TY - JOUR
A1 - Hartmann, Yannic
A1 - El Abbassi, Abdelouahad
A1 - Mayer, Bernhard
A1 - Resch-Genger, Ute
A1 - Müller, Thomas J. J.
T1 - Ester‐Aroyl‐S,N‐Ketene Acetals with Solid‐State Luminescence: AIEgens from Sequential Three‐Component Desymmetrization
N2 - AbstractDi(hetero)aroyl dichlorides are desymmetrized upon sequential reaction with alcohols and 2‐methyl N‐benzyl thiazolium salts within the course of a one‐pot three‐component reaction yielding ester‐substituted aroyl‐S,N‐ketene acetals under mild conditions in good yields. A prerequisite for the concise one‐pot process is the different nucleophilicity of the alcohols and in situ generated S,N‐ketene acetals. The resulting compounds are merocyanines with dominant charge‐transfer absorption bands which are fluorescent in the solid state, but not in solution. In water/ethanol solvent mixtures of increasing water content, the water‐insoluble dyes display typical aggregation‐induced emission (AIE) characteristics. The water fraction inducing AIE as well as the emission color, and fluorescence quantum yield (Φf) of the aggregated dyes can be controlled by the alcohol part of the ester moiety. Encapsulation into polystyrene nanoparticles can lead to a considerable increase of the fluorescence quantum yield Φf to 30% as shown for a representatively chosen dye revealing the highest Φf of 11% within the dye series in the water/ethanol mixtures and enabling the usage of these dyes as fluorescent reporters in aqueous environments.
KW - Dye
KW - Fluorescence
KW - Aggregation
KW - Mechanism
KW - Signal enhancement
KW - Nano
KW - Particle
KW - Characterization
KW - Quantum yield
KW - Photophysics
KW - Probe
KW - Sensor
KW - Lifetime
KW - Polarity
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642400
DO - https://doi.org/10.1002/chem.202502071
SN - 0947-6539
SP - 1
EP - 10
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-64240
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Reichenauer, F.
A1 - Wang, Cui
A1 - Förster, C.
A1 - Boden, P.
A1 - Ugur, N.
A1 - Báez-Cruz, R.
A1 - Kalmbach, J.
A1 - Carrella, L. M.
A1 - Rentschler, E.
A1 - Ramanan, C.
A1 - Niedner-Schatteburg, G.
A1 - Gerhards, M.
A1 - Seitz, M.
A1 - Resch-Genger, Ute
A1 - Heinze, K.
T1 - Strongly Red-Emissive Molecular Ruby [Cr(bpmp)2]3+ Surpasses [Ru(bpy)3]2+
N2 - Gaining chemical control over the thermodynamics and kinetics of photoexcited states is paramount to an efficient and sustainable utilization of photoactive transition metal complexes in a plethora of technologies. In contrast to energies of charge Transfer states described by spatially separated orbitals, the energies of spinflip states cannot straightforwardly be predicted as Pauli Repulsion and the nephelauxetic effect play key roles. Guided by multireference quantum chemical calculations, we report a novel highly luminescent spin-flip emitter with a quantum chemically predicted blue-shifted luminescence. The spin-flip emission band of the chromium complex [Cr(bpmp)2]3+ (bpmp = 2,6-bis(2-pyridylmethyl) pyridine) shifted to higher energy from ca. 780 nm observed for known highly emissive chromium(III) complexes to 709 nm. The photoluminescence quantum yields climb to 20%, and very long excited state lifetimes in the millisecond range are achieved at room temperature in acidic D2O solution. Partial ligand deuteration increases the quantum yield to 25%. The high excited state energy of [Cr(bpmp)2]3+ and its facile reduction to [Cr(bpmp)2]2+ result in a high excited state redox potential. The ligand’s methylene bridge acts as a Brønsted acid quenching the luminescence at high pH. Combined with a pH-insensitive chromium(III) emitter, ratiometric optical pH sensing is achieved with single wavelength excitation. The photophysical and Ground state properties (quantum yield, lifetime, redox potential, and acid/base) of this spin-flip complex incorporating an earth-abundant metal surpass those of the classical precious metal [Ru(α-diimine)3]2+ charge transfer complexes, which are commonly employed in optical sensing and photo(redox) catalysis, underlining the bright future of these molecular ruby analogues.
KW - Fluorescence
KW - Optical probe
KW - Sensor
KW - PH
KW - Quantum yield
KW - Quality assurance
KW - Complex
KW - Cr(III)
KW - Lifetime
KW - Ligand
KW - Theory
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530548
DO - https://doi.org/10.1021/jacs.1c05971
VL - 143
IS - 30
SP - 11843
EP - 11855
PB - ACS Publications
AN - OPUS4-53054
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Auxillos, J.
A1 - Crouigneau, R.
A1 - Li, Y.-F.
A1 - Dai, Y.
A1 - Stigliani, A.
A1 - Tavernaro, Isabella
A1 - Resch-Genger, Ute
A1 - Sandelin, A.
A1 - Marie, R.
A1 - Pedersen, S. F.
T1 - Spatially resolved analysis of microenvironmental gradient impact on cancer cell phenotypes
N2 - Despite the physiological and pathophysiological significance of microenvironmental gradients, e.g., for diseases such as cancer, tools for generating such gradients and analyzing their impact are lacking. Here, we present an integrated microfluidic-based workflow that mimics extracellular pH gradients characteristic of solid tumors while enabling high-resolution live imaging of, e.g., cell motility and chemotaxis, and preserving the capacity to capture the spatial transcriptome. Our microfluidic device generates a pH gradient that can be rapidly controlled to mimic spatiotemporal microenvironmental changes over cancer cells embedded in a 3D matrix. The device can be reopened allowing immunofluorescence analysis of selected phenotypes, as well as the transfer of cells and matrix to a Visium slide for spatially resolved analysis of transcriptional changes across the pH gradient. This workflow is easily adaptable to other gradients and multiple cell types and can therefore prove invaluable for integrated analysis of roles of microenvironmental gradients in biology.
KW - Bioimaging
KW - Fluorescence
KW - Cell
KW - Cancer
KW - Method
KW - Microfluids
KW - Model
KW - Calibration
KW - Sensor
KW - Ph
KW - Probe
KW - Workflow
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604631
DO - https://doi.org/10.1126/sciadv.adn3448
VL - 19
IS - 18
SP - 1
EP - 17
AN - OPUS4-60463
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Geißler, Daniel
A1 - Nirmalananthan-Budau, Nithiya
A1 - Scholtz, Lena
A1 - Tavernaro, Isabella
A1 - Resch-Genger, Ute
T1 - Analyzing the surface of functional nanomaterials — how to quantify the total and derivatizable number of functional groups and ligands
N2 - Functional nanomaterials (NM) of different size, shape, chemical composition, and surface chemistry are of increasing relevance for many key technologies of the twenty-first century. This includes polymer and silica or silica-coated nanoparticles (NP) with covalently bound surface groups, semiconductor quantum dots (QD), metal and metal oxide NP, and lanthanide-based NP with coordinatively or electrostatically bound ligands, as well as surface-coated nanostructures like micellar encapsulated NP. The surface chemistry can significantly affect the physicochemical properties of NM, their charge, their processability and performance, as well as their impact on human health and the environment. Thus, analytical methods for the characterization of NM surface chemistry regarding chemical identification, quantification, and accessibility of functional groups (FG) and surface ligands bearing such FG are of increasing importance for quality control of NM synthesis up to nanosafety. Here, we provide an overview of analytical methods for FG analysis and quantification with special emphasis on bioanalytically relevant FG broadly utilized for the covalent attachment of biomolecules like proteins, peptides, and oligonucleotides and address methodand material-related challenges and limitations. Analytical techniques reviewed include electrochemical titration methods, optical assays, nuclear magnetic resonance and vibrational spectroscopy, as well as X-ray based and thermal analysis methods, covering the last 5–10 years. Criteria for method classification and evaluation include the need for a signal-generating label, provision of either the total or derivatizable number of FG, need for expensive instrumentation, and suitability for process and production control during NM synthesis and functionalization.
KW - Functional group quantification
KW - Surface ligand
KW - Nanomaterial
KW - Optical detection
KW - Electrochemical titration
KW - Nanosafety (Safe-by-design)
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-533597
DO - https://doi.org/10.1007/s00604-021-04960-5
VL - 188
IS - 10
SP - 1
EP - 28
PB - Springer Nature
AN - OPUS4-53359
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wang, Cui
A1 - Kitzmann, W.R.
A1 - Weigert, Florian
A1 - Förster, Ch.
A1 - Wang, X.
A1 - Heintze, K.
A1 - Resch-Genger, Ute
T1 - Matrix Effects on Photoluminescence and Oxygen Sensitivity of a Molecular Ruby
N2 - The molecular ruby analogue [Cr(ddpd)2]3+ (ddpd=N,N’-dimethyl-N,N’-dipyridine-2-ylpyridine-2,6-diamine) exhibits near infrared (NIR) emission with a high photoluminescence (PL) quantum yield ΦPL of 11 % and a lifetime of 898 μs in deaerated water at room temperature. While ligand-based control of the photophysical properties has received much attention, influences of the counter anions and microenvironment are still underexplored. In this study, the luminescence properties of the molecular ruby were systematically examined for the counter anions Cl−, Br−, [BF4]−, [PF6]−, [BPh4]−, and [BArF24]− in acetonitrile (MeCN) solution, in crystals, and embedded into polystyrene nanoparticles (PSNP). Stern-Volmer analyses of the oxygen quenching studies in the intensity and lifetime domain showed the highest oxygen sensitivity of the complexes with the counter anions of [BF4]− and [BArF24]−, which also revealed the longest luminescence lifetimes. Embedding [Cr(ddpd)2][PF6]3 in PSNPs and shielding with poly(vinyl alcohol) yields a strongly NIR-emissive oxygen-insensitive material with a record ΦPL of 15.2 % under ambient conditions.
KW - Fluorescence
KW - Sensor
KW - Oxygen
KW - Quantum yield
KW - Quality assurance
KW - Complex
KW - Cr(III)
KW - Lifetime
KW - Ligand
KW - Solid state
KW - X-Ray analysis
KW - Structure-property relationship
KW - Nano
KW - Polymer
KW - Particle
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546057
DO - https://doi.org/10.1002/cptc.202100296
SN - 2367-0932
VL - 6
IS - 6
SP - 1
EP - 9
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-54605
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 -
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 - JOUR
A1 - Witte, F.
A1 - Rietsch, P.
A1 - Nirmalananthan-Budau, Nithiya
A1 - Weigert, Florian
A1 - Götze, J. P.
A1 - Resch-Genger, Ute
A1 - Eigler, S.
A1 - Paulus, B.
T1 - Aggregation-induced emission leading to two distinct emissive species in the solid-state structure of high-dipole organic chromophores
N2 - The concept of aggregation-induced emission represents a means to rationalise photoluminescence of usually nonfluorescent excimers in solid-state materials. In this publication, we study the photophysical properties of selected diaminodicyanoquinone (DADQ) derivatives in the solid state using a combined approach of experiment and theory. DADQs are a class of high-dipole organic chromophores promising for applications in non-linear optics and light-harvesting devices. Among the compounds investigated, we find both aggregation-induced emission and aggregation-caused quenching effects rationalised by calculated energy transfer rates. Analysis of fluorescence spectra and lifetime measurements provide the interesting result that (at least) two emissive species seem to contribute to the photophysical properties of DADQs. The main emission peak is notably broadened in the long-wavelength limit and exhibits a blue-shifted shoulder. We employ high-level quantum-chemical methods to validate a molecular approach to a solid-state problem and show that the complex emission features of DADQs can be attributed to a combination of H-type aggregates, monomers, and crystal structure defects.
KW - Fluorescence
KW - Optical probe
KW - Dye
KW - Photophysics
KW - Theory
KW - Quantum yield
KW - Mechanism
KW - Quantum chemistry
KW - Modelling
KW - Aggregation
KW - Lifetime
KW - Single particle
KW - Microscopy
KW - Solid
KW - Crystal
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531138
DO - https://doi.org/10.1039/d1cp02534a
SP - 1
EP - 9
PB - Royal Society of Chemistry
AN - OPUS4-53113
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Andresen, Elina
A1 - Radunz, Sebastian
A1 - Resch-Genger, Ute
T1 - Novel PET-Operated Rosamine Sensor Dyes with Substitution Pattern-Tunable pKa Values and Temperature Sensitivity
N2 - We present the synthesis and characterization of a family of regioisomerically pure pH-sensitive rosamine fluorophores consisting of xanthene fluorophore cores, which determine the dyes’ photophysical properties such as excitation/emission wavelength, fluorescence quantum yield, and fluorescence lifetime, and differently substituted phenol moieties. The hydroxyl substituent of the phenol moiety introduces a pH sensitivity of the dyes’ fluorescence exploiting a photoinduced electron transfer (PET), that leads to a protonation-induced switching ON of the rosamine emission. Rational tuning of the pKa value of the rosamine fluorescence between 4 to 9 is achieved by altering the substitution pattern and degree of bromination of the phenolic subunits. Additionally, a temperature sensitivity of the fluorescence quantum yield is introduced or suppressed based upon the degree of rigidity of the xanthene scaffold.
KW - Fluorescence
KW - Optical probe
KW - Sensor
KW - Dye
KW - Rosamine
KW - Synthesis
KW - Photophysics
KW - PH
KW - Quantum yield
KW - Quality assurancemechanism
KW - temperature
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530562
DO - https://doi.org/10.1039/d1nj02505h
VL - 45
IS - 31
SP - 13934
EP - 13940
PB - Royal Society of Chemistry
AN - OPUS4-53056
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Le Guevel, X.
A1 - Wegner, Karl David
A1 - Würth, Christian
A1 - Baulin, V. A.
A1 - Musnier, B.
A1 - Josserand, V.
A1 - Resch-Genger, Ute
A1 - Koll, J-C
T1 - Tailoring the SWIR emission of gold nanoclusters by surface ligand rigidification and their application in 3D bioimaging
N2 - The influence of solvent polarity and surface ligand rigidification on the SWIR emission profile of gold nanoclusters with an anistropic surface was investigated. A strong enhancement of the SWIR emission band at 1200 nm was observed when measuring in different local environments: in solution, in polymer composites, and in solids. SWIR in vivo imaging of mice assisted by deep learning after intravenous administration of these gold nanoclusters provides high definition pseudo-3D views of vascular blood vessels.
KW - Nano
KW - Nanomaterial
KW - Metal cluster
KW - Photoluminescence
KW - Quantum yield
KW - Photophysics
KW - Lifetime
KW - Sensor
KW - NIR
KW - SWIR
KW - Ligand
KW - Gold
KW - Mechanism
KW - Charge transfer
KW - Enhancement strategy
KW - Imaging
KW - Application
KW - Contrast agent
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543582
DO - https://doi.org/10.1039/D1CC06737K
VL - 58
IS - 18
SP - 2967
EP - 2970
PB - RSC
AN - OPUS4-54358
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nowatzky, Yannek
A1 - Russo, Francesco Friedrich
A1 - Lisec, Jan
A1 - Kister, Alexander
A1 - Reinert, Knut
A1 - Muth, Thilo
A1 - Benner, Philipp
T1 - FIORA: Local neighborhood-based prediction of compound mass spectra from single fragmentation events
N2 - Non-targeted metabolomics holds great promise for advancing precision medicine and biomarker discovery. However, identifying compounds from tandem mass spectra remains a challenging task due to the incomplete nature of spectral reference libraries. Augmenting these libraries with simulated mass spectra can provide the necessary references to resolve unmatched spectra, but generating high-quality data is difficult. In this study, we present FIORA, an open-source graph neural network designed to simulate tandem mass spectra. Our main contribution lies in utilizing the molecular neighborhood of bonds to learn breaking patterns and derive fragment ion probabilities. FIORA not only surpasses state-of-the-art fragmentation algorithms, ICEBERG and CFM-ID, in prediction quality, but also facilitates the prediction of additional features, such as retention time and collision cross section. Utilizing GPU acceleration, FIORA enables rapid validation of putative compound annotations and large-scale expansion of spectral reference libraries with high-quality predictions.
KW - Metabolomics
KW - Machine Learning
KW - Mass spectrometry
KW - Bioinformatics
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-627585
DO - https://doi.org/10.1038/s41467-025-57422-4
SN - 2041-1723
VL - 16
IS - 1
SP - 1
EP - 17
PB - Springer Science and Business Media LLC
AN - OPUS4-62758
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - López-Puertollano, Daniel
A1 - Duncan, Hadyn
A1 - Abad-Somovilla, Antonio
A1 - Abad-Fuentes, Antonio
A1 - Rurack, Knut
T1 - Competitive cytometry-based immunoassay for patulin determination in apple juice
N2 - Patulin is a mycotoxin that is frequently found in apples and apple-derived products. Given the potential harm it can cause to humans, maximum levels for patulin in food have been set worldwide. Conventional methods for the detection of patulin are often time-consuming or lack sensitivity. In this study, a novel cytometry approach based on specific monoclonal antibodies is presented. These high-affinity binders do not target patulin itself, but a stable derivative (adduct) that is rapidly obtained in an aqueous medium at room temperature. To develop the assay, a specific fluorescent competitor was designed and synthesized. After optimizing the assay conditions, including the concentration of the fluorescent competitor and of the antibody bound to polystyrene-silica core–shell microparticles, a detection limit of 0.03 μg L-1 in buffer was achieved. Finally, validation according to Commission Regulation (EU) 2023/2782 demonstrated that apple juice samples spiked with patulin at 25 or 50 μg L-1 (permissible limits set by the EU) were properly scored as non-compliant without any additional treatment other than a simple dilution step in buffer. The developed assay offers several key advantages, including rapid analysis, high sensitivity and specificity, and the potential for multiplexing, making it a promising analytical tool for routine monitoring of patulin contamination in food.
KW - Bead-based assay
KW - Cytometry
KW - Derivatization
KW - Mycotoxin
KW - Patulin
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-627659
DO - https://doi.org/10.1016/j.microc.2025.113287
SN - 1095-9149
VL - 212
SP - 1
EP - 8
PB - Elsevier B.V.
AN - OPUS4-62765
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - López-Puertollano, Daniel
A1 - Tobias, Charlie
A1 - Bell, Jérémy
A1 - Abad-Somovilla, A.
A1 - Abad-Fuentes, A.
A1 - Rurack, Knut
T1 - Superparamagnetic Bead-Based Microfluidic Fluoroimmunoassay Platform for Rapid Ochratoxin A Detection in Flour
N2 - Simplification and reduction of time and costs are the primary goals in the development and use of onsite methods in diagnostics and food safety. To facilitate the transition from laboratory techniques to simple, miniaturized devices, we have developed a modular microfluidic platform. This platform integrates a competitive fluorescence immunoassay on the surface of superparamagnetic beads, serving as a complementary technique to traditional cytometry assays. In the first chip module, a fast competitive reaction (5 min) occurs, after which the particles are retained in the second module. This module consists of a PDMS chip and a permanent magnet, allowing only the fluorescent competitor to reach the detection module. Ochratoxin A (OTA) was chosen as the model analyte for device development, using fluorescein-labeled OTA as a competitor. The system efficiently separates particles, with OTA concentration directly correlated to the amount of fluorescent competitor remaining in solution after the competitive reaction. This innovative setup allows to perform rapid measurements with small sample volumes in a short time (10 min), achieving a limit of detection for OTA of 1.2 μg L–1. The system was successfully applied to the accurate determination of OTA in wheat flour spiked at regulatorily relevant concentrations. Using this device, conventional cytometry immunoassays can be seamlessly transformed into user-friendly, miniaturized analytical methods at reduced cost for applications outside of a laboratory directly at the point of need.
KW - Bead-based assay
KW - Fluorescence
KW - Immunoassay
KW - Microfluidics
KW - mycotoxins
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638472
DO - https://doi.org/10.1021/acssensors.5c01119
SN - 2379-3694
SP - 1
EP - 10
PB - American Chemical Society
CY - Washington, D.C.
AN - OPUS4-63847
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Winckelmann, Alexander
A1 - Nowak, S.
A1 - Richter, Silke
A1 - Recknagel, Sebastian
A1 - Riedel, Jens
A1 - Vogl, Jochen
A1 - Panne, Ulrich
A1 - Abad Andrade, Carlos Enrique
T1 - High-Resolution Atomic Absorption Spectrometry Combined With Machine Learning Data Processing for Isotope Amount Ratio Analysis of Lithium
N2 - An alternative method for lithium isotope amount ratio analysis based on a combination of high-resolution atomic absorption spectrometry and spectral data analysis by machine learning (ML) is proposed herein. It is based on the well-known isotope shift of approximately 15 pm for the electronic transition 22P←22S at around the wavelength of 670.8 nm, which can be measured by the state-of-the-art high-resolution continuum source graphite furnace atomic absorption spectrometry. For isotope amount ratio analysis, a scalable tree boosting ML algorithm (XGBoost) was employed and calibrated using a set of samples with 6Li isotope amount fractions, ranging from 0.06 to 0.99 mol mol–1, previously determined by a multicollector inductively coupled plasma mass spectrometer (MC-ICP-MS). The calibration ML model was validated with two certified reference materials (LSVEC and IRMM-016). The procedure was applied toward the isotope amount ratio determination of a set of stock chemicals (Li2CO3, LiNO3, LiCl, and LiOH) and a BAM candidate reference material NMC111 (LiNi1/3Mn1/3Co1/3O2), a Li-battery cathode material. The results of these determinations were compared with those obtained by MC-ICP-MS and found to be metrologically comparable and compatible. The residual bias was −1.8‰, and the precision obtained ranged from 1.9 to 6.2‰. This precision was sufficient to resolve naturally occurring variations, as demonstrated for samples ranging from approximately −3 to +15‰. To assess its suitability to technical applications, the NMC111 cathode candidate reference material was analyzed using high-resolution continuum source atomic absorption spectrometry with and without matrix purification. The results obtained were metrologically compatible with each other.
KW - Lithium
KW - Isotope
KW - Machine learning
KW - Algorithms
KW - Reference material
KW - AAS
KW - Atomic Absorption Spectrometry
PY - 2021
DO - https://doi.org/10.1021/acs.analchem.1c00206
SN - 1520-6882
VL - 93
IS - 29
SP - 10022
EP - 10030
PB - American Chemical Society
CY - Washington, DC, USA
AN - OPUS4-53028
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sun, Yijuan
A1 - Gawlitza, Kornelia
A1 - Valderrey, Virginia
A1 - Bell, Jérémy
A1 - Rurack, Knut
T1 - Polymerizable BODIPY probe crosslinker for the molecularly imprinted polymer-based detection of organic carboxylates via fluorescence
N2 - This contribution reports the development of a polymerizable BODIPY-type fluorescent probe targeting small-molecule carboxylates for incorporation into molecularly imprinted polymers (MIPs). The design of the probe crosslinker includes a urea recognition site p-conjugated to the 3-position of the BODIPY core and two methacrylate moieties. Titration experiments with a carboxylate-expressing antibiotic, levofloxacin (LEVO), showed a blue shift of the absorption band as well as a broadening and decrease in emission, attributed to hydrogen bonding between the probe’s urea group and the carboxylate group of the antibiotic. Using this probe crosslinker, core–shell particles with a silica core and a thin MIP shell were prepared for the detection of LEVO. The MIP exhibited highly selective recognition of LEVO, with an imprinting factor of 18.1 compared to the non-imprinted polymer. Transmission electron microscopy confirmed the core–shell structure and spectroscopic studies revealed that the receptor’s positioning leads to a unique perturbation of the polymethinic character of the BODIPY chromophore, entailing the favourable responses. These features are fully preserved in the MIP, whereas no such response was observed for competitors such as ampicillin. The sensory particles allowed to detect LEVO down to submicromolar concentrations in dioxane. We have developed here for the first time a BODIPY probe for organic carboxylates and incorporated it into polymers using the imprinting technique, paving the way for BODIPY-type fluorescent MIP sensors.
KW - Fluorescence
KW - BODIPY probe
KW - Molecularly Imprinted Polymers
KW - Sensor Materials
KW - Dyes
KW - Water analysis
KW - Advanced materials
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598629
DO - https://doi.org/10.1039/D3MA00476G
SP - 1
EP - 11
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-59862
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Verhassel, Alejandra
A1 - Kimani, Martha Wamaitha
A1 - Gidwani, Kamlesh
A1 - Sandholm, Jouko
A1 - Gawlitza, Kornelia
A1 - Rurack, Knut
A1 - Härkönen, Pirkko
T1 - Detection of Tn-antigen in breast and prostate cancer models by VVL-labeled red dye-doped nanoparticles
N2 - Aim: Fluorescence detection of breast and prostate cancer cells expressing Tn-antigen, a tumor marker, with Vicia villosa lectin (VVL)-labeled nanoparticles.
Materials & methods: Breast and prostate cancer cells engineered to express high levels of Tn-antigen and non-engineered controls were incubated with VVL-labeled or unlabeled red dye-doped silica-coated polystyrene nanoparticles. The binding to cells was studied with flow cytometry, confocal microscopy, and electron microscopy.
Results: Flow cytometry showed that the binding of VVL-labeled nanoparticles was significantly higher to Tn-antigen-expressing cancer cells than controls. Confocal microscopy demonstrated that particles bound to the cell surface. According to the correlative light and electron microscopy the particles bound mostly as aggregates.
Conclusion: VVL-labeled nanoparticles could provide a new tool for the detection of Tn-antigen-expressing breast and prostate cancer cells.
KW - Breast cancer cells
KW - Fluorescence detection
KW - Lectin labeling
KW - Prostate cancer cells
KW - Silica-coated polystyrene nanoparticles
KW - Tn-antigen
KW - VVL
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613451
DO - https://doi.org/10.1080/17435889.2024.2405454
SN - 1743-5889
VL - 19
SP - 2463
EP - 2478
PB - Taylor & Francis
CY - London
AN - OPUS4-61345
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Morcillo, Dalia
A1 - Winckelmann, Alexander
A1 - Frick, Daniel A.
A1 - Jacobsen, Lars
A1 - Seger, Tino
A1 - Florek, Stefan
A1 - Richter, Silke
A1 - Vogl, Jochen
A1 - Recknagel, Sebastian
A1 - Panne, Ulrich
A1 - Abad Andrade, Carlos Enrique
T1 - Lithium isotope ratio analysis of geological samples using atomic absorption spectrometry with improved spectral resolution
N2 - This study introduces an improved spectrometric method with enhanced precision to determine isotope ratios in geological samples without chromatographic separation. Firstly, the improvement is achieved by increasing the spectral resolution of the spectrometer applied in well-known high-resolution continuum source atomic absorption spectrometry (HR-CS-AAS). The resulting resolving power and linear dispersion of the upgraded setup, which is denoted in the following as HR+CS-AAS, is well adapted to the line widths of the Li isotope components we investigated. Secondly, our proposed method combines optical absorption spectrometry with machine learning data analysis using an extreme gradient boosting algorithm (XGBoost). This method was applied to analyze certified geological reference materials with δLSVEC(7Li/6Li) (hereafter δ7Li) values ranging from −0.5 ‰ to 4.5 ‰. With a pixel related optical resolving power of λ/∆λ ≈ 780 000, we obtain precisions in δ7Li measurements from 1.0 ‰ to 2.5 ‰. The method is validated by comparing the results with multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS), confirming its metrological compatibility. This work presents a fast, robust, and reliable method for δ7Li measurement in geological samples.
KW - Isotope
KW - High-resolution continuum source atomic absorption spectroscopy
KW - Lithium
KW - Machine learning
KW - Echelle spectrometer
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611807
DO - https://doi.org/10.1016/j.sab.2024.107013
VL - 220
SP - 1
EP - 5
PB - Elsevier BV
AN - OPUS4-61180
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pauli, Jutta
A1 - Ramírez, A.
A1 - Crasselt, C.
A1 - Schmidt, W.
A1 - Resch-Genger, Ute
T1 - Utilizing optical spectroscopy and 2',7'-difluorofluorescein to characterize the early stages of cement hydration
N2 - The increasingly sophisticated nature of modern, more environmentally friendly cementitious binders requires a better understanding and control particularly of the complex, dynamic processes involved in the early phase of cement hydration. In-situ monitoring of properties of a constantly changing system over a defined period of time calls for simple, sensitive, fast, and preferably also non-invasive methods like optical spectroscopy
KW - Flourescence
KW - Optical probe
KW - Sensor
KW - Dye
KW - Flourescin
KW - Photophysics
KW - PH
KW - Quantum yield
KW - Quality assurance
KW - Mechanism
KW - Cement
KW - Concrete
KW - Building material
KW - Hydration
KW - Process monitoring
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-537176
DO - https://doi.org/10.1088/2050-6120/ac2da0
SN - 2050-6120
VL - 10
IS - 1
SP - 2
EP - 13
PB - IOP Science
AN - OPUS4-53717
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yanbaeva, M.
A1 - Soyka, J.
A1 - Holthoff, J. M.
A1 - Rietsch, P.
A1 - Engelage, E.
A1 - Ruff, A.
A1 - Resch-Genger, Ute
A1 - Weiss, R.
A1 - Eigler, S.
A1 - Huber, S. M.
T1 - Dimethylene-Cyclopropanide Units as Building Blocks for Fluorescence Dyes
N2 - Many organic dyes are fluorescent in solution. In the solid state, however, quenching processes often dominate, hampering material science applications such as light filters, light-emitting devices, or coding tags. We show that the dimethylene-cyclopropanides caffold can be used to form two structurally different types of chromophores, which feature fluorescence quantum yields up to 0.66 in dimethyl sulfoxide and 0.53 in
solids. The increased fluorescence in the solid state for compounds bearing malonate substituents instead of dicyanomethide ones is rationalized by the induced twist between the planes of the cyclopropanide core and a pyridine ligand.
KW - Fluorescence
KW - Dye
KW - Sensor
KW - Quantum yield
KW - Spectroscopy
KW - Photophysics
KW - Synthesis
KW - Solvatochromism
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-614931
DO - https://doi.org/10.1002/chem.202402476
VL - 30
IS - 56
SP - 1
EP - 7
PB - Chemistry - A European Journal
AN - OPUS4-61493
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Abram, Sarah-Luise
A1 - Tavernaro, Isabella
A1 - Resch-Genger, Ute
A1 - Johnston, L. J.
A1 - Zou, S.
T1 - Nanoscale reference and test materials for the validation of characterization methods for engineered nanomaterials — current state, limitations, and needs
N2 - The rational design of engineered nanomaterials (NMs) with improved functionality and their increasing industrial application requires reliable, validated, and ultimately standardized characterization methods for their application-relevant, physicochemical key properties such as size, size distribution, shape, or surface chemistry. This calls for nanoscale (certified)
reference materials (CRMs; RMs) and well-characterized reference test materials (RTMs) termed also quality control (QC) samples, assessed, e.g., in interlaboratory comparisons, for the validation and standardization of commonly used characterization methods. Thereby, increasing concerns regarding potential risks of NMs are also addressed and the road for safe and
sustainable-by-design concepts for the development of new functional NMs and their use as nanomedicines is paved. With this respect, we will provide an overview of relevant international standardization and regulatory activities, definitions, and recommendations on characterization methods and review currently available organic or inorganic nanoscale CRMs, RMs, and RTMs, including their characterization or certification. In addition, we will highlight typical applications to streamline the regulatory approval process and improve manufacturability including the special challenges imposed by the colloidal nature and sometimes limited stability of NMs. Subsequently, we will critically assess the limitations of currently available nanoscale RMs and RTMs and address the gaps to be filled in the future such as the availability of NMs that come with reference data on properties other than commonly addressed particle size, such as surface chemistry or particle number concentration, or
more closely resemble commercially available formulations or address application-relevant matrices.
KW - Nano
KW - Particle
KW - Silica
KW - Quality assurance
KW - Reference material
KW - Review
KW - Surface chemistry
KW - Size
KW - Shape
KW - Particle number concentration
KW - Lipid nanoparticles
KW - Metal nanoparticles
KW - Liposomes
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625746
DO - https://doi.org/10.1007/s00216-024-05719-6
SN - 1618-2650
SP - 1
EP - 21
PB - Springer
AN - OPUS4-62574
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
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 - Epping, Ruben
A1 - Bliesener, Lilly
A1 - Weiss, Tilman
A1 - Koch, Matthias
T1 - Marker Substances in the Aroma of Truffles
N2 - The aim of this study was to identify specific truffle marker substances within the truffle aroma. The aroma profile of different truffle species was analyzed using static headspace sampling with gas chromatography mass spectrometry analysis (SHS/GC-MS). Possible marker substances were identified, taking the additional literature into account. The selected marker substances were tested in an experiment with 19 truffle dogs. The hypothesis “If trained truffle dogs recognize the substances as supposed truffles in the context of an experiment, they can be regarded as specific” was made. As it would be nearly impossible to investigate every other possible emitter of the same compounds to determine their specificity, this hypothesis was a reasonable approximation. We were interested in the question of what it is the dogs actually search for on a chemical level and whether we can link their ability to find truffles to one or more specific marker substances. The results of the dog experiment are not as unambiguous as could have been expected based on the SHS/GC-MS measurements. Presumably, the truffle aroma is mainly characterized and perceived by dogs by dimethyl sulfide and dimethyl disulfide. However, as dogs are living beings and not analytical instruments, it seems unavoidable that one must live with some degree of uncertainty regarding these results.
KW - Truffle
KW - Volatile organic compounds;
KW - Gas chromatography
KW - Mass spectrometry
KW - Canine olfactometry
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-556116
DO - https://doi.org/10.3390/molecules27165169
SN - 1420-3049
VL - 27
IS - 16
SP - 1
EP - 19
PB - MDPI
CY - Basel
AN - OPUS4-55611
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Epping, Ruben
A1 - Koch, Matthias
T1 - On-Site Detection of Volatile Organic Compounds (VOCs)
N2 - Volatile organic compounds (VOCs) are of interest in many different fields. Among them are food and fragrance analysis, environmental and atmospheric research, industrial applications, security or medical and life science. In the past, the characterization of these compounds was mostly performed via sample collection and off-site analysis with gas chromatography coupled to mass spectrometry (GC-MS) as the gold standard. While powerful, this method also has several drawbacks such as being slow, expensive, and demanding on the user. For decades, intense research has been dedicated to find methods for fast VOC analysis on-site with time and spatial resolution. We present the working principles of the most important, utilized, and researched technologies for this purpose and highlight important publications from the last five years. In this overview, non-selective gas sensors, electronic noses, spectroscopic methods, miniaturized gas chromatography, ion mobility spectrometry and direct injection mass spectrometry are covered. The advantages and limitations of the different methods are compared. Finally, we give our outlook into the future progression of this field of research.
KW - Volatile organic compounds
KW - On-site detection
KW - Mobile analytics
KW - Sensors
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-570885
DO - https://doi.org/10.3390/molecules28041598
VL - 28
IS - 4
SP - 1
EP - 19
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-57088
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scholtz, Lena
A1 - Eckert, J. G.
A1 - Elahi, T.
A1 - Lübkemann, F.
A1 - Hübner, Oskar
A1 - Bigall, N. C.
A1 - Resch-Genger, Ute
T1 - Luminescence encoding of polymer microbeads with organic dyes and semiconductor quantum dots during polymerization
N2 - Luminescence-encoded microbeads are important tools for many applications in the life and material sciences that utilize luminescence detection as well as multiplexing and barcoding strategies. The preparation of such beads often involves the staining of premanufactured beads with molecular luminophores using simple swelling procedures or surface functionalization with layer-by-layer (LbL) techniques. Alternatively, these luminophores are sterically incorporated during the polymerization reaction yielding the polymer beads. The favorable optical properties of semiconductor quantum dots (QDs), which present broadly excitable, size-tunable, narrow emission bands and low photobleaching sensitivity, triggered the preparation of beads stained with QDs. However, the colloidal nature and the surface chemistry of these QDs, which largely controls their luminescence properties, introduce new challenges to bead encoding that have been barely systematically assessed. To establish a straightforward approach for the bead encoding with QDs with minimized loss in luminescence, we systematically assessed the incorporation of oleic acid/oleylamine-stabilized CdSe/CdS-core/shell-QDs into 0.5–2.5 μm-sized polystyrene (PS) microspheres by a simple dispersion polymerization synthesis that was first optimized with the organic dye Nile Red. Parameters addressed for the preparation of luminophore-encoded beads include the use of a polymer-compatible ligand such as benzyldimethyloctadecylammonium chloride (OBDAC) for the QDs, and crosslinking to prevent luminophore leakage. The physico-chemical and optical properties of the resulting beads were investigated with electron microscopy, dynamic light scattering, optical spectroscopy, and fluorescence microscopy. Particle size distribution, fluorescence quantum yield of the encapsulated QDs, and QD leaking stability were used as measures for bead quality. The derived optimized bead encoding procedure enables the reproducible preparation of bright PS microbeads encoded with organic dyes as well as with CdSe/CdS-QDs. Although these beads show a reduced photoluminescence quantum yield compared to the initially very strongly luminescent QDs, with values of about 35%, their photoluminescence quantum yield is nevertheless still moderate.
KW - Polymerization
KW - Quantum dots
KW - Microbeads
KW - Fluorescence
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-553430
DO - https://doi.org/10.1038/s41598-022-16065-x
SN - 2045-2322
VL - 12
SP - 1
EP - 16
PB - Nature Publishing Group
CY - London
AN - OPUS4-55343
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Clark, P.C.J
A1 - Andresen, Elina
A1 - Sear, M. J.
A1 - Favaro, M.
A1 - Girardi, L.
A1 - van de Krol, R.
A1 - Resch-Genger, Ute
A1 - Starr, D.E.
T1 - Quantification of the Activator and Sensitizer Ion Distributions in NaYF4:Yb3+, Er3+ Upconverting Nanoparticles Via Depth-Profiling with Tender X-Ray Photoemission
N2 - The spatial distribution and concentration of lanthanide activator and sensitizer dopant ions are of key importance for the luminescence color and efficiency of upconverting nanoparticles (UCNPs). Quantifying dopant ion distributions and intermixing, and correlating them with synthesis methods require suitable analytical techniques. Here, X-ray photoelectron spectroscopy depth-profiling with tender X-rays (2000–6000 eV), providing probe depths ideally matched to UCNP sizes, is used to measure the depth-dependent concentration ratios of Er3+ to Yb3+, [Er3+]/[Yb3+], in three types of UCNPs prepared using different reagents and synthesis methods. This is combined with data simulations and inductively coupled plasma-optical emission spectroscopy (ICP-OES) measurements of the lanthanide ion concentrations to construct models of the UCNPs’ dopant ion distributions. The UCNP sizes and architectures are chosen to demonstrate the potential of this approach. Core-only UCNPs synthesized with XCl3·6H2O precursors (β-phase) exhibit a homogeneous distribution of lanthanide ions, but a slightly surface-enhanced [Er3+]/[Yb3+] is observed for UCNPs prepared with trifluroacetate precursors (α-phase). Examination of Yb-core@Er-shell UCNPs reveals a co-doped, intermixed region between the single-doped core and shell. The impact of these different dopant ion distributions on the UCNP's optical properties is discussed to highlight their importance for UCNP functionality and the design of efficient UCNPs.
KW - Shell
KW - Nanomaterial
KW - Nano
KW - Upconversion nanoparticle
KW - Lanthanide
KW - Photoluminescence
KW - Quantum yield
KW - Photophysics
KW - Excitation power density
KW - Surface
KW - Coating
KW - Core-shell
KW - XPS
KW - Intermixing
KW - HAXPES
KW - Method
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552075
DO - https://doi.org/10.1002/smll.202107976
SN - 1613-6813
SP - 1
EP - 13
PB - Wiley-VCH-Verlag
CY - Weinheim, Germany
AN - OPUS4-55207
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kromer, C.
A1 - Schwibbert, Karin
A1 - Gadicherla, A. K.
A1 - Thiele, Dorothea
A1 - Nirmalananthan-Budau, Nithiya
A1 - Laux, P.
A1 - Resch-Genger, Ute
A1 - Luch, A.
A1 - Tschiche, H. R.
T1 - Monitoring and imaging pH in biofilms utilizing a fluorescent polymeric nanosensor
N2 - Biofilms are ubiquitous in nature and in the man-made environment. Given their harmful effects on human health, an in-depth understanding of biofilms and the monitoring of their formation and growth are important. Particularly relevant for many metabolic processes and survival strategies of biofilms is their extracellular pH. However, most conventional techniques are not suited for minimally invasive pH measurements of living biofilms. Here, a fluorescent nanosensor is presented for ratiometric measurements of pH in biofilms in the range of pH 4.5–9.5 using confocal laser scanning microscopy. The nanosensor consists of biocompatible polystyrene nanoparticles loaded with pH-inert dye Nile Red and is surface functionalized with a pH-responsive fluorescein dye. Its performance was validated by fluorometrically monitoring the time-dependent changes in pH in E. coli biofilms after glucose inoculation at 37 °C and 4 °C. This revealed a temperature-dependent decrease in pH over a 4-h period caused by the acidifying glucose metabolism of E. coli. These studies demonstrate the applicability of this nanosensor to characterize the chemical microenvironment in biofilms with fluorescence methods.
KW - Dye
KW - Fluorescence
KW - Signal enhancement
KW - Sensor
KW - Quantum yield
KW - Synthesis
KW - Nanoparticle
KW - Nano
KW - Polymer
KW - Ph
KW - Biofilm
KW - MIC
KW - Corrosion
KW - Microorganism
KW - Bacteria
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550751
DO - https://doi.org/10.1038/s41598-022-13518-1
SN - 2045-2322
VL - 12
IS - 1
SP - 1
EP - 10
PB - Nature Publishing Group
CY - London
AN - OPUS4-55075
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Knoche, Lisa
A1 - Lisec, Jan
A1 - Koch, Matthias
T1 - Analysis of electrochemical and liver microsomal transformation products of lasalocid by LC/HRMS
N2 - Rationale: Lasalocid (LAS), an ionophore, is used in cattle and poultry farming as feed additive for its antibiotic and growth-promoting properties. Literature on transformation products (TP) resulting from LAS degradation is limited. So far, only hydroxylation is found to occur as the metabolic reaction during the LAS degradation. To investigate potential TPs of LAS, we used electrochemistry (EC) and liver microsome (LM) assays to synthesize TPs, which were identified using liquid chromatography high-resolution mass spectrometry (LC/HRMS).
Methods: Electrochemically produced TPs were analyzed online by direct coupling of the electrochemical cell to the electrospray ionization (ESI) source of a Sciex Triple-TOF high resolution mass spectrometer. Then, EC-treated LAS solution was collected and analyzed offline using LC/HRMS to confirm stable TPs and improve their annotation with a chemical structure due to informative MS/MS spectra. In a complementary approach, TPs formed by rat and human microsomal incubation were investigated using LC/HRMS. The resulting data were used to investigate LAS modification reactions and elucidate the chemical structure of obtained TPs.
Results: The online measurements identified a broad variety of TPs, resulting from modification reactions like (de-)hydrogenation, hydration, methylation, oxidation as well as adduct formation with methanol. We consistently observed different ion complexations of LAS and LAS-TPs (Na+; 2Na+ K+; NaNH4 +; KNH4 +). Two stable methylated EC-TPs were found, structurally annotated, and assigned to a likely modification reaction. Using LM incubation, seven TPs were formed, mostly by oxidation/hydroxylation. After the identification of LM-TPs as Na+-complexes, we identified LM-TPs as K+-complexes.
Conclusion: We identified and characterized TPs of LAS using EC- and LM-based methods. Moreover, we found different ion complexes of LAS-based TPs. This knowledge, especially the different ion complexes, may help elucidate the metabolic and environmental degradation pathways of LAS.
KW - Mass Spectrometry
KW - Electrochemistry
KW - ECR
KW - Lasalocid
KW - Ionophore
KW - Transformation products
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-553919
DO - https://doi.org/10.1002/rcm.9349
VL - 36
IS - 18
SP - 1
EP - 10
PB - Wiley online library
AN - OPUS4-55391
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Koch, Matthias
A1 - Mauch, Tatjana
A1 - Riedel, Juliane
T1 - Development of a Hydrazine-Based Solid-Phase Extraction and Clean-Up Method for Highly Selective Quantification of Zearalenone in Edible Vegetable Oils by HPLC-FLD
N2 - Rapid, cost-efficient, and eco-friendly methods are desired today for routine analysis of the Fusarium mycotoxin zearalenone (ZEN) in edible vegetable oils. Liquid chromatography with fluorescence detection (HPLC-FLD) is commonly used to reliably control the specified ZEN maximum levels, which requires efficient sample clean-up to avoid matrix interferences. Therefore, a highly selective extraction and clean-up method based on reversible covalent hydrazine chemistry (RCHC) using hydrazine-functionalized silica was developed. This efficient solid-phase extraction (SPE) involves reversible hydrazone formation of ZEN with the hydrazine moiety covalently bound to a solid phase. Optimal conditions were achieved with 1 mL SPE cartridges filled with 400 mg of hydrazine-functionalized silica. The developed RCHC-SPE method was validated in an interlaboratory comparison study (ILC) with twelve participants analyzing six edible vegetable oils with a focus on maize oils. The derived method parameters (ZEN recovery 83%, repeatability 7.0%, and reproducibility 18%) meet the performance criteria of Commission Regulation (EC) No 401/2006. The developed RCHC-SPE-based HPLC-FLD method allows the reliable quantification of ZEN in the range of 47–494 μg/kg for different types of edible vegetable oils, also for matrix-reach native oils. Due to the high efficiency, the significantly reduced matrix load helps to extend the lifetime of analytical equipment. Furthermore, the re-useability of the RCHC-SPE cartridges contributes to an eco-friendly approach and reduced analysis costs. To our knowledge, this is the first report on ZEN quantification in edible vegetable oils based on manual RCHC-SPE cartridges. Due to its high performance, the developed RCHC-SPE method is a promising alternative to the current European standard method EN 16924:2017 (HPLC-FLD part).
KW - Mycotoxin
KW - Food
KW - Reversible covalent hydrazine chemistry (RCHC)
KW - Quantitative determination
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-554812
DO - https://doi.org/10.3390/toxins14080549
VL - 14
IS - 8
PB - MDPI
CY - Basel
AN - OPUS4-55481
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stein, L.
A1 - Wang, Cui
A1 - Förster, C.
A1 - Resch-Genger, Ute
A1 - Heinze, K.
T1 - Bulky ligands protect molecular ruby from oxygen quenching
N2 - Chromium(III) complexes can show phosphorescence from the spin-flip excited doublet states 2E/2T1 in the near-infrared with high photoluminescence quantum yields and extremely long lifetimes in the absence of dioxygen. The prototype molecular ruby, [Cr(ddpd)2]3+ (ddpd = N,N’-dimethyl-N,N’-dipyridine-2-ylpyridine-2,6-diamine), has a photoluminescence quantum yield and a luminescence lifetime of 13.7% and 1.1 ms in deaerated acetonitrile, respectively. However, its luminescence is strongly quenched by 3O2 via an efficient Dexter-type energy transfer process. To enable luminescence applications of molecular rubies in solution under aerobic conditions, we explored the potential of sterically demanding ddpd ligands to shield the chromium(III) center from O2 using steady state and time-resolved photoluminescence spectroscopy. The structures of the novel complexes with sterically demanding ligands were investigated by single crystal X-ray diffraction and quantum chemically by density functional theory calculations. The O2 sensitivity of the photoluminescence was derived from absolutely measured photoluminescence quantum yields and excited state lifetimes under inert and aerobic conditions and by Stern–Volmer analyses of these data. Optimal sterically shielded chromium(III) complexes revealed photoluminescence quantum yields of up to 5.1% and excited state lifetimes of 518 μs in air-saturated acetonitrile, underlining the large potential of this ligand design approach to broaden the applicability of highly emissive chromium(III) complexes.
KW - Fluorescence
KW - Synthesis
KW - Production
KW - Optical spectroscopy
KW - Ligand
KW - Photophysics
KW - Cr(III)
KW - Mechanism
KW - NIR
KW - Sensor
KW - Oxygen
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-570807
DO - https://doi.org/10.1039/d2dt02950b
VL - 51
IS - 46
SP - 17664
EP - 17670
PB - The Royal Society of Chemistry
CY - Berlin
AN - OPUS4-57080
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Epping, Ruben
A1 - Lisec, Jan
A1 - Koch, Matthias
T1 - Changes in Black Truffle (Tuber melanosporum) Aroma during Storage under Different Conditions
N2 - The enticing aroma of truffles is a key factor for their culinary value. Although all truffle species tend to be pricy, the most intensely aromatic species are the most sought after. Research into the aroma of truffles encompasses various disciplines including chemistry, biology, and sensory science. This study focusses on the chemical composition of the aroma of black truffles (Tuber melanosporum) and the changes occurring under different storage conditions. For this, truffle samples were stored under different treatments, at different temperatures, and measured over a total storage time of 12 days. Measurements of the truffle aroma profiles were taken with SPME/GC–MS at regular intervals. To handle the ample data collected, a systematic approach utilizing multivariate data analysis techniques was taken. This approach led to a vast amount of data which we made publicly available for future exploration. Results reveal the complexity of aroma changes, with 695 compounds identified, highlighting the need for a comprehensive understanding. Principal component analyses offer initial insights into truffle composition, while individual compounds may serve as markers for age (formic acid, 1-methylpropyl ester), freshness (2-Methyl-1-propanal; 1-(methylthio)-propane), freezing (tetrahydrofuran), salt treatment (1-chloropentane), or heat exposure (4-hydroxy-3-methyl-2-butanone). This research suggests that heat treatment or salt contact significantly affects truffle aroma, while freezing and cutting have less pronounced effects in comparison. The enrichment of compounds showing significant changes during storage was investigated with a metabolomic pathway analysis. The involvement of some of the enriched compounds on the pyruvate/glycolysis and sulfur pathways was shown.
KW - Mass Spectrometry
KW - Metabolomics
KW - Tuber melanosporum
KW - Truffle Aroma
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601731
DO - https://doi.org/10.3390/jof10050354
VL - 10
IS - 5
SP - 1
EP - 22
PB - MDPI
AN - OPUS4-60173
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scholtz, Lena
A1 - Tavernaro, Isabella
A1 - Eckert, J. G.
A1 - Lutowski, Marc
A1 - Geißler, Daniel
A1 - Hertwig, Andreas
A1 - Hidde, Gundula
A1 - Bigall, N. C.
A1 - Resch-Genger, Ute
T1 - Influence of nanoparticle encapsulation and encoding on the surface chemistry of polymer carrier beads
N2 - Surface-functionalized polymer beads encoded with molecular luminophores and nanocrystalline emitters such as semiconductor nanocrystals, often referred to as quantum dots (QDs), or magnetic nanoparticles are broadly used in the life sciences as reporters and carrier beads. Many of these applications require a profound knowledge of the chemical nature and total number of their surface functional groups (FGs), that control bead charge, colloidal stability, hydrophobicity, and the interaction with the environment and biological systems. For bioanalytical applications, also the number of groups accessible for the subsequent functionalization with, e.g., biomolecules or targeting ligands is relevant. In this study, we explore the influence of QD encoding on the amount of carboxylic acid (COOH) surface FGs of 2 μm polystyrene microparticles (PSMPs). This is done for frequently employed oleic acid and oleylamine stabilized, luminescent core/shell CdSe QDs and two commonly used encoding procedures. This included QD addition during bead formation by a thermally induced polymerization reaction and a post synthetic swelling procedure. The accessible number of COOH groups on the surface of QD-encoded and pristine beads was quantified by two colorimetric assays, utilizing differently sized reporters and electrostatic and covalent interactions. The results were compared to the total number of FGs obtained by a conductometric titration and Fourier transform infrared spectroscopy (FTIR). In addition, a comparison of the impact of QD and dye encoding on the bead surface chemistry was performed. Our results demonstrate the influence of QD encoding and the QD-encoding strategy on the number of surface FG that is ascribed to an interaction of the QDs with the carboxylic acid groups on the bead surface. These findings are of considerable relevance for applications of nanoparticle-encoded beads and safe-by-design concepts for nanomaterials.
KW - Optical spectroscopy
KW - Particle
KW - Optical assay
KW - IR spectroscopy
KW - Fluorescence
KW - Quantum yield
KW - Quality assurance
KW - Nano
KW - Synthesis
KW - Surface chemistry
KW - Quantification
KW - Method
KW - Conductometry
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581502
DO - https://doi.org/10.1038/s41598-023-38518-7
SN - 2045-2322
VL - 13
IS - 1
SP - 1
EP - 15
PB - Springer Nature
CY - London
AN - OPUS4-58150
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
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 - Mohammad, W.
A1 - Wegner, Karl David
A1 - Comby-Zerbino, C.
A1 - Trouillet, V.
A1 - Ogayer, M. P.
A1 - Coll, J.-L.
A1 - Marin, R.
A1 - Jaque Garcia, D.
A1 - Resch-Genger, Ute
A1 - Antoine, R.
A1 - Le Guevel, X.
T1 - Enhanced brightness of ultra-small gold nanoparticles in the second biological window through thiol ligand shell control
N2 - Gold-based nanoparticles below 2 nm in size are promising as luminescent probes for in vivo bioimaging, owing to their brightness and rapid renal clearance. However, their use as contrast agents in the near-infrared II (NIR-II, 1000–1700 nm) range remains challenging due to their low photoluminescence (PL) quantum yield. To address this, PL enhancement can be achieved by either rigidifying the ligand-shell structure or increasing the size of the ligand shell. In this study, we synthesized ultra-small gold nanoparticles stabilized by co-ligands, namely monothiol and short dithiol molecules. By precisely controlling the amount of reducing agent used during particle preparation, we successfully modulated the physicochemical properties of the co-ligand shell, including its size, composition, and structure. Consequently, we achieved a remarkable 60-fold increase in the absorption cross-section at 990 nm while maintaining the small size of the 1.5-nm metal core. The analytical and optical characterization of our thiol-capped gold nanoparticles indicates that the ligand shell size is governed by the quantity of the reducing agent, which, in turn, impacts the balance between radiative and non-radiative processes, thereby influencing the PL quantum yield.
KW - Gold nanocluster
KW - NIR-II fluorescence
KW - SWIR
KW - Nanomaterial design
KW - Calibrated fluorescence measurements
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588117
DO - https://doi.org/10.1039/D3TC03021K
SN - 2050-7526
VL - 11
IS - 42
SP - 14714
EP - 14724
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-58811
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
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 - Wang, Cui
A1 - Ebel, Kenny
A1 - Heinze, Katja
A1 - Resch-Genger, Ute
A1 - Bald, Ilko
T1 - Quantum Yield of DNA Strand Breaks under Photoexcitation of a Molecular Ruby
N2 - Photodynamic therapy (PDT) used for treating cancer relies on the generation of highly reactive oxygen species, for example, singlet oxygen 1O2, by light-induced excitation of a photosensitizer (PS) in the presence of molecular oxygen, inducing DNA damage in close proximity of the PS. Although many precious metal complexes have been explored as PS for PDT and received clinical approval, only recently, the potential of photoactive complexes of nonnoble metals as PS has been discovered. Using the DNA origami technology that can absolutely quantify DNA strand break cross sections, we assessed the potential of the luminescent transition metal complex [Cr(ddpd)2]3+ (ddpd=N,N’-dimethyl-N,N’-dipyridine-2-ylpyridine-2,6-diamine) to damage DNA in an air-saturated aqueous environment upon UV/Vis illumination. The quantum yield for strand breakage, that is, the ratio of DNA strand breaks to the number of absorbed photons, was determined to 1–4%, indicating efficient transformation of photons into DNA strand breaks by [Cr(ddpd)2]3+.
KW - Fluorescence
KW - Synthesis
KW - Production
KW - Optical spectroscopy
KW - Ligand
KW - Photophysics
KW - Cr(III)
KW - Mechanism
KW - NIR
KW - PDT
KW - Singlet oxygen
KW - DNA
KW - Origami
KW - Quantum yield
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573631
DO - https://doi.org/10.1002/chem.202203719
SP - 1
EP - 7
AN - OPUS4-57363
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
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 -
TY - JOUR
A1 - Tavernaro, Isabella
A1 - Sander, P. C.
A1 - Andresen, Elina
A1 - Schedler, U.
A1 - Resch-Genger, Ute
T1 - Expanding the Toolbox of Simple, Cost-Efficient, and Automatable Methods for Quantifying Surface Functional Groups on Nanoparticles� Potentiometric Titration
N2 - Measuring surface functional groups (FGs) on nanomaterials (NMs) is essential for designing dispersible and stable NMs with tailored and predictable functionality. FG screening and quantification also plays a critical role for subsequent processing steps, NM long-term stability, quality control of NM production, and risk assessment studies and enables the implementation of sustainable and safe(r)-by-design concepts. This calls for simple and cost-efficient methods for broadly utilized FGs that can be ideally automated to speed up FG screening, monitoring, and quantification. To expand our NM surface analysis toolbox, focusing on simple methods and broadly available, cost-efficient instrumentation, we explored a NM-adapted pH titration method with potentiometric and optical readout for measuring the total number of (de)protonable FGs on representatively chosen commercial and custom-made aminated silica nanoparticles (SiO2 NPs). The accuracy and robustness of our stepwise optimized workflows was assessed by several operators in two laboratories and method validation was done by cross-comparison with two analytical methods relying on different signal generation principles. This included traceable, chemo-selective quantitative nuclear magnetic resonance spectroscopy (qNMR) and thermogravimetric analysis (TGA), providing the amounts of amino silanes released by particle dissolution and the total mass of the surface coatings. A comparison of the potentiometric titration results with the reporter-specific amounts of surface amino FGs determined with the previously automated fluorescamine (Fluram) assay highlights the importance of determining both quantities for surface-functionalized NMs. In the future, combined NM surface analysis with optical assays and pH titration will simplify quality control of NM production processes and stability studies and can yield large data sets for NM grouping that facilitates further developments in regulation and standardization.
KW - Quality assurance
KW - Fluorescence
KW - Nano
KW - Particle
KW - Synthesis
KW - Characterization
KW - Advanced material
KW - Surface
KW - Standardization
KW - Reference material
KW - Functional group
KW - Quantification
KW - Coating
KW - Automation
KW - Potentiometry
KW - Method
KW - Validation
KW - Optical assay
KW - Fluram
KW - Fluorescamine
KW - qNMR
KW - Comparison
KW - ILC
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642371
DO - https://doi.org/10.1021/acsmeasuresciau.5c00062
SN - 2694-250X
SP - 1
EP - 13
PB - American Chemical Society
CY - Washington, DC
AN - OPUS4-64237
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Herter, Sven-Oliver
A1 - Haase, Hajo
A1 - Koch, Matthias
T1 - Semisynthesis of Stable Isotope-Labeled Ergot Alkaloids for HPLC-MS/MS Analysis
N2 - Ergot alkaloids (EAs) are prevalent food contaminants affecting cereals, such as rye, wheat, and barley worldwide. To ensure EU safety standards, the six most common EAs: ergometrine, ergotamine, ergosine, ergocornine, ergocristine, and ergocryptine, and their epimers, are quantified using HPLC-MS/MS, as described in the European Standard Method EN 17425:2021. However, this can be challenging and time-consuming in food matrices without appropriate internal standards and highlights the need for more robust and precise analytical tools to support their monitoring. The development of isotope-labeled EAs directly addresses this gap, offering improved accuracy and leading to more consistency across laboratories and consequently to more consumer safety. Therefore, we developed a semisynthetic approach, building upon our previous work where native ergotamine was N6-demethylated to norergotamine and subsequently remethylated using iodomethane (13CD3-I). Herein, we are now able to present the successful synthesis of all of the isotopically labeled priority EAs. These isotope-labeled standards were tested against their native counterparts using HPLC coupled with HR-MS/MS. The chromatographic and mass spectrometric properties of the unlabeled and isotopically labeled EAs match exactly, confirming their successful synthesis and structure. These standards can now be utilized to enhance the accuracy and reliability of EA quantification in food and feed.
KW - Reference Material
KW - HPLC-MS/MS
KW - Mycotoxins
KW - Ergot Alkaloids
KW - Stable Isotope Dilution Analysis
KW - Semisynthesis
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639692
DO - https://doi.org/10.1021/acs.jafc.5c03345
SN - 0021-8561
VL - 73
IS - 29
SP - 18412
EP - 18419
PB - American Chemical Society (ACS)
AN - OPUS4-63969
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stiegler, L. M. S.
A1 - Wegner, Karl David
A1 - Weigert, Florian
A1 - Peukert, W.
A1 - Resch-Genger, Ute
A1 - Walter, J.
T1 - Analysis of Giant-Shell CdSe/CdS Quantum Dots via Analytical Ultracentrifugation Combined with Spectrally Resolved Photoluminescence
N2 - Knowledge of the structure–property relationships of functional nanomaterials, including, for example, their size- and composition-dependent photoluminescence (PL) and particle-to-particle variations, is crucial for their design and reproducibility. Herein, the Angstrom-resolution capability of an analytical ultracentrifuge combined with an in-line multiwavelength emission detection system (MWE-AUC) for measuring the sedimentation coefficient-resolved spectrally corrected PL spectra of dispersed nanoparticles is demonstrated. The capabilities of this technique are shown for giant-shell CdSe/CdS quantum dots (g-QDs) with a PL quantum yield (PL QY) close to unity capped with oleic acid and oleylamine ligands. The MWE-AUC PL measurements are calibrated and validated with certified fluorescence standards. The spectrally corrected and size-dependent PL spectra of the g-QDs derived from a single MWE-AUC experiment are then analyzed and compared with the results of single-particle spectroscopic studies, yielding the PL spectra, decay kinetics, and blinking behavior of individual g-QDs. This study underlines the vast potential of MWE-AUC with in-line optical detection for the characterization of advanced nanomaterials with a complex structure.
KW - Quantum dots
KW - Analytical ultracentrifugation
KW - Photoluminescence
KW - Advanced nanomaterial characterization
KW - Calibrated fluorescence measurements
KW - Reference materials
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624357
DO - https://doi.org/10.1002/smtd.202401700
SN - 2366-9608
SP - 1
EP - 7
PB - Wiley VHC-Verlag
AN - OPUS4-62435
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Richter, Maria
A1 - Güttler, Arne
A1 - Pauli, Jutta
A1 - Vogel, K.
A1 - Homann, Christian
A1 - Würth, Christian
A1 - Resch-Genger, Ute
T1 - Extending certified spectral fluorescence standards for the calibration and performance validation of fluorescence instruments to the NIR—closing the gap from 750 to 940 nm with two novel NIR dyes
N2 - Fluorescence techniques such as fluorescence spectroscopy, microfluorometry, and fluorescence microscopy, providing spectral, intensity, polarization, and lifetime information, are amongst the most broadly utilized analytical methods in the life and materials sciences. However, the measured fluorescence data contain sample- and instrument-specific contributions, which hamper their comparability across instruments and laboratories. Comparable, instrument-independent fluorescence data require the determination of the fluorescence instrument’s wavelength-dependent spectral responsivity, also termed emission correction curve, for the same instrument settings as those used for the fluorescence measurements as a prerequisite for the subsequent correction of the measured instrument-specific data. Such a spectral correction is essential for the performance comparison of different fluorescent labels and reporters, quantitative fluorescence measurements, the determination of the fluorescence quantum yield, and the spectroscopic measure for the fluorescence efficiency of a fluorophore. Simple-to-use tools for obtaining emission correction curves are chromophore-based reference materials (RMs), referred to as fluorescence standards, with precisely known, preferably certified instrument-independent fluorescence spectra. However, for the increasingly used near-infrared (NIR) wavelength region >700 nm, at present, no spectral fluorescence standards are available. To close this gap, we developed two novel spectral fluorescence standards, BAM F007 and BAM-F009, with broad emission bands from about 580 to 940 nm in ethanolic solution. These liquid fluorescence standards currently under certification, which will be released in 2025, will expand the wavelength range of the already available certified Calibration Kit BAM F001b-F005b from about 300–730 to 940 nm. In this research article, we will detail the criteria utilized for dye and matrix selection and the homogeneity and stability tests accompanying dye certification as well as the calculation of the wavelength-dependent uncertainty budgets of the emission spectra BAM F007 and BAM-F009, determined with the traceably calibrated BAM reference spectrofluorometer. These fluorescence standards can provide the basis for comparable fluorescence measurements in the ultraviolet, visible, and NIR for the fluorescence community.
KW - Quality assurance
KW - Reference material
KW - Fluorescence
KW - Dye
KW - Traceability
KW - Metrology
KW - Calibration
KW - Reference data
KW - Reference product
KW - Digital certificate
KW - NIR
KW - Instrument performance validation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626317
DO - https://doi.org/10.1007/s00216-024-05723-w
SN - 1618-2650
SP - 1
EP - 15
PB - Springer
AN - OPUS4-62631
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Deumer, J.
A1 - Andresen, Elina
A1 - Gollwitzer, C.
A1 - Schürmann, R.
A1 - Resch-Genger, Ute
T1 - Adding More Shape to Nanoscale Reference Materials-LiYF4:Yb,Tm Bipyramids as Standards for Sizing Methods and Particle Number Concentration
N2 - The increasing industrial use of nanomaterials calls for the reliable characterization of their physicochemical key properties like size, size distribution, shape, and surface chemistry, and test and reference materials (RMs) with sizes and shapes, closely matching real-world nonspheric nano-objects. An efficient strategy to minimize efforts in producing nanoscale RMs (nanoRMs) for establishing, validating, and standardizing methods for characterizing nanomaterials are multimethod nanoRMs.
Ideal candidates are lanthanide-based, multicolor luminescent, and chemically inert nanoparticles (NPs) like upconversion nanoparticles (UCNPs), which can be prepared in different sizes, shapes, and chemical composition with various surface coatings. This makes UCNPs interesting candidates as standards not only for sizing methods, but also for element-analytical methods like laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS), quantitative bioimaging methods like X-ray fluorescence computed tomography (XFCT), and luminescence methods and correlative measurements.
Here, we explore the potential of two monodisperse LiYF4:Yb,Tm bipyramids with peak-to-peak distances of (43 ± 2) nm and (29 ± 2) nm as size standards for small-angle X-ray scattering (SAXS) and tools for establishing and validating the sophisticated simulations required for the analysis of SAXS data derived from dispersions of nonspheric nano-objects. These SAXS studies are supplemented by two-dimensional (2D)-transmission electron microscopy measurements of the UCNP bipyramids. Additionally, the particle number concentration of cyclohexane dispersions of these UCNP bipyramids is determined by absolute SAXS measurements, complemented by gravimetry, thermogravimetric analysis (TGA), and inductively coupled plasma optical emission spectrometry (ICP-OES). This approach enables traceable particle number concentration measurements of ligand-capped nonspheric particles with unknown chemical composition.
KW - Fluorescence
KW - Upconversion nanoparticles
KW - SAXS
KW - Particle number concentration
KW - Reference material
KW - Traceability
KW - Quality assurance
KW - Quantum yield
KW - Spectroscopy
KW - Synthesis
KW - Quantification
KW - NanoRM
KW - Nano
KW - Particle
KW - Bipyramid
KW - Reference data
KW - Simulation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-617940
DO - https://doi.org/10.1021/acs.analchem.4c03641
SP - 1
EP - 8
PB - ACS Publications
AN - OPUS4-61794
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Knoche, Lisa
A1 - Lisec, Jan
A1 - Schwerdtle, T.
A1 - Koch, Matthias
T1 - LC-HRMS-Based Identification of Transformation Products of the Drug Salinomycin Generated by Electrochemistry and Liver Microsome
N2 - The drug salinomycin (SAL) is a polyether antibiotic and used in veterinary Medicine as coccidiostat and growth promoter. Recently, SAL was suggested as a potential anticancer drug.
However, transformation products (TPs) resulting from metabolic and environmental degradation of SAL are incompletely known and structural information is missing. In this study, we therefore systematically investigated the formation and identification of SAL derived TPs using electrochemistry (EC) in an electrochemical reactor and rat and human liver microsome incubation (RLM and HLM) as TP generating methods. Liquid chromatography (LC) coupled to high-resolution mass spectrometry (HRMS) was applied to determine accurate masses in a suspected target analysis to identify TPs and to deduce occurring modification reactions of derived TPs. A total of 14 new, structurally different TPs were found (two EC-TPs, five RLM-TPs, and 11 HLM-TPs). The main modification reactions are decarbonylation for EC-TPs and oxidation (hydroxylation) for RLM/HLM-TPs. Of particular interest are potassium-based TPs identified after liver microsome incubation because these might have been overlooked or declared as oxidated sodium adducts in previous, non-HRMS-based studies due to the small mass difference between K and O + Na of 21 mDa. The MS fragmentation pattern of TPs was used to predict the position of identified modifications in the SAL molecule. The obtained knowledge regarding transformation reactions and novel TPs of SAL will contribute to elucidate SAL-metabolites with regards to structural prediction.
KW - Salinomycin
KW - Ionophore antibiotics
KW - Transformation product
KW - Electrochemistry
KW - Rat/human liver microsomes
KW - HRMS
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542543
DO - https://doi.org/10.3390/antibiotics11020155
SN - 2079-6382
VL - 11
IS - 2
SP - 155
PB - MDPI
CY - Basel
AN - OPUS4-54254
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ahiboz, D.
A1 - Andresen, Elina
A1 - Manley, P.
A1 - Resch-Genger, Ute
A1 - Würth, Christian
A1 - Becker, C.
T1 - Metasurface-Enhanced Photon Upconversion upon 1550 nm Excitation
N2 - Photon upconversion upon 1550 nm excitation is of high relevance for applications in the third biological excitation window, for photovoltaics beyond current limitations, and enables appealing options in the field of glass Fiber telecommunications. Trivalent doped erbium ions (Er3+) are the material of choice for 1550 nm excited upconversion, however, they suffer from a low absorption cross-section and a low brightness. Therefore, the ability of Silicon metasurfaces to provide greatly enhanced electrical near-fields is employed to enable efficient photon upconversion even at low external Illumination conditions. Hexagonally shaped β-NaYF4:Er3+ nanoparticles are placed on large-area silicon metasurfaces designed to convert near-infrared (1550 nm) to visible light. More than 2400-fold enhanced photon upconversion luminescence is achieved by using this metasurface instead of a planar substrate.
With the aid of optical simulations based on the finite-element method, this result is attributed to the coupling of the excitation source with metasurface resonances at appropriate incident angles. Analysis of the excitation power density dependence of upconversion luminescence and red-to-green-emission ratios enables the estimation of nanoscale near-field enhancement on the metasurface. The findings permit the significant reduction of required external excitation intensities for photon upconversion of 1550 nm light, opening perspectives in biophotonics, telecommunication, and photovoltaics.
KW - Nano
KW - Nanomaterial
KW - Upconversion nanoparticle
KW - Lanthanide
KW - Photoluminescence
KW - Quantum yield
KW - Photophysics
KW - Lifetime
KW - Sensor
KW - Excitation power density
KW - Single particle
KW - Brightness
KW - NIR
KW - Mechanism
KW - Single enhancement
KW - SWIR
KW - Method
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-537193
DO - https://doi.org/10.1002/adom.202101285.
SN - 2195-1071
VL - 9
IS - 24
SP - 2101285
PB - Wiley-VCH-GmbH
AN - OPUS4-53719
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Resch-Genger, Ute
A1 - Carl, F.
A1 - Grauel, Bettina
A1 - Pons, Monica
A1 - Würth, Christian
A1 - Haase, M.
T1 - LiYF4:Yb/LiYF4 and LiYF4:Yb,Er/LiYF4 core/shell nanocrystals with luminescence decay times similar to YLF laser crystals and the upconversion quantum yield of the Yb,Er doped nanocrystals
N2 - We developed a procedure to prepare luminescent LiYF4:Yb/LiYF4 and LiYF4:Yb,Er/LiYF4 core/shell nanocrystals with a size of approximately 40 nm revealing luminescence decay times of the dopant ions that approach those of high-quality laser crystals of LiYF4:Yb (Yb:YLF) and LiYF4:Yb,Er (Yb,Er:YLF) with identical doping concentrations. As the luminescence decay times of Yb3+ and Er3+ are known to be very sensitive to the presence of quenchers, the long decay times of the core/shell nanocrystals indicate a very low number of defects in the core particles and at the core/shell interfaces. This improvement in the performance was achieved by introducing two important modifications in the commonly used oleic acid based synthesis. First, the shell was prepared via anewly developed method characterized by a very low nucleation rate for particles of pure LiYF4 shell material. Second, anhydrous acetates were used as precursors and additional drying steps were applied to reduce the incorporation of OH− in the crystal lattice, known to quench the emission of Yb3+ ions. Excitation power density (P)-dependent absolute measurements of the upconversion luminescence quantum yield (Φ,UC) of LiYF4:Yb,Er/LiYF4 core/shell particles reveal a maximum value of 1.25% at P of 180 W·cm−2.
Although lower than the values reported for NaYF4:18%Yb,2%Er core/shell nanocrystals with comparable sizes, these Φ, UC values are the highest reported so far for LiYF4:18%Yb,2%Er/LiYF4 nanocrystals without additional dopants. Further improvements May nevertheless be possible by optimizing the dopant concentrations in the LiYF4 nanocrystals.
KW - Nano
KW - Crystal
KW - Quantum yield
KW - LiYF4
KW - Synthesis
KW - Lifetime
KW - Fluorescence
KW - NIR
KW - Photoluminescence
KW - Lanthanide
KW - Upconversion nanoparticle
KW - Nanomaterial
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515395
DO - https://doi.org/10.1007/s12274-020-3116-y
SN - 1998-0124
VL - 14
IS - 3
SP - 797
EP - 806
PB - Springer
AN - OPUS4-51539
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Würth, Christian
A1 - Grauel, Bettina
A1 - Pons, Monika
A1 - Frenzel, Florian
A1 - Rissiek, P.
A1 - Rücker, Kerstin
A1 - Haase, Markus
A1 - Resch-Genger, Ute
T1 - Yb- and Er concentration dependence of the upconversion luminescence of highly doped NaYF4:Yb,Er/NaYF4:Lu core/shell nanocrystals prepared by a water-free synthesis
N2 - High sensitizer and activator concentrations have been increasingly examined to improve the performance of multi-color emissive upconversion (UC) nanocrystals (UCNC) like NaYF4:Yb,Er and first strategies were reported to reduce concentration quenching in highly doped UCNC. UC luminescence (UCL) is, however, controlled not only by dopant concentration, yet by an interplay of different parameters including size, crystal and shell quality, and excitation power density (P). Thus, identifying optimum dopant concentrations requires systematic studies of UCNC designed to minimize additional quenching pathways and quantitative spectroscopy. Here, we quantify the dopant concentration dependence of the UCL quantum yield (ΦUC) of solid
NaYF4:Yb,Er/NaYF4:Lu upconversion core/shell nanocrystals of varying Yb3+ and Er3+ concentrations (Yb3+ series: 20%‒98% Yb3+; 2% Er3+; Er3+ series: 60% Yb3+; 2%‒40% Er3+). To circumvent other luminescence quenching processes, an elaborate synthesis yielding OH-free UCNC with record ΦUC of ~9% and ~25 nm core particles with a thick surface shell were used. High Yb3+ concentrations barely reduce ΦUC from ~9% (20% Yb3+) to ~7% (98% Yb3+) for an Er3+ concentration of 2%, thereby allowing to strongly increase the particle absorption cross section and UCNC brightness. Although an increased Er3+ concentration reduces ΦUC from ~7% (2% Er3+) to 1% (40%) for 60% Yb3+. Nevertheless, at very high P (> 1 MW/cm2) used for microscopic studies, highly Er3+-doped UCNC display a high brightness because of reduced saturation. These findings underline the importance of synthesis control and will pave the road to many fundamental studies of UC materials.
KW - Upconverion
KW - Nanoparticle
KW - Lanthanides
KW - Quantum yield
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551346
DO - https://doi.org/10.1007/s12274-022-4570-5
SP - 1
EP - 8
PB - Springer
AN - OPUS4-55134
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kuner, Maximilian
A1 - Lisec, Jan
A1 - Picher, Marie-Idrissa
A1 - Rigo, Massimo
A1 - Konetzki, Jörg
A1 - Haase, Hajo
A1 - Koch, Matthias
T1 - Development and Application of Isotope Labelled Internal Standards in a Sum Parameter Method for Ergot Alkaloid Screening of Food
N2 - Ergot alkaloids are a group of toxic compounds, formed by fungi on infested grasses. In 2022, the European Commission set into effect maximum levels for the sum of the twelve major ergot alkaloids in multiple foods. To facilitate the laborious and costly individual quantification of the twelve major ergot alkaloids by HPLC–MS/MS or -FLD, we recently reported a sum parameter method (SPM) for ergot alkaloid quantification. Here, derivatization to lysergic acid hydrazide—a derivative of the mutual ergoline backbone in all ergot alkaloids—allowed simplified determination of all ergot alkaloids in flour via HPLC-FLD. For the measurement of more complex matrices like processed foods, we now developed a MS/MS-based SPM. Two internal standards (IS), isotopically labelled at different positions of the molecule, were synthesized and employed in the MS/MS-measurements. Method performance using either the 13CD3-labelled or the 15N2-labelled IS was evaluated on naturally contaminated rye and wheat flour samples as well as on processed food matrices. Employing the 13CD3-labelled IS leads to lower variances and better consistency with the reference data (obtained by the FLD-based SPM) in flour samples compared to the 15N2-labelled IS. The novel method significantly improves the measurement of ergot alkaloids in complex food matrices, due to their increased selectivity and thus lower interferences. Furthermore, the application of isotope labelled IS obviates the need for time-consuming steps like the determination of recovery rate based, matrix specific correction factors as described in the MS/MS-based European standard method for ergot alkaloid quantification (EN 17425).
KW - Mycotoxins
KW - Sum Parameter Method
KW - Isotope Labelling
KW - HPLC-MS/MS
KW - Analytical Chemistry
KW - Lysergic acid hydrazide
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588582
DO - https://doi.org/10.1007/s12161-023-02553-x
SN - 1936-976X
VL - 17
IS - 1
SP - 119
EP - 128
PB - Springer
CY - New York, NY
AN - OPUS4-58858
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 -
TY - JOUR
A1 - Krappe, Alexander R.
A1 - Mayer, Jacob C.
A1 - Zhang, Wuai
A1 - Filla, Lina M.
A1 - Ligorio, Giovanni
A1 - Hermerschmidt, Felix
A1 - Eitelhuber, Larissa S.
A1 - Güttler, Arne
A1 - Weber, Manuela
A1 - Paulus, Beate
A1 - Resch-Genger, Ute
A1 - List-Kratochvil, Emil J.W.
A1 - Eigler, Siegfried
T1 - Highly Emissive Hexa-peri-benzocoronene-fluoranthene Hybrid as Easily Processable and Stable OLED Material
N2 - We report the synthesis of a fluorescent polycyclic aromatic hydrocarbon dye with a “symmetry-broken” core, derived from the related hexa-peri-benzocoronene (HBC) core with fluoranthene subunit. The fluorophore is composed of a pure Carbon skeleton without heteroatoms and exhibits remarkable photo luminescence properties with a photoluminescence Quantum yield (PLQY) of up to 67% in toluene, exceeding that of theparent HBC by a factor of 30. The single crystal X-ray structure reveals the distorted polycyclic aromatic hydrocarbon structure, which is responsible for the optoelectronic properties, as supported by density functional theory calculations. We show that the new fluorescent dye can be readily used for the fabrication of organic light-emitting diodes (OLED) without extensive optimization, whereby solubility in a variety of solvents and successful film formation are decisive.
KW - Quantum Yield
KW - OLED
KW - Fluorescence
KW - Synthesis
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631298
DO - https://doi.org/10.1002/chem.202500742
SN - 1521-3765
SP - 1
EP - 7
PB - John Wiley & Sons, Inc
AN - OPUS4-63129
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Biesen, L.
A1 - Nirmalananthan-Budau, Nithiya
A1 - Hoffmann, Katrin
A1 - Resch-Genger, Ute
A1 - Müller, T. J. J.
T1 - Solid-State Emissive Aroyl-S,N-Ketene Acetals with Tunable
N2 - N-Benzyl aroyl-S,N-ketene acetals can be readily synthesized by condensation of aroyl chlorides and N-Benzyl 2-methyl benzothiazolium salts in good to excellent yields, yielding a library of 35 chromophores with bright solid-state emission and aggregation-induced emission characteristics.
Varying the substituent from electron-donating to electronwithdrawing enables the tuning of the solid-state emission Color from deep blue to red.
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
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509072
DO - https://doi.org/10.1002/anie.201916396
VL - 59
IS - 25
SP - 10037
EP - 10041
PB - Wiley Online Libary
AN - OPUS4-50907
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Würth, Christian
A1 - Behnke, Thomas
A1 - Gienger, J.
A1 - Resch-Genger, Ute
T1 - Efficiency scale for scatteringluminescent particles linkedto fundamental and measurablespectroscopic properties
N2 - Comparing the performance of molecular and nanoscale luminophores and luminescent microand nanoparticles and estimating achievable signal amplitudes and limits of detection requires a standardizable intensity scale. This initiated the development of the relative MESF (number of molecules of equivalent soluble fluorochromes) and ERF (equivalent reference fluorophores) scales for flow cytometry and fluorescence microscopy. Both intensity scales rely on fluorescence intensity values assigned to fluorescent calibration beads by an intensity comparison to spectrally closely matching fluorophore solutions of known concentration using a spectrofluorometer. Alternatively, the luminophore or bead brightness (B) can be determined that equals the product of the absorption cross section (σa) at the excitation wavelength (σa(λex)) and the photoluminescence quantum yield (Φpl).
Thereby, an absolute scale based on fundamental and measurable spectroscopic properties can be realized which is independent of particle size, material, and luminophore staining or labeling density and considers the sensitivity of the optical properties of luminophores to their environment. Aiming for establishing such a brightness scale for light-scattering dispersions of luminescent particles with sizes exceeding a few ten nanometers, we demonstrate how the brightness of quasi-monodisperse 25 nm, 100 nm, and 1 μm sized polystyrene particles (PSP), loaded with two different dyes in varying concentrations, can be obtained with a single custom-designed integrating sphere setup that enables the absolute determination of Φpl and transmittance and diffuse reflectance measurements. The resulting Φpl, σa(λex), imaginary parts of the refractive index, and calculated B values of these samples are given in dependence of the number of incorporated dye molecule per particle. Finally, a unitless luminescence efficiency (LE) is defined allowing for the direct comparison of luminescence efficiencies of particles with different sizes.
KW - Brightness
KW - Quantum yield
KW - Cross section
KW - Lluminescence
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573680
DO - https://doi.org/10.1038/s41598-023-32933-6
VL - 13
IS - 1
SP - 14
PB - Nature
AN - OPUS4-57368
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Biesen, L.
A1 - May, L.
A1 - Nirmalananthan-Budau, Nithiya
A1 - Hoffmann, Katrin
A1 - Resch-Genger, Ute
A1 - Müller, T. J. J.
T1 - Communication of Bichromophore Emission upon Aggregation – Aroyl-S,N-ketene Acetals as Multifunctional Sensor Merocyanines
N2 - Aroyl-S,N-ketene acetal-based bichromophores can be readily synthesized in a consecutive three-component synthesis in good to excellent yields by condensation of aroyl chlorides and an N-(p-bromobenzyl) 2-methyl benzothiazolium salt followed by a Suzuki coupling, yielding a library of 31 bichromophoric fluorophores with substitution patterntunable emission properties. Varying both chromophores enables different communication pathways between the chromophores, exploiting aggregation-induced emission (AIE) and energy transfer (ET) properties, and thus, furnishing aggregation-based fluorescence switches. Possible applications range from fluorometric analysis of alcoholic beverages to pH sensors.
KW - Dye
KW - Fluorescence
KW - Aggregation induced emission
KW - Signal enhancement
KW - Energy transfer
KW - Switch
KW - Sensor
KW - Quantum yield
KW - Lifetime
KW - Photophysics
KW - Synthesis
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531123
DO - https://doi.org/10.1002/chem.202102052
VL - 27
IS - 53
SP - 13426
EP - 13434
PB - Wiley-VCH
AN - OPUS4-53112
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Frenzel, F.
A1 - Fiedler, S.
A1 - Bardan, A.
A1 - Güttler, Arne
A1 - Würth, Christian
A1 - Resch-Genger, Ute
T1 - Influence of Measurement Geometry and Blank on Absolute Measurements of Photoluminescence Quantum Yields of Scattering Luminescent Films
N2 - For a series of 500 μm-thick polyurethane films containing different concentrations of luminescent and scattering YAG:Ce microparticles, we systematically explored and quantified pitfalls of absolute measurements of photoluminescence quantum yields (Φf) for often employed integrating sphere (IS) geometries, where the sample is placed either on a sample holder at the bottom of the IS surface or mounted in the IS center. Thereby, the influence of detection and illumination geometry and sample position was examined using blanks with various scattering properties for measuring the number of photons absorbed by the sample. Our results reveal that (i) setup configurations where the scattering sample is mounted in the IS center and (ii) transparent blanks can introduce systematic errors in absolute Φf measurements.
For strongly scattering, luminescent samples, this can result in either an under- or overestimation of the absorbed photon flux and hence an under- or overestimation of Φf. The size of these uncertainties depends on the scattering properties of the sample and instrument parameters, such as sample position, IS size, wavelength-dependent reflectivity of the IS surface coating, and port configuration. For accurate and reliable absolute Φf measurements, we recommend (i) a blank with scattering properties closely matching those of the sample to realize similar distributions of the diffusely scattered excitation photons within the IS, and (ii) a sufficiently high sample absorption at the excitation wavelength. For IS setups with center-mounted samples, measurement geometries should be utilized that prevent the loss of excitation photons by reflections from the sample out of the IS.
KW - Quality assurance
KW - Fluorescence
KW - Nano
KW - Particle
KW - Quantum yield
KW - Characterization
KW - Silica
KW - Scattering
KW - Uncertainty
KW - Film
KW - Pphosphor
KW - YAG:Ce
KW - LED
KW - Converter material
KW - Solid material
KW - Polymer
KW - Composite material
KW - Advanced material
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638304
DO - https://doi.org/10.1021/acs.analchem.4c06726
SN - 1520-6882
SP - 1
EP - 8
PB - ACS Publications
AN - OPUS4-63830
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kuner, Maximilian
A1 - Lisec, Jan
A1 - Mauch, Tatjana
A1 - Konetzki, J.
A1 - Haase, H.
A1 - Koch, Matthias
T1 - Quantification of Ergot Alkaloids via Lysergic Acid Hydrazide—Development and Comparison of a Sum Parameter Screening Method
N2 - Ergot alkaloids are a group of mycotoxins occurring in products derived from various grasses (e.g., rye) and have been regulated in the EU recently. The new maximum levels refer to the sum of the six most common ergot alkaloids in their two stereoisomeric forms in different food matrices. Typically, these twelve compounds are individually quantified via HPLC-MS/MS or -FLD and subsequently summed up to evaluate food safety in a time-consuming process. Since all these structures share the same ergoline backbone, we developed a novel sum parameter method (SPM) targeting all ergot alkaloids simultaneously via lysergic acid hydrazide. After extraction and clean-up, in analogy to the current European standard method EN 17425 (ESM) for ergot alkaloid quantitation, the samples were derivatized by an optimized hydrazinolysis protocol, which allowed quantitative conversion after 20 min at 100 °C. The new SPM was evaluated against another established HPLC-FLD-based method (LFGB) and the HPLC-MS/MS-based ESM using six naturally contaminated rye and wheat matrix reference materials. While the SPM provided comparable values to the ESM, LFGB showed deviating results. Determined recovery rates, limits of detection and quantification of all three employed methods confirm that the new SPM is a promising alternative to the classical approaches for ergot alkaloid screening in food.
KW - Ergot alkaloids
KW - Sum Parameter
KW - Mycotoxins
KW - Derivatization
KW - Hydrazinolysis
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573968
DO - https://doi.org/10.3390/molecules28093701
SN - 0015-2684
VL - 28
IS - 9
SP - 3701
PB - MDPI
CY - Basel
AN - OPUS4-57396
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hoffmann, A.
A1 - Lischeid, G.
A1 - Koch, Matthias
A1 - Lentzsch, P.
A1 - Sommerfeld, Thomas
A1 - Müller, M.H.
T1 - Co-Cultivation of Fusarium, Alternaria, and Pseudomonas on Wheat-Ears Affects Microbial Growth and Mycotoxin Production
N2 - Mycotoxigenic fungal pathogens Fusarium and Alternaria are a leading cause of loss in cereal production. On wheat-ears, they are confronted by bacterial antagonists such as pseudomonads.
Studies on these groups’ interactions often neglect the infection process’s temporal aspects and the associated priority effects. In the present study, the focus was on how the first colonizer affects the subsequent ones. In a climate chamber experiment, wheat-ears were successively inoculated with two different strains (Alternaria enuissima At625, Fusarium graminearum Fg23, or Pseudomonas simiae Ps9).
Over three weeks, microbial abundances and mycotoxin concentrations were analyzed and visualized via Self Organizing Maps with Sammon Mapping (SOM-SM). All three strains revealed different characteristics and strategies to deal with co-inoculation: Fg23, as the first colonizer, suppressed the establishment of At625 and Ps9. Nevertheless, primary inoculation of At625 reduced all of the Fusarium toxins and stopped Ps9 from establishing. Ps9 showed priority effects in delaying and blocking the production of the fungal mycotoxins. The SOM-SM analysis visualized the competitive strengths: Fg23 ranked first, At625 second, Ps9 third. Our findings of species-specific priority effects in a natural environment and the role of the mycotoxins involved are relevant for developing biocontrol strategies.
KW - Antagonists
KW - Microbe interactions
KW - Mycotoxins
KW - Priority effect
KW - SOM-SM
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521554
DO - https://doi.org/10.3390/microorganisms9020443
VL - 9
IS - 2
SP - 443
PB - MDPI
AN - OPUS4-52155
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Xu, R.
A1 - Teich, W.
A1 - Frenzel, Florian
A1 - Hoffmann, Katrin
A1 - Radke, J.
A1 - Rösler, J.
A1 - Faust, K.
A1 - Blank, A.
A1 - Brandenburg, S.
A1 - Misch, M.
A1 - Vajkoczy, P.
A1 - Onken, J. S.
A1 - Resch-Genger, Ute
T1 - Optical characterization of sodium fluorescein in vitro and ex vivo
N2 - Objective: The utilization of fluorescein-guided biopsies and resection has been recently discussed as a suitable strategy to improve and expedite operative techniques for the resection of central nervous system (CNS) tumors. However, little is known about the optical properties of sodium fluorescein (NaFl) in human tumor tissue and their potential impact on ex vivo analyses involving fluorescence-based methods.
Methods: Tumor tissue was obtained from a study cohort of an observational study on the utilization of fluorescein-guided biopsy and resection (n=5). The optical properties of fluorescein-stained tissue were compared to the optical features of the dye in vitro and in control samples consisting of tumor tissue of high-grade glioma patients (n=3) without intravenous (i.v.) application of NaFl. The dye-exposed tumor tissues were used for optical measurements to confirm the detectability of NaFl emission ex vivo. The tissue samples were fixed in 4%PFA, immersed in 30% sucrose, embedded in Tissue-Tek OCT compound, and cut to 10 mm cryosections. Spatially resolved emission spectra from tumor samples were recorded on representative slides with a Confocal Laser Scanning Microscope FV1000 (Olympus GmbH, Hamburg, Germany) upon excitation with lexc = 488 nm.
Results: Optical measurements of fluorescein in 0.9% sodium chloride (NaCl) under in vitro conditions showed an absorption maximum of lmax abs = 479 nm as detected with spectrophotometer Specord 200 and an emission peak at lmax em = 538 nm recorded with the emCCD detection system of a custom-made microscope-based single particle setup using a 500 nm long-pass filter. Further measurements revealed pH- and concentration-dependent emission spectra of NaFl. Under ex vivo conditions, confocal laser scanning microscopy of fluorescein tumor samples revealed a slight bathochromic shift and a broadening of the emission band.
Conclusion: Tumor uptake of NaFl leads to changes in the optical properties – a bathochromic shift and broadening of the emission band – possibly caused by the dye’s high pH sensitivity and concentration-dependent reabsorption acting as an innerfilter of the dye’s emission, particularly in the short wavelength region of the Emission spectrum where absorption and fluorescence overlap. Understanding the ex vivo optical properties of fluorescein is crucial for testing and validating its further applicability as an optical probe for intravital microscopy, immunofluorescence localization studies, and flow cytometry analysis.
KW - Fluorescence
KW - Optical probe
KW - Sensor
KW - Fluorescein
KW - PH
KW - Imaging
KW - Tissue
KW - Cancer
KW - Medical diagnostics
KW - Tumor
KW - In vivo
KW - Ex vivo
KW - Quantum yield
KW - Dye
KW - Quality assurance
KW - Microscopy
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527843
DO - https://doi.org/10.3389/fonc.2021.654300
SN - 2234-943X
VL - 11
SP - 1
EP - 8
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-52784
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nelson, G.
A1 - Boehm, U.
A1 - Bagley, S.
A1 - Bajcsy, P.
A1 - Bischof, J.
A1 - Brown, C. M.
A1 - Dauphin, A.
A1 - Dobbie, I. M.
A1 - Eriksson, J. E.
A1 - Faklaris, O.
A1 - Fernandez-Rodriguez, J.
A1 - Ferrand, A.
A1 - Gelman, L,
A1 - Gheisari, A.
A1 - Hartmann, H.
A1 - Kukat, C.
A1 - Laude, A.
A1 - Mitkovski, M.
A1 - Munck, S.
A1 - North, A. J.
A1 - Rasse, T.
A1 - Resch-Genger, Ute
A1 - Schuetz, L. C.
A1 - Seitz, A.
A1 - Strambio-De-Castillia, C.
A1 - Swedlow, J. R.
A1 - Alexopoulos, I.
A1 - Aumayr, K.
A1 - Avilov, S.
A1 - Bakker, G.-J.
A1 - Bammann, R. R.
A1 - Bassi, A.
A1 - Beckert, H.
A1 - Beer, S.
A1 - Belyaev, Y.
A1 - Bierwagen, J.
A1 - Birngruber, K. A.
A1 - Bosch, M.
A1 - Breitlow, J.
A1 - Cameron, L. A.
A1 - Chalfoun, J.
A1 - Chambers, J. J.
A1 - Chen, C.-L.
A1 - Conde-Sousa, E.
A1 - Corbett, A. D.
A1 - Cordelieres, F. P.
A1 - Del Nery, E.
A1 - Dietzel, R.
A1 - Eismann, F.
A1 - Fazeli, E.
A1 - Felscher, A.
A1 - Fried, H.
A1 - Gaudreault, N.
A1 - Goh, W. I.
A1 - Guilbert, T.
A1 - Hadleigh, R.
A1 - Hemmerich, P.
A1 - Holst, G. A.
A1 - Itano, M. S.
A1 - Jaffe, C. B.
A1 - Jambor, H. K.
A1 - Jarvis, S. C.
A1 - Keppler, A.
A1 - Kirchenbuechler, D.
A1 - Kirchner, M.
A1 - Kobayashi, N.
A1 - Krens, G.
A1 - Kunis, S.
A1 - Lacoste, J.
A1 - Marcello, M.
A1 - Martins, G. G.
A1 - Metcalf, D. J.
A1 - Mitchell, C. A.
A1 - Moore, J.
A1 - Mueller, T.
A1 - Nelson, M. S.
A1 - Ogg, S.
A1 - Onami, S.
A1 - Palmer, A. L.
A1 - Paul-Gilloteaux, P.
A1 - Pimentel, J. A.
A1 - Plantard, L.
A1 - Podder, S.
A1 - Rexhepaj, E.
A1 - Royon, A.
A1 - Saari, M. A.
A1 - Schapman, D.
A1 - Schoonderwoert, V.
A1 - Schroth-Diez, B.
A1 - Schwartz, S.
A1 - Shaw, M.
A1 - Spitaler, M.
A1 - Stoeckl, M. T.
A1 - Sudar, D.
A1 - Teillon, J.
A1 - Terjung, S.
A1 - Thuenauer, R.
A1 - Wilms, C. D.
A1 - Wright, G. D.
A1 - Nitschke, R.
T1 - QUAREP-LiMi: A community-driven initiative to establish guidelines for quality assessment and reproducibility for instruments and images in light microscopy
N2 - A modern day light microscope has evolved from a tool devoted to making primarily empirical observations to what is now a sophisticated, quantitative device that is an integral part of both physical and life science research. Nowadays, microscopes are found in nearly every experimental laboratory. However, despite their prevalent use in capturing and quantifying scientific phenomena, neither a thorough understanding of the principles underlying quantitative imaging techniques nor appropriate knowledge of how to calibrate, operate and maintain microscopes can be taken for granted. This is clearly demonstrated by the well-documented and widespread difficulties that are routinely encountered in evaluating acquired data and reproducing scientific experiments. Indeed, studies have shown that more than 70% of researchers have tried and failed to repeat another scientist’s experiments, while more than half have even failed to reproduce their own experiments1. One factor behind the reproducibility crisis of experiments published in scientific journals is the frequent underreporting of imaging methods caused by a lack of awareness and/or a lack of knowledge of the applied technique2,3. Whereas quality control procedures for some methods used in biomedical research, such as genomics (e.g., DNA sequencing, RNA-seq) or cytometry, have been introduced (e.g. ENCODE4), this issue has not been tackled for optical microscopy instrumentation and images. Although many calibration standards and protocols have been published, there is a lack of awareness and agreement on common Standards and guidelines for quality assessment and reproducibility5.
In April 2020, the QUality Assessment and REProducibility for instruments and images in Light Microscopy (QUAREP-LiMi) initiative6 was formed. This initiative comprises imaging scientists from academia and industry who share a common interest in achieving a better understanding of the performance and limitations of microscopes and improved quality control (QC) in light microscopy. The ultimate goal of the QUAREP-LiMi initiative is to establish a set of common QC standards, guidelines, metadata models7,8, and tools9,10, including detailed protocols, with the ultimate aim of improving reproducible advances in scientific research.
This White Paper 1) summarizes the major obstacles identified in the field that motivated the launch of the QUAREP-LiMi initiative; 2) identifies the urgent need to address these obstacles in a grassroots manner, through a community of Stakeholders including, researchers, imaging scientists11, bioimage analysts, bioimage informatics developers, corporate partners, Funding agencies, standards organizations, scientific publishers, and observers of such; 3) outlines the current actions of the QUAREPLiMi initiative, and 4) proposes future steps that can be taken to improve the dissemination and acceptance of the proposed guidelines to manage QC.
To summarize, the principal goal of the QUAREP-LiMi initiative is to improve the overall quality and reproducibility of light microscope image data by introducing broadly accepted standard practices and accurately captured image data metrics.
KW - Fluorescence
KW - Microscopy
KW - Quality assurance
KW - Comparability
KW - Imaging
KW - Standards
KW - Reference materials
KW - Reliability
KW - Data
KW - Reference data
KW - Biology
KW - Medicine
KW - Life science
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530629
DO - https://doi.org/10.1111/jmi.13041
SN - 1365-2818
VL - 284
IS - 1
SP - 56
EP - 73
PB - Wiley-Blackwell
CY - Oxford
AN - OPUS4-53062
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Riedel, Juliane
A1 - Recknagel, Sebastian
A1 - Sassenroth, Diana
A1 - Mauch, Tatjana
A1 - Buttler, Sabine
A1 - Sommerfeld, Thomas
A1 - Penk, Sibylle
A1 - Koch, Matthias
T1 - Development and certification of a reference material for zearalenone in maize germ oil
N2 - Zearalenone (ZEN), an estrogenic mycotoxin produced by several species of Fusarium fungi, is a common contaminant of cereal-based food worldwide. Due to frequent occurrences associated with high levels of ZEN, maize oil is a particular source of exposure. Although a European maximumlevel for ZEN in maize oil exists according to Commission Regulation (EC) No. 1126/2007 along with a newly developed international standard method for analysis, certified reference materials (CRM) are still not available. To overcome this lack, the first CRM for the determination of ZEN in contaminated maize germ oil (ERM®-BC715) was developed in the frame of a European Reference Materials (ERM®) project according to the requirements of ISO Guide 35. The whole process of CRM development including preparation, homogeneity and stability studies, and value assignment is presented. The assignment of the certified mass fraction was based upon an in-house study using high-performance liquid chromatography isotope dilution tandem mass spectrometry. Simultaneously, to support the in-house certification study, an interlaboratory comparison study was conducted with 13 expert laboratories using different analytical methods. The certified mass fraction and expanded uncertainty (k=2) of ERM®-BC715 (362± 22) μg kg−1 ZEN are traceable to the SI. This reference material is intended for analytical quality control and contributes to the improvement of consumer protection and food safety.
KW - Fusarium mycotoxin
KW - Vegetable edible oil
KW - Food analysis
KW - European Reference Material
KW - Quality assurance
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531831
DO - https://doi.org/10.1007/s00216-021-03532-z
SN - 1618-2642
SN - 1618-2650
VL - 413
IS - 21
SP - 5483
EP - 5491
PB - Springer
CY - Berlin
AN - OPUS4-53183
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Biesen, L.
A1 - Krenzer, J.
A1 - Nirmalananthan-Budau, Nithiya
A1 - Resch-Genger, Ute
A1 - Müller, Th. J. J.
T1 - Asymmetrically bridged aroyl-S,N-ketene acetalbased multichromophores with aggregationinduced tunable emission
N2 - Asymmetrically bridged aroyl-S,N-ketene acetals and aroyl-S,N-ketene acetal multichromophores can be readily synthesized in consecutive three-, four-, or five-component syntheses in good to excellent yields by several successive Suzuki-couplings of aroyl-S,N-ketene acetals and bis(boronic)acid esters. Different aroyl-S,N-ketene acetals as well as linker molecules yield a library of 23 multichromophores with substitution and linker pattern-tunable emission properties. This allows control of different communication pathways between the chromophores and of aggregation-induced emission (AIE) and energy transfer (ET) properties, providing elaborate aggregation-based fluorescence switches.
KW - Dye
KW - Aggregation
KW - Aggregation induced emission
KW - Signal enhancement
KW - Energy transfer
KW - Switch
KW - Sensor
KW - Quantum yield
KW - Lifetime
KW - Photophysics
KW - Sythesis
KW - Nanaoparticle
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550719
DO - https://doi.org/10.1039/d2sc00415a
VL - 13
SP - 5374
EP - 5381
PB - Royal Society of Chemistry
AN - OPUS4-55071
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Moll, J.
A1 - Wang, Cui
A1 - Päpcke, A.
A1 - Förster, C.
A1 - Resch-Genger, Ute
A1 - Lochbrunner, S.
A1 - Heinze, K.
T1 - Green Light Activation of Push-Pull Ruthenium(II) Complexes
N2 - Synthesis, characterization, electrochemistry, and photophysics of novel homo- and heteroleptic ruthenium(II) complexes [Ru(cpmp)2] 2+ (22+) and [Ru(cpmp)(ddpd)]2+ (32+) bearing the tridentate ligands 6,2’’-carboxypyridyl-2,2’-methylamine-pyridylpyridine (cpmp) and N,N’-dimethyl-N,N’-dipyridin-2-ylpyridine-2,6-diamine (ddpd) are reported. The complexes possess one (32+) or two (22+) electron-deficient dipyridyl ketone fragments as electron accepting sites enabling intraligand charge transfer (ILCT), ligand-toligand charge transfer (LL’CT) and low-energy metal-to-ligand charge transfer (MLCT) absorptions. The latter peak around 544 nm (green light). 22+ shows 3MLCT phosphorescence in the red to near-infrared spectral region at room temperature in deaerated acetonitrile solution with an emission quantum yield of 1.3 % and a 3MLCT lifetime of 477 ns, while 3
2+ is much less luminescent. This different behaviour is ascribed to the energy gap law and the shape of the parasitic excited 3MC state potential energy surface. This study highlights the importance of the excited state energies and geometries for the actual excited state dynamics. Aromatic and aliphatic amines reductively quench the excited state of 22+ paving the way to photocatalytic applications using low-energy green light as exemplified with the green-light sensitized thiol-ene click reaction.
KW - Green light excitation
KW - Ruthenium(II) complexes
KW - Phosphorescence
KW - MLCT
KW - Photoinduced electron transfer
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506759
DO - https://doi.org/10.1002/chem.202000871
SP - 1
EP - 13
PB - Wiley-VCH Verlag
AN - OPUS4-50675
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Soares, J. X.
A1 - Wegner, Karl David
A1 - Ribeiro, D. S. M.
A1 - Melo, A.
A1 - Häusler, I.
A1 - Santos, J. L. M.
A1 - Resch-Genger, Ute
T1 - Rationally designed synthesis of bright AgInS2/ZnS quantum dots with emission control
N2 - In the blossoming field of Cd-free semiconductor quantum dots (QDs), ternary I–III–VI QDs have received increasing attention due to the ease of the environmentally friendly synthesis of high-quality materials in water, their high photoluminescence (PL) Quantum yields (QYs) in the red and near infrared (NIR) region, and their inherently low toxicity. Moreover, their oxygen-insensitive long PL lifetimes of up to several hundreds of nanoseconds close a gap for applications exploiting the compound-specific parameter PL lifetime. To overcome the lack of reproducible synthetic methodologies and to enable a design-based control of their PL properties, we assessed and modelled the synthesis of high-quality MPA-capped AgInS2/ZnS (AIS/ZnS) QDs. Systematically refined Parameters included reaction time, temperature, Ag:In ratio, S:In ratio, Zn:In ratio, MPA:In ratio, and pH using a design-of-experiment approach.
Guidance for the optimization was provided by mathematical models developed for the application-relevant PL parameters, maximum PL wavelength, QY, and PL lifetime as well as the elemental composition in terms of Ag:In:Zn ratio. With these experimental data-based models, MPA:In and Ag:In ratios and pH values were identified as the most important synthesis parameters for PL Control and an insight into the connection of these parameters could be gained. Subsequently, the experimental conditions to synthetize QDs with tunable emission and high QY were predicted. The excellent agreement between the predicted and experimentally found PL features confirmed the reliability of our methodology for the rational design of high quality AIS/ZnS QDs with defined PL features.
This approach can be straightforwardly extended to other ternary and quaternary QDs and to doped QDs.
KW - Modelling
KW - Nanoparticle
KW - AIS
KW - Semiconductor quantum dot
KW - Design of experiment
KW - Photoluminescence
KW - Quantum yield
KW - Surface chemistry
KW - Synthesis
KW - Lifetime
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510075
DO - https://doi.org/10.1007/s12274-020-2876-8
VL - 13
IS - 9
SP - 2438
EP - 2450
PB - Springer
AN - OPUS4-51007
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kalot, G.
A1 - Godard, A.
A1 - Busser, B.
A1 - Pliquett, J.
A1 - Broekgaarden, M.
A1 - Motto-Ros, V.
A1 - Wegner, Karl David
A1 - Resch-Genger, Ute
A1 - Köster, U.
A1 - Denat, F.
A1 - Coll, J.-L.
A1 - Bodio, E.
A1 - Goze, C.
A1 - Sancey, L.
T1 - Aza-BODIPY: A New Vector for Enhanced Theranostic Boron Neutron Capture Therapy Applications
N2 - Boron neutron capture therapy (BNCT) is a radiotherapeutic modality based on the nuclear capture of slow neutrons by stable 10B atoms followed by charged particle Emission that inducing extensive damage on a very localized level (<10 um). To be effcient, a suffcient amount of 10B should accumulate in the tumor area while being almost cleared from the normal surroundings. A water-soluble aza-boron-dipyrromethene dyes (BODIPY) fluorophore was reported to strongly accumulate in the tumor area with high and BNCT compatible Tumor/Healthy Tissue ratios.
The clinically used 10B-BSH (sodium borocaptate) was coupled to the water-soluble aza-BODIPY platform for enhanced 10B-BSH tumor vectorization. We demonstrated a strong uptake of the compound in tumor cells and determined its biodistribution in mice-bearing tumors. A model of chorioallantoic membrane-bearing glioblastoma xenograft was developed to evidence the BNCT potential of such compound, by subjecting it to slow neutrons. We demonstrated the Tumor accumulation of the compound in real-time using optical imaging and ex vivo using elemental imaging based on laser-induced breakdown spectroscopy. The tumor growth was significantly reduced as compared to BNCT with 10B-BSH. Altogether, the fluorescent aza-BODIPY/10B-BSH compound is able to vectorize and image the 10B-BSH in the tumor area, increasing its theranostic potential for effcient approach of BNCT.
KW - Aza-BODIPY
KW - SWIR
KW - NIR-I
KW - Theranostic
KW - Boron compound
KW - Optical imaging
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512280
DO - https://doi.org/10.3390/cells9091953
VL - 9
IS - 9
SP - 1953
PB - MDPI
AN - OPUS4-51228
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kage, Daniel
A1 - Hoffmann, Katrin
A1 - Borcherding, H.
A1 - Schedler, U.
A1 - Resch-Genger, Ute
T1 - Lifetime encoding in flow cytometry for bead‑based sensing of biomolecular interaction
N2 - To demonstrate the potential of time-resolved flow cytometry (FCM) for bioanalysis, clinical diagnostics, and optically encoded bead-based assays, we performed a proof-of-principle study to detect biomolecular interactions utilizing fluorescence lifetime (LT)-encoded micron-sized polymer beads bearing target-specific bioligands and a recently developed prototype lifetime flow cytometer (LT-FCM setup). This instrument is equipped with a single excitation light source and different fluorescence detectors, one operated in the photon-counting mode for time-resolved measurements of fluorescence decays and three detectors for conventional intensity measurements in different spectral windows. First, discrimination of bead-bound biomolecules was demonstrated in the time domain exemplarily for two targets, Streptavidin (SAv) and the tumor marker human chorionic gonadotropin (HCG). In a second step, the determination of biomolecule concentration levels was addressed representatively for the inflammation-related biomarker tumor necrosis factor (TNF-α) utilizing fluorescence intensity measurements in a second channel of the LT-FCM instrument. Our results underline the applicability of LT-FCM in the time domain for measurements of biomolecular interactions in suspension assays. In the future, the combination of spectral and LT encoding and multiplexing and the expansion of the time scale from the lower nanosecond range to the longer nanosecond and the microsecond region is expected to provide many distinguishable codes. This enables an increasing degree of multiplexing which could be attractive for high throughput screening applications.
KW - Fluorescence
KW - Sensor
KW - Assay
KW - Protein
KW - Multiplexing
KW - Flow cytometry
KW - Barcoding
KW - Lifetime
KW - Dye
KW - Bead
KW - Bead-based assay
KW - Method
KW - Quantification
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-516007
DO - https://doi.org/10.1038/s41598-020-76150-x
VL - 10
IS - 1
SP - 19477
PB - Nature
AN - OPUS4-51600
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hoffmann, Katrin
A1 - Nirmalananthan-Budau, Nithiya
A1 - Resch-Genger, Ute
T1 - Fluorescence calibration standards made from broadband emitters encapsulated in polymer beads for fluorescence microscopy and flow cytometry
N2 - We present here the design and characterization of a set of spectral calibration beads. These calibration beads are intended for the determination and regular control of the spectral characteristics of fluorescence microscopes and other fluorescence measuring devices for the readout of bead-based assays. This set consists of micrometer-sized polymer beads loaded with dyes from the liquid Calibration Kit Spectral Fluorescence Standards developed and certified by BAM for the wavelength-dependent Determination of the spectral responsivity of fluorescencemeasuring devices like spectrofluorometers. To cover the wavelength Region from 400 to 800 nm, two new near-infrared emissive dyes were included, which were spectroscopically characterized in solution and encapsulated in the beads. The resulting set of beads presents the first step towards a new platform of spectral calibration beads for the determination of the spectral characteristics of fluorescence instruments like fluorescence microscopes, FCM setups, and microtiter plate readers, thereby meeting the increasing demand for reliable and comparable fluorescence data especially in strongly regulated areas, e.g., medical diagnostics. This will eventually provide the basis for standardized calibration procedures for imaging systems as an alternative to microchannel slides containing dye solutions previously reported by us.
KW - Fluorescence standard
KW - Fluorescence
KW - Dye
KW - Microscopy
KW - Bead
KW - Particle
KW - NIR
KW - calibration
KW - Quality assurance
KW - Traceability
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508117
DO - https://doi.org/10.1007/s00216-020-02664-y
SN - 1618-2642
VL - 412
IS - 24
SP - 6499
EP - 6507
PB - Springer
AN - OPUS4-50811
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rietsch, P.
A1 - Sobottka, S.
A1 - Hoffmann, K.
A1 - Popov, A. A.
A1 - Hildebrandt, P.
A1 - Sarkar, B.
A1 - Resch-Genger, Ute
A1 - Eigler, S.
T1 - Between Aromatic and Quinoid Structure: A Symmetrical UV to Vis/NIR Benzothiadiazole Redox Switch
N2 - Reversibly switching the light absorption of organic molecules by redox processes is of interest for applications in sensors, light harvesting, smart materials, and medical diagnostics. This work presents a symmetrical benzothiadiazole (BTD) derivative with a high fluorescence quantum yield in solution and in the crystalline state and shows by spectroelectrochemical analysis that reversible switching of UV absorption in the neutral state, to broadband Vis/NIR absorption in the 1st oxidized state, to sharp band Vis absorption in the 2nd oxidized state, is possible.
For the one-electron oxidized species, formation of a delocalized radical is confirmed by electron paramagnetic resonance spectroelectrochemistry. Furthermore, our results reveal an increasing quinoidal distortion upon the 1st and 2nd oxidation, which can be used as the leitmotif for the development of BTD based redox switches.
KW - Dye
KW - Electrochemistry
KW - Switch
KW - Redox
KW - Sensor
KW - Photophysics
KW - Quantum yield
KW - photoluminescence
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517222
DO - https://doi.org/10.1002/chem.202004009
VL - 26
IS - 72
SP - 17361
EP - 17365
PB - Wiley-VCH GmbH
AN - OPUS4-51722
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Srivastava, Priyanka
A1 - Fürstenwerth, Paul Christian
A1 - Witte, J. F.
A1 - Resch-Genger, Ute
T1 - Synthesis and spectroscopic characterization of a fluorescent phenanthrene-rhodamine dyad for ratiometric measurements of acid pH values
N2 - We present the rational design, synthesis and spectroscopic characterization of a novel dual excitation, three color emitting, pH-responsive fluorescent probe consisting of two phenanthrene and one rhodamine B units linked by click chemistry. The rhodamine moiety, excitable at λEx = 315 nm and at λEx = 560 nm in its ring-opened form, provides the pH-responsive fluorophore, while the pH-insensitive phenanthrene, excited at λEx = 315 nm, serves as inert internal reference, The presence of two phenanthrene moieties enables a blue monomer and a blueish green excimer emission at 351 nm and 500 nm, respectively. Opening of the rhodamine B spirolactam ring at an acidic pH below 5.0 (pKa = 2.59 ± 0.04) switches on its emission at 580 nm. Simultaneously, the phenanthrene excimer emission decreases caused by a change in orientation of the phenanthrene units, while the monomer emission is barely affected. This sensor design enables ratiometric measurements in the low acidic pH range utilizing the intensity ratios of the rhodamine B and phenanthrene excimer emission at 580 nm and 500 nm. Alternatively, also the intensity ratios of the rhodamine B and the phenanthrene monomer emission could be exploited or the sum of the phenanthrene monomer and excimer fluorescence. To the best of our knowledge, this is the first report of ratiometric sensing utilizing such a versatile type of tricolor emissive dyad probe bearing phenanthrene moieties and showing phenanthrene monomer and excimer emission.
KW - Fluorescence
KW - Optical probe
KW - Sensor
KW - Dye
KW - Rhodamine
KW - Synthesis
KW - Photophysics
KW - PH
KW - Quantum yield
KW - Quality assurance
KW - Mechanism
KW - Chemodosimeter
KW - Phenanthrene
KW - Ratiometric
KW - Dyad
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530554
DO - https://doi.org/10.1039/d1nj01573g
SN - 1144-0546
VL - 45
IS - 31
SP - 13755
EP - 13762
PB - Royal Society of Chemistry
AN - OPUS4-53055
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tavernaro, Isabella
A1 - Simon, Fabian
A1 - Gehrenkemper, Lennart
A1 - Tobias, Charlie
A1 - Resch-Genger, Ute
A1 - Meermann, Björn
T1 - Quantification of the amount of surface groups of aminated silica nano- and microparticles utilizing a fluorine tag and HR-CS-GFMAS
N2 - The performance, bioavailability, and safe use of engineered nanomaterials (NMs) depends not only on properties such as size, shape, and surface area, but largely on surface chemistry. While many sizing methods have been established, there is still a lack of validated screening methods for determining NM surface functional groups (FGs). In this context, we present a fast and simple method for FG quantification using high resolution-continuum source-graphite furnace molecular absorption spectrometry (HR-CS-GFMAS) and assess its applicability for the surface analysis of representatively chosen aminated silica nanoparticles (NPs) and microparticles (MPs) in conjunction with amino FG labeling with a fluorine tag. For this proof-of-concept study, first surface amino FG screening of the silica NPs and MPs was done with a potentiometric back titration method, providing the total amount of protonatable surface FGs, and two optical assays relying on reporter dyes with sizes and spatial requirements, i.e., surface binding areas smaller or larger than that of the fluorine tag to estimate the maximum and reporter-accessible number of amino FGs. Subsequently, the surface amino FGs were labeled with the fluorine tag 4-(trifluoromethyl)benzoic acid (TFMB) and the amount of fluorine originating from the bound TFMB molecules was quantified by HR-CS-GFMAS in two common organic solvents, i.e., dimethyl sulfoxide (DMSO) or ethanol (EtOH) to assess possible interferences from organic matrices. Our study revealed limits of detection (LODs) and quantification (LOQs) for fluorine of 1.0 µg/L and 3.5 µg/L in EtOH and 1.5 µg/L and 5.0 µg/L in DMSO, respectively. Overall, a quick and simple method for analyzing surface FGs on NPs and MPs was presented utilizing broadly available fluorine tags and HR-CS-GFMAS for fluorine quantification, which can be applied, e.g., for homogeneity, stability, and aging studies of surface-modified particles. This could contribute to ease the understanding of property-safety relationships for surface-functionalized NMs.
KW - Fluorine Analysis
KW - Nano- and microparticles
KW - Surface group quantification
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-641965
DO - https://doi.org/10.1007/s00216-025-06107-4
SN - 1618-2642
SP - 1
EP - 11
PB - Springer Science and Business Media LLC
CY - Berlin ; Heidelberg
AN - OPUS4-64196
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kuner, Maximilian
A1 - Kühn, S.
A1 - Haase, H.
A1 - Meyer, Klas
A1 - Koch, Matthias
T1 - Cleaving Ergot Alkaloids by Hydrazinolysis - A Promising Approach for a Sum Parameter Screening Method
N2 - Ergot alkaloids are mycotoxins formed by fungi of the Claviceps genus, which are some of the most common contaminants of food and feed worldwide. These toxins are a structurally heterogeneous group of compounds, sharing an ergoline backbone. Six structures and their corresponding stereoisomers are typically quantified by either HPLC-FLD or HPLC-MS/MS and the values subsequently summed up to determine the total ergot alkaloid content. For the development of a screening method targeting all ergot alkaloids simultaneously, the alkaloids need to be transferred to one homogeneous structure: a lysergic acid derivative. In this study, two promising cleaving methods—acidic esterification and hydrazinolysis—are compared, using dihydroergocristine as a model compound. While the acidic esterification proved to be unsuitable, due to long reaction times and oxidation sensitivity, hydrazinolysis reached a quantitative yield in 40-60 min. Parallel workup of several samples is possible. An increasing effect on the reaction rate by the addition of ammonium iodide was demonstrated. Application of hydrazinolysis to a major ergot alkaloid mix solution showed that all ergopeptines were cleaved, but ergometrine/-inine was barely affected. Still, hydrazinolysis is a suitable tool for the development of a sum parameter screening method for ergot alkaloids in food and feed.
KW - Ergot alkaloids
KW - Sum parameter method
KW - Hydrazinolysis
KW - Esterification
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527508
DO - https://doi.org/10.3390/toxins13050342
VL - 13
IS - 5
SP - 342
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-52750
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wasternack, J.
A1 - Schröder, H. V.
A1 - Witte, J. F.
A1 - Ilisson, M.
A1 - Hupatz, H.
A1 - Hille, J. F.
A1 - Gaedke, M.
A1 - Valkonen, A. M.
A1 - Sobottka, S.
A1 - Krappe, A.
A1 - Schubert, M.
A1 - Paulus, B.
A1 - Rissanen, K.
A1 - Sarkar, B.
A1 - Eigler, S.
A1 - Resch-Genger, Ute
A1 - Schalley, C. A.
T1 - Switchable protection and exposure of a sensitive squaraine dye within a redox active rotaxane
N2 - In nature,molecular environments in proteins can sterically protect and stabilize reactive species such as organic radicals through non-covalent interactions.Here, wereport a near-infrared fluorescent rotaxane in which the stabilization of a chemically labile squaraine fluorophore by the coordination of a tetralactam macrocycle can be controlled chemically and electrochemically. The rotaxane can be switched between two co-conformations inwhich thewheel either stabilizes or exposes the fluorophore. Coordination by the wheel affects the squaraine’s stability across four redox states and renders the radical anion significantly more stable—by a factor of 6.7—than without protection by a mechanically bonded wheel. Furthermore, the fluorescence properties can be tuned by the redox reactions in a stepwise manner. Mechanically interlockedmolecules provide an excellent scaffold to stabilize and selectively expose reactive species in a co-conformational switching process controlled by external stimuli.
KW - Fluorescence
KW - Dye
KW - Sensor
KW - Quantum yield
KW - Spectroscopy
KW - Photophysics
KW - Synthesis
KW - Squaraine
KW - Switch
KW - Redox-active
KW - Rotaxane
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-614959
DO - https://doi.org/10.1038/s42004-024-01312-1
VL - 7
SP - 1
EP - 11
AN - OPUS4-61495
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scharek, Vera M.
A1 - Kröger, Tommy
A1 - Keil, Karin
A1 - Traub, Heike
A1 - Meermann, Björn
T1 - A new elemental analytical approach for microplastic sum parameter analysis—ETV/ICP-MS with CO2
N2 - Microplastics (MPs) are pervasive environmental pollutants and are considered one of the main challenges of our time. However, a fast and comprehensive analytical approach for MP analysis in complex matrices traceable to SI units is still lacking. In this context, we report a fast screening tool for the sum parameter analysis of MPs using electrothermal vaporization (ETV) coupled to inductively coupled plasma-mass spectrometry (ICP-MS). In our proof-of-concept study, we observed size-independent detection of MPs as peaks above the 13C+ signal background in the nano- to micrometer range without limitations regarding the polymer type. Quantification of the 13C+ MP signals was accomplished via an external gas calibration utilizing dynamic dilution of carbon dioxide with argon, yielding recovery rates of 80–96% for MP reference material (RM) of polymer types commonly found in the environment. The applicability to a soil sample was demonstrated through spiking experiments with a polyethylene (PE) MP RM in soil. The limit of detection (LOD) was estimated to be 0.13 µg C, equaling the detection of a single spherical low-density-PE particle of about 70 µm, and a limit of quantification (LOQ) of 0.42 µg C.
KW - ETV/ICP-MS
KW - Mikroplastik
KW - Summenparameter
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-646418
DO - https://doi.org/10.1007/s00216-025-06146-x
SN - 1618-2642
SP - 1
EP - 10
PB - Springer
CY - Berlin ; Heidelberg
AN - OPUS4-64641
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bayerl, C.
A1 - Shahryari, M.
A1 - Reiter, R.
A1 - Proß, V.
A1 - Lehmann, K.
A1 - Kühl, A. A.
A1 - Becker, Dorit
A1 - Schulz, Andreas
A1 - Infante Duarte, C.
A1 - Taupitz, M.
A1 - Geisel, D.
A1 - Tzschätzsch, H.
A1 - Saatz, Jessica
A1 - Traub, Heike
A1 - Asbach, P.
T1 - Quantitative Analysis of Gadolinium Deposits in Liver Tissue of Patients After Single or Multiple Gadolinium-based Contrast Agent Application
N2 - Gadolinium-based contrast agents (GBCAs) are widely used in magnetic resonance imaging. Concerns exist regarding gadolinium deposition and its potential histopathologic tissue alterations, especially after repeated administrations of linear, less stable GBCAs. This study aimed to quantify gadolinium mass fractions in liver specimens of subjects exposed to GBCAs in correlation with histopathologic features.
In this study, mass fractions of gadolinium in human liver specimens from 25 subjects who underwent liver tumor resection surgery and had received GBCA (1 to 9 times over 4 years), were quantitatively analyzed using inductively coupled plasma–mass spectrometry (ICP-MS). Histomorphology was assessed based on the nonalcoholic fatty liver disease activity score (NAS).
Our results suggest that after intravenous administration of GBCA, a small fraction of gadolinium is retained in the liver over a time period of at least several weeks. A relationship was observed between Gadolinium retention and the number of GBCA administrations, but not with the cumulative dose and the degree of fatty liver disease.
KW - ICP-MS
KW - Contrast agent
KW - Gadolinium
KW - Liver
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-646608
DO - https://doi.org/10.1097/RLI.0000000000001254
SN - 1536-0210
SP - 1
EP - 10
PB - Lippincott Williams & Wilkins
CY - Philadelphia, Pa.
AN - OPUS4-64660
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lozano-Martín, Daniel
A1 - Tuma, Dirk
A1 - Chamorro, César R.
T1 - Evaluation of Reference Equations of State for Density Prediction in Regasified LNG Mixtures Using High-Precision Experimental Data
N2 - This study evaluates the performance of three reference equations of state (EoS), AGA8-DC92, GERG-2008, and SGERG-88, in predicting the density of regasified liquefied natural gas (RLNG) mixtures. A synthetic nine-component RLNG mixture was gravimetrically prepared. High-precision density measurements were obtained using a single-sinker magnetic suspension densimeter over a temperature range of (250 to 350) K and pressures up to 20 MPa. The experimental data were compared with EoS predictions to evaluate their accuracy. AGA8-DC92 and GERG-2008 showed excellent agreement with the experimental data, with deviations within their stated uncertainty. In contrast, SGERG-88 exhibited significantly larger deviations for this RLNG mixture, particularly at low temperatures of (250 to 260) K, where discrepancies reached up to 3 %. Even at 300 K, deviations larger than 0.4 % were observed at high pressures, within the model’s uncertainty, but notably higher than those of the other two EoSs. The analysis was extended to three conventional 11-component natural gas mixtures (labeled G420 NG, G431 NG, and G432 NG), previously studied by our group using the same methodology. While SGERG-88 showed reduced accuracy for the RLNG mixture, it performed reasonably well for these three mixtures, despite two of them have a very similar composition to the RLNG. This discrepancy is attributed to the lower CO2 and N2 content typical in RLNG mixtures, demonstrating the sensitivity of EoS performance to minor differences in composition. These findings highlight the importance of selecting appropriate EoS models for accurate density prediction in RLNG applications.
KW - Regasified LNG
KW - Equation of state
KW - Density
KW - Gravimetric preparation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-646506
DO - https://doi.org/10.1007/s10765-025-03669-4
SN - 0195-928X
VL - 46
SP - 1
EP - 25
PB - Springer Science and Business Media LLC
CY - Heidelberg
AN - OPUS4-64650
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Krahl, T.
A1 - Beer, F.
A1 - Relling, A.
A1 - Gawlitza, Kornelia
A1 - Rurack, Knut
A1 - Kemnitz, E.
T1 - Toward Luminescent Composites by Phase Transfer of SrF2 :Eu3+ Nanoparticles Capped with Hydrophobic Antenna Ligands
N2 - Transparent dispersions of hydrophobic SrF2 :Eu3+ nanoparticles in cyclohexane with up to 20% europium were obtained by fluorolytic sol-gel synthesis followed by Phase transfer into cyclohexane through capping with sodium dodecylbenzenesulfonate (SDBS). The particles were characterized by TEM, XRD and DLS as spherical objects with a diameter between 6 and 11 nm in dry state. 1H-13CP MAS NMR experiments revealed the binding of the anionic sulfonate head group to the particle surface. The particles show bright red luminescence upon excitation of the aromatic capping agents, acting as antennas for an Energy transfer from the benzenesulfonate unit to the Eu3+ centers in the particles. This synthesis method overcomes the current obstacle of the fluorolytic sol-gel synthesis that transparent dispersions can be obtained directly only in hydrophilic solvents. To demonstrate the potential of such hydrophobized alkaline-earth fluoride particles, transparent luminescent organic-inorganic composites with 10% SrF2 :Eu3+ embedded into polyTEGDMA, polyBMA, poly-BDDMA and polyD3MA, respectively, were prepared, endowing the polymers with the luminescence features of the nanoparticles.
KW - Nanoparticles
KW - Fluorides
KW - Sol-gel process
KW - Organic-inorganic hybrid composites
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508668
DO - https://doi.org/10.1002/cnma.202000058
SP - 1
EP - 11
PB - Wiley
AN - OPUS4-50866
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tjaden, B.
A1 - Lisec, Jan
A1 - Schramm, A.
T1 - N-Myc-induced metabolic rewiring creates novel therapeutic vulnerabilities in neuroblastoma
N2 - N-Myc is a transcription factor that is aberrantly expressed in many tumor types and is often correlated with poor patient prognosis. Recently, several lines of evidence pointed to the fact that oncogenic activation of Myc family proteins is concomitant with reprogramming of tumor cells to cope with an enhanced need for metabolites during cell growth. These adaptions are driven by the ability of Myc proteins to act as transcriptional amplifiers in a tissue-of-origin specific manner. Here, we describe the effects of N-Myc overexpression on metabolic reprogramming in neuroblastoma cells. Ectopic expression of N-Myc induced a glycolytic switch that was concomitant with enhanced sensitivity towards 2-deoxyglucose, an inhibitor of glycolysis. Moreover, global metabolic profiling revealed extensive alterations in the cellular metabolome resulting from overexpression of N-Myc. Limited supply with either of the two main carbon sources, glucose or glutamine, resulted in distinct shifts in steady-state metabolite levels and significant changes in glutathione metabolism. Interestingly, interference with glutamine-glutamate conversion preferentially blocked proliferation of N-Myc overexpressing cells, when glutamine levels were reduced. Thus, our study uncovered N-Myc induction and nutrient levels as important metabolic master switches in neuroblastoma cells and identified critical nodes that restrict tumor cell proliferation.
KW - Mass-Spectrometry
KW - Cancer
KW - MYCN
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-507193
DO - https://doi.org/10.1038/s41598-020-64040-1
VL - 10
IS - 1
SP - 7157
AN - OPUS4-50719
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Climent Terol, Estela
A1 - Rurack, Knut
T1 - Streifenschnelltest mit ppt-Empfindlichkeit durch Kombination von Elektrochemilumineszenz-Detektion mit Aptamer-gesteuerter Indikatorfreisetzung aus mesoporösen Nanopartikeln
N2 - Die Kombination aus elektrogenerierter Chemilumineszenz (ECL) und Aptamer-gesteuerter Indikatorfreisetzung (gAID) aus magnetischen mesoporösen Silica-Nanopartikeln, die in mit Poly(ethylenglycol) und N-(3-Triethoxysilylpropyl) diethanolamin funktionalisiertes Glasfaserpapier eingebettet sind, ermöglichte die Entwicklung eines Schnelltests, mit dem sich Penicillin direkt in verdünnter Milch bis auf 50 +/- 9 ppt in <5 min nachweisen lässt. Die kovalente Bindung der Aptamer-Kappe an das Siliciumdioxid-Gerüst ermöglichte den Verschluss der Poren durch nicht-kovalente elektrostatische Wechselwirkungen mit Oberflächen-Aminogruppen. Die Bindung von Penicillin führte zu einer Faltung des Aptamers, wodurch der zuvor in das Material geladene ECL-Reporter Ru(bpy)32+ freigesetzt wurde und nach lateralem Fluss von einer Smartphone-Kamera nach elektrochemischer Anregung mit einer in einen 3D-gedruckten Halter eingesetzten Siebdruckelektrode detektiert wird. Der Ansatz ist einfach, generisch und bietet Vorteile hinsichtlich Empfindlichkeit, Messunsicherheit und Robustheit gegenüber konventioneller Fluoreszenz- oder elektrochemischer Detektion, insbesondere für Point-of-Need-Analysen anspruchsvoller Matrices und Analyten im Ultraspurenbereich.
KW - Schnelltests
KW - Elektrochemilumineszenz
KW - Aptamere
KW - Teststreifen
KW - Gesteuerte Freisetzung
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540205
DO - https://doi.org/10.1002/ange.202110744
VL - 133
IS - 50
SP - 26491
EP - 26501
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-54020
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Smeir, E.
A1 - Leberer, S.
A1 - Blumrich, A.
A1 - Vogler, G.
A1 - Vasiliades, A.
A1 - Dresen, S.
A1 - Jaeger, Carsten
A1 - Gloaguen, Y.
A1 - Klose, C.
A1 - Beule, D.
A1 - Schulze, P.
A1 - Bodmer, R.
A1 - Foryst-Ludwig, A.
A1 - Kintscher, U.
T1 - Depletion of Cardiac Cardiolipin Synthase Alters Systolic and Diastolic Function
N2 - Cardiolipin (CL) is a major cardiac mitochondrial phospholipid maintaining regular mitochondrial morphology and function in cardiomyocytes. Cardiac CL production includes ist biosynthesis and a CL-remodeling process. Here we studied the impact of CL-biosynthesis and the enzyme Cardiolipin Synthase (CLS) on cardiac function.
CLS and cardiac CL-species were significantly downregulated in cardiomyocytes following catecholamine-induced cardiac damage in mice, accompanied by increased oxygen consumption rates, signs of oxidative stress and mitochondrial uncoupling. RNAi-mediated cardiomyocyte-specific knockdown of CLS in Drosophila melanogaster resulted in marked cardiac dilatation, severe impairment of systolic performance and slower diastolic filling velocity assessed by fluorescence-based heart imaging. Finally, we showed that CL72:8 is significantly decreased in cardiac samples from patients with heart failure with reduced ejection fraction (HFrEF). In summary, we identified CLS as a regulator of cardiac function. Considering the cardiac depletion of CL-species in HFrEF, pharmacological targeting of CLS may be a promising therapeutic approach.zeige mehrzeige weniger
KW - High-resolution mass spectrometry
KW - Nontarget analysis
KW - Heart failure
KW - Cardiolipins
KW - Lipidomics
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-536833
DO - https://doi.org/10.1016/j.isci.2021.103314
VL - 24
IS - 11
SP - 103314
PB - Cell Press
AN - OPUS4-53683
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hudson, A.D.
A1 - Jamieson, O.
A1 - Crapnell, R.D.
A1 - Rurack, Knut
A1 - Soares, T.C.C.
A1 - Mecozzi, F.
A1 - Laude, A.
A1 - Gruber, J.
A1 - Novakovic, K.
A1 - Peeters, M.
T1 - Dual detection of nafcillin using a molecularly imprinted polymer-based platform coupled to thermal and fluorescence read-out
N2 - Reported here is the production of molecularly imprinted polymer (MIP) films, integrating a fluorescent moiety that serves as both an element for template interaction and signalling, for the thermal and optical detection of the beta-lactam antibiotic nafcillin. Fluorescein methacrylate (FluMa) was synthesized and introduced during the molecular imprinting process as the sole monomer and in a 1 : 1 mixture with methacrylic acid (MAA), allowing to draw first conclusions on the MIP formation potential of such a rather large and rigid monomer. At first, MIP microparticles containing FluMa were prepared by free radical polymerisation. Optical batch rebinding experiments revealed that FluMa can act as a functional monomer for selective detection of nafcillin; however, the addition of MAA as co-monomer significantly improved performance. Subsequently, thin MIP films containing FluMa were deposited onto functionalised glass slides and the influence of porogen, drying time, and monomer composition was studied. These MIP-functionalised glass electrodes were mounted into a customised 3D-printed flow cell, where changes in the liquid were either evaluated with a thermal device or using fluorescence bright field microscopy. Thermal analysis demonstrated that multiple MIP layers enhanced sensor specificity, with detection in the environmentally relevant range. The fluorescence bright field microscope investigations validated these results, showing an increase in the fluorescence intensity upon exposure of the MIP-functionalised glass slides to nafcillin solutions. These are promising results for developing a portable sensor device that can be deployed for antibiotics outside of a dedicated laboratory environment, especially if sensor design and fluorophore architecture are optimised.
KW - Molecularly Imprinted Polymers
KW - Fluorescence
KW - Antibiotics
KW - Heat-transfer Measurements
KW - Thin films
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540044
DO - https://doi.org/10.1039/D1MA00192B
VL - 2
IS - 15
SP - 5105
EP - 5115
PB - Royal Society of Chemistry
CY - Cambridge
AN - OPUS4-54004
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heide, Maximilian
A1 - Reifenrath, Jonas
A1 - Herrmann, Alexander
A1 - Engelhard, Carsten
T1 - Fast and Sustainable Active Pharmaceutical Ingredient (API) Screening in Over-the-Counter and Prescription Drug Products by Surface-Assisted Plasma-Based Desorption/Ionization High-Resolution Mass Spectrometry
N2 - Fast chemical analysis of pharmaceutical preparations is important for quality assurance, counterfeit drug detection, and consumer health. While quantitative methods such as high-performance liquid chromatography mass spectrometry (HPLC-MS) are powerful, there is a need for sustainable and environmentally friendly methods, which require less chemicals and produce less waste. Here, solvent-free ambient desorption/ionization (ADI) MS methods are attractive because they do not require time-consuming chromatography, produce little to no chemical waste, and, thus, contribute to green chemistry practice. In addition, sample throughput can be higher compared to HPLC-MS. In this study, a method for direct analysis of single- and multi agent drugs using a plasma-based ADI source (flowing atmospheric-pressure afterglow, FAPA) coupled to high-resolution (HR) MS was developed and optimized for best performance. The approach is rapid and only requires analytes to be in solution (only a few µL) before application onto thin-layer chromatography (TLC) surfaces, specifically dimethyl (RP2-) and cyano (CN-) modified silica, for surface-assisted (SA) FAPA-HRMS measurements. No chromatographic separation was required, and the TLC plates served only as sample carriers. A broad variety of 19 active pharmaceutical ingredients (APIs) was carefully selected to cover analgesics, anesthetics, antibiotics, antiepileptics, calcium channel blockers, diuretics, expectorants, opioids, peripheral vasodilators, stimulants, and sympathomimetics. Fast screening and identification of APIs was performed by SA-FAPA-HRMS. Typically, the protonated molecular ion ([M+H]+) was the most abundant species, while some compounds (codeine, metamizole, phenoxymethylpenicillin, and torasemide) did show some degree of fragmentation. As a proof-of-principle application, benzocaine was directly detected in saliva samples post-intake of a lozenge. Time-resolved semi-quantitative screening was performed. The limit of detection for benzocaine in saliva was 8 ng/mL (48.4 fmol) using internal standard calibration and CN-HPTLC plates. In addition, direct quantification of artificially spiked saliva was performed with minimal sample preparation. Here, SA-FAPA-HRMS with a CN-HPTLC sample substrate yielded best performance (20.02±0.52 µg/mL, RSD=2.6%, deviation of -1.9% from the theoretical value) compared to RP2-TLC (18.97±1.37 µg/mL, RSD=7.2%, -7.0%), and HPLC-UV (18.51±0.03 µg/mL, RSD=0.2%, -9.3%) results. In conclusion, SA FAPA HRMS is considered attractive for rapid and sustainable analysis of pharmaceuticals with potential in non-invasive patient monitoring.
KW - Mass Spectrometry
KW - Pharmaceuticals
KW - Green Chemistry
KW - Ambient Desorption/Ionization
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640718
DO - https://doi.org/10.1039/D5AY01050K
SN - 1759-9660
VL - 17
IS - 18
SP - 7799
EP - 7809
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-64071
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Homann, Christian
A1 - Peeters, Régis
A1 - Mirmajidi, Hana
A1 - Berg, Jessica
A1 - Fay, Michael
A1 - Rodrigues, Lucas Carvalho Veloso
A1 - Radicchi, Eros
A1 - Jain, Akhil
A1 - Speghini, Adolfo
A1 - Hemmer, Eva
T1 - Rapid microwave-assisted synthesis of morphology-controlled luminescent lanthanide-doped Gd2O2S nanostructures
N2 - Gadolinium oxysulfide (Gd2O2S) is an attractive material of demonstrated suitability for a variety of imaging applications, leveraging its magnetic, scintillating, and luminescent properties, particularly when doped with optically active lanthanide ions (Ln3+). For many of these applications, control over size and morphology at the nanoscale is crucial. This study demonstrates the rapid microwave-assisted Synthesis of colloidal Ln2O2S (Ln = Gd and dopants Yb, Er, Tb) nanostructures in as little as 20 min. Structural characterization using X-ray diffraction analysis (XRD), Raman spectroscopy, as well as Transmission electron microscopy (TEM), including elemental mapping via energy dispersive X-ray spectroscopy (EDS), unveiled the key role of elemental sulphur (S8) in the reaction mixtures for materials growth. By systematically varying the Ln-to-S ratio from 1 : 0.5 to 1 : 15, controlled morphologies ranging from triangular nanoplatelets to berry- and flower-like shapes were achieved. Doping with Er3+/Yb3+ endowed the nano-triangles with upconverting and near-infrared emitting properties. Tb3+-doped Gd2O2S exhibited the characteristic green Tb3+ emission under UV excitation, while also showing X-ray excited optical luminescence (XEOL), rendering the material interesting as a potential nano-scintillator.
KW - Upconversion
KW - Microwave-assisted synthesis
KW - Synthesis
KW - Fluorescence
KW - Nano
KW - Particle
KW - NIR
KW - XRD
KW - X-ray fluoressence
KW - Morphology control
KW - Raman
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647907
DO - https://doi.org/10.1039/D5TC01646K
SN - 2050-7526
VL - 13
IS - 35
SP - 18492
EP - 18507
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-64790
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Frenzel, Olivia
A1 - Westphalen, Tanja
A1 - Kaminski, Katja
A1 - Kluge, Stephanie
A1 - Bücker, Michael
A1 - Piechotta, Christian
T1 - Evaluation and Validation of an Accelerated Weathering Procedure to Characterise the Release of Bisphenol A from Polycarbonate Under Exposure to Simulated Environmental Conditions
N2 - Bisphenol A (BPA) has been listed as a substance of very high concern (SVHC) due to its endocrine-disrupting properties according to REACH in 2017. European competent authorities have prepared a REACH restriction proposal to reduce BPA levels in the environment. The proposed limit for the concentration of free BPA and other bisphenols in articles is 10 mg kg−1. If exceeded, migration testing can demonstrate that no more than 0.04 mg L−1 is released from the product or material over its lifetime. German authorities are drafting a new restriction proposal after the original was temporarily withdrawn. The residual and migration limits mentioned above were key requirements from the previous restriction proposal. Numerous national and international standards exist for assessing how environmental factors affect the physical and chemical properties of products and materials—such as notch impact strength and tensile strength—but these standards do not cover the release of pollutants. A standardised procedure that covers all aspects of artificial weathering and monitors the subsequent release of pollutants is necessary, especially in the context of the regulation of these substances. An accelerated weathering procedure was established for non-protected samples. This material was not intended for outdoor applications. The testing procedure applied a typical weathering scenario that represents Central European climate conditions. The procedure was validated and applied to samples under distinct quality assurance aspects. Released BPA is quantified via an organic isotope dilution LC-MS/MS method. In parallel, identical samples were weathered outdoors on a weathering rack. Haze and yellowness index are measured to compare outdoor and weathering chamber results.
KW - Artificial weathering
KW - Polycarbonate
KW - Bisphenol A
KW - Simulated environmental conditions
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-645020
DO - https://doi.org/10.3390/app151910361
SN - 2076-3417
VL - 15
IS - 19
SP - 1
EP - 15
PB - MDPI AG
AN - OPUS4-64502
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Matiushkina, Anna
A1 - Abram, Sarah-Luise
A1 - Tavernaro, Isabella
A1 - Richstein, R.
A1 - Reithofer, M. R.
A1 - Andresen, Elina
A1 - Michaelis, Matthias
A1 - Koch, Matthias
A1 - Resch-Genger, Ute
T1 - Quantifying Citrate Surface Ligands on Iron Oxide Nanoparticles with TGA, CHN Analysis, NMR, and RP-HPLC with UV Detection
N2 - Although citrate is frequently used as a surface ligand for nanomaterials (NMs) such as metal, metal oxide, and lanthanide-based NMs in hydrophilic environments due to its biocompatibility and simple replacement by other more strongly binding ligands in postsynthetic surface modification reactions, its quantification on NM surfaces has rarely been addressed. Here, we present a multimethod approach for citrate quantification on iron oxide nanoparticles (IONPs) broadly applied in the life and material sciences. Methods explored include thermogravimetric (TGA) and elemental (CHN) analysis, providing citrate-nonspecific information on the IONP coating, simple photometry, and citrate-selective reversed-phase high-performance liquid chromatography (RP-HPLC) with absorption (UV) detection and quantitative nuclear magnetic resonance spectroscopy (qNMR). Challenges originating from the strongly absorbing magnetic NM and paramagnetic iron species interfering with optical and NMR Methods were overcome by suitable sample preparation workflows. Our multimethod approach to citrate quantification highlights the advantages of combining specific and unspecific methods for characterizing NM Surface chemistry and method cross-validation. It also demonstrates that chemically nonselective measurements can favor an overestimation of the amount of a specific surface ligand by signal contributions from molecules remaining on the NM surface, e.g., from particle synthesis, such as initially employed ligands and/or surfactants. Our results emphasize the potential of underexplored selective RPHPLC for quantifying ligands on NMs, which does not require a multistep sample preparation workflow such as qNMR for many NMs and provides a higher sensitivity. These findings can pave the road to future applications of versatile HPLC methods in NM characterization.
KW - Advanced material
KW - Functional group
KW - Iron oxide
KW - Ligand
KW - Nano
KW - Particle
KW - Quantification
KW - Surface analysis
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-648632
DO - https://doi.org/10.1021/acs.analchem.5c03024
SN - 0003-2700
VL - 97
IS - 36
SP - 19627
EP - 19634
PB - American Chemical Society (ACS)
CY - Washington, DC
AN - OPUS4-64863
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jaeger, Carsten
A1 - Lintelmann, Jutta
A1 - Franke, Raimo
A1 - Artati, Anna
A1 - Cecil, Alexander
A1 - Broda, Frank
A1 - Klawonn, Frank
A1 - Erban, Alexander
A1 - Kopka, Joachim
A1 - Fuchs, Beate
A1 - Sommer, Ulf
A1 - Neumann-Schaal, Meina
A1 - O'Connor, Gavin
T1 - Analytical practices, use and needs of standard and reference materials in the German-speaking metabolomics community: results of an online survey
N2 - Introduction
Since the early 2000s, metabolomics has grown rapidly, becoming integral to fields like life sciences, health, and environmental research. This expansion has led to the formation of national and international societies, such as Germany’s DGMet, to tackle emerging challenges. One of DGMet’s goals is to improve measurement quality by assessing community needs for harmonization and standardization. A recent survey within the German-speaking community aimed to identify current practices and gaps in the use of chemical standards and reference materials, to guide future standardization efforts and collaborative initiatives.
Methods
An online survey was conducted between June 2023 and April 2024. The survey consisted of 38 key questions and was open to research institutions from Germany, Austria, and Switzerland.
Results
The survey was accessed by 68 laboratories, with 23 institutes providing complete or partial responses (34% response rate), which is comparable to rates reported in similar surveys within the metabolomics and lipidomics communities. Respondents were mainly experienced researchers from Germany, focusing mainly on health-related (“red”) metabolomics, as indicated by 78% of the respondents, followed by microbial (“grey”, 48%) and plant (“green”, 39%) metabolomics (multiple answers possible). The use of targeted methods was reported more frequently (91%) than that of non-targeted methods (78%), whereas metabolite fractions studied were equally split between polar, midpolar and lipid fractions (83% each). Human (74%), mouse (61%) and Arabidopsis (30%) were the most frequently studied organisms. Most participants used synthetic chemical standards for instrument qualification (83%), calibration (78%), and metabolite identification (74%), while matrix reference materials were mainly applied for quality control (52%) and method validation (44%). There was a strong demand for more standards, especially for metabolite identification and quantification, with cost being a major barrier, particularly for isotopically labelled standards and certified reference materials.
Conclusions
Valuable insights into the use of standards and reference materials within the German-speaking metabolomics community were obtained. Moving forward, the community should address critical gaps in metabolomics standardization. To achieve this, it must share its knowledge, articulate its needs clearly, and actively engage in joint efforts with national metrology institutes and international standardization initiatives.
KW - Reference material
KW - Chemical standard
KW - Metabolomics
KW - Mass spectrometry
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647303
DO - https://doi.org/10.1007/s11306-025-02360-x
VL - 21
IS - 6
SP - 1
EP - 11
PB - Springer-Nature
CY - Heidelberg
AN - OPUS4-64730
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Li, Xunyu
A1 - Riedel, Jens
A1 - You, Yi
T1 - Practical high-resolution spectroscopy with a spatial heterodyne spectrometer: Determination of instrumental function for lineshape recovery
N2 - The spatial heterodyne spectrometer (SHS) is a well-recognized platform for its high resolving power in various use cases of spectroscopy. Same as other spectrometer topologies, the SHS, unfortunately, also suffers from classical challenges such as distorted lineshape due to the instrumental function. The goal of this work is to tackle this persisting issue through a simple numerical approach. With the inherent characteristics of an SHS interferogram, we report the direct extraction and determination of the instrumental function in its numerical representation from an SHS interferogram; this instrumental function was further used for spectral data processing that enables significant improvements in spectral resolution through deconvolution algorithms.Here, we systematically discuss the recognition of the embedded instrumental function among various ingredients within an interferogram. To verify the numerical approach, lithium was chosen as the model sample, resembling the use of SHS in an isotopic analysis application. Specifically, the resonance transition of lithium D-lines (2P1/2,3/2 ← 2S1/2) was selected to assess the performance of the spectral processing. With the spectral deconvolution, the spectral features that represent the 6Li and 7Li were nearly baseline-separated, allowing for the accurate measure of the isotopic abundance without external references or algorithm adjustments (e.g., curve fitting).
KW - SHS
KW - Isotopic analysis
KW - High Resolution
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613401
DO - https://doi.org/10.1016/j.sab.2024.107053
SN - 0584-8547
VL - 221
SP - 1
EP - 5
PB - Elsevier
AN - OPUS4-61340
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Steinbeck, Christoph
A1 - Jung, Nicole
A1 - Bach, Felix
A1 - Neumann, Steffen
A1 - Herres-Pawlis, Sonja
A1 - Liermann, Johannes
A1 - Koepler, Oliver
A1 - Bannwarth, Christoph
A1 - Bender, Theo
A1 - Bocklitz, Thomas
A1 - Boehm, Franziska
A1 - Bonatto Minella, Christian
A1 - Biedermann, Frank
A1 - Brack, Werner
A1 - Cunha, Ricardo
A1 - Czodrowski, Paul
A1 - Eberl, Franziska
A1 - Engel, Thomas
A1 - Engstfeld, Albert
A1 - Fischer, Tillmann G.
A1 - Friedrich, Pascal
A1 - Glorious, Frank
A1 - Golub, Benjamin
A1 - Grathwol, Christoph
A1 - Haag, Rainer
A1 - Hunold, Johannes
A1 - Jacob, Christoph
A1 - Johannsen, Jochen
A1 - Jollife, John
A1 - Kast, Stefan
A1 - Kettner, Carsten
A1 - Kuhn, Stefan
A1 - Lanza, Giacomo
A1 - Lisec, Jan
A1 - Manolikakes, Georg
A1 - Mata, Ricardo
A1 - Meiler, Jens
A1 - Müller, Matthias
A1 - Müller-Pfefferkorn, Ralph
A1 - Ortmeyer, Jochen
A1 - Patterson, Wendy
A1 - Pleiss, Jürgen
A1 - Riedel, Annalisa
A1 - Riedel, Jens
A1 - Schatzschneider, Ulrich
A1 - Schuster, Leonie
A1 - Seeberger, Peter
A1 - Seibert, Johann-Nikolaus
A1 - Stadler, Peter
A1 - Zeitler, Kirsten
T1 - Proposal NFDI4Chem 2025-2030 In the National Research Data Infrastructure (NFDI) — Our Vision: All Chemists Publish FAIR Data
N2 - The first funding period of NFDI4Chem established a robust foundation for research data management (RDM) in chemistry by promoting FAIR data principles and creating a cohesive infrastructure to capture well-annotated data early in the lab through electronic lab notebooks (ELNs) and making this data available in public repositories. Key achievements include standardised data formats and metadata, a federated repository environment, and improved data visibility and accessibility. Training programs and outreach have significantly increased awareness and adoption of best RDM practices. In the second funding period, the consortium aims to advance these achievements by consolidating this infrastructure, developing a model for its sustainable maintenance and operation, and fostering cultural change for its widespread adoption. Goals include ensuring seamless data workflows from laboratories to open repositories, enhancing interoperability, and supporting innovative research through AI-ready data. The work plan is organised into six task areas (TAs). TA1 (Management) provides leadership and supports all other TAs in achieving their objectives. TA2 (Smart Lab) aims to develop a fully digital research environment, including an ELN as a modular platform. This environment will support data collection, management, storage, analysis, and sharing. Integrating devices and external resources will enable seamless data transfer to repositories. TA3 (Repositories) will consolidate the repository ecosystem. The goal is to integrate repositories into a federated system for better accessibility and interoperability, ensuring long-term data availability and sustainability. TA4 (Metadata, Data Standards, and Publication Standards) focuses on developing and promoting new data and metadata standards in an international community process. This includes applying ontologies to create a semantic foundation for linking research data, making it machine-readable and enabling knowledge graphs. TA5 (Community and Training) is dedicated to fostering a cultural shift towards digital chemistry through continuous engagement, collecting requirements, and providing extensive training and support through workshops and open education resources. It will promote FAIR-compliant machine learning applications, embedding RDM into academic curricula to ensure future scientists are well-versed in these practices. TA6 (Synergies and Cross-Cutting Topics) aims to enhance collaboration across NFDI consortia and beyond. This includes developing ontologies, terminology services, the search service, and other cross-cutting solutions, integrating these developments into existing infrastructure, enabling interdisciplinary data harmonisation and fostering machine learning applications.
KW - Research Data Management
KW - FAIR
KW - Chemistry
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-648540
DO - https://doi.org/10.3897/rio.11.e177037
SN - 2367-7163
VL - 11
SP - 1
EP - 100
PB - Pensoft Publishers
AN - OPUS4-64854
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - You, Yi
A1 - Riedel, Jens
T1 - Approaching phase-imaging through defocusing shadowgraphy for acoustic resonator diagnosis and the capability of direct index-of-refraction measurements
N2 - The visualization of index-of-refraction (IoR) distribution is one of the common methods to investigate fluid flow or pressure fields. While schlieren and shadowgraphy imaging techniques are widely accepted, their inherent limitations often lead to difficulties in elucidating the IoR distribution and extracting the true IoR information from the resulting images. While sophisticated solutions exist, the IoR-gradient-to-image was achieved by purposely introducing a commonly avoided “defect” into the optical path of a conventional coincident schlieren/shadowgraphy setup; the defect is a combination of slight defocusing and the use of non-conjugate optical components. As such, the method presented in this work is referred to as defocusing shadowgraphy, or DF-shadowgraphy. While retaining the ease of a conventional schlieren/shadowgraphy geometry, this DF approach allows direct visualization of complicated resonant acoustic fields even without any data processing. For instance, the transient acoustic fields of a common linear acoustic resonator and a two-dimensional one were directly visualized without inversion. Moreover, the optical process involved in DF-shadowgraphy was investigated from a theoretical perspective. A numerical solution of the sophisticated impulse response function was obtained, which converts the phase distortion into intensity distributions. Based on this solution, the IoRs of various gas streams (e.g., CO2 and isopropanol vapor) were determined from single images.
KW - Imaging Technique
KW - Phase Imaging
KW - Shadowgraphy
KW - Schlieren Imaging
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-537116
DO - https://doi.org/10.1063/5.0058334
SN - 1089-7623
VL - 92
IS - 10
SP - 103703
PB - AIP Publishing Group
AN - OPUS4-53711
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - You, Yi
A1 - Danischewski, Julia
A1 - Molnar, Brian
A1 - Riedel, Jens
A1 - Shelley, Jacob
T1 - Manipulation of Gaseous Ions with Acoustic Fields at Atmospheric Pressure
N2 - The ability to controllably move gaseous ions is an essential aspect of ion-based spectrometry (e.g., mass spectrometry and ion mobility spectrometry) as well as materials processing. At higher pressures, ion motion is largely governed by diffusion and multiple collisions with neutral gas molecules. Thus, high-pressure ion optics based on electrostatics require large fields, radio frequency drives, complicated geometries, and/or partially transmissive grids that become contaminated. Here, we demonstrate that low-power standing acoustic waves can be used to guide, block, focus, and separate beams of ions akin to electrostatic ion optics. Ions preferentially travel through the static-pressure regions (“nodes”) while neutral gas does not appear to be impacted by the acoustic field structure and continues along a straight trajectory. This acoustic ion manipulation (AIM) approach has broad implications for ion manipulation techniques at high pressure, while expanding our fundamental understanding of the behavior of ions in gases.
KW - Ion mobility spectrometry
KW - Acoustic
KW - Mass spectrometry
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600704
DO - https://doi.org/10.1021/jacs.4c01224
SP - 1
EP - 6
PB - ACS Publications
AN - OPUS4-60070
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Riedel, Jens
A1 - Hufgard, Josefin
A1 - You, Yi
T1 - LIBS at high duty-cycles: effect of repetition rate and temporal width on the excitation laser pulses
N2 - Laser-induced breakdown spectroscopy (LIBS) is becoming a more mature technology every year with new variants such as laser ablation molecular isotopic spectrometry, reheating by various discharge techniques, and multiple pulse excitation schemes, in which sometimes lasers of different pulse lengths are used. However, lasers with inherent parameters like pulse length and repetition rate are still almost exclusively employed. Recent years have witnessed the advent of novel high-repetition-rate laser concepts for machining processes, like welding, milling, and engraving. Here, a comprehensive study of single-pulse LIBS spectra of a single aluminum target is presented to showcase the applicability of flexible high duty-cycle master oscillator power amplifier (MOPA) lasers. Although traditional flashlamp-pumped Fabry–Pérot lasers only permit a variation in the pulse energy and are operated at very low duty-cycles, MOPA lasers add repetition rate and pulse length as variable parameters. A thorough analysis of the temporal plasma behavior revealed the emission dynamic to closely match the excitation laser pulse pattern. An aluminum sample’s spectral response was shown to be significantly impacted by variations in both rate and length. Although the spectral emission strength of the elemental lines of Al, Sr, and Ca all peaked at slightly different parameter settings, the strongest impact was found on the relative abundance of molecular AlO bands. Unlike in previous laser ablation molecular isotopic spectrometry (LAMIS) publications, the latter could be readily detected with a good intensity and well-resolved spectral features without any temporal gating of the detector. This finding, together with the fact that MOPA lasers are both inexpensive and dependable, makes for a promising combination for future studies including the detection of diatomic band structures.
KW - Laser-induced breakdown spectroscopy
KW - LIBS
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-583300
DO - https://doi.org/10.3389/fphy.2023.1241533
SN - 2296-424X
VL - 11
SP - 1
EP - 8
AN - OPUS4-58330
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kalmbach, J.
A1 - Wang, Cui
A1 - You, Yi
A1 - Förster, C.
A1 - Schubert, H.
A1 - Heinze, K.
A1 - Resch-Genger, Ute
A1 - Seitz, M.
T1 - Near-IR to near-IR upconversion luminescence in molecular chromium ytterbium salts
N2 - Upconversion photoluminescence in hetero-oligonuclear metal complex architectures featuring organic ligands is an interesting but still rarely observed phenomenon, despite its great potential from a basic research and application perspective. In this context, a new photonic material consisting of molecular chromium(III) and ytterbium(III) complex Ions was developed that exhibits excitation-power density-dependent cooperative sensitization of the chromium-centered 2E/2T1 phosphorescence at approximately 775 nm after excitation of the ytterbium band 2F7/2!2F5/2 at approximately 980 nm in the solid state at ambient temperature. The upconversion process is insensitive to atmospheric oxygen and can be observed in the presence of water molecules in the crystal lattice.
KW - Upconversion
KW - Lanthanide
KW - Photoluminescence
KW - Quantum yield
KW - Photophysics
KW - Lifetime
KW - Sensor
KW - NIR
KW - Cr(III)
KW - Yb(III) complex
KW - Crystal
KW - Triplet-triplet annihilation
KW - Sensitization
KW - Light harvesting
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512619
DO - https://doi.org/10.1002/anie.202007200
SN - 1433-7851
SN - 1521-3773
VL - 59
IS - 42
SP - 18804
EP - 18808
PB - Wiley
CY - Weinheim
AN - OPUS4-51261
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Xue, Boyang
A1 - Wang, Zhangjun
A1 - Zhu, Tao
A1 - Gu, Yezhen
A1 - Sun, Weihong
A1 - Chen, Chao
A1 - Li, Zhigang
A1 - Riedel, Jens
A1 - You, Yi
T1 - High repetition-rate laser-induced breakdown spectroscopy combined with two-dimensional correlation method for analysis of sea-salt aerosols
N2 - Laser-induced breakdown spectroscopy (LIBS) offers a tantalizing glimpse into real-time, on-the-spot aerosol analysis. Yet, the reliance on traditional lasers, with their limitations in energy and frequency, hampers optimal sample handling, dissociation, and excitation. To address those challenges, we propose a novel tactic: utilize a high repetition-rate (rep.-rate) laser with low pulse energy in combination with the two-dimensional correlation (2D-corr.) technique for sea-salt aerosols analyses. By examining the emission patterns from both the laser pulse train and individual pulses, we recognize distinctive analyte-specific rep.-rate responses, which allowed spectral reconstruction of analytes, avoiding background interferences. This discovery enabled the rep.-rate modulation for a 2D-corr. spectroscopy workflow. Consequently, we successfully differentiated between particle-related and air-species-related spectral components, obviating expensive spectrometers or intensified image detectors. For instance, the Na I at 589 nm stemming from aerosols exhibited an entirely different correlation contribution compared to O I at 777 nm, resulting in reconstructed clean aerosol-spectra without spectral peaks originated from air species. This 2D-corr. aerosol LIBS approach shows promising analytical potential streamlining aerosol particle analysis.
KW - LIBS
KW - Aerosol
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613392
DO - https://doi.org/10.1016/j.sab.2024.107048
SN - 0584-8547
VL - 221
SP - 1
EP - 8
PB - Elsevier
AN - OPUS4-61339
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Li, Xunyu
A1 - Riedel, Jens
A1 - You, Yi
T1 - Spectrally resolved lithium isotope quantification through high-resolution spatial heterodyne spectrometry
N2 - Isotope ratio determination of lithium is increasingly important in fields ranging from geochemistry to battery diagnostics. While mass spectrometry remains the gold standard, it is costly, cumbersome, and incompatible with portable or inline implementations. Optical emission spectroscopy presents an appealing alternative. However, it is traditionally limited by insufficient spectral resolution or resolving power to separate lithium isotope emissions due to their generalized designs for a wide spectral range; this often requires overly complicated algorithms to overcome the instrumental drawbacks. (79)
Results Here, we report a high-resolution optical method for lithium isotope quantification using a custom-built spatial heterodyne spectrometer (SHS) combined with a reduced-pressure glow discharge source. This configuration yielded a resolving power of 189,000 and enabled baseline resolution of lithium d-line emission features even without the need for preliminary data processing. Despite the inherent low sensitivity of SHS, a detection limit of 30 pmol was achieved using a standard industrial camera. To improve quantitative accuracy, we introduced a deconvolution-based spectral lineshape recovery technique alongside a bootstrapping-based error propagation strategy. These methods facilitated robust isotope ratio calibration using both peak-height and peak-area metrics. The SHS platform additionally enabled the determination of relative transition probabilities, suggesting the feasibility of calibration-free operation.
This work demonstrates the practical viability of SHS for high-specificity, high-resolution lithium isotope analysis. The approach is compact, potentially field-deployable, and adaptable to other elements with optically resolvable isotope shifts, offering a route toward accessible and calibration-free optical isotopic analyses.
KW - SHS
KW - Isotope
KW - High-resolution spectroscopy
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-635139
DO - https://doi.org/10.1016/j.aca.2025.344329
SN - 1873-4324
VL - 1368
SP - 1
EP - 8
PB - Elsevier B.V.
AN - OPUS4-63513
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mohan, M.
A1 - Prochazka, D.
A1 - You, Yi
A1 - Riedel, Jens
A1 - Gornushkin, Igor
A1 - Rocnakova, I.
A1 - Papula, M.
A1 - Porízka, P.
A1 - Kaizer, J.
T1 - Investigating plasma morphology at material boundaries under varying ambient pressures
N2 - Laser-Induced Breakdown Spectroscopy (LIBS) is a widely used technique for elemental analysis. The analysis of the obtained LIBS spectra generally assumes plasma homogeneity. However, using focused laser beams for interrogation, LIBS probes materials on the microscale and is, thus, prone to artefacts from sample heterogeneities on the micrometer scale. An ablation at a material boundary of two matrices may result in a significant inhomogeneity in the plasma plume, which can severely impact the accuracy of quantitative analysis. Since this propagation of the surface morphology into the plasma plume is driven by the plasma expansion, its final impact is strongly pressure dependent. This study examines the influence of varying ambient pressures (7–1000 mbar) on plasma morphology, spectral characteristics, and key plasma properties such as electron number density at a well-defined Cu–Sn boundary, in comparison with the results obtained using homogeneous alloys. Several approaches of plasma imaging with bandpass filters, spectroscopy, and Radon transform-based 3D reconstruction were employed to analyze elemental distribution, signal-to-noise (SNR) and signal-to-background (SBR) ratios, as well as electron number densities. The 3D reconstructions revealed a pronounced plasma asymmetry for the ablation at the material boundary, in contrast to the near-axial symmetry observed for the ablation of homogeneous alloys. At lower pressures, this distinct elemental separation in plasma persisted, while higher pressures led to an increased collisional mixing and homogenization. SNR and SBR were consistently lower for ablation at the boundary compared to homogeneous samples. These findings highlight how boundary ablation contributes to plasma inhomogeneities in LIBS analysis of heterogeneous materials and emphasize the need to account for these
effects when using LIBS for elemental mapping of fine heterogeneous structures.
KW - Laser-induced breakdown spectroscopy
KW - Plasma inhomogeneity
KW - Plasma tomography
KW - Radon transform
KW - Material boundaries
KW - Ambient pressure effects
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634777
DO - https://doi.org/10.1016/j.talanta.2025.128377
SN - 1873-3573
VL - 295
SP - 1
EP - 8
PB - Elsevier B.V.
AN - OPUS4-63477
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - You, Yi
A1 - Xue, Boyang
A1 - Riedel, Jens
T1 - Enhancement of LIBS plasma in air with organic solvent vapors
N2 - Laser-induced breakdown spectroscopy (LIBS) offers versatile, field-deployable elemental analysis; however, compact, high-repetition-rate nanosecond laser systems typically face constraints in power consumption and size, often compromising emission intensity and thus analytical performance. We demonstrate a significant improvement in LIBS signals through the controlled introduction of common organic solvent vapors into a sheath gas, with a diode-pumped solid-state laser (1064 nm, 2–28 kHz repetition rate, 450–600-μJ pulse energy). Optical and acoustic diagnostics reveal up to ca. 40-fold enhancement of the N II emission line at 567 nm when ambient air serves as the analyte. Maximal enhancement occurs at intermediate repetition rates of ca. 15 kHz, particularly at pulse energies approaching the optical breakdown threshold; this observation suggests a viable strategy for operating LIBS at lower pulse energies and higher repetition rates. Enhancement effects scale jointly with both vapor pressure and ionization energy of the organic species, with acetone and toluene markedly outperforming methanol and isopropanol. These findings provide a rational foundation for significantly improving the analytical performance of portable LIBS instruments without exceeding platform-specific constraints.
KW - LIBS
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653758
DO - https://doi.org/10.1016/j.sab.2025.107309
SN - 0584-8547
VL - 236
SP - 1
EP - 6
PB - Elsevier B.V.
AN - OPUS4-65375
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wittwer, Philipp
A1 - Roesch, Philipp
A1 - Vogel, Christian
A1 - Simon, Fabian
A1 - Gehrenkemper, Lennart
A1 - Feldmann, Ines
A1 - Simon, Franz-Georg
T1 - Less Is More: Influence of Cross-Linking Agent Concentration on PFOS Adsorption in Chitosan
N2 - As a result of the continuous use of persistent per- and polyfluoroalkyl substances (PFAS), e.g., in aviation firefighting foams, contamination with PFAS has been found in soil, groundwater, and surface water around thousands of industrial and military installations. Due to their harmful (environmental) potential, further dispersion in the environment needs to be stopped, which can be achieved by appropriate absorption materials. In this work, the influence of the cross-linking agent epichlorohydrin (ECH) concentration on the perfluorooctanesulfonic acid (PFOS) adsorption capacity of chitosan gel was investigated. It was found that higher ECH concentration during the cross-linking step decreases the PFOS adsorption capacity of the cross-linked chitosan gel from 0% to 4% ECH solution by about 15%. Using a concentration of 1%, ECH resulted still in an acid-stable material, and a maximum PFOS loading capacity of 4.04 mmol/g was obtained, one of the highest described in the literature. Furthermore, we used a rapid small-scale column test to compare the PFOS adsorption capacity of chitosan and activated carbon, each in both milled and unmilled form. Unmilled chitosan showed the highest PFOS adsorption capacity considering adsorption material dry masses (>0.9 and <0.4 mmol/g for both types of chitosan and activated carbon, respectively). Milled activated carbon proved to be the better adsorption material, considering the fixed volume of the adsorber (>99.9% PFOS adsorbed). Overall, the cross-linking agent concentration in chitosan is a crucial factor influencing its PFOS absorption potential. Our results feature cross-linked chitosan as an effective economic and ecologic alternative for PFOS adsorption in aqueous solutions.
KW - Combustion Ion Chromatography
KW - Per- and Polyfluoroalkyl substances (PFAS)
KW - Remediation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-618406
DO - https://doi.org/10.3390/app142311145
VL - 14
IS - 23
SP - 1
EP - 13
PB - MDPI
AN - OPUS4-61840
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schutter, Jan David
A1 - Eberhardt, Karl
A1 - Elert, Anna Maria
A1 - Radnik, Jörg
A1 - Geißler, Daniel
A1 - Özcan Sandikcioglu, Özlem
T1 - Synthesis and characterization of lipopolysaccharide (LPS) anchored polystyrene microparticles as a synthetic model system for attachment studies
N2 - Outer membrane lipopolysaccharides (LPS) play a crucial role in determining attachment behavior and pathogenicity of bacteria. The aim of this study was to develop a simple procedure for anchoring bacterial lipopolysaccharides to polystyrene (PS) microparticles as a model system for in situ attachment studies. By using a swellcapture methodology, commercially available LPS of Pseudomonas aeruginosa (strain ATCC 27316 serotype 10.22) was anchored onto PS microparticles in a proof-of-concept study. A detailed chemical and morphological characterization has proven the success of LPS incorporation. It was shown that the coverage and structure of the LPS film was concentration dependent. The procedure can easily be adapted to LPS of other bacterial strains to generate a synthetic model toolkit for attachment studies.
KW - Bacterial lipopolysaccharides
KW - Pseudomonas aeruginosa
KW - Polystyrene microparticles
KW - Swell-capture
KW - Biomimicry
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-579818
DO - https://doi.org/10.1016/j.colsurfb.2023.113301
SN - 0927-7765
VL - 226
SP - 1
EP - 7
PB - Elsevier B.V.
AN - OPUS4-57981
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wetzel, Annica
A1 - von der Au, Marcus
A1 - Dietrich, P. M.
A1 - Radnik, Jörg
A1 - Özcan Sandikcioglu, Özlem
A1 - Witt, Julia
T1 - The comparison of the corrosion behavior of the CrCoNi medium entropy alloy and CrMnFeCoNi high entropy alloy
N2 - This work presents the determination of the corrosion characteristics of CrCoNi (medium entropy alloy) and CrMnFeCoNi (high entropy alloy) in 0.1 M NaCl and 0.1 M H2SO4. The morphology and chemical composition of the oxide layers formed on CrCoNi and CrMnFeCoNi were comparatively analyzed by scanning Kelvin probe microscopy (SKPFM) and scanning electron microscopy (SEM) and supported with chemical analysis by means of inductively coupled plasma mass spectrometry (ICP-MS) and X-Ray photoelectron spectroscopy (XPS). The analysis of the 3p core level peaks showed that the oxide layer (native and after anodic passivation) on CrCoNi consisted mainly of Cr oxides, while the oxide layer on CrMnFeCoNi was primarily composed of a mixture of Cr and Fe oxides. In addition, XPS was utilized to assess the oxide layer thicknesses. These results were compared to the thicknesses obtained by means of electrochemical impedance spectroscopy (EIS), with both approaches yielding values up to about 4 nm depending on the electrolyte and the alloy. Cyclic polarization measurements indicated superior corrosion resistance of CrCoNi in both aqueous environments compared to CrMnFeCoNi, as well as to AISI 304 stainless steel.
KW - Medium entropy alloy
KW - High entropy alloy
KW - SKPFM
KW - XPS
KW - Passivation
KW - Corrosion
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559902
DO - https://doi.org/10.1016/j.apsusc.2022.154171
SN - 0169-4332
VL - 601
SP - 1
EP - 10
PB - Elsevier B.V.
AN - OPUS4-55990
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wen, Keqing
A1 - Gorbushina, Anna
A1 - Schwibbert, Karin
A1 - Bell, Jérémy
T1 - Microfluidic platform with precisely controlled hydrodynamic parameters and integrated features for generation of microvortices to accurately form and monitor biofilms in flow
N2 - Microorganisms often live in habitats characterized by fluid flow, and their adhesion to surfaces in industrial systems or clinical settings may lead to pipe clogging, microbially influenced corrosion, material deterioration, food spoilage, infections, and human illness. Here, a novel microfluidic platform was developed to investigate biofilm formation under precisely controlled (i) cell concentration, (ii) temperature, and (iii) flow conditions. The developed platform central unit is a single-channel microfluidic flow cell designed to ensure ultrahomogeneous flow and condition in its central area, where features, e.g., with trapping properties, can be incorporated. In comparison to static and macroflow chamber assays for biofilm studies, microfluidic chips allow in situ monitoring of biofilm formation under various flow regimes and have better environment control and smaller sample requirements. Flow simulations and experiments with fluorescent particles were used to simulate bacteria flow in the platform cell for calculating flow velocity and direction at the microscale level. The combination of flow analysis and fluorescent strain injection in the cell showed that microtraps placed at the center of the channel were efficient in capturing bacteria at determined positions and to study how flow conditions, especially microvortices, can affect biofilm formation. The microfluidic platform exhibited improved performances in terms of homogeneity and robustness for in vitro biofilm formation. We anticipate the presented platform to be suitable for broad, versatile, and high-throughput biofilm studies at the microscale level.
KW - Topographical pattern
KW - E. coli
KW - Fluorescence
KW - Bacteria trapping
KW - Particle velocimetry
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-610450
DO - https://doi.org/10.1021/acsbiomaterials.4c00101
SN - 2373-9878
VL - 10
IS - 7
SP - 4626
EP - 4634
PB - ACS Publ.
CY - Washington, DC
AN - OPUS4-61045
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wetzel, Annica
A1 - Morell, Daniel
A1 - von der Au, Marcus
A1 - Wittstock, Gunther
A1 - Özcan Sandikcioglu, Özlem
A1 - Witt, Julia
T1 - Transpassive Metal Dissolution vs. Oxygen Evolution Reaction: Implication for Alloy Stability and Electrocatalysis
T1 - Transpassive Metallauflösung vs. Sauerstoffentwicklung:
Auswirkungen auf Legierungsstabilität und Elektrokatalyse
N2 - Multi-principal element alloys (MPEAs) are gaining interest in corrosion and electrocatalysis research due to their electrochemical stability across a broad pH range and the design flexibility they offer. Using the equimolar CrCoNi alloy, we observe significant metal dissolution in a corrosive electrolyte (0.1 M NaCl, pH 2) concurrently with the oxygen evolution reaction (OER) in the transpassive region despite the absence of hysteresis in polarization curves or other obvious corrosion indicators. We present a characterization scheme to delineate the contribution of OER and alloy dissolution, using scanning electrochemical microscopy (SECM) for OER-onset detection, and quantitative chemical analysis with inductively coupled-mass spectrometry (ICP-MS) and ultraviolet visible light (UV-Vis) spectroscopy to elucidate metal dissolution processes. In-situ electrochemical atomic force microscopy (EC-AFM) revealed that the transpassive metal dissolution on CrCoNi is dominated by intergranular corrosion. These results have significant implications for the stability of MPEAs in corrosion systems, emphasizing the necessity of analytically determining metal ions released from MPEA electrodes into the electrolyte when evaluating Faradaic efficiencies of OER catalysts. The release of transition metal ions not only reduces the Faradaic efficiency of electrolyzers but may also cause poisoning and degradation of membranes in electrochemical reactors.
N2 - Multi-Hauptelement-Legierungen (MPEAs) gewinnen in der Korrosions- und Elektrokatalyseforschung aufgrund ihrer elektrochemischen Stabilität über einen breiten pH-Bereich und der Vielfalt der möglichen chemischen Zusammensetzungen zunehmend an Interesse. In unseren Untersuchungen mit der äquimolaren CrCoNi-Legierung in einem sauren Elektrolyten (0.1 M NaCl, pH 2) beobachteten wir eine signifikante Metallauflösung, die mit der Sauerstoffentwicklungsreaktion (OER) im transpassiven Bereich einhergeht, obwohl in zyklischen Polarisationskurven keine Hysterese auftrat oder andere offensichtliche Korrosionsindikatoren vorlagen. In diesem Artikel wird ein Charakterisierungskonzept eingeführt, dass die Beiträge der OER und der Legierungsauflösung differenziert. Hierfür kommt die elektrochemische Rastermikroskopie (SECM) zum Nachweis des Beginns der OER und die quantitative chemische Analyse mit induktiv gekoppelter Massenspektrometrie (ICP-MS) und UV/Vis-Spektrometrie zur Aufklärung der Metallauflösungsprozesse zum Einsatz. Die elektrochemische In situ-Atomkraftmikroskopie (EC-AFM) zeigte, dass die intergranulare Korrosion der dominierende Mechanismus der transpassive Metallauflösung von CrCoNi ist. Diese Ergebnisse besitzen erhebliche Auswirkungen für die Beurteilung der Stabilität von MPEAs in Korrosionssystemen und der Stromausbeute von OER-Katalysatoren auf der Basis von MPEAs. Die Daten unterstreichen die Notwendigkeit der analytischen Bestimmung von Metallionen, die von MPEA-Elektroden freigesetzt werden. Die Freisetzung von Übergangsmetallionen verringert nicht nur die Stromausbeute von Elektrolyseuren, sondern kann zu einer Schädigung von Membranen in elektrochemischen Reaktoren führen.
KW - Transpassive dissolution
KW - Corrosion
KW - Multi-prinicpal element alloys (MPEAs)
KW - Passivation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597045
DO - https://doi.org/10.1002/anie.202317058
SP - 1
EP - 8
PB - Wiley VHC-Verlag
AN - OPUS4-59704
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kleinbub, Sherin
A1 - Braymer, Joseph J
A1 - Pfeiffer, Friedhelm
A1 - Dyall-Smith, Mike
A1 - Spirgath, Kristin
A1 - Alfaro-Espinoza, Gabriela
A1 - Koerdt, Andrea
T1 - From Genes to Black Rust: Genomic insights into corrosive methanogens
N2 - Within the past ten years, genetic evidence has been increasing for the direct role that microbes play in microbiologically influenced corrosion (MIC), also known as biocorrosion or biodeterioration. One prominent example is the correlation between the corrosion of metal and the presence of genes encoding an extracellular [NiFe]-hydrogenase (MIC hydrogenase) in the methanogenic archaeon, Methanococcus maripaludis. In this study, DNA sequencing and bioinformatic analysis were used to classify the MIC hydrogenase as belonging to a core set of genes, the MIC core, found so far in Methanococci and Methanobacteria classes of methanogens. Genetic evidence is provided for the mobilization of the MIC core via multiple mechanisms, including a horizontal gene transfer event from Methanobacteria to Methanococci and a newly described MIC-transposon. A detailed comparison of M. maripaludis genomes further pointed to the relevance that cell wall modifications involving N-glycosylation of S-layer proteins and the MIC hydrogenase likely play in methanogen-induced MIC (Mi-MIC). Microscopic analysis of corrosive methanogens encoding the MIC core indicated that Methanobacterium-affiliated strain IM1 can form extensive biofilms on the surface of corrosion products whereas individual cells of M. maripaludis Mic1c10 were only found localized to crevices in the corrosion layer. An updated model of Mi-MIC involving two modes of action is presented, which predicts that the propensity of cells to adhere to iron surfaces directly influences the rate of corrosion due to the localization of the MIC hydrogenase at the metal-microbe interface.
KW - Biocorrosion
KW - Hydrogenases
KW - Metalloprotein
KW - Microbes
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-649425
DO - https://doi.org/10.1093/femsmc/xtaf018
SN - 2633-6685
VL - 6
SP - 1
EP - 19
PB - Oxford University Press (OUP)
AN - OPUS4-64942
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Richter, Matthias
A1 - Schühle, Florian
T1 - Experimental determination of 7-day uptake rates for diffusive sampling of 86 volatile and semi-volatile organic compounds relevant for indoor air monitoring and investigation on their sensitivity to exposure time and indoor climate
N2 - This study aimed to experimentally determine uptake rates for 86 indoor relevant volatile and semi-volatile organic compounds (VOC, SVOC) for the passive sampler type Perkin Elmer/Markes™ with Tenax® TA as sorbent, which was used in the German Environmental Survey on Health (GerES VI) carried out by the German Environmental Agency (UBA) in the years 2023-2024. For this purpose, single reference gas atmospheres of 76 pure VOCs (liquid at room temperature) and a group of 10 SVOCs and VOCs (solid at room temperature) were generated using two generation procedures. By exposing the samplers to individual components, it was ruled out that interactions in a mixture have a influence on the uptake rate. Another aspect was to precisely describe the methodology and the resulting uncertainties, as there are gaps in the literature in this regard. The selection of the compounds was based on the findings of the preceding GerES V study for which data was missing or needed to be verified. In each experiment, a number of six passive samplers was exposed to the test gas atmospheres in dynamically operated exposure chambers for seven days. The sensitivity of the uptake rates of a group of 10 selected VOCs to variations in exposure time, ambient temperature, and air humidity in a multi-component reference gas atmosphere was investigated. Here, a decrease in the uptake rate with the exposure time could be observed stabilising from the fifth day of exposure onwards. A significant effect of temperature and humidity on the uptake rate was not apparent. The determined uptake rates exhibit uncertainties of < 20 % for 71 substances, and < 10 % for 51 substances which are also in good agreement with the literature, if already published elsewhere. The quantity of investigated substances, the detailed description of the methodology used to determine the uptake rates complemented by the respective uncertainties, as well as the compilation of comparative data, contribute to a better assessment of the quality and relevance of such data, which had not been published before.
KW - Indoor air quality
KW - Volatile organic compounds
KW - Uptake rates
KW - Passive sampling
KW - Tenax TA
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-629913
DO - https://doi.org/10.1016/j.indenv.2025.100095
VL - 2
IS - 2
SP - 1
EP - 11
PB - Elsevier
AN - OPUS4-62991
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sun, Yijuan
A1 - Pérez-Padilla, Víctor
A1 - Valderrey, Virginia
A1 - Bell, Jérémy
A1 - Gawlitza, Kornelia
A1 - Rurack, Knut
T1 - Ratiometric detection of perfluoroalkyl carboxylic acids using dual fluorescent nanoparticles and a miniaturised microfluidic platform
N2 - The widespread contamination of soil and water with perfluoroalkyl substances (PFAS) has caused considerable societal and scientific concern. Legislative measures and an increased need for remediation require effective on-site analytical methods for PFAS management. Here we report on the development of a green-fluorescent guanidine-BODIPY indicator monomer incorporated into a molecularly imprinted polymer (MIP) for the selective detection of perfluorooctanoic acid (PFOA). Complexation of PFOA by the indicator, which is mediated by concerted protonation-induced ion pairing-assisted hydrogen bonding, significantly enhances fluorescence in polar organic solvents. The MIP forms as a thin layer on silica nanoparticles doped with tris(bipyridine)ruthenium(II) chloride, which provides an orange emission signal as internal reference, resulting in low measurement uncertainties. Using a liquid-liquid extraction protocol, this assay enables the direct detection of PFOA in environmental water samples and achieves a detection limit of 0.11 µM. Integration into an opto-microfluidic system enables a compact and user-friendly system for detecting PFOA in less than 15 minutes.
KW - PFAS
KW - Molecular imprinting
KW - Microfluidics
KW - Fluorescence
KW - Onsite assay
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-650270
DO - https://doi.org/10.1038/s41467-025-66872-9
SN - 2041-1723
VL - 16
IS - 1
SP - 1
EP - 16
PB - Springer Science and Business Media LLC
AN - OPUS4-65027
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Oskoei, Párástu
A1 - Afonso, Rúben
A1 - Bastos, Verónica
A1 - Nogueira, João
A1 - Keller, Lisa-Marie
A1 - Andresen, Elina
A1 - Saleh, Maysoon I.
A1 - Rühle, Bastian
A1 - Resch-Genger, Ute
A1 - Daniel-da-Silva, Ana L.
A1 - Oliveira, Helena
T1 - Upconversion Nanoparticles with Mesoporous Silica Coatings for Doxorubicin Targeted Delivery to Melanoma Cells
N2 - Melanoma is one of the most aggressive skin cancers and requires innovative therapeutic strategies to overcome the limitations of conventional therapies. In this work, upconversion nanoparticles coated with mesoporous silica and functionalized with folic acid (UCNP@mSiO2-FA) were developed as a targeted nanocarrier system for the delivery of doxorubicin (DOX). The UCNPs were synthesized via thermal decomposition, coated with mesoporous silica shells, and functionalized with folic acid (FA) to enable receptor-mediated targeting. DOX was then loaded into the mesoporous silica coating by adsorption, yielding UCNP@mSiO2-FA-DOX. The different UCNPs were characterized for size, composition, colloidal stability, and loading and release of DOX. This comprehensive physicochemical characterization confirmed a high DOX loading efficiency and a slightly increased drug release under acidic conditions, mimicking the tumour microenvironment. In vitro assays using four melanoma cell lines (A375, B16-F10, MNT-1, and SK-MEL-28) revealed an excellent biocompatibility of UCNP@mSiO2-FA and a significantly higher cytotoxicity of UCNP@mSiO2-FA-DOX compared to unloaded UCNPs, in a dose-dependent manner. Cell cycle analysis demonstrated G2/M phase arrest after treatment with UCNP@mSiO2-FA-DOX, confirming its antiproliferative effect. Overall, UCNP@mSiO2-FA-DOX represents a promising nanoplatform for targeted melanoma therapy, combining active tumour targeting and enhanced anticancer efficacy.
KW - Fluorescence
KW - Synthesis
KW - Nano
KW - Particle
KW - Silica
KW - Cell
KW - Uptake
KW - Drug
KW - Characterization
KW - DOX
KW - Imaging
KW - Toxicity
KW - Release
KW - pH
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653596
DO - https://doi.org/10.3390/molecules31010074
SN - 1420-3049
VL - 31
IS - 1
SP - 1
EP - 18
PB - MDPI AG
AN - OPUS4-65359
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -