TY - JOUR A1 - Kothavale, S. A1 - Jadhav, A. G. A1 - Scholz, Norman A1 - Nirmalananthan-Budau, Nithiya A1 - Behnke, Thomas A1 - Resch-Genger, Ute A1 - Sekar, N. T1 - Corrigendum to "Deep red emitting triphenylamine based coumarin-rhodamine hybrids with large stokes shift and viscosity sensing: Synthesis, photophysical properties and DFT studies of their spirocyclic and open forms" [Dyes Pigments 137 (2017) 329-341] JF - Dyes and pigments N2 - We designed and synthesized triphenylamine based and coumarin fused rhodamine hybrid dyes and characterized using 1H, 13C NMR and HR-LCMS analysis. Both the newly synthesized hybrid dyes were found to show red shifted absorption as well as emissions and large Stokes shift (40e68 nm) as compared to the small Stokes shift (25e30 nm) of reported dyes Rhodamine B and 101. Photophysical properties of these dyes were studied in different solvents and according to the solvents acidity or basicity they preferred to remain in their spirocyclic or open form in different ratio. We studied the spirocyclic as well as open form derivatives of these dyes for their viscosity sensitivity in three different mixture of solvents i.e. polar-protic [EtOH-PEG 400], polar-aprotic [toluene-PEG 400] and non-polaraprotic [toluene-paraffin]. They are found to show very high viscosity sensitivity in polar-protic mixture of solvents [EtOH-PEG 400] and hence concluded that both polarity as well as viscosity factor worked together for the higher emission enhancement rather than only viscosity factor. As these dyes showed very high viscosity sensitivity in their spirocyclic as well as open form, they can be utilized as viscosity sensors in visible as well as deep red region. We also correlated our experimental finding theoretically by using Density Functional theory computations. KW - Dye KW - Fluorescence KW - Synthesis KW - Quantum yield KW - Lifetime KW - Coumarin KW - Rhodamine KW - Probe KW - Viscosity PY - 2018 DO - https://doi.org/10.1016/j.dyepig.2017.06.021 SN - 0143-7208 SN - 1873-3743 N1 - Geburtsname von Nirmalananthan-Budau, Nithiya: Nirmalananthan, N. - Birth name of Nirmalananthan-Budau, Nithiya: Nirmalananthan, N. VL - 149 SP - 929 PB - Elsevier CY - Amsterdam AN - OPUS4-44038 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute A1 - Hoffmann, Katrin A1 - Wegmann, Marc A1 - Hannemann, M. A1 - Somma, V. A1 - Jochum, T. A1 - Niehaus, J. A1 - Roggenbuck, D. T1 - Automated determination of genotoxicity of nanoparticles with DNA-based optical assays - The NANOGENOTOX project 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 procedures1,2 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 as a sign for genotoxicity3. 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 - SPIE 2018 CY - San Francisco, USA DA - 27.01.2018 KW - Nanoparticle KW - Fluorescence KW - Surface chemistry KW - Size KW - Assay KW - Microscopy KW - Nanotoxicity KW - Toxicity KW - Automation KW - Calibration KW - Standard PY - 2018 AN - OPUS4-44186 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Resch-Genger, Ute ED - Wang, Cui ED - Otto, S. ED - Dorn, M. ED - Kreidt, E. ED - Lebon, J. ED - Srsan, L. ED - di Martino-Fumo, P. ED - Gerhards, M. ED - Seitz, M. ED - Heinze, K. T1 - Deuterated Molecular Ruby with Record Luminescence Quantum Yield JF - GDCh N2 - The recently reported luminescent chromium(III) complex 13+ ([Cr(ddpd)2]3+; ddpd=N,N’-dimethyl-N,N’-dipyridine-2-yl-pyridine-2,6-diamine) shows exceptionally strong near-IR emission at 775 nm in water under ambient conditions (F=11%) with a microsecond lifetime as the ligand design in 13+ effectively eliminates non-radiative decay pathways, such as photosubstitution, back-intersystem crossing, and trigonal twists. In the absence of energy acceptors, such as dioxygen, the remaining decay pathways are energy transfer to high energy solvent and ligand oscillators, namely OH and CH stretching vibrations. Selective deuteration of the solvents and the ddpd ligands probes the efficiency of these oscillators in the excited state deactivation. Addressing these energytransfer pathways in the first and second coordination sphere furnishes a record 30% quantum yield and a 2.3 millisecond lifetime for a metal complex with an earth-abundant metal ion in solution at room temperature. KW - Fluorescence KW - Quantum yield KW - Ligand design KW - Cr(III) KW - Complex KW - Oxygen sensor KW - NIR KW - Fluorescence lifetime PY - 2018 DO - https://doi.org/10.1002/ange.201711350 SN - 1521-3773 VL - 57 IS - 4 SP - 1112 EP - 1116 PB - Wiley-VCH Verlag & Co. KGaA CY - Weinheim AN - OPUS4-44045 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Keller, Julia A1 - Moldenhauer, Daniel A1 - Byrne, L. A1 - Haase, H. A1 - Resch-Genger, Ute A1 - Koch, Matthias T1 - Complexes of the mycotoxins citrinin and ochratoxin A with aluminum ions and their spectroscopic properties JF - Toxins N2 - The sensitive detection of the mycotoxin citrinin (CIT) utilizing ist fluorescence requires approaches to enhance the emission. In this respect, we studied the complexation of CIT and ochratoxin A (OTA) with Al3+ in methanol using absorption and fluorescence spectroscopy. In this context, an isocratic high performance liquid chromatography (HPLC) method using a polymer column and a fluorescence detector was also developed that enables the separation of the metal ion complexes from the free ligands and non-complexed Al3+. CIT and OTA showed distinct changes in their absorption and fluorescence properties upon Al3+-coordination, and the fluorescence of CIT was considerably enhanced. Analysis of the photometrically assessed titration of CIT and OTA with Al3+ using the Job plot method revealed 1:2 and 1:1 stoichiometries for the Al3+ complexes of CIT (Al:CIT) and OTA (Al:OTA), respectively. In the case of CIT, only one -diketone moiety participates in Al3+ coordination. These findings can be elegantly exploited for signal amplification and provide the base to reduce the limit of detection for CIT quantification by about an order of magnitude, as revealed by HPLC measurements using a fluorescence detector. KW - Complexation KW - Aluminum KW - Fluorescence KW - Job plot KW - HPLC-DAD/FLD PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-470502 DO - https://doi.org/10.3390/toxins10120538 SN - 2072-6651 VL - 10 IS - 12 SP - 538, 1 EP - 8 PB - MDPI CY - Basel AN - OPUS4-47050 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Otto, S. A1 - Förster, C. A1 - Wang, Cui A1 - Resch-Genger, Ute A1 - Heinze, K. T1 - A Strongly Luminescent Chromium(III) ComplexAcid JF - GDCh N2 - The synthesis, structure, reactivity,and photophysical properties of anovel acidic,luminescentchromium(III) complex [Cr(H2tpda)2]3+ (23+ +)bearing the tridentate H2tpda (2,6-bis(2-pyridylamino)pyridine) ligand are presented. Excitation of 23+ + at 442 nm results in strong, long-lived NIR luminescence at 782 nm in water and in acetonitrile. X-ray diffraction analysis and IR spectroscopy revealhydrogen-bonding interactions of the counter ions to the NH groups of 23+ + in the solidstate. Deprotonation of the NH groups of 23+ + by using anon-nucleophilic Schwesinger base in CH3CN switches off the luminescence. Re-protonation by using HClO4 restores the emission. In water,the pKa value of 23+ + amountsto8 .8, yet deprotonation is not reversible in the presence of hydroxide ions. Dioxygen quenches the emission of 23+ +,but to aweaker extent than expected. This is possibly due to the strong ion-pairing properties of 23+ + even in solution, reducing the energy transfer efficiency to O2.Deuteration of the NH groups of 23+ + approximately doubles the quantum yield and lifetime in water,demonstrating the importance of multiphoton relaxation in these NIR emitters. KW - Cr(III) complex KW - Oxygen sensor KW - pH sensor KW - Luminescence KW - Luminescence lifetime KW - Quantum yield KW - NIR emitter PY - 2018 DO - https://doi.org/10.1002/chem.201802797 SN - 0947-6539 VL - 24 IS - 48 SP - 12555 EP - 12563 PB - Wiley‐VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-45929 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute A1 - Nirmalanthan-Budau, Nithiya A1 - Moser, Marko A1 - Roloff, Alexander A1 - Moldenhauer, Daniel T1 - Quantification of Surface Groups on Nanomaterials with Simple Optical Methods N2 - Surface functionalization of nanomaterials is nowadays at the core of many applications of functional materials in the life and material sciences. Examples range from membranes and microarrays over bead-based assays, and next generation sequencing to nanometer-sized optical reporters, nanosensors, and magnetic and optical contrast agents. Typical function-nalization steps include silanization and grafting reactions with reactive monomers to introduce functional groups like amino or carboxylic acid groups or the attachment of ligands like polyethylene glycol (PEG) molecules and biomolecules. [1-3] This enables to tune e.g., dis-persibility, hydrophilicity and biocompatibility, minimize unspecific interactions, improve biofunctionalization efficiencies, and enhance blood circulation times and allows for the use of nanomaterials as reporters in assays or the design of targeted probes for bioimaging. At the core of all functionalization strategies are reliable and validated methods for surface group and ligand quantification that can be preferably performed with routine laboratory instrumentation, require only small amounts of substances, and are suitable for many different types of nanomaterials. [3] There is meanwhile a considerable need to make these methods traceable. We present here versatile and simple concepts for the quantification of common functional groups, ligands, and biomolecules on different types of organic and inorganic nanomaterials, using conventional and newly developed cleavable and multimodal reporters, that can be detected with optical spectroscopy. [4-7] These reporters are chosen to enable method validation with the aid of method comparisons and mass balances. Also, strategies how to make these simple assays traceable to SI units using quantitative nuclear resonance spectroscopy (qNMR) and X-ray photoelectron spectroscopy (XPS) are derived. T2 - JRC-NIST Workshop CY - Ispra, Italy DA - 04.12.2018 KW - Nanoparticle KW - Nanocrystal KW - Absolute fluorometry KW - Fluorescence KW - Surface chemistry KW - Assay KW - Cleavable probe KW - Conductometry KW - Quantification KW - Functional group PY - 2018 AN - OPUS4-46950 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute A1 - Würth, Christian A1 - Geissler, Daniel A1 - Weigert, Florian A1 - Kaiser, Martin T1 - Spectroscopic characterization of semiconductor and lanthanide-based nanocrystals with vis and NIR emission N2 - Common approaches to improve the optical properties of semiconductor quantum dots and lanthanide doped nanophosphors present core/shell structures as radiationless deactivation at the particle surface is usually the main energy loss mechanism. This has led to increasingly sophisticated particle architectures using multishell systems with shells of different chemical composition and thickness and initiated an increasing number of quantitative spectroscopic studies focusing on the key performance parameter photoluminescence quantum yield to identify optimum particle structures. This is particularly challenging in the long wavelength region > 1000 nm and for nonlinear emitters like upconversion nanocrystals. Here, we present suitable absolute methods to quantify the photoluminescence of these different emitters in the vis/NIR/IR and as function of excitation power density and underline the impact of such measurements on a profound mechanistic understanding of the nonradiative deactivation pathways in semiconductor and upconversion nanocrystals of different size and particle architecture in different environments. T2 - NANO 2018 CY - Hong Kong, People's Republic of China DA - 24.06.2018 KW - Upconversion KW - Semiconductor KW - Quantum dot KW - Nanoparticle KW - Absolute fluorometry KW - Integrating sphere spectroscopy KW - NIR KW - IR KW - Fluorescence KW - Surface chemistry KW - Deactivation pathways KW - Modeling KW - Size PY - 2018 AN - OPUS4-45797 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Grunert, B. A1 - Saatz, Jessica A1 - Hoffmann, Katrin A1 - Appler, F. A1 - Lubjuhn, Dominik A1 - Jakubowski, Norbert A1 - Resch-Genger, Ute A1 - Emmerling, Franziska A1 - Briel, A. T1 - Multifunctional rare-earth element nanocrystals for cell labeling and multimodal imaging JF - ACS Biomaterials Science & Engineering N2 - In this work, we describe a simple solvothermal route for the synthesis of Eu3+-doped gadolinium orthovanadate nanocrystals (Eu:GdVO4−PAA) functionalized with poly(acrylic)acid (PAA), that are applicable as cell labeling probes for multimodal cellular imaging. The Eu3+ doping of the vanadate matrix provides optical functionality, due to red photoluminescence after illumination with UV light. The Gd3+ ions of the nanocrystals reduce the T1 relaxation time of surrounding water protons, allowing these nanocrystals to act as a positive MRI contrast agent with a r1 relaxivity of 1.97 mM−1 s−1. Low background levels of Eu3+, Gd3+, and V5+ in biological systems make them an excellent label for elemental microscopy by Laser Ablation (LA)-ICP-MS. Synthesis resulted in polycrystalline nanocrystals with a hydrodynamic diameter of 55 nm and a crystal size of 36.7 nm, which were further characterized by X-ray diffraction (XRD), photoluminescence spectroscopy (PL) and transmission electron microscopy (TEM). The multifunctional nanocrystals were subsequently used for intracellular labeling of both human adipose-derived stem cells (MSCs) and A549 (adenocarcinomic human alveolar basal epithelial) cells. KW - Bioimaging KW - Nanoparticle KW - Multimodal KW - Lanthanide PY - 2018 DO - https://doi.org/10.1021/acsbiomaterials.8b00495 SN - 2373-9878 VL - 4 IS - 10 SP - 3578 EP - 3587 PB - ACS Publications CY - Washington, USA AN - OPUS4-46244 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute A1 - Weigert, Florian A1 - Frenzel, Florian A1 - Würth, Christian A1 - Hoffmann, Katrin A1 - Martynenko, Irena A1 - Dhamo, Lorena T1 - Photoluminescence Properties of Different Types of Nanocrystals at the Ensemble and Single Emitter Level N2 - Correlating the photoluminescence (PL) properties of nanomaterials like semiconductor nanocrystals (QDs) and upconversion nanocrystals (UCNPs) assessed in ensemble studies and at the single particle level is increasingly relevant for applications of these nanomaterials in the life sciences like bioimaging studies or their use as reporters in microfluidic assays. Here we present a comparison of the spectroscopic properties of ensembles and single emitters for QDs like II/VI QDs and cadmium-free AIS/ZnS QDs as well as different UCNPs. The overall goal of this study was to derive particle architectures well suited for spectroscopic and microscopic applications. T2 - BIOSSPIE CY - San Francisco, CA, USA DA - 02.02.2019 KW - Quantum yield KW - Nanomaterial KW - Photoluminescence KW - Absolute fluorometry KW - Integrating sphere spectroscopy, KW - NIR KW - IR KW - Fluorescence KW - Nanoparticle KW - Semiconductor KW - Quantum dot KW - Single particle spectroscopy KW - Surface chemistry PY - 2019 AN - OPUS4-47358 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - You, Zengchao A1 - Nirmalananthan-Budau, Nithiya A1 - Resch-Genger, Ute A1 - Panne, Ulrich A1 - Weidner, Steffen T1 - Separation of polystyrene nanoparticles bearing different carboxyl group densities and functional groups quantification with capillary electrophoresis and asymmetrical flow field flow fractionation JF - Journal of Chromatography A N2 - Two sets of polystyrene nanoparticles (PSNPs) with comparable core sizes but different carboxyl group densities were made and separated using asymmetric flow field flow fractionation (AF4), capillary electrophoresis (CE), and the off-line hyphenation of both methods. Our results revealed the significant potential of two-dimensional off-line AF4-CE hyphenation to improve the separation and demonstrated for the first time, the applicability of CE to determine the functional group density of nanoparticles (NPs). Compared to the result acquired with conductometric titration, the result obtained with synthesized 100 nm sized PSNPs revealed only a slight deviation of 1.7%. Commercial 100 nm sized PSNPs yielded a deviation of 4.6 %. For 60 nm sized PSNPs, a larger deviation of 10.6 % between both methods was observed, which is attributed to the lower separation resolution. KW - Nanoparticle KW - A4F KW - Capillary electrophoresis KW - Carboxyl group PY - 2020 DO - https://doi.org/10.1016/j.chroma.2020.461392 VL - 1626 SP - 461392 PB - Elsevier B.V. AN - OPUS4-51080 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute A1 - Keller, Lisa-Marie A1 - Scholz, Lena A1 - Weigert, Florian A1 - Radnik, Jörg A1 - Rühle, Bastian A1 - Bresch, Harald T1 - Nanocarriers – Challenges Imposed by Material Characterization N2 - A brief perspective of BAM on nanocarriers is presented including examples with special emphasis on the characterization of such materials and underlying challenges. In this respect, also ongoing activities at BAM on different types of core/shell nanomaterials and related systems are briefly summarized. T2 - Kolloquium BfR CY - Online meeting DA - 18.03.2021 KW - Nanomaterial KW - Nanocarrier KW - Size KW - Surface chemistry KW - Release kinetics KW - Chemical composition KW - Core/shell nanoparticle KW - Quantum dot KW - Spectroscopy KW - Fluorescence PY - 2021 AN - OPUS4-52412 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Recknagel, Sebastian A1 - Bresch, Harald A1 - Kipphardt, Heinrich A1 - Resch-Genger, Ute A1 - Koch, Matthias A1 - Rosner, M. T1 - Trends in selected fields of reference material production JF - Analytical and bioanalytical chemistry N2 - For more than 110 years, BAM has been producing reference materials for a wide range of application fields. With the development of new analytical methods and new applications as well as continuously emerging more stringent requirements of laboratory accreditation with regard to quality control and metrological traceability, the demand and requirements for reference materials are increasing. This trend article gives an overview of general developments in the field of reference materials as well as developments in selected fields of application in which BAM is active. This includes inorganic and metal analysis, gas analysis, food and consumer products, and geological samples. In addition to these more traditional fields of application, developments in the areas of optical spectroscopy, particulary fluorescence methods, and nanomaterials are considered. T2 - 150 years BAM: Science with impact CY - Berlin, Germany DA - 01.01.2021 KW - Reference material KW - ISO REMCO KW - Gas analysis KW - Food KW - Nanomaterials KW - Fluorescence PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548407 DO - https://doi.org/10.1007/s00216-022-03996-7 SN - 1618-2642 SN - 1618-2650 VL - 414 IS - Topical collection: Analytical methods and applications in the materials and life sciences SP - 4281 EP - 4289 PB - Springer CY - Berlin AN - OPUS4-54840 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Billimoria, K. A1 - Diaz Fernandez, Y. A. A1 - Andresen, Elina A1 - Sorzabal-Bellido, I. A1 - Huelga-Suarez, G. A1 - Bartczak, D. A1 - Ortiz de Solórzano, C. A1 - Resch-Genger, Ute A1 - Goenaga Infante, H. T1 - The potential of bioprinting for preparation of nanoparticle-based calibration standards for LA-ICP-ToF-MS quantitative imaging JF - Metallomics N2 - This paper discusses the feasibility of a novel strategy based on the combination of bioprinting nano-doping technology and laser ablation-inductively coupled plasma time-of-flight mass spectrometry analysis for the preparation and characterization of gelatin- based multi-element calibration standards suitable for quantitative imaging. To achieve this, lanthanide up-conversion nanoparticles were added to a gelatin matrix to produce the bioprinted calibration standards. The features of this bioprinting approach were com- pared with manual cryosectioning standard preparation, in terms of throughput, between batch repeatability and elemental signal homogeneity at 5 μm spatial resolution. By using bioprinting, the between batch variability for three independent standards of the same concentration of 89 Y (range 0–600 mg/kg) was reduced to 5% compared to up to 27% for cryosectioning. On this basis, the relative standard deviation ( RSD ) obtained between three independent calibration slopes measured within 1 day also reduced from 16% (using cryosectioning ) to 5% (using bioprinting), supporting the use of a single standard preparation replicate for each of the concentrations to achieve good calibration performance using bioprinting. This helped reduce the analysis time by approximately 3-fold. With cryosectioning each standard was prepared and sectioned individually, whereas using bio-printing it was possible to have up to six different standards printed simultaneously, reducing the preparation time from approximately 2 h to under 20 min (by approxi- mately 6-fold). The bio-printed calibration standards were found stable for a period of 2 months when stored at ambient temperature and in the dark. KW - Environmental analysis KW - LA-ICP-MS KW - Lanthanide KW - Tag KW - Fluorescence KW - Nanoparticles KW - Reference material KW - Quality assurance KW - 3D-printing KW - Synthesis KW - Production KW - Multimodal PY - 2022 DO - https://doi.org/10.1093/mtomcs/mfac088 SN - 1756-591X VL - 14 IS - 12 SP - 1 EP - 9 PB - Oxford University Press CY - Oxford AN - OPUS4-57018 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Labrador-Paez, Lucia, L. A1 - Kankare, J. A1 - Hyppanen, I. A1 - Soukka, T. A1 - Andresen, Elina A1 - Resch-Genger, Ute A1 - Widengren, J A1 - Liu, H. T1 - Frequency-Domain Method for Characterization of Upconversion Luminescence Kinetics JF - The journal of physical chemistry letters N2 - The frequency-domain (FD) method provides an alternative to the commonly used time-domain (TD) approach in characterizing the luminescence kinetics of luminophores, with its own strengths, e.g., the capability to decouple multiple lifetime components with higher reliability and accuracy. While extensively explored for characterizing luminophores with down-shifted emission, this method has not been investigated for studying nonlinear luminescent materials such as lanthanide-doped upconversion nanoparticles (UCNPs), featuring more complicated kinetics. In this work, employing a simplified rate-equation model representing a standard two-photon energy-transfer upconversion process, we thoroughly analyzed the response of the luminescence of UCNPs in the FD method. We found that the FD method can potentially obtain from a single experiment the effective decay rates of three critical energy states of the sensitizer/activator ions involved in the upconversion process. The validity of the FD method is demonstrated by experimental data, agreeing reasonably well with the results obtained by TD methods. KW - Quality assurance KW - Luminescence KW - Method KW - Quantitative spectroscopy KW - Nano KW - Particle KW - Lifetime KW - Method development PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597435 DO - https://doi.org/10.1021/acs.jpclett.3c00269 SP - 3436 EP - 3444 AN - OPUS4-59743 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fiedler, Saskia A1 - Frenzel, Florian A1 - Würth, Christian A1 - Tavernaro, Isabella A1 - Grüne, M. A1 - Schweizer, S. A1 - Engel, A. A1 - Resch-Genger, Ute T1 - Interlaboratory Comparison on Absolute Photoluminescence Quantum Yield Measurements of Solid Light Converting Phosphors with Three Commercial Integrating Sphere Setups JF - American Chemical Society N2 - Scattering luminescent materials dispersed in liquid and solid matrices and luminescent powders are increasingly relevant for fundamental research and industry. Examples are luminescent nano- and microparticles and phosphors of different compositions in various matrices or incorporated into ceramics with applications in energy conversion, solid-state lighting, medical diagnostics, and security barcoding. The key parameter to characterize the performance of these materials is the photoluminescence/fluorescence quantum yield (Φf), i.e., the number of emitted photons per number of absorbed photons. To identify and quantify the sources of uncertainty of absolute measurements of Φf of scattering samples, the first interlaboratory comparison (ILC) of three laboratories from academia and industry was performed by following identical measurement protocols. Thereby, two types ofcommercial stand-alone integrating sphere setups with different illumination and detection geometries were utilized for measuring the Φf of transparent and scattering dye solutions and solid phosphors, namely, YAG:Ce optoceramics of varying surface roughness, used 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 the Φf values of the liquid samples matched between instruments, Φf measurements of the optoceramics with different blanks revealed substantial differences. The ILC results underline the importance of the measurement geometry, sample position, and blank for reliable Φf data of scattering the YAG:Ce optoceramics, with the blank’s optical properties accounting for uncertainties exceeding 20%. KW - Nano KW - Fluorescence KW - Reference material KW - Luminescence KW - Quantitative spectroscopy KW - Particle KW - Quantum yield KW - Quality assurance KW - Phosphor KW - Converter material KW - Lifetime KW - Interlaboratory comparison KW - Method KW - Uncertainty PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600945 DO - https://doi.org/10.1021/acs.analchem.4c00372 SN - 0003-2700 SP - 6730 EP - 6737 PB - ACS Publications AN - OPUS4-60094 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Geißler, Daniel A1 - Wegner, Karl David A1 - Fischer, C. A1 - Resch-Genger, Ute T1 - Exploring Simple Particle-Based Signal Amplification Strategies in a Heterogeneous Sandwich Immunoassay with Optical Detection JF - Analytical Chemistry N2 - Heterogeneous sandwich immunoassays are widely used for biomarker detection in bioanalysis and medical diagnostics. The high analyte sensitivity of the current “gold standard” enzyme-linked immunosorbent assay (ELISA) originates from the signal-generating enzymatic amplification step, yielding a high number of optically detectable reporter molecules. For future point-of-care testing (POCT) and point-of-need applications, there is an increasing interest in more simple detection strategies that circumvent time-consuming and temperature-dependent enzymatic reactions. A common concept to aim for detection limits comparable to those of enzymatic amplification reactions is the usage of polymer nanoparticles (NP) stained with a large number of chromophores. We explored different simple NP-based signal amplification strategies for heterogeneous sandwich immunoassays that rely on an extraction-triggered release step of different types of optically detectable reporters. Therefore, streptavidinfunctionalized polystyrene particles (PSP) are utilized as carriers for (i) the fluorescent dye coumarin 153 (C153) and (ii) hemin (hem) molecules catalyzing the luminol reaction enabling chemiluminescence (CL) detection. Additionally, (iii) NP labeling with hemin-based microperoxidase MP11 was assessed. For each amplification approach, the PSP was first systematically optimized regarding size, loading concentration, and surface chemistry. Then, for an immunoassay for the inflammation marker C- eactive protein (CRP), the analyte sensitivity achievable with optimized PSP ystems was compared with the established ELISA concept for photometric and CL detection. Careful optimization led to a limit of detection (LOD) of 0.1 ng/mL for MP11-labeled PSP and CL detection, performing similarly well to a photometric ELISA (0.13 ng/mL), which demonstrates the huge potential of our novel assay concept. KW - Nanoparticle KW - Fluorescence KW - Immunoassay KW - Quality assurance KW - Antibody KW - Polymer KW - Dye KW - Signal enhancement KW - CRP KW - Biosensing PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597853 DO - https://doi.org/10.1021/acs.analchem.3c03691 SN - 1520-6882 VL - 96 IS - 13 SP - 5078 EP - 5085 PB - American Chemical Society CY - Columbus, Ohio AN - OPUS4-59785 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wegner, Karl David A1 - Resch-Genger, Ute T1 - The 2023 Nobel Prize in Chemistry: Quantum dots JF - Analytical and Bioanalytical Chemistry N2 - The 2023 Nobel Prize in Chemistry was awarded to Aleksey I. Ekimov (prize share 1/3), Louis E. Brus (prize share 1/3), and Moungi G. Bawendi (prize share 1/3) for groundbreaking inventions in the field of nanotechnology, i.e., for the discovery and synthesis of semiconductor nanocrystals, also termed quantum dots, that exhibit size-dependent physicochemical properties enabled by quantum size effects. This feature article summarizes the main milestones of the discoveries and developments of quantum dots that paved the road to their versatile applications in solid-state lighting, display technology, energy conversion, medical diagnostics, bioimaging, and image-guided surgery. KW - Quantum dots KW - Semiconductor nanocrystals KW - Luminescence KW - Quantitative spectroscopy KW - Quantum yield KW - Advanced nanomaterials KW - Quality assurance KW - Energy transfer PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597843 DO - https://doi.org/10.1007/s00216-024-05225-9 VL - 2024 SP - 1 EP - 11 PB - Springer CY - Cham AN - OPUS4-59784 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Potopnyk, M. A1 - Mech-Piskorz, J. A1 - Angulo, G. A1 - Ceborska, M. A1 - Luboradzki, R. A1 - Andresen, Elina A1 - Gajek, A. A1 - Wisniewska, A. A1 - Resch-Genger, Ute T1 - Aggregation/Crystallization-Induced Emission in Naphthyridine-Based Carbazolyl-Modified Donor-Acceptor Boron Dyes Tunable by Fluorine Atoms JF - Chemistry-A European Journal N2 - Four donor-acceptor boron difluoride complexes based on the carbazole electron donor and the [1,3,5,2]oxadiazaborinino[3,4-a][1,8]naphthyridine acceptor were designed, synthesized, and systematically spectroscopically investigated in solutions, in the solid states, and dye-doped polymer films. The dyes exhibit an intense blue to red solid-state emission with photoluminescence quantum yields of up to 56% in pure dye samples and 86% in poly(methyl methacrylate) films. All boron complexes show aggregation-induced emission and reversible mechanofluorochromism. The optical properties of these dyes and their solid state luminescence can be tuned by substitution pattern, i.e., the substituents at the naphthyridine unit. Exchange of CH3- for CF3-groups does not only increase the intramolecular charge transfer character, but also provides a crystallization-induced emission enhancement. KW - Spectroscopy KW - Dye KW - Luminescence KW - Sensor KW - Fluorescence KW - Quantum yield KW - Lifetime KW - Quality assurance KW - Synthesis PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597426 DO - https://doi.org/10.1002/chem.202400004 SN - 0947-6539 SP - 1 EP - 12 PB - Wiley VHC-Verlag AN - OPUS4-59742 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - López-Iglesias, C. A1 - Markovina, A. A1 - Nirmalananthan-Budau, N. A1 - Resch-Genger, Ute A1 - Klinger, D. T1 - Optically monitoring the microenvironment of a hydrophobic cargo in amphiphilic nanogels: influence of network composition on loading and release JF - Nanoscale N2 - Amphiphilic nanogels (ANGs) are promising carriers for hydrophobic cargos such as drugs, dyes, and catalysts. Loading content and release kinetics of these compounds are controlled by type and number of hydrophobic groups in the amphiphilic copolymer network. Thus, understanding the interactions between cargo and colloidal carrier is mandatory for a tailor-made and cargo-specific ANG design. To systematically explore the influence of the network composition on these interactions, we prepared a set of ANGs of different amphiphilicity and loaded these ANGs with varying concentrations of the solvatochromic dye Nile Red (NR). Here, NR acts as a hydrophobic model cargo to optically probe the polarity of its microenvironment. Analysis of the NR emission spectra as well as measurements of the fluorescence quantum yields and decay kinetics revealed a decrease in the polarity of the NR microenvironment with increasing hydrophobicity of the hydrophobic groups in the ANG network and dye–dye interactions at higher loading concentrations. At low NR concentrations, the hydrophobic cargo NR is encapsulated in the hydrophobic domains. Increasing NR concentrations resulted in probe molecules located in a more hydrophilic environment, i.e., at the nanodomain border, and favored dye–dye interactions and NR aggregation. These results correlate well with release experiments, indicating first NR release from more hydrophilic network locations. Overall, our findings demonstrate the importance to understand carrier–drug interactions for efficient loading and controlled release profiles in amphiphilic nanogels. KW - Particle KW - Energy transfer KW - Limit of detection KW - Polymer KW - Luminescence KW - Quantitative spectroscopy KW - Nano KW - Quantum yield KW - Lifetime KW - Quality assurance KW - Dye KW - Probe KW - Sensor KW - Nile Red PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601603 DO - https://doi.org/10.1039/d4nr00051j SN - 2040-3364 IS - 16 SP - 9525 EP - 9535 PB - The Royal Society of Chemistry AN - OPUS4-60160 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -