TY - CONF A1 - Resch-Genger, Ute T1 - Introduction to Fluorescence Spectroscopy N2 - A brief introduction to fluorescence spectroscopy will be provided, ranging from typically measured fluorescence quantities over instrument-specific contributions to measured fluorescence signals to selected applications. In this context, an overview of the photoluminescence properties of molecular and nanoscale luminescence reporters will be given including a brief insight into their photophysics and fluorescence standards designed by division Biophotonics for the calibration and instrument performance validation of fluorescence measuring devices will be presented. T2 - Analytical Academy BAM CY - Online meeting DA - 17.11.2020 KW - Fluorescence KW - Quality assurance KW - Quantification KW - Linearity KW - Measurement uncertainty KW - Method KW - Nano particle KW - Dye PY - 2020 AN - OPUS4-51619 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute T1 - Functional Luminophores – From Photophysics to Standardized Luminescence Measurements N2 - Inorganic nanocrystals with linear and nonlinear luminescence in the ultraviolet, visible, near infrared and short-wave infrared like semiconductor quantum dots and spectrally shifting lanthanide-based nanophosphors have meanwhile found applications in the life and material sciences ranging from optical reporters for bioimaging and sensing over security barcodes to solid state lighting and photovoltaics. These nanomaterials commonly have increasingly sophisticated core/shell particle architectures with shells of different chemical composition and thickness to minimize radiationless deactivation at the particle surface that is usually the main energy loss mechanism [1]. For lanthanide-based spectral shifters, particularly for very small nanoparticles, also surface coatings are needed which protect near-surface lanthanide ions from luminescence quenching by high energy vibrators like O-H groups and prevent the disintegration of these nanoparticles under high dilution conditions. [2,3,4]. The identification of optimum particle structures requires quantitative spectroscopic studies focusing on the key performance parameter photoluminescence quantum yield [5,6], ideally flanked by single particle studies to assess spectroscopic inhomogeneities on a particle-to-particle level for typical preparation methods [7,8], Moreover, in the case of upconversion nanoparticles with a multi-photonic and hence, excitation power density (P)-dependent luminescence, quantitative luminescence studies over a broad P range are required to identify particle architectures that are best suited for applications in fluorescence assays up to fluorescence microscopy. Here, we present methods to quantify the photoluminescence of these different types of emitters in the vis/NIR/SWIR and as function of P and demonstrate the importance of such measurements for a profound mechanistic understanding of the nonradiative deactivation pathways in semiconductor and upconversion nanocrystals of different size and particle architecture in different environments. T2 - Eingeladener Vortrag Uni Erlangen CY - Erlangen, Germany DA - 18.01.2023 KW - Semiconductor quantum dot KW - Upconversion nanocrystal KW - Luminescence KW - Quantitative spectroscopy KW - Photophysics KW - Quality assurance KW - Nano KW - Particle KW - Quantum yield KW - Lifetime KW - Standard KW - Reference material KW - Surface analysis KW - Quantification PY - 2023 AN - OPUS4-57011 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute T1 - A journey in science from a graduate student in physical chemistry to head of division biophotonics N2 - I will provide a personal overview of the most important steps of my career in science, a journey from a graduate student in physical chemistry in an environment dominated by male-scientists over a postdoc with a female professor in the US to the leader of a research group, head of division Biophotonics at BAM. This will include my choices of research topics, how I learnt to write well cited publications, even on topics such as reference materials and quality assurance,1-4 and eventually started to give lectures at Free University Berlin granting me the right to act as first supervisor of undergraduate and graduate students. T2 - Women in Science CY - Erlangen, Germany DA - 22.07.2024 KW - Lanthanide KW - Nanoparticle KW - Silica KW - Quantum dot KW - Polymer KW - Surface group KW - Luminescence KW - Quantitative spectroscopy KW - Quantum yield KW - Lifetime KW - Quality assurance KW - Synthesis KW - Surface modification KW - Photophysics PY - 2024 AN - OPUS4-60724 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute T1 - Photoluminescence quantum yields of molecular & nanoscale luminophores in the UV/VIS/NIR/SWIR in dispersion and in the solid state N2 - Photophysical and mechanistic studies, the comparison of different emitter classes, and the rational design of the next generation of molecular and nanoscale reporters require quantitative photoluminescence measurements and the reliable determination of the key performance parameter photoluminescence quantum yield (QY), i.e., the number of emitted per absorbed photons. This is of special importance for all photoluminescence applications in the life and material sciences in the UV/vis/NIR/SWIR. T2 - MAF 2024 Conference CY - Valencia, Spain DA - 08.09.2024 KW - Nanoparticle KW - Nano KW - Luminescence KW - Quality assurance KW - Synthesis KW - Standardization KW - Reference material KW - Quantum yield KW - Fluorescence KW - Reference data KW - Integrating sphere spectroscopy KW - ILC KW - Converter material PY - 2024 AN - OPUS4-61072 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pauli, J. A1 - Güttler, Arne A1 - Schneider, T. A1 - Würth, Christian A1 - Resch-Genger, Ute T1 - Fluorescence Quantum Yield Standards for the UV/Visible/NIR: Development, Traceable Characterization, and Certification N2 - The rational design of next generation molecular and nanoscale reporters and the comparison of different emitter classes require the determination of the fluorometric key performance parameter fluorescence quantum yield (Φf), i.e., the number of emitted photons per number of absorbed photons. Main prerequisites for reliable Φf measurements, which are for transparent luminophore solutions commonly done relative to a reference, i.e., a fluorescence quantum yield standard of known Φf, are reliable and validated instrument calibration procedures to consider wavelength-, polarization-, and time-dependent instrument specific signal contributions, and sufficiently well characterized fluorescence quantum yield standards. As the standard’s Φf value directly contributes to the calculation of the sample’s Φf, its accuracy presents one of the main sources of uncertainty of relative Φf measurements. To close this gap, we developed a first set of 12 fluorescence quantum yield standards, which absorb and emit in the wavelength region of 330−1000 nm and absolutely determined their Φf values with two independently calibrated integrating sphere setups. Criteria for standard selection and the configuration of these novel fluorescence reference materials are given, and the certification procedure is presented including homogeneity and stability studies and the calculation of complete uncertainty budgets for the certified Φf values. The ultimate goal is to provide the community of fluorescence users with available reference materials as a basis for an improved comparability and reliability of quantum yield data since the measurement of this spectroscopic key property is an essential part of the characterization of any new emitter. KW - Optical spectroscopy KW - Traceability KW - Reference product KW - Dye KW - Fluorescence KW - Quantum yield KW - Reference material KW - Reference data KW - Certification KW - Quality assurance PY - 2023 DO - https://doi.org/10.1021/acs.analchem.2c05530 VL - 95 SP - 5671 EP - 5677 PB - American Chemical Society AN - OPUS4-58151 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute T1 - Absolute Determination of Photoluminescence Quantum Yields of Scattering LED Converter Materials – How to Get it Right N2 - Optical measurements of scattering luminescent materials dispersed in liquid and solid matrices and luminescent powders play an important role in fundamental research and industry. Typical examples are luminescent nano- and microparticles and phosphors of different composition in different matrices or incorporated into ceramics with applications in energy conversion, solid-state lighting, medical diagnostics, and security barcoding. The key parameter for the performance of these materials is the photoluminescence quantum yield QY, i.e., the number of emitted photons per number of absorbed photons. QY of transparent luminophore solutions can be determined relatively to a fluorescence quantum yield standard of known QY. Such standards are meanwhile available as certified reference materials.[1] The determination of QY of scattering liquid and solid samples like dispersions of luminescent nanoparticles, solid phosphors, and optoceramics requires, however, absolute measurements with an integrating sphere setup. Although the importance of reliable absolute QY measurements has been recognized, no interlaboratory comparisons (ILCs) on measurement uncertainties and the identification of typical sources of uncertainty have been yet reported. Also, no scattering reference materials with known QY are available. We present here the results of a first ILC of 3 laboratories from academia and industry performed to identify and quantify sources of uncertainty of absolute QY measurements of scattering samples. Thereby, two types of commercial stand-alone integrating sphere setups with different illumination and detection geometries were utilized for measuring QY of transparent and scattering dye solutions and solid phosphors. As representative and industrially relevant solid and scattering samples, YAG:Ce optoceramics of varying surface roughness were chosen, applied, e.g., as converter materials for blue light emitting diodes. Special emphasis was dedicated to the influence of the measurement geometry, the optical properties of the blank, utilized to determine the number of photons of the incident excitation light absorbed by the sample, and the sample-specific surface roughness. While matching QY values could be obtained for transparent dye solutions and scattering dispersions, here using a blank with scattering properties closely matching those of the sample, QY measurements of optoceramic samples with different blanks revealed substantial differences, with the blank's optical properties accounting for measurement uncertainties of more than 20 %. Based upon the ILC results, we recommend non-absorbing blank materials with a high reflectivity (>95 %) such as a 2 mm-thick PTFE target placed on the sample holder which reveals a near-Lambertian light scattering behavior, yielding a homogeneous light distribution within the integrating sphere. T2 - e-MRS 2024 CY - Strasbourg, France DA - 27.05.2024 KW - Luminescence KW - Quantitative spectroscopy KW - Nano KW - Particle KW - Quantum yield KW - Lifetime KW - Quality assurance KW - Phosphor KW - Converter marterial KW - Fluorescence KW - Interlaboratory KW - Comparison KW - Method KW - Uncertainty KW - Reference material PY - 2024 AN - OPUS4-60490 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tavernaro, Isabella T1 - Rational Design of Analyte-responsive Fluorescent Particle Sensors for Life Sciences Applications N2 - Engineered and tailor-made nanomaterials (NM) are of increasing relevance for current and future developments in the life and material sciences for applications, e.g., as drug carriers, fluorescent sensors, and multimodal labels in bioanalytical assays, and reporters for imaging applications. For instance, NM-based reporters and sensors, that are labelled or stained with a multitude of conventional or sensor dyes, have several advantages as compared to molecular probes like enhanced brightness, i.e., amplified signals, ease of designing ratiometric systems by combining analyte-sensitive and inert reference dyes, and increased photostability. Moreover, this can enable the use of hydrophobic dyes in aqueous environments. For rational NM design, choosing and tailoring the intrinsic physicochemical properties, such as particle size, size distribution, morphology, and surface chemistry of the NM application-specific considerations like biocompatibility, ease and low cost of preparation, and colloidal stability and performance in the targeted environment must be considered. In this lecture, different design concepts of inorganic, organic, and hybrid NM and microparticles with hydrophilic surface chemistries and different functionalities are presented that can be used for the targeting of lysosomes; and to monitor functional parameters of endo-lysosomal compartments, like pH or enable oxygen sensing. T2 - Chemical Probes for Lysosomal Biology CY - York, United Kingdom DA - 09.09.2024 KW - Luminescence KW - Quantification KW - Nano KW - Particle KW - Quality assurance KW - Fluorescence KW - Method KW - Uncertainty KW - Reference material KW - Sensor KW - Synthesis KW - Dye KW - pH KW - Silica KW - Polystyrene KW - Surface analysis PY - 2024 AN - OPUS4-62173 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute T1 - New project on the quantification of functional groups (FGS) on nanomaterials N2 - The surface chemistry of nanomaterials controls their interaction with the environment and biological species and their fate and is hence also relevant for their potential toxicity. This has meanwhile led to an increasing interest in validated and preferably standardized methods for the determination and quantification of surface functionalities on nanomaterials and initiated different standardization projects within ISO/TC 229 and IEC/TC 113 as well as interlaboratory comparisons (ILCs) of different analytical methods for the quantification of surface coatings by OECD. Here we present the results of a first ILC on the quantification of the amount of amino functionalities on differently sized inorganic nanoparticles done by division Biophotonics and the National Research Council of Canada (NRC) and the PWI 19257 on the Characterization and Quantification of Surface Functional Groups and Coatings on Nanoobjects approved by ISO/TC 229 (WG2) in fall 2022 that will result in a VAMAS study on this topic organized by division Biophotonics. Key words: nanoparticles, surface analysis, surface functional groups, quantification, optical assay, qNMR, VAMAS, standardization, ICL, quality assurance, reference material. T2 - Eingeladener Vortrag Universität Erlangen CY - Erlangen, Germany DA - 18.01.2023 KW - Quality assurance KW - Nano KW - Particle KW - Standard KW - Reference material KW - Surface analysis KW - Quantification KW - Interlaboratory comparison KW - Standardization KW - VAMAS PY - 2023 AN - OPUS4-57044 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kunc, F. A1 - Nirmalananthan-Budau, Nithiya A1 - Rühle, Bastian A1 - Sung, Y. A1 - Johnston, L.J. A1 - Resch-Genger, Ute T1 - Interlaboratory Comparison on the Quantification of Total and Accessible Amine Groups on Silica Nanoparticles with qNMR and Optical Assays N2 - Risk assessment of nanomaterials requires not only standardized toxicity studies but also validated methods for nanomaterial surface characterization with known uncertainties. In this context, a first bilateral interlaboratory comparison on Surface group quantification of nanomaterials is presented that assesses different reporter-free and labeling methods for the quantification of the total and accessible number of amine functionalities on commercially available silica nanoparticles that are widely used in the life sciences. The overall goal of this comparison is the identification of optimum methods as well as achievable measurement uncertainties and the comparability of the results across laboratories. We also examined the robustness and ease of implementation of the applied analytical methods and discussed method-inherent limitations. In summary, this comparison presents a first step toward the eventually required standardization of methods for surface group quantification. KW - Nano KW - Nanomaterial KW - Surface KW - Method KW - QNMR KW - Quantification KW - Comparison KW - Quality assurance KW - Optical probe KW - Sensor KW - Interlabority comparison KW - Standardization KW - Optical assay KW - Functional group analysis KW - Silica KW - Particle KW - Safety KW - Environment PY - 2021 DO - https://doi.org/10.1021/acs.analchem.1c02162 SN - 1520-6882 VL - 93 IS - 46 SP - 15271 EP - 15278 PB - ASC Publications AN - OPUS4-53818 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Billimoria, K. A1 - Andresen, Elina A1 - Resch-Genger, Ute A1 - Goenaga-Infante, H. T1 - A Strategy for Quantitative Imaging of Lanthanide Tags in A549 Cells Using the Ratio of Internal Standard Elements N2 - One remaining handicap for spatially resolved elemental quantification in biological samples is the lack of a suitable internal standard (IS) that can be reliably measured across both calibration standards and samples. In this work, multielement quantitative intracellular imaging of cells tagged with lanthanide nanoparticles containing key lanthanides, e.g., Eu and Ho, is described using a novel strategy that uses the ratio of IS elements and LA-ICP-TOFMS analysis. To achieve this, an internal standard layer is deposited onto microscope slides containing either gelatin calibration standards or Euand Ho-tagged cell samples. This IS layer contains both gallium (Ga) and indium (In). Monitoring either element as an IS individually showed significant variability in intensity signal between sample or standards prepared across multiple microscope slides, which is indicative of the difficulties in producing a homogeneous film at intracellular resolution. However, normalization of the lanthanide signal to the ratio of the IS elements improved the calibration correlation coefficients from 0.9885 to 0.9971 and 0.9805 to 0.9980 for Eu and Ho, respectively, while providing a consistent signal to monitor the ablation behavior between standards and samples. By analyzing an independent quality control (QC) gelatin sample spiked with Eu and Ho, it was observed that without normalization to the IS ratio the concentrations of Eu and Ho were highly biased by approximately 20% in comparison to the expected values. Similarly, this overestimation was also observed in the lanthanide concentration distribution of the cell samples in comparison with the normalized data. KW - Nanoparticle KW - Nano KW - Luminescence KW - Quality assurance KW - Synthesis KW - Standardization KW - Reference material KW - ICP-MS KW - LA-ICP-MS KW - Quantification KW - Bioimaging PY - 2024 DO - https://doi.org/10.1021/acs.analchem.4c02763 SN - 0003-2700 VL - 96 IS - 30 SP - 12570 EP - 12576 AN - OPUS4-60768 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -