TY - JOUR A1 - Descalzo López, Ana Belén A1 - Martínez-Mánez, Ramon A1 - Sancenón, F. A1 - Hoffmann, Katrin A1 - Rurack, Knut T1 - The Supramolecular Chemistry of Organic-Inorganic Hybrid Materials N2 - The combination of nanomaterials as solid supports and supramolecular concepts has led to the development of hybrid materials with improved functionalities. These hetero-supramolecular ideas provide a means of bridging the gap between molecular chemistry, materials sciences, and nanotechnology. In recent years, relevant examples have been reported on functional aspects, such as enhanced recognition and sensing by using molecules on preorganized surfaces, the reversible building of nanometer-sized networks and 3D architectures, as well as biomimetic and gated chemistry in hybrid nanomaterials for the development of advanced functional protocols in three-dimensional frameworks. This approach allows the fine-tuning of the properties of nanomaterials and offers new perspectives for the application of supramolecular concepts. KW - Aggregation KW - Mesoporous materials KW - Molecular recognition KW - Nanoparticles KW - Sensors PY - 2006 DO - https://doi.org/10.1002/anie.200600734 SN - 1433-7851 SN - 1521-3773 SN - 0570-0833 VL - 45 IS - 36 SP - 5924 EP - 5948 PB - Wiley-VCH CY - Weinheim AN - OPUS4-12824 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Martínez, R. A1 - Sancenón, F. A1 - Hoffmann, Katrin A1 - Rurack, Knut A1 - Descalzo López, Ana Belén T1 - Materiales híbridos en química analítica N2 - El desarrollo de receptores sintéticos complejos basados en conceptos de la química supramolecular no garantiza en ocasiones un reconocimiento molecular selectivo. Una alternativa en ciertos aspectos más simple y prometedora es el empleo de materiales híbridos orgánico-inorgánicos preparados mediante la funcionalización de sólidos inorgánicos porosos con receptores sintéticos adecuados. El anclaje de estos sistemas coordinantes a un soporte sólido da lugar a ciertos efectos sinérgicos que no están presentes ni en el material inicial ni en el receptor por separado y que sugieren que estos nuevos materiales híbridos pueden ser empleados en el desarrollo de nuevos sensores y nuevos protocolos de reconocimiento molecular y/o iónico. The development of synthetic receptors based in supramolecular chemistry concepts will no allow a selective molecular recognition. A more simple, convenient and innovative approach relies on the use of organic-inorganic hybrid materials. These hybrid materials will be prepared by the grafting of certain synthetic receptors onto porous inorganic solids. The grafting of these coordinating systems onto a solid support leads to synergic effects that are hardly achievable with only the synthetic receptors or the solids alone. The presence of these synergic effects suggests that these organic-inorganic hybrid materials will be used for the development of novel sensory systems and novel molecular and/or ionic recognitionprotocols. KW - Soportes inorgánicos KW - Receptores sintéticos KW - Materiales híbridos KW - Efectos sinérgicos KW - Química analítica KW - Inorganic supports KW - Synthetic receptors KW - Hybrid materials KW - Synergic effects KW - Analytical chemistry PY - 2007 SN - 1575-3417 VL - 103 IS - 4 SP - 22 EP - 27 PB - Springer AN - OPUS4-17512 LA - spa AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hoffmann, Katrin T1 - Glass-based Reference Standards for Fluorescence Applications T2 - XIII International Symposium on Luminescence Spectrometry CY - Bologna, Italy DA - 2008-09-07 PY - 2008 AN - OPUS4-18055 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rietsch, P. A1 - Sobottka, S. A1 - Hoffmann, Katrin A1 - Hildebrandt, P. A1 - Sarkar, B. A1 - Resch-Genger, Ute A1 - Eigler, S. T1 - Identification of the Irreversible Redox Behavior of Highly Fluorescent Benzothiadiazoles N2 - Redox switches are applied in various fields of research, including molecular lifts, electronic devices and sensors. Switching the absorbance between UV and Vis/NIR by redox processes is of interest for applications in light harvesting or biomedicine. Here, we present a series of push-pull benzothiadiazole derivatives with high fluorescence quantum yields in solution and in the crystalline solid state. Spectroelectrochemical analysis reveals the switching of UV-absorption in the neutral state to Vis/NIR absorption in the reduced state. We identify the partial irreversibility of the switching process, which appears to be reversible on the cyclic voltammetry timescale. KW - Redox switch KW - Electrochemistry KW - Dye KW - Fluorescence KW - Absorption KW - Sensor KW - Benzothiadiazole PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520865 DO - https://doi.org/10.1002/cptc.202000050 SN - 2367-0932 VL - 4 IS - 9 SP - 668 EP - 673 PB - Wiley Online Library AN - OPUS4-52086 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hoffmann, Katrin T1 - Fluorescence standards for the characterization of the performance of spectral scanning fluorescence microscopes T2 - Focus on Microscopy 2006 CY - Perth, Australia DA - 2006-04-09 PY - 2006 AN - OPUS4-12067 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hoffmann, Katrin A1 - Mix, Renate A1 - Resch-Genger, Ute A1 - Friedrich, Jörg Florian T1 - Fluorescence Measurements on Functionalized Polymer Surfaces - Problems and Troubleshooting KW - Fluorescence spectroscopy KW - Polymer functionalization KW - Surface labeling KW - Pyrylium label PY - 2008 DO - https://doi.org/10.1196/annals.1430.015 SN - 0077-8923 SN - 1749-6632 SN - 0094-8500 VL - 1130 SP - 28 EP - 34 PB - New York Academy of Sciences CY - New York, NY AN - OPUS4-17567 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Engel, A. A1 - Ottermann, C. A1 - Resch-Genger, Ute A1 - Hoffmann, Katrin A1 - Schweizer, S. A1 - Selling, J. A1 - Spaeth, J.-M. A1 - Rupertus, V. ED - Grzymala, R. ED - Haeberlé, O. T1 - Glass based fluorescence reference materials used for optical and biophotonic applications N2 - Fluorescence techniques are known for their high sensitivity and are widely used as analytical tools and detection methods for product and process control, material sciences, environmental and biotechnical analysis, molecular genetics, cell biology, medical diagnostics, and drug screening. For routine measurements by fluorescence techniques the existence of an improved quality assurance is one of the basic needs. According to DIN/ISO 17025 certified standards are used for fluorescence diagnostics having the drawback of giving relative values only. Typical requirements onto fluorescence reference materials or standards deal with the verification of the instrument performance as well as the improvement of the data comparability. Especially for biomedical applications fluorescence labels are used for the detection of proteins. In particular these labels consist of nano crystalline materials like CdS and CdSe. The field of Non-Cadmium containing materials is under investigation. In order to evaluate whether glass based materials can be used as standards it is necessary to calculate absolute values like absorption/excitation cross sections or relative quantum yields. This can be done using different quantities of dopands in glass, glass ceramics or crystals. The investigated materials are based on different types of glass, silicate, phosphate and boron glass, which play a dominant role for the absorption and emission mechanism. Additional to the so-called elementary fluorescence properties induced by raw earth elements the formation of defects lead to higher cross sections additionally. The main investigations deal with wavelength accuracy and lifetime of doped glasses, glass ceramics and crystalline samples. Moreover intensity patterns, homogeneity aspects and photo stability will be discussed. KW - Fluorescence KW - Reference material KW - Glass KW - Glass ceramics KW - Biophotonic KW - Multiplexing PY - 2006 DO - https://doi.org/10.1117/12.663627 SN - 1605-7422 VL - 6191 SP - 619110-1-619110-10 AN - OPUS4-14429 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Würth, Christian A1 - Lochmann, Cornelia A1 - Spieles, Monika A1 - Pauli, Jutta A1 - Hoffmann, Katrin A1 - Schüttrigkeit, T. A1 - Franzl, T. A1 - Resch-Genger, Ute T1 - Evaluation of a commercial integrating sphere setup for the determination of absolute photoluminescence quantum yields of dilute dye solutions N2 - The commercial availability of stand-alone setups for the determination of absolute photoluminescence quantum yields (φf) in conjunction with the increasing use of integrating sphere accessories for spectrofluorometers is expected to have a considerable influence not only on the characterization of chromophore systems for use in optical and opto-electronic devices, but also on the determination of this key parameter for (bio)analytically relevant dyes and functional luminophores. Despite the huge potential of systems measuring absolute φf values and the renewed interest in dependable data, evaluated protocols for even the most elementary case, the determination of the fluorescence quantum yield of transparent dilute solutions of small organic dyes with integrating sphere methods, are still missing. This encouraged us to evaluate the performance and sources of uncertainty of a simple commercial integrating sphere setup with dilute solutions of two of the best characterized fluorescence quantum yield standards, quinine sulfate dihydrate and rhodamine 101, strongly differing in spectral overlap between absorption and emission. Special attention is dedicated to illustrate common pitfalls of this approach, thereby deriving simple procedures to minimize measurement uncertainties and improve the comparability of data for the broad community of users of fluorescence techniques. KW - Lifetime KW - Fluorescence KW - Luminescence KW - Quantum yield KW - Quantum efficiency KW - Integrating sphere KW - Reabsorption KW - Rhodamine 101 KW - Quinine sulfate dihydrate KW - Method KW - Photoluminescence KW - Standard KW - Emission KW - Spectral correction KW - Excitation KW - Anisotropy PY - 2010 DO - https://doi.org/10.1366/000370210791666390 SN - 0003-7028 SN - 1943-3530 VL - 64 IS - 7 SP - 733 EP - 741 PB - Society for Applied Spectroscopy CY - Frederick, Md. AN - OPUS4-22089 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hoffmann, Katrin 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 T1 - Characterization of Surface Functionalities of Plasma-modified Polymer Films by Fluorescence Spectroscopy and Microscopy T2 - ANAKON 2005 CY - Regensburg, Germany DA - 2005-03-15 PY - 2005 AN - OPUS4-7390 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Resch-Genger, Ute A1 - Hoffmann, Katrin A1 - Pfeifer, Dietmar ED - Chris D. Geddes, T1 - Simple calibration and validation standards for fluorometry KW - Fluorescence KW - Standard KW - Spectral correction KW - Emission KW - Glass KW - Quantum yield KW - Fluorescence intensity KW - Quality assurance PY - 2009 SN - 978-0-387-88721-0 DO - https://doi.org/10.1007/978-0-387-88722-7_1 SN - 1573-8086 N1 - Serientitel: Reviews in Fluorescence – Series title: Reviews in Fluorescence VL - 4 SP - 1 EP - 31 PB - Springer Science + Business Media AN - OPUS4-19830 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hoffmann, Katrin A1 - Spieles, Monika A1 - Bremser, Wolfram A1 - Resch-Genger, Ute T1 - Narrow-band emitting solid fluorescence reference standard with certified intensity pattern N2 - The development of a lanthanum-phosphate glass doped with several rare-earth-ions for use as solid fluorescence standard is described. The cuvette-shaped reference material which shows a characteristic emission intensity pattern upon excitation at 365 nm consisting of a multitude of relatively narrow emission bands in the wavelength region between 450 nm and 700 nm is intended for the day-to-day performance validation of fluorescence measuring devices. Evaluation of the fluorescent glass include the determination of all properties which can affect its relative emission intensity profile or contribute to the uncertainty of the certified values like absorption spectra, fluorescence anisotropy, excitation wavelength and temperature dependence of the spectroscopic features, homogeneity of fluorophore distribution, photo- and long-term stability. Moreover, a certification procedure was developed including the normalization of the intensity profile consisting of several narrow emission bands and the calculation of wavelength-dependent uncertainties. Criteria for the design, characterization, and working principle of the new reference material BAM-F012 are presented, and possible applications of this ready-to-use fluorescence standard are discussed. PY - 2015 DO - https://doi.org/10.1021/acs.analchem.5b02209 SN - 0003-2700 SN - 1520-6882 VL - 87 SP - 7204 EP - 7210 PB - American Chemical Society CY - Washington, DC AN - OPUS4-33615 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hoffmann, Katrin T1 - Fluorescence studies on functionalized polypropylene supports using an amino-sensitive fluorogenic pyrylium T2 - Method and Application of Fluorescence (MAF10) CY - Salzburg, Austria DA - 2007-09-09 PY - 2007 AN - OPUS4-16409 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hoffmann, Katrin 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 - JOUR A1 - Nirmalananthan-Budau, Nithiya A1 - Budau, J. H. A1 - Moldenhauer, Daniel A1 - Hermann, G. A1 - Kraus, Werner A1 - Hoffmann, Katrin A1 - Paulus, Beate A1 - Resch-Genger, Ute T1 - Substitution pattern controlled aggregation-induced emission in donor-acceptor-donor dyes with one and two propeller-like triphenylamine donors N2 - We present a comparative study of the spectroscopic properties of the donor–acceptor–donor substituted dyes triphenylamine-allylidenemalononitrile-julolidine (TMJ) and triphenylamine-allylidenemalononitriletriphenylamine (TMT), bearing one and two propeller-like triphenylamine donor moieties, in solvents of varying polarity and viscosity and in the aggregated and solid state. Our results reveal control of the aggregation-induced spectroscopic changes and the packing motifs of the dye molecules in the solid state by the chemical nature and structure of the second nitrogen-containing donor, i.e., a planar and a rigid julolidine or a twisted triphenyl group. Assuming that the TMT and TMJ aggregates show a comparable arrangement of the molecules to the respective crystals, these different molecular interactions in the solid state are responsible for aggregation induced emission (AIE) in the case of TMT and its absence for TMJ. Moreover, a versatile strategy for the fluorescence enhancement of only weakly emissive AIE dyes is shown, turning these dyes into bright nanoscale fluorescent reporters by using them as stains for preformed polymer particles. KW - Nano KW - Nanoparticle KW - Photoluminescence KW - Fluorescence KW - Quantum yield KW - Photophysics KW - Lifetime KW - Sensor KW - Dye KW - Enhancement KW - Particle KW - Polarity KW - AIE KW - Aggregation KW - Aggregation-induced emission KW - Solid state emission PY - 2020 DO - https://doi.org/10.1039/d0cp00413h VL - 22 IS - 25 SP - 14142 EP - 14154 AN - OPUS4-50967 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Descalzo López, Ana Belén A1 - Martínez-Mánez, Ramon A1 - Sancenón, F. A1 - Hoffmann, Katrin A1 - Rurack, Knut T1 - Die supramolekulare Chemie organisch-anorganischer Hybrid-Nanomaterialien N2 - Die Entwicklung von Hybridmaterialien mit stark verbesserten Funktionen gelingt durch die Kombination geeigneter Nanomaterialien als Träger mit Motiven aus der supramolekularen Chemie. Diese hetero-supramolekularen Konzepte bieten vielfältige Möglichkeiten, die Lücken zwischen der Molekülchemie, Materialwissenschaften und Nanotechnologie zu schließen. Im Hinblick auf funktionelle Aspekte wurden in jüngster Zeit wichtige Fortschritte erzielt, z. B. verbesserte Erkennungs- und Sensoreigenschaften durch die Anordnung von Molekülen auf vororganisierten Oberflächen, der reversible Aufbau von nanometergroßen Netzwerken und dreidimensionalen Strukturen oder biomimetische und gesteuerte chemische Prozesse in Hybrid-Nanomaterialien, die als Grundlage für hoch spezialisierte Protokolle in dreidimensionalen Gerüststrukturen dienen können. Diese Ansätze ermöglichen eine Feinabstimmung der Eigenschaften von Nanomaterialien und eröffnen neue Perspektiven für die Anwendung supramolekularer Konzepte. KW - Supramolekulare Chemie KW - Anorganisch-organische Hybridmaterialien KW - Sensorik KW - Molekulare Maschinen KW - Aggregation KW - Mesoporöse Materialien KW - Molekulare Erkennung KW - Nanopartikel KW - Sensoren PY - 2006 DO - https://doi.org/10.1002/ange.200600734 SN - 0044-8249 SN - 0932-2140 SN - 1521-3757 VL - 118 IS - 36 SP - 6068 EP - 6093 PB - Wiley-VCH CY - Weinheim AN - OPUS4-12821 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Descalzo López, Ana Belén A1 - Hoffmann, Katrin A1 - Rurack, Knut A1 - Martínez-Mánez, Ramon A1 - Sancenón, F. T1 - Hybridmaterialien in der analytischen Chemie KW - Analytische Chemie KW - Hybridmaterialien KW - Sensorik KW - Fluoreszenz KW - Absorption KW - Mesoporöse Silicate KW - Goldnanopartikel KW - Quantenpunkte PY - 2007 SN - 1439-9598 SN - 1521-3854 VL - 55 IS - 02 SP - 124 EP - 129 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-16080 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hoffmann, Katrin A1 - Behnke, Thomas A1 - Drescher, Daniela A1 - Kneipp, Janina A1 - Resch-Genger, Ute T1 - Near-infrared-emitting nanoparticles for lifetime-based multiplexed analysis and imaging of living cells N2 - The increase in information content from bioassays and bioimaging requires robust and efficient strategies for the detection of multiple analytes or targets in a single measurement, thereby addressing current health and security concerns. For fluorescence techniques, an attractive alternative to commonly performed spectral or color multiplexing presents lifetime multiplexing and the discrimination between different fluorophores based on their fluorescence decay kinetics. This strategy relies on fluorescent labels with sufficiently different lifetimes that are excitable at the same wavelength and detectable within the same spectral window. Here, we report on lifetime multiplexing and discrimination with a set of nanometer-sized particles loaded with near-infrared emissive organic fluorophores chosen to display very similar absorption and emission spectra, yet different fluorescence decay kinetics in suspension. Furthermore, as a first proof-of-concept, we describe bioimaging studies with 3T3 fibroblasts and J774 macrophages, incubated with mixtures of these reporters employing fluorescence lifetime imaging microscopy. These proof-of-concept measurements underline the potential of fluorescent nanoparticle reporters in fluorescence lifetime multiplexing, barcoding, and imaging for cellular studies, cell-based assays, and molecular imaging. KW - Fluorescence lifetime imaging microscopy KW - FLIM KW - Lifetime multiplexing KW - Near infrared KW - NIR KW - Cell imaging KW - Nanoparticles PY - 2013 DO - https://doi.org/10.1021/nn4029458 SN - 1936-0851 VL - 7 IS - 8 SP - 6674 EP - 6684 PB - ACS Publ. CY - Washington, DC, USA AN - OPUS4-29031 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hoffmann, Katrin A1 - Resch-Genger, Ute A1 - Mix, Renate A1 - Friedrich, Jörg Florian T1 - Fluorescence Spectroscopic Studies on Plasma-Chemically Modified Polymer Surfaces with Fluorophore-Labeled Functionalities N2 - Molecular engineering of polymer surfaces that includes the attachment of functional molecules to existing or previously generated reactive chemical groups like e.g., - OH, - NH2, or - CHO requires simple strategies and tools for the controlled generation of surface functionalities and their derivatization as well as for their identification and eventually quantification. Here, we systematically investigate the plasma-chemical surface modification of polypropylene films in combination with dansyl labeling chemistry and conventional, yet costly, XPS and highly sensitive fluorescence spectroscopy for the detection of surface groups. Based on these results, the potential of and requirements on the fluorometric characterization and quantification of surfaces functionalities are discussed. KW - Fluorescence spectroscopy KW - Surface functionalization KW - Covalent labeling of polymer surfaces KW - Plasma modification KW - Fluorescent probe PY - 2006 DO - https://doi.org/10.1007/s10895-006-0076-x SN - 1053-0509 SN - 1573-4994 VL - 16 IS - 3 SP - 441 EP - 448 PB - Plenum Publ. Corp. CY - New York, NY AN - OPUS4-12560 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hoffmann, Katrin A1 - Resch-Genger, Ute A1 - Marlow, Frank T1 - Reversible Photosensitive Refractive Index Changes of Chromophor/Zeolite Nanocomposites T2 - Abschlußkolloquium "Nanostrukturierte Wirt/Gast-Systeme" CY - Berlin, Germany DA - 2002-10-21 PY - 2002 AN - OPUS4-1753 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kage, Daniel A1 - Hoffmann, Katrin A1 - Wittkamp, M. A1 - Ameskamp, J. A1 - Göhde, W. A1 - Resch-Genger, Ute T1 - Luminescence lifetime encoding in time-domain flow cytometry N2 - Time-resolved flow cytometry represents an alternative to commonly applied spectral or intensity multiplexing in bioanalytics. At present, the vast majority of the reports on this topic focuses on phase-domain techniques and specific applications. In this report, we present a flow cytometry platform with time-resolved detection based on a compact setup and straightforward time-Domain measurements utilizing lifetime-encoded beads with lifetimes in the nanosecond range. We provide general assessment of time-domain flow cytometry and discuss the concept of this platform to address achievable resolution limits, data analysis, and requirements on suitable encoding dyes. Experimental data are complemented by numerical calculations on photon count numbers and impact of noise and measurement time on the obtained lifetime values. KW - Flow cytometry KW - Fluorescence KW - Life sciences KW - Lifetime encoding KW - Polymer particles PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-465765 DO - https://doi.org/10.1038/s41598-018-35137-5 SN - 2045-2322 VL - 8 IS - 1 SP - 16715, 1 EP - 11 PB - Nature CY - London AN - OPUS4-46576 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rietsch, P. A1 - Zeyat, M. A1 - Hübner, Oskar A1 - Hoffmann, Katrin A1 - Resch-Genger, Ute A1 - Kutter, M. A1 - Paskin, A. A1 - Uhlig, J. A1 - Lentz, D. A1 - Eigler, S. T1 - Substitution Pattern-Controlled Fluorescence Lifetimes of Fluoranthene Dyes N2 - The absorption and emission properties of organic dyes are generally tuned by altering the substitution pattern. However, tuning the fluorescence lifetimes over a range of several 10 ns while barely affecting the spectral features and maintaining a moderate fluorescence quantum yield is challenging. Such properties are required for lifetime multiplexing and barcoding applications. Here, we show how this can be achieved for the class of fluoranthene dyes, which have substitution-dependent lifetimes between 6 and 33 ns for single wavelength excitation and emission. We explore the substitution-dependent emissive properties in the crystalline solid state that would prevent applications. Furthermore, by analyzing dye mixtures and embedding the dyes in carboxyfunctionalized 8 μm-sized polystyrene particles, the unprecedented potential of these dyes as labels and encoding fluorophores for time-resolved fluorescence detection techniques is demonstrated. KW - Fluorescence KW - Label KW - Fluoranthene KW - Quantum yield KW - Reporter KW - Crystal KW - Encoding KW - Multiplexing KW - Particle KW - Bead KW - Lifetime KW - Dye KW - Barcoding PY - 2021 DO - https://doi.org/10.1021/acs.jpcb.0c08851 SN - 1520-5207 VL - 125 IS - 4 SP - 1207 EP - 1213 PB - American Chemical Society AN - OPUS4-52087 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hoffmann, Katrin T1 - Fluorescence microscopic and spetroscopic studies on functionalized polymer-supports labeled with amino sensitive fluorophores T2 - Focus on Microscopy (FoM) CY - Valencia, Spain DA - 2007-04-10 PY - 2007 AN - OPUS4-14864 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Preiss, J. A1 - Kage, Daniel A1 - Hoffmann, Katrin A1 - Martínez, T. J. A1 - Resch-Genger, Ute A1 - Presselt, M. T1 - Ab initio prediction of fluorescence lifetimes involving solvent environments by means of COSMO and vibrational broadening N2 - The fluorescence lifetime is a key property of fluorophores that can be utilized for microenvironment probing, analyte sensing, and multiplexing as well as barcoding applications. For the rational design of lifetime probes and barcodes, theoretical methods have been developed to enable the ab initio prediction of this parameter, which depends strongly on interactions with solvent molecules and other chemical species in the emitters' immediate environment. In this work, we investigate how a conductor-like screening model (COSMO) can account for variations in fluorescence lifetimes that are caused by such fluorophore−solvent interactions. Therefore, we calculate vibrationally broadened fluorescence spectra using the nuclear ensemble method to obtain distorted molecular geometries to sample the electronic transitions with time-dependent density functional theory (TDDFT). The influence of the solvent on fluorescence lifetimes is accounted for with COSMO. For example, for 4-hydroxythiazole fluorophore containing different heteroatoms and acidic and basic moieties in aprotic and protic solvents of varying polarity, this approach was compared to experimentally determined lifetimes in the same solvents. Our results demonstrate a good correlation between theoretically predicted and experimentally measured fluorescence lifetimes except for the polar solvents Ethanol and acetonitrile that can specifically interact with the heteroatoms and the carboxylic acid of the thiazole derivative. KW - Fluorescence lifetime KW - Ab initio calculation KW - COSMO KW - Conductor-like screening model PY - 2018 DO - https://doi.org/10.1021/acs.jpca.8b08886 SN - 1089-5639 SN - 1520-5215 VL - 122 IS - 51 SP - 9813 EP - 9820 PB - American Chemical Society CY - Washington, DC AN - OPUS4-47177 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Resch-Genger, Ute A1 - Hoffmann, Katrin A1 - Pauli, Jutta ED - Brahme, A. T1 - Signal-relevant properties of fluorescent labels and optical probes and their determination N2 - Luminescence techniques are among the most populär analytical and detection tools in the life Sciences (Das et al., 2012; Kobayashi et al., 2010; Lakowicz, 2006; Weissleder and Pittet, 2008). The ever-growing interest in these methods that yield fluorophore-specific quantities such as emission and excitation spectra, fluorescence quantum yields, fluorescence lifetimes, and emission anisotropies is due to their comparable ease of use; noninvasive character; potential for combining spectrally, temporally, and spatially resolved ineasurements; and suitability for multiplexing and remote sensing (Resch-Genger et al., 2005a). Moreover, fluorescence detection techniques can provide sensitivity down to the single-molecule level. As the vast majority of analytes or targets of interest are nonfluorescent and most endogenous chromophores typically display rather low fluorescence quantum yields, the tremendous analytical potential of photoluminescence techniques initiated also the development of an ever-growing number of fluorescent labels and probes as readily available tools for a broad variety of analytes and applications and the labeling of biomolecules such as oligonucleotides, antibodies, or peptides as detailed in the chapter "Fluorescent Reporters and Optical Probes: Dye Conjugation Chemistry, Spectroscopic Properties, and Design Concepts" (Berezin and Achilefu, 2010; Escobedo et al., 2010; Luo et al., 2011; Resch-Genger and Licha, 2011; Resch-Genger et al., 2008). Prominent examples of such dye-biomolecule conjugates are fluorophore-labeled secondary antibodies, for example, for immunohistochemistry or flow cytometry, and conventional contrast agents, consisting of a fluorescent reporter and a biomarker-specific biomolecule like a peptide, antibody, or antibody fragment for in vivo near-infrared (NIR) fluorescence imaging of pathological changes in the spectral window of 650-950 nm. These contrast agents are often referred to as targeted optical probes. In addition, more sophisticated Systems are increasingly emerging, the optical properties of which can be modulated selectively by Chemical or biological inputs (Elias et al., 2008; Kobayashi et al., 2011; Resch-Genger and Licha, 2011). PY - 2014 SN - 978-0-444-53632-7 DO - https://doi.org/10.1016//B978-0-444-53632-7.00408-1 VL - 4 SP - Chapter 4.02, 15 EP - 26 PB - Elsevier CY - Amsterdam AN - OPUS4-31433 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kage, Daniel A1 - Hoffmann, Katrin A1 - Nifontova, G. A1 - Krivenkov, V. A1 - Sukhanova, A. A1 - Nabiev, I. A1 - Resch-Genger, Ute T1 - Tempo-spectral multiplexing in flow cytometry with lifetime detection using QD-encoded polymer beads N2 - Semiconductor quantum dots (QDs) embedded into polymer microbeads are known to be very attractive emitters for spectral multiplexing and colour encoding. Their luminescence lifetimes or decay kinetics have been, however, rarely exploited as encoding parameter, although they cover time ranges which are not easily accessible with other luminophores. We demonstrate here the potential of QDs made from II/VI semiconductors with luminescence lifetimes of several 10 ns to expand the lifetime range of organic encoding luminophores in multiplexing applications using time-resolved flow cytometry (LT-FCM). For this purpose, two different types of QD-loaded beads were prepared and characterized by photoluminescence measurements on the ensemble level and by single-particle confocal laser scanning microscopy. Subsequently, these lifetime-encoded microbeads were combined with dye-encoded microparticles in systematic studies to demonstrate the potential of these QDs to increase the number of lifetime codes for lifetime multiplexing and combined multiplexing in the time and colour domain (tempo-spectral multiplexing). These studies were done with a recently developed novel luminescence lifetime flow cytometer (LT-FCM setup) operating in the time-domain, that presents an alternative to reports on phase-sensitive lifetime detection in flow cytometry. KW - Fluorescence life time KW - Flow cytometry KW - Lifetime-encoded beads KW - Quantum dots KW - Multiplexing PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503316 DO - https://doi.org/10.1038/s41598-019-56938-2 VL - 10 IS - 1 SP - Article number: 653 PB - nature.com AN - OPUS4-50331 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -