TY - CONF A1 - Resch-Genger, Ute T1 - Standardization of fluorescence measurements: Design, development, validation, and fabrication of format-adaptable fluorescence standards for intensity, spectral, and temporal quantities N2 - Photoluminescence techniques are amongst the most widely used tools in the material and life sciences, with new and exciting applications continuously emerging, due to their many advantages like comparative ease of use, unique sensitivity, non-invasive character, and potential for multiplexing, remote sensing, and miniaturization. Drawbacks are , however, signals, that contain unwanted wavelength- and polarization contributions from instrument-dependent effects, which are time-dependent due to the aging of instrument components, and difficulties to measure absolute fluorescence intensities. Thus, there is a considerable need for standards for intensity, spectral, and temporal fluorescence quantities to meet the increasing need for instrument performance validation and global trends to harmonize physicochemical measurements. In this respect, instrument calibration strategies together with different types of fluorescence standards are presented as well as design concepts for robust, easy-to-use, and format-adaptable fluorescence standards useable for the determination of different fluorescence parameters and a broad variety of fluorescence techniques. T2 - SALSA-Kolloquien CY - Berlin, Germany DA - 07.06.2016 KW - Fluorescence KW - Standard KW - Quality assurance KW - Spectral correction KW - Quantum yield PY - 2016 AN - OPUS4-37070 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute T1 - Standardization of Fluorescence Measurements in the UV/vis/NIR/IR - Needs for and requirements on calibration tools N2 - Photoluminescence techniques are amongst the most widely used tools in the life sciences, with new and exciting applications in medical diagnostics and molecular imaging continuously emerging. Advantages include their comparative ease of use, unique sensitivity, non-invasive character, and potential for multiplexing, remote sensing, and miniaturization. General drawbacks are, however, signals, that contain unwanted wavelength- and polarization contributions from instrument-dependent effects, which are also time-dependent due to aging of instrument-components, and difficulties to measure absolute fluorescence intensities. Moreover, scattering systems require special measurement geometries and the interest in new optical reporters with emission > 1000 nm strategies for reliable measurements in the second diagnostic for the comparison of material performance and the rational design of new fluorophores with improved properties. Here, we present strategies to versatile method-adaptable liquid and solid fluorescence standards for different fluorescence parameters including traceable instrument calibration procedures and the design of integrating sphere setups for the absolute measurement of emission spectra and quantum yields in the wavelength region of 350 to 1600 nm. Examples are multi-emitter glasses, spectral fluorescence standards, and quantum yield standards for the UV/vis/NIR T2 - Spie Photonics west 2017 CY - San Francisco, USA DA - 28.01.2017 KW - Fluorescence standard KW - Instrument calibration KW - Integrating sphere spectroscopy KW - Absolute fluorescence quantum yield KW - Fluorescent glasses KW - Nanoparticles PY - 2017 AN - OPUS4-39074 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pauli, Jutta A1 - Hoffmann, Katrin A1 - Würth, Christian A1 - Behnke, Thomas A1 - Resch-Genger, Ute T1 - Standardization of fluorescence measurements in the UV/vis/NIR/IR N2 - Photoluminescence techniques are amongst the most widely used Tools in the life sciences, with new and exciting applications in medical diagnostics and molecular Imaging continuously emerging. Advantages include their comparative ease of use, unique sensitivity, non-invasive character, and potential for Multiplexing, remote sensing, and miniaturization. General drawbacks are, however, signals, that contain unwanted wavelength- and polarization contributions from Instrument-dependent effects, which are also time-dependent due to aging of Instrument-components, and difficulties to measure absolute flourescence entensities. Moreover, scattering Systems require Special measurement geometries and the interest in new optical Reporters with Emission > 1000 nm strategies for reliable measurements in the second diagnostic for the comparison of material Performance and the rational designg of new flourophores with improved properties. Here, we present strategies to versatile method-adaptable liquid and solid flourescence Standards for different flourescence paramters including traceable Instrument calibration procedures and the design of integrating spere setups for the absolute measurements of emission spectra and Quantum yields in the wavelength Region of 350 to 1600 nm. Examples are multi-Emitter glasses, spectral flourescence Standards, and quantum yield Standards for the UV/vis/NIR. T2 - Conference on Molecular-Guided Surgery - Molecules, Devices, and Applications III CY - San Francisco, CA, USA DA - 28.01.2017 KW - Fluorescence KW - Reference material KW - Standard KW - Calibration KW - Nanoparticle KW - Absolute flourometry KW - Integrating sphere spectroscopy KW - NIR KW - IR KW - Quantum yield standard KW - Emission standards PY - 2017 SN - 978-1-5106-0539-8 DO - https://doi.org/10.1117/12.2255728 SN - 0277-786X VL - 10049 SP - 1 PB - Proceedings of SPIE AN - OPUS4-41783 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute T1 - Standardization of Flourescence Measurements in the UV/VIS/NIR/IR at BAM N2 - Photoluminescence techniques are amongst the most widely used tools in the life sciences, with new and exciting applications in medical diagnostics and molecular imaging continuously emerging. Advantages include their comparative ease of use, unique sensitivity, non-invasive character, and potential for multiplexing, remote sensing, and miniaturization. General drawbacks are, however, signals, that contain unwanted wavelength- and polarization contributions from instrument-dependent effects, which are also time-dependent due to aging of instrument-components, and difficulties to measure absolute fluorescence intensities. Moreover, scattering systems require special measurement geometries and the interest in new optical reporters with emission > 1000 nm strategies for reliable measurements in the second diagnostic for the comparison of material performance and the rational design of new fluorophores with improved properties. Here, we present strategies to versatile method-adaptable liquid and solid fluorescence standards for different fluorescence parameters. Examples are multi-emitter glasses, spectral fluorescence standards, and quantum yield standards for the UV/vis/NIR. T2 - Konsortiumtreffen Mikroskopie CY - Universität Münster, Germany DA - 20.01.2020 KW - Fluorescence standard KW - Instrument calibration KW - Integrating sphere spectroscopy KW - Fluorescence quantum yield KW - Fluorescent glasses KW - Fluorescence microscopy KW - Particle, imaging PY - 2020 AN - OPUS4-50308 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute T1 - Standardised Measurements of Surface Functionalities on Nanoparticles N2 - Engineered nanoparticles (NPs) with various chemical compositions and surface functionalities are routinely fabricated for industrial applications such as medical diagnostics, drug delivery, sensing, catalysis, energy conversion and storage, opto-electronics, and information storage which improve the quality of life and European prosperity. NP function, performance, interaction with biological species, and environmental fate are largely determined by their surface functionalities. Standardized repeatable surface characterization methods are therefore vital for quality control of NPs, and to meet increasing concerns regarding their safety. Therefore, industry, regulatory agencies, and policymakers need validated traceable measurement methods and reference materials. This calls for fit-for-purpose, validated, and standardized methods, and reference data and materials on the surface chemistry of engineered NPs. Here, we present a concept for the development of such standardized measurement protocols utilizing method cross-validation and interlaboratory comparisons (ILCs) with emphasis on both advanced measurement methods such as quantitative Nuclear Magnetic Resonance (qNMR), X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS) and cost-efficient, non-surface specific methods like optical assays and electrochemical titration methods. T2 - European Partnership on Metrology 2023 Review Conference CY - Amsterdam, Netherlands DA - 07.11.2023 KW - Surface chemistry KW - Quality assurance KW - Traceability PY - 2023 AN - OPUS4-59142 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bastos, V. A1 - Oskoei, P. A1 - Andresen, Elina A1 - Saleh, Maysoon I. A1 - Rühle, Bastian A1 - Resch-Genger, Ute A1 - Oliveira, H. T1 - Stability, dissolution, and cytotoxicity of NaYF4‑upconversion nanoparticles with different coatings N2 - Upconversion nanoparticles (UCNPs) have attracted considerable attention owing to their unique photophysical properties. Their utilization in biomedical applications depends on the understanding of their transformations under physiological conditions and their potential toxicity. In this study, NaYF4: Yb,Er UCNPs, widely used for luminescence and photophysical studies, were modified with a set of four different coordinatively bound surface ligands, i.e., citrate, alendronate (AA), ethylendiamine tetra(methylene phosphonate) (EDTMP), and poly(maleic anhydride-alt-1-octadecene) (PMAO), as well as silica coatings with two different thicknesses. Subsequently, the aging-induced release of fluoride ions in water and cell culture media and their cytotoxic profile to human keratinocytes were assessed in parallel to the cytotoxic evaluation of the ligands, sodium fluoride and the lanthanide ions. The cytotoxicity studies of UCNPs with different surface modifications demonstrated the good biocompatibility of EDTMP-UCNPs and PMAO-UCNPs, which is in line with the low amount of fluoride ions released from these samples. An efficient prevention of UCNP dissolution and release of cytotoxic ions, as well as low cytotoxicity was also observed for UCNPs with a sufficiently thick silica shell. Overall, our results provide new insights into the understanding of the contribution of surface chemistry to the stability, dissolution behavior, and cytotoxicity of UCNPs. Altogether, the results obtained are highly important for future applications of UCNPs in the life sciences and bioimaging studies. KW - Nano KW - Nanomaterial KW - Upconversion nanoparticle KW - Lanthanide KW - Photoluminescence KW - Quantum yield KW - Photophysics KW - Excitation power density KW - Surface chemistry KW - Coating PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-544681 DO - https://doi.org/10.1038/s41598-022-07630-5 SN - 2045-2322 VL - 12 SP - 1 EP - 13 PB - Springer Nature CY - London AN - OPUS4-54468 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute T1 - Spectroscopic properties of upconversion nanoparticles N2 - Lanthanide-doped up-converting nanoparticles (UCNPs) are promising reporters for medical diagnostics and bioimaging. Current limitations present their relative low absorption cross sections and low fluorescence efficiencies, with the latter being affected by particle size, surface chemistry, and microenvironment, particularly water. Here, we present results from systematic studies of the excitation power density dependent upconversion luminescence spectra, intensities/intensity ratios of the individual emission bands, slope factors, and quantum yields of UCNPs of varying size, dopant concentration, and surface chemistry in different microenvironments as well as the up- and downconversion luminescence decay kinetics of the different emission bands. Moreover, first studies of the energy transfer from UCNPs to surface-bound organic dyes acting as fluorescence acceptors are shown. Based upon these measurements, fluorescence deactivation channels are identified and spectroscopic parameters for the screening of material performance are derived. T2 - Projekttreffen COST CY - Straßbourg, France DA - 09.01.2017 KW - Upconverting nanoparticles KW - Size KW - FRET KW - Fluorescence KW - Absolute fluorescence quantum yield KW - Fluorescence decay kinetics KW - Power density dependence PY - 2017 AN - OPUS4-39076 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute T1 - Spectroscopic characterization of semiconductor and lanthanide-based nanocrystals with vis and NIR emission N2 - The increasing interest in molecular and nanoscale emitters with photoluminescence > 800 nm and recently also > 1000 nm for bioanalysis, medical diagnostics, bioimaging, and safety Barcodes requires quantitative spectroscopic studies, which are, however still challenging in this long wavelength region. This is of special relevance for nanocrystalline emitters like semiconductor quantum dots and rods as well as lanthanide-based upconversion and downconversion nanocrystals, where surface states and the accessibility of emissive states by quenchers largely control accomplishable photoluminescence quantum yields and hence, signal sizes and detection sensitivities from the reporter side. Moreover, nonlinear emitters like lanthanide-based upconversion nanocrystals require also power density-dependent studies of their luminescence spectra, quantum yields, and decay kinetics. Here, we present suitable absolute methods and underline the impact of such measurements on a profound mechanistic understanding of the nonradiative deactivation pathways in semiconductor and upconversion nanocrystals of different chemical composition and particle architecture. T2 - PCNSPA 2018 - Photonic Colloidal Nanostructures: Synthesis, Properties, and Applications CY - St. Petersburg, Russia DA - 04.06.2018 KW - Semiconductor KW - Nanoparticle KW - Quantum dot KW - Absolute fluorometry KW - Integrating sphere spectroscopy KW - NIR KW - IR KW - Fluorescence KW - Surface chemistry KW - Deactivation pathways KW - Photophysics KW - Modeling PY - 2018 AN - OPUS4-45796 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute A1 - Fallisch, A. A1 - Petrov, E. P. A1 - Salhany, R. A1 - Forthman, C. A1 - Guttenberg, Z. A1 - Nitschke, R. T1 - Spectral fluorescence standards for the calibration and performance validation of fluorescence microscopes N2 - The standardization and calibration of fluorescence microscopy have become increasingly vital due to the wide-spread use of in life and materials sciences. As the demand for reliable and user-friendly methods to assess micro-scope performance grows, universal calibration tools accessible to both researchers and vendors are needed. To support the standardization of characterization methods in microscopy, it is crucial to provide calibration tools together with standardized operating procedures for their effective implementation. The public-funded project "FluMiKal"* develops calibration tools in the shape of typical microscopic slides to assess key parameters such as spatial resolution, point spread function, spectral sensitivity, linearity and sensitivity of the detection system. The focus is on creating calibration tools that are user-friendly, robust, and versatile in their application. This work addresses the critical parameter of wavelength-dependent spectral sensitivity, which affects the meas-ured signals from the instrument side, yielding instrument-specific data and instrument aging-induced changes over time. For this purpose, μ-slides from ibidi with six channels are used, allowing them to be filled with different solutions containing molecular or nanoscale fluorophores with well-characterized absorption and fluorescence properties. The certified spectral fluorescence standards BAM-F003, F004, F005, and F007 assessed provided as ethanolic solutions by the Federal Institute for Materials Research and Testing (BAM), cover a broad spectral range from the blue to the near-infrared [1], [2]. Dye-based slide prototypes have been used to determine the spectral sensitivity of confocal microscopes from different vendors with various detector types by acquiring the spectral data of the BAM dyes under standardized measurement conditions, demonstrating the applicability of this concept. Proof-of-concept experiments could demonstrate the proper sealing of the slides. Further experiments will explore long-term stability and their potential as standards for relative intensity calibrations. * FluMiKal is funded by the Federal Ministry for Economic Affairs and Climate Action, Germany (WIPANO FKZ 03TN0047B) [1] doi: 10.1007/4243_2008_028. [2] doi: 10.1007/s00216-024-05723-w. T2 - European Light Microscopy Initiative - ELMI 2025 CY - Heidelberg, Germany DA - 03.06.2025 KW - Fluorescence KW - Advanced material KW - Validation KW - Calibration KW - Method comparison KW - Reference material KW - Dye KW - Fluorescence standard KW - Microscopy KW - CLSM KW - Imaging PY - 2025 AN - OPUS4-64206 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sun, C. A1 - Schäferling, Michael A1 - Resch-Genger, Ute A1 - Gradzielski, M. T1 - Solvothermal Synthesis of Lanthanide-doped NaYF4 Upconversion N2 - Lanthanide-doped NaYF4 upconversion nano- and microcrystals were synthesized via a facile solvothermal approach. Thereby, the influence of volume ratios of ethylene glycol (EG)/H2O, molar ratios of NH4F/RE3+ (RE3+ represents the total amount of Y3+ and rare-earth dopant ions), Gd3+ ion contents, types of activator dopant ions, and different organic co-solvents on the crystal phase, size, and morphology of the resulting particles were studied systematically. A possible formation mechanism for the growth of crystals of different morphology is discussed. Our results show that the transition from the α- to the β-phase mainly depends on the volume ratio of EG/H2O and the molar ratio of NH4F/RE3+, while the morphology and size could be controlled by the type of organic co-solvent and Gd3+ dopant ions. Furthermore, the reaction time has to be long enough to convert α-NaYF4 into β-NaYF4 during the growth process to optimize the upconversion luminescence. The formation of larger β-NaYF4 crystals, which possess a higher upconversion luminescence than smaller particles, proceeds via intermediates of smaller crystals of cubic structure. In summary, our synthetic approach presents a facile route to tailor the size, Crystal phase, morphology, and luminescence features of upconversion materials. KW - Nano KW - Nanomaterial KW - Upconversion nanoparticle KW - Photoluminescence KW - Lanthanide KW - Quantum yield KW - Photophysics KW - Lifetime KW - Surface chemistry KW - Single particle KW - Brightness KW - NIR KW - Synthesis PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520307 DO - https://doi.org/10.1002/cnma.202000564 VL - 7 IS - 2 SP - 174 EP - 183 PB - Wiley AN - OPUS4-52030 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -