass-based fluorescence standards for instrument performance validation (IPV) and determination instrument-to-instrument variations can also be used as wavelength standard for fluorescence instruments with low requirements on spectral resolution and allow monitoring of temporal changes of the wavelength-dependent spectral responsivity. iii) Novel calibration tools and validation concepts for microarray-based platforms used in molecular diagnostics and food safety control. iv) We currently develop reference materials, which can be used as reliable quantum yield standards for relative methods for the determination of QY and can be valuable in the evaluation of the performance and sources of uncertainty of absolute, standard-free methods using e.g. integrating spheres. T2 - 14th Conference on Methods and Applications in Fluorescence CY - Würzburg, Germany DA - 13.09.2015 KW - Fluorescence KW - Standards KW - Quantum yield KW - Microarray PY - 2015 AN - OPUS4-38882 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hoffmann, Katrin A1 - Resch-Genger, Ute A1 - Behnke, Thomas A1 - Würth, Christian T1 - Rationally Designed NIR-Flourescent Nanoparticles for Bioanalytical Applications T2 - EUCheMS 2012 CY - Prague, Czech Republic DA - 2012-08-26 PY - 2012 AN - OPUS4-27807 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hoffmann, Katrin A1 - Resch-Genger, Ute A1 - Tannert, S. A1 - Kapusta, P. A1 - Glatz, A. A1 - Goschew, A. A1 - Ortmann, U. A1 - Erdmann, R. T1 - On the Spectral Sensitivity Calibration of Fluorescence Spectrometers: Extensions to the NIR, Polarization and Grating Effects T2 - 12th Conference on Methods and Applications of Fluorescence: Spectroscopy, Imaging and Probes (MAF-12) CY - Strasbourg, France DA - 2011-09-11 PY - 2011 AN - OPUS4-24521 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hoffmann, Katrin A1 - Pauli, Jutta A1 - Resch-Genger, Ute T1 - New NIR fluorescence reference materials and quantum yield standards for standardization of fluorescence-based measurements N2 - Luminescence techniques are amongst the most commonly used analytical methods in the life and the material sciences due to their sensitivity and nondestructive character. All photoluminescence signals are, however, affected by wavelength-, polarization- and time-dependent instrument-related effects. Furthermore, substantial challenges to measure absolute luminescence intensities complicate the comparison of data recorded with different instruments and on the same instrument at different times. These problems can be easily resolved with fluorescence standards used for instrument performance validation (IPV) and determination of instrument-to-instrument variations, which allow to measure, quantify, and monitor the wavelength-dependent spectral responsivity for typically used instrument settings. For example, a set of liquid fluorescence standards, the BAM Kit F001-F005, and a ready-to-use glass-based fluorescence standard BAM F-012 developed and certified by BAM enable the characterization of many fluorescence parameters in the UV/vis wavelength range. For the increasingly used near infrared (NIR) region, standards and calibration tools are still very rare. Reliable spectral fluorescence standards and intensity or quantum yield standards are currently not available for the NIR, even though in biology, molecular imaging, and clinical diagnostics fluorescence labels absorbing and emitting in the long wavelength region beyond 650 nm are being increasingly used. This limitation hampers the reliability and comparability of fluorescence measurements in the NIR and calls for simple fluorescence standards for instrument characterization and for the quantification of fluorescence intensities and efficiencies to improve the comparability of the emission measurements in the NIR. This encouraged us to assess the potential of several NIR-emitting materials as spectral fluorescence standards, thereby extending the BAM Kit from the UV/vis into the NIR up to 950 nm. Moreover, we currently certify quantum yield standards for the UV/vis/NIR to improve the reliability of relative measurements of this spectroscopic key quantity particularly > 650 nm. These tools enable an instrument characterization, signal referencing, quality assurance, traceability, and method validation now also for wavelengths > 650 nm, thereby improving the reliability of fluorescence data in pharmaceutical research, medical and clinical diagnostics, material analysis, and environmental monitoring. T2 - 15th Conference on Methods and Applications in Fluorescence (MAF) CY - Brugge, Belgium DA - 10.09.2017 KW - Fluorescence reference materials KW - Quantum yield standard KW - Glass-based fluorescence standard PY - 2017 AN - OPUS4-41990 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hoffmann, Katrin A1 - Resch-Genger, Ute A1 - Behnke, Thomas A1 - Drescher, D. A1 - Kneipp, J. T1 - Nanoparticles for FLIM-based Multiplexed Analysis and Imaging T2 - Focus on Microscopy (FOM 2013) CY - Maastricht, Netherlands DA - 2013-03-24 PY - 2013 AN - OPUS4-28470 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hoffmann, Katrin A1 - Wegmann, Marc A1 - Hannemann, Mandy A1 - Somma, Valentina A1 - Jochum, Tobias A1 - Niehaus, Jan A1 - Roggenbuck, Dirk A1 - Resch-Genger, Ute T1 - NanoGenotox - Automatable determination of genotoxicity of nanoparticles with DNA-based optical assays N2 - The overall interest in nanotoxicity, triggered by the increasing use of nanomaterials in the material and life sciences, and the synthesis of an ever increasing number of new functional nanoparticles calls for standardized test procedures and for efficient approaches to screen the potential genotoxicity of these materials. Aiming at the development of fast and easy to use, automated microscopic methods for the determination of the genotoxicity of different types of nanoparticles, we assess the potential of the fluorometric γH2AX assay for this purpose. This assay, which can be run on an automated microscopic detection system, relies on the detection of DNA double strand breaks (DSB) as a sign for genotoxicity. Here, we provide first results obtained with broadly used nanomaterials like CdSe/CdS and InP/ZnS quantum dots as well as iron oxide, gold, and polymer particles of different surface chemistry with previously tested colloidal stability and different cell lines like Hep-2 and 8E11 cells, which reveal a dependence of the genotoxicity on the chemical composition as well as the surface chemistry of these nanomaterials. These studies will be also used to establish nanomaterials as positive and negative genotoxicity controls or standards for assay performance validation for users of this fluorometric genotoxicity assay. In the future, after proper validation, this microscopic platform technology will be expanded to other typical toxicity assays. T2 - Nanoworkshop 2018 CY - PTB Berlin-Adlershof, Germany DA - 14.05.2018 KW - Qdots KW - Surface functions KW - Quantification KW - Nanogenotoxicity PY - 2018 AN - OPUS4-45126 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hoffmann, Katrin A1 - Behnke, Thomas A1 - Drescher, Daniela A1 - Kneipp, Janina A1 - Resch-Genger, Ute T1 - Lifetime-based Discrimination between Spectrally Matching vis and NIR Ermitting Particle Labels and Probes T2 - BIOS SPIE Photonics West 2011 CY - San Francisco, CA, USA DA - 2011-01-22 PY - 2011 AN - OPUS4-23534 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -