TY - JOUR A1 - Hallier, Dorothea C. A1 - Smales, Glen Jacob A1 - Seitz, H. A1 - Hahn, Marc Benjamin T1 - Bio-SAXS of single-stranded DNA-binding proteins: Radiation protection by the compatible solute ectoine N2 - Small-angle X-ray scattering (SAXS) can be used for structural determination of biological macromolecules and polymers in their native states (e.g. liquid phase). This means that the structural changes of (bio-)polymers, such as proteins and DNA, can be monitored in situ to understand their sensitivity to changes in chemical environments. In an attempt to improve the reliability of such experiments, the reduction of radiation damage occurring from exposure to X-rays is required. One such method, is to use scavenger molecules to protect macromolecules against radicals produced during radiation exposure, such as reactive oxygen species (ROS). In this study we investigate the feasibility of applying the compatible solute, osmolyte and radiation protector Ectoine (THP(B)), as a scavenger molecule during SAXS measurements of the single-stranded DNA-binding protein Gene-V Protein (G5P/GVP). In this case, we monitor the radiation induced changes of G5P during bio-SAXS measurments and the resulting microscopic energy-damage relation was determined from microdosimetric calculations by Monte-Carlo based particle scattering simulations with TOPAS/Geant4 and a custom target-model. This resulted in a median-lethal energy deposit of pure G5P at 4 mg mL−1 of E1/2 = 7 ± 5 eV, whereas a threefold increase of energy-deposit was needed under the presence of Ectoine to reach the same level of damage. This indicates that Ectoine increases the possible exposure time before radiation-damage to G5P is observed. Furthermore, the dominant type of damage shifted from aggregation in pure solutions towards a fragmentation for solutions containing Ectoine as a cosolute. These results are interpreted in terms of indirect radiation damage by reactive secondary species, as well as post-irradiation effects, related to preferential-exclusion of the cosolute from the protein surface. Hence, Ectoine is shown to provide a non-disturbing way to improve structure-determination of proteins via bio-SAXS in future studies. KW - BioSAXS KW - Bio-SAXS KW - Cosolute KW - Ectoine KW - G5P KW - GVP KW - Radiation damage KW - Radical Scavenger KW - Single-stranded DNA-binding proteins KW - X-ray scattering KW - DNA KW - ssDNA KW - Protein KW - SAXS KW - Small-angle xray scattering KW - McSAS3 KW - Dosimetry KW - Microdosimetry KW - Geant4 KW - Geant4-DNA KW - Topas KW - Topas-MC KW - Monte-Carlo simulations KW - Particle scattering simulations KW - Topas-nBio KW - OH Radical KW - OH radical scavenger KW - LEE KW - Ionizing radiation damage KW - Protein unfolding KW - Ectoin PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568909 DO - https://doi.org/10.1039/d2cp05053f SN - 1463-9076 SN - 1463-9084 VL - 25 IS - 7 SP - 5372 EP - 5382 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-56890 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hallier, Dorothea C. A1 - Smales, Glen Jacob A1 - Seitz, H. A1 - Hahn, Marc Benjamin T1 - Inside back cover for the article "Bio-SAXS of single-stranded DNA-binding proteins: Radiation protection by the compatible solute ectoine" N2 - Showcasing research from the Federal Institute for Material Research and Testing Berlin and Fraunhofer Institute for Celltherapy and Immunology Branch Bioanalytics and Bioprocesses Potsdam. Bio-SAXS of single-stranded DNA-binding proteins: Radiation protection by the compatible solute ectoine. We aimed to increase the possible undisturbed exposure time during bio-SAXS measurements of single-stranded DNA-binding proteins. Therefore small angle X-ray scattering was performed on Gene-V Protein (G5P/GVP), which is involved in DNA repair processes. To achieve this, irradiations were performed in presence and absence of the hydroxyl-radical scavenger and osmolyte Ectoine, which showed efficient radiation protection and prevented protein aggregation, thus allows for a non-disturbing way to improve structure-determination of biomolecules. KW - Bio-SAXS KW - BioSAXS KW - Cosolute KW - DNA KW - Dosimetry KW - Ectoin KW - Ectoine KW - G5P KW - GVP KW - Geant4 KW - Geant4-DNA KW - Ionizing radiation damage KW - LEE KW - McSAS3 KW - Microdosimetry KW - Monte-Carlo simulations KW - OH Radical KW - OH radical scavenger KW - Protein KW - Protein unfolding KW - Radiation damage KW - Radical Scavenger KW - SAXS KW - Single-stranded DNA-binding proteins KW - Small-angle xray scattering KW - Topas-MC KW - Topas-nBio KW - TopasMC KW - X-ray scattering KW - Particle scatterin simulations KW - ssDNA PY - 2023 DO - https://doi.org/10.1039/D3CP90056H SN - 1463-9076 SN - 1463-9084 VL - 25 IS - 7 SP - 5889 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-57006 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hunter, R. D. A1 - Hayward, E. C. A1 - Smales, Glen Jacob A1 - Pauw, Brian Richard A1 - Kulak, A. A1 - Guan, S. A1 - Schnepp, Z. T1 - The effect of nitrogen on the synthesis of porous carbons by iron-catalyzed graphitization N2 - This paper reports a systematic study into the effect of nitrogen on iron-catalyzed graphitization of biomass. Chitin, chitosan, N-acetylglucosamine, gelatin and glycine were selected to represent nitrogen-rich saccharides and amino-acid/polypeptide biomass precursors. The materials were pyrolyzed with an iron catalyst to produce carbons with a wide range of chemical and structural features such as mesoporosity and nitrogen-doping. Many authors have reported the synthesis of nitrogen-doped carbons by pyrolysis and these have diverse applications. However, this is the first systematic study of how nitrogen affects pyrolysis of biomass and importantly the catalytic graphitization step. Our data demonstrates that nitrogen inhibits graphitization but that some nitrogen survives the catalytic graphitization process to become incorporated into various chemical environments in the carbon product. KW - Graphitization KW - Nanoparticles KW - Nanocomposite KW - Porous carbon KW - Nitrogen KW - Scattering PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575351 DO - https://doi.org/10.1039/d3ma00039g VL - 4 SP - 2070 EP - 2077 PB - Royal Society of Chemistry AN - OPUS4-57535 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Marc Benjamin T1 - Extending Bio-SAXS measurements of Single-Stranded DNA-Binding Proteins: Radiation Protection of G5P by Cosolutes N2 - Small-angle X-ray scattering (SAXS) can be used for structural de- termination of biological macromolecules and polymers in their na- tive states. To improve the reliability of such experiments, the re- duction of radiation damage occurring from exposure to X-rays is needed.One method, is the use of scavenger molecules that protect macromolecules against radicals produced by radiation exposure.In this study we investigate the feasibility to apply the compatible solute, osmolyte and radiation protector Ectoine (THP(B)) as a scavenger throughout SAXS measurements of single-stranded DNA-binding protein Gene-V Protein (G5P/GVP). Therefore we monitor the radiation induced changes of G5P during bio-SAXS. The resulting microscopic energy-damage relation was determined by particle scattering simu- lations with TOPAS/Geant4. The results are interpreted in terms of radical scavenging as well as post-irradiation effects, related to preferential-exclusion from the protein surface. Thus, Ectoine provides an non-disturbing way to improve structure-determination of proteins via bio-SAXS in future studies. T2 - MultiChem Conference 2023 CY - Prague, Czech Republic DA - 26.04.2023 KW - Bio-SAXS KW - BioSAXS KW - Compatible solute KW - Cosolute KW - DNA KW - Dosimetry KW - Ectoin KW - Ectoine KW - Ectoin KW - G5P KW - GVP KW - Geant4 KW - Geant4-DNA KW - Gene five protein KW - Hydroxyectoine KW - Ionizing radiation damage KW - LEE KW - McSAS3 KW - Microdosimetry KW - Monte-Carlo simulations KW - OH Radical KW - OH radical scavenger KW - Osmolyte KW - Particle scattering simulations KW - Protein KW - Protein unfolding KW - Proteins KW - ROS KW - Radiation damage KW - Radical Scavenger KW - Radical scavenger KW - SAXS KW - Single-stranded DNA-binding proteins KW - Small-angle xray scattering KW - Topas KW - Topas-MC KW - Topas-nBio KW - X-ray scattering KW - ssDNA KW - Median lethal energy deposit PY - 2023 AN - OPUS4-57407 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Pauw, Brian Richard A1 - Smales, Glen Jacob T1 - Electric Safety Interlock N2 - This interlock is designed to prevent electrical shock from high voltage (>60V) equipment. While the general safety interlock can be generically applied, this particular example employs an external vacuum-activated switch. It is for safeguarding human operations inside a vacuum sample chamber while the chamber doors are open. The circuit is closed (output is active) when a sufficient level of vacuum is reached, i.e. when all accessible openings are necessarily closed. The initial application is to interrupt power to a 220V, 250W heating cartridge (itself mounted inside a small sample holder with potentially exposed contacts) when the sample chamber is open. The external circuit can be modified to use different interlock mechanisms as needed. Note that the external interlock circuit is only a single circuit (with two signal lines) and thus is not protected against external shorts. To accomodate a range of safety interlocks, the 4-pin M12 connector is wired as follows: Pin 1 (Brown): +24V for power supply, max current 0.6A Pin 2 (White): Safety interlock system signal 1 (0 or 24V) Pin 3 (Blue) : Safety interlock system signal 2 (0 or 24V) Pin 4 (Black): 0V for power supply The safety is interlocked (output active) when both signal pins are set high (24V), with sufficient current to activate the two relays. Pin 1 and 4 can be used to power safety hardware (such as light curtains or proximity detectors) with 24VDC up to a current of 0.6A. A larger power supply can be installed when higher currents are needed, while staying within the current limits imposed by the wiring cross-section. KW - Electric Safety Interlock KW - MOUSE KW - 60-230V PY - 2023 DO - https://doi.org/10.6084/m9.figshare.22265920.v1 PB - Digital Science CY - Cambridge, MA, USA AN - OPUS4-57138 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pauw, Brian Richard T1 - X-ray Scattering USAXS/SAXS/WAXS (/XRD/PDF) N2 - A ten minute introduction to the technique of X-ray scattering. This talk discusses the foundation and the resulting morphological parameters that can be obtained from the technique. The talk is prepared for discussion within the framework of the OECD REACH guideline for nanomaterials. T2 - Digitaler Info-Tag "Nano or not Nano" CY - Berlin, Germany DA - 16.02.2023 KW - X-ray scattering KW - BAM Academy KW - SAXS KW - XRD KW - WAXS KW - Nanomaterial KW - REACH KW - OECD KW - Guideline PY - 2023 AN - OPUS4-57013 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Aliyah, K. A1 - Prehal, C. A1 - Diercks, J. S. A1 - Diklić, N. A1 - Xu, L. A1 - Ünsal, S. A1 - Appel, C. A1 - Pauw, Brian Richard A1 - Smales, Glen Jacob A1 - Guizar-Sicairos, M. A1 - Herranz, J. A1 - Gubler, L. A1 - Büchi, F. N. A1 - Eller, J. T1 - Quantification of PEFC Catalyst Layer Saturation via In Silico, Ex Situ, and In Situ Small-Angle X-ray Scattering N2 - The complex nature of liquid water saturation of polymer electrolyte fuel cell (PEFC) catalyst layers (CLs) greatly affects the device performance. To investigate this problem, we present a method to quantify the presence of liquid water in a PEFC CL using small-angle X-ray scattering (SAXS). This method leverages the differences in electron densities between the solid catalyst matrix and the liquid water filled pores of the CL under both dry and wet conditions. This approach is validated using ex situ wetting experiments, which aid the study of the transient saturation of a CL in a flow cell configuration in situ. The azimuthally integrated scattering data are fitted using 3D morphology models of the CL under dry conditions. Different wetting scenarios are realized in silico, and the corresponding SAXS data are numerically simulated by a direct 3D Fourier transformation. The simulated SAXS profiles of the different wetting scenarios are used to interpret the measured SAXS data which allows the derivation of the most probable wetting mechanism within a flow cell electrode. KW - Polymer electrolyte fuel cell KW - Water management KW - Catalyst layer KW - Representative morphology modeling KW - Small-angle X-ray scattering KW - MOUSE KW - SAXS PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575973 DO - https://doi.org/10.1021/acsami.3c00420 SN - 1944-8244 VL - 15 IS - 22 SP - 26538 EP - 26553 PB - ACS Publications AN - OPUS4-57597 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Pauw, Brian Richard A1 - Smales, Glen Jacob T1 - Small-angle scattering data analysis round robin dataset - Original for participants N2 - These are four datasets that were made available to the participants of the Small-angle Scattering data analysis round robin. The intent was to find out how comparable results from different researchers are, who analyse exactly the same processed, corrected dataset. In this repository, there are: 1) a PDF document with more details for the study, 2) the datasets for people to try and fit, 3) an Excel spreadsheet to document the results. Datasets 1 and 2 were modified from: Deumer, Jerome, & Gollwitzer, Christian. (2022). npSize_SAXS_data_PTB (Version 5) [Data set]. Zenodo. https://doi.org/10.5281/zenodo.5886834 Datasets 3 and 4 were collected in-house on the MOUSE instrument. KW - Round robin KW - SAXS KW - Small angle scattering KW - SANS KW - X-ray KW - Neutron KW - Human factor KW - Data analysis KW - Data fitting KW - Human influence PY - 2023 DO - https://doi.org/10.5281/zenodo.7506365 PB - Zenodo CY - Geneva AN - OPUS4-56799 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Pauw, Brian Richard T1 - McSAS3 N2 - McSAS3 is a refactored version of the original McSAS (see DOI 10.1107/S1600576715007347). This software fits scattering patterns to obtain size distributions without assumptions on the size distribution form. The refactored version has some neat features: - Multiprocessing is included, spread out over as many cores as number of repetitions! - Full state of the optimization is stored in an organized HDF5 state file. - Histogramming is separate from optimization and a result can be re-histogrammed as many times as desired. - SasModels allow a wide range of models to be used - If SasModels does not work (e.g. because of gcc compiler issues on Windows or Mac), an internal sphere model is supplied - Simulated data of the scattering of a special shape can also be used as a McSAS fitting model. Your models are infinite! - 2D fitting also works. KW - X-ray scattering KW - Polydispersity KW - Monte carlo KW - Scattering pattern analysis KW - Analysis approach KW - Neutron scattering KW - Automation KW - Command line PY - 2023 DO - https://doi.org/10.6084/m9.figshare.21814128.v1 PB - Digital Science CY - Cambridge, MA, USA AN - OPUS4-56787 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Smales, Glen Jacob A1 - Hahn, Marc Benjamin A1 - Hallier, Dorothea C. A1 - Seitz, H. T1 - X-ray scattering datasets and simulations associated with the publication "Bio-SAXS of single-stranded DNA-binding proteins: Radiation protection by the compatible solute ectoine" N2 - This dataset contains the processed and analysed small-angle X-ray scattering data associated with all samples from the publications "Bio-SAXS of Single-Stranded DNA-Binding Proteins: Radiation Protection by the Compatible Solute Ectoine" (https://doi.org/10.1039/D2CP05053F). Files associated with McSAS3 analyses are included, alongside the relevant SAXS data, with datasets labelled in accordance to the protein (G5P), its concentration (1, 2 or 4 mg/mL), and if Ectoine is present (Ect) or absent (Pure). PEPSIsaxs simulations of the GVP monomer (PDB structure: 1GV5 ) and dimer are also included. TOPAS-bioSAXS-dosimetry extension for TOPAS-nBio based particle scattering simulations can be obtained from https://github.com/MarcBHahn/TOPAS-bioSAXS-dosimetry which is further described in https://doi.org/10.26272/opus4-55751. This work was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under grant number 442240902 (HA 8528/2-1 and SE 2999/2-1). We acknowledge Diamond Light Source for time on Beamline B21 under Proposal SM29806. This work has been supported by iNEXT-Discovery, grant number 871037, funded by the Horizon 2020 program of the European Commission. KW - SAXS KW - Radiation protection KW - Microdosimetry KW - G5P KW - Ectoine KW - DNA-Binding protein PY - 2023 DO - https://doi.org/10.5281/zenodo.7515394 PB - Zenodo CY - Geneva AN - OPUS4-56811 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Burkert, Andreas T1 - Bedeutung der Wirksumme bei Nichtrostenden Stählen N2 - Anhand der Wirksumme ist eine Abschätzung des legierungsabhängigen Einflusses auf den Korrosionswiderstand gegen chloridhaltige Medien möglich. Die berechneten Werte sind nur bei optimaler Wärmebehandlung und Verarbeitung zutreffend. Die Anwendung einer einfachen Formel unter Berücksichtigung von Chrom, Molybdän und Stickstoff ist in der Regel völlig ausreichend. Das daraus abgeleitete Ranking von Werkstoffen ist für diverse technische Regelwerke und zur Unterstützung der Werkstoffauswahl geeignet. Für die Warenein-/Ausgangskontrolle ist die alleinige Feststellung der Wirksumme unzureichend. Ergänzende Korrosionsuntersuchungen/-prüfungen zur Beschreibung des Korrosionswiderstandes sind dafür notwendig. Gleiches gilt für die Beurteilung von Schadensfällen. Hier sind Verarbeitung, Einsatzbedingungen und die Konstruktion von ausschlaggebender Bedeutung. T2 - Fortbildung Kursleiter Kompetenzzentren Edelstahl Rostfrei CY - Trier, Germany DA - 25.09.2023 KW - Nichtrostender Stahl KW - Korrosion KW - Wirksumme PY - 2023 AN - OPUS4-58453 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tavernaro, Isabella T1 - (Nano-)Partikel-Tracking-Analyse (PTA/NTA) N2 - Einführung in die Partikelgrößenbestimmung von (Nano)Materialien mittels NTA/PTA. Normative Grundlagen (ISO 19430:2016 und ASTM E2834), Messprinzip, Messgeräte, Einflussfaktoren und Besonderheiten, Implementierung, Informationsgehalt der Daten, Reporting. T2 - BAM Akademie: Info-Tage "NANO OR NOT NANO" CY - Online meeting DA - 16.02.2023 KW - Partikelgrößenbestimmung KW - Partikelkonzentration KW - Nano KW - Standardisierung KW - Brownsche Molekularbewegung KW - Lichtstreuung PY - 2023 AN - OPUS4-59132 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cheng, Z. A1 - Meng, M. A1 - Qiao, X. A1 - Liu, Y. A1 - Resch-Genger, Ute A1 - Ou, J. T1 - The synthesis of Er3+/Yb3+/K+ triple-doped NaYF4 phosphors and its high sensitivity optical thermometers at low power N2 - Optical Thermometry is popular among researchers because of its non-contact, high sensitivity, and fast measurement properties. In the present experiment, Er3+/Yb3+/K+ co-doped NaYF4 nanoparticles with different K+ concentrations were synthesized by solvothermal method, and the samples showed bright upconversion green emission under the excitation of a 980 nm laser. The powder X-ray diffractometer and transmission electron microscope were used to characterize the crystal structure and its surface morphology, respectively. The spectral characteristics of nanoparticles with K+ doping concentration from 10% to 30% (Molar ratio) were investigated by fluorescence spectroscopy, and it was observed that the fluorescence intensity reached the maximum at the K+ concentration of 20%, after which the intensity weakened when the K+ content continued to increase. According to the dependence between the luminescence intensity of the sample and the laser power density and fluorescence lifetime, the intrinsic mechanism was carefully investigated. Temperature-dependent spectra of the samples were recorded in the temperature range of 315–495 K, and the maximum values of absolute sensitivity (Sa) and relative sensitivity (Sr) were measured at 0.0041 K−1 (455 K) and 0.9220%K−1 (315 K). The experimental results show that K+/Er3+/Yb3+ triple-doped NaYF4 green fluorescent nanoparticles (GFNs) have good prospects for applications in display devices, temperature sensing, and other fields. KW - K+ doped KW - Upconversion luminescence KW - Optical temperature sensing KW - Thermal coupling energy level PY - 2023 DO - https://doi.org/10.1016/j.jallcom.2022.168299 VL - 937 SP - 1 EP - 9 PB - Elsevier B.V. AN - OPUS4-57106 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Meng, M. A1 - Zhang, T. A1 - Wang, J. A1 - Cheng, Z. A1 - Liu, Y. A1 - Qiao, X. A1 - Wen, J. A1 - Resch-Genger, Ute A1 - Long, W. A1 - Ou, J. T1 - NaYF4:Yb3+/Tm3+@NaYF4:Yb3+ Upconversion Nanoparticles for Optical Temperature Monitoring and Self-Heating in Photothermal Therapy N2 - The core−shell NaYF4:Yb3+/Tm3+@NaYF4:Yb3+ upconversion nanoparticles were successfully prepared by a solvothermal method, and a layer of mesoporous silica (mSiO2) was successfully coated on the periphery of the core−shell nanoparticles to transform their surface from lipophilic to hydrophilic, further expanding their applications in biological tissues. The physical phase, morphology, structure, and fluorescence properties were characterized by X-ray diffraction (XRD), field emission transmission electron microscopy (TEM), Fourier infrared spectroscopy (FT-IR), ζ potential analysis, and fluorescence spectroscopy. It was found that the material has a hexagonal structure with good hydrophilicity and emits intense fluorescence under 980 nm pump laser excitation. The non-contact temperature sensing performance of nanoparticles was evaluated by analyzing the upconversion fluorescence of Tm3+ (1G4 → 3F4 and 3F3 → 3H6) in the temperature range of 284−344 K. The absolute and relative sensitivities were found to be 0.0067 K−1 and 1.08 % K−1, respectively, with high-temperature measurement reliability and good temperature cycling performance. More importantly, its temperature measurement in phosphate-buffered saline (PBS) solution is accurate. In addition, the temperature of the cells can be increased by adjusting the laser power density and laser irradiation time. Therefore, an optical temperature sensing platform was built to realize the application of real-time monitoring of cancer cell temperature and the dual function of photothermal therapy. KW - Sensor KW - Temperature KW - Lanthanide KW - Tag KW - Fluorescence KW - Nanoparticles KW - Synthesis KW - Environment KW - Monitoring KW - Sensing KW - Nano KW - Life sciences KW - Upconversion PY - 2023 DO - https://doi.org/10.1021/acsanm.2c05110 VL - 6 IS - 1 SP - 759 EP - 771 PB - ACS Publications AN - OPUS4-57081 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Meng, M. A1 - Zhang, T. A1 - Wang, J. A1 - Cheng, Z. A1 - Li, Z. A1 - Qiao, X. A1 - Wen, J. A1 - Resch-Genger, Ute A1 - Long, W. A1 - Ou, Jun T1 - Preparation of NaYF4: Yb3+/Tm3+@NaYF4@β-CD upconversion nanoparticles and application of their fluorescence temperature sensing properties N2 - The NaYF4: Yb3+/Tm3+@NaYF4@β-CD upconversion nanoparticles were successfully prepared by the solvothermal method, and the samples were pure hexagonal phase with good crystallinity and homogeneous size, asevidenced by XRD and TEM analysis. The FT-IR analysis shows that β-CD is successfully encapsulated on the surface of NaYF4: Yb3+/Tm3+@NaYF4 nanoparticles. The fluorescence intensity 3and lifetime were significantly increased after coating the inert layer on the surface of core nanoparticles. After further surface modification of β-CD, the fluorescence intensity and fluorescence lifetime were reduced, but the overall fluorescence was stronger. Temperature measurements using the fluorescence intensity ratio technique were found to have relatively low reliability and absolute sensitivity for temperature measurements using thermally coupled energy levels. However, the reliability of temperature measurements using non-thermally coupled energy levels is significantly higher and the absolute sensitivity is much higher than for measurements at thermally coupled levels. Since the maximum absolute sensitivity, maximum relative sensitivity and minimum temperature resolution are determined to be 0.1179 K-1, 2.19 %K􀀀 1 and 0.00019 K, respectively, NaYF4: Yb3+/Tm3+@NaYF4@β-CD upconversion nanoparticles are expected to be widely used in the biomedical field due to their feasibility, reliability, non-toxicity and harmlessness. KW - Upconversion KW - Surface modification KW - Fluorescence intensity ratio KW - Thermally coupled levels KW - Non-thermally coupled levels PY - 2023 DO - https://doi.org/10.1016/j.optmat.2022.113389 SN - 0925-3467 VL - 136 SP - 1 EP - 11 PB - Elsevier B.V. AN - OPUS4-57105 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 - 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 - 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 - 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 - CONF A1 - Resch-Genger, Ute T1 - Luminescent Nanoparticles – Photophysics, Mechanistic Studies, and Applications N2 - Inorganic nanocrystals with linear and nonlinear luminescence in the ultraviolet, visible, near infrared and short-wave infrared like semiconductor quantum dots and spectrally shifting lanthanide-based nanophosphors have meanwhile found many applications in the life and material sciences. This includes optical reporters for bioimaging and sensing, security and authentication barcodes, solid state lighting, converter materials, and photovoltaics. The identification of optimum particle structures requires quantitative spectroscopic studies under application-relevant conditions, focusing on the key performance parameter photoluminescence quantum yield, ideally flanked by single particle studies to assess spectroscopic inhomogeneities on a particle-to-particle level for typical preparation methods. In this context, methods to quantify the photoluminescence of these different nanoscale emitters are shown and utilized as a basis for a profound mechanistic understanding of the nonradiative deactivation pathways in semiconductor and upconversion nanocrystals of different size and particle architecture in different environments. Exemplary for the application potential of such nanomaterials, in addition, the design of optical sensors from different nanomaterials and functional organic dyes is briefly summarized. T2 - CRC 1411 Symposium CY - Nürnberg, Germany DA - 20.03.2023 KW - Semiconductor quantum dot KW - Upconversion nanocrystal KW - Luminescence KW - Quantitative spectroscopy KW - Photophysics PY - 2023 AN - OPUS4-57364 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tavernaro, Isabella T1 - Development of multimodal methods to quantify the total and accessible number of functional groups and ligands on nanomaterials N2 - Engineered and tailored nanomaterials (NM) are of great interest in the life and material sciences, as they can be used, e.g., as drug carriers, barcodes, fluorescent sensors, and multimodal labels in bioanalytical assays and imaging applications. Their performance and safety depend not only on their particle size, size distribution, and morphology, but also on their surface chemistry, i.e., the total number of surface functional groups (FG) and the number of FG accessible for subsequent functionalization with ligands or biomolecules, which in turn determines surface charge, colloidal stability, biocompatibility, and toxicity. It also underlines the importance of validated analytical methods that provide accurate information on these application-relevant physicochemical properties with a known uncertainty. In the case of FG quantification, this calls for robust, fast, inexpensive, and reliable methods which allow for the characterization of a broad variety of NM differing in size, chemical composition, and optical properties. Methods Aiming at the development of simple, versatile, and multimodal tools for the quantification of bioanalytically relevant FG such as amine, carboxy, thiol, and aldehyde functionalities, we investigated and compared various analytical methods commonly used for FG quantification. This includes electrochemical titration methods, dye-based optical assays, and other instrumental analytical techniques such as nuclear magnetic resonance (NMR), mass spectrometry (MS), and thermal analysis methods. Results Here, we will present examples for different types of NMs and FGs including results from a currently running interlaboratory comparison (ILC) with the National Research Council of Canada (NRC) to pave the road for method standardization. Innovative aspects • Surface analysis • Performance and safety of nanomaterials • Standardization T2 - ANAKON 2023 CY - Vienna, Austria DA - 11.04.2023 KW - Engineered Nanomaterials KW - Surface group analysis KW - Optical spectroscopy KW - Quantitative NMR KW - Ligands KW - Dye KW - Particle synthesis KW - Optical Assays KW - Titration KW - Safe-by-Design KW - Nano KW - Nanosafety KW - Silica- and Polystyrene Particles PY - 2023 AN - OPUS4-59127 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute T1 - Forschung in einer Bundesoberbehörde wie der BAM N2 - Die Bundesanstalt für Materialforschung und -prüfung (BAM) ist eine forschende Bundesoberbehörde und Einrichtung der Ressortforschung der Bundesrepublik Deutschland. Unter ihrer Leitlinie „Sicherheit in Technik und Chemie“ ist sie zuständig für die öffentliche technische Sicherheit und für metrologische Aufgaben in der Chemie. Das Aufgabenspektrum der BAM, das sich an aktuellen Fragestellungen aus Wissenschaft, Wirtschaft, Politik und Normung orientiert, bietet sehr viele interessante Tätigkeitsfelder für Naturwissenschaftler*Innen und Ingenieur*Innen. T2 - WIFO Leipzig 2023 CY - Leipzig, Germany DA - 05.09.2023 KW - Quality assurance KW - Optical spectroscopy KW - Certification KW - Reference product KW - Integrating sphere spectroscopy KW - Fluorescence KW - Quantum yield KW - Reference material KW - Reference data KW - Traceability KW - Nano KW - Particle KW - Analytical chemistry KW - Sensor KW - Safety PY - 2023 AN - OPUS4-58397 LA - mul AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tavernaro, Isabella T1 - pH- and O2-Responsive Nanoparticles – The MiGraGen Project N2 - In recent years, the demand for reliable, versatile, fluorescent pH and oxygen sensors has increased rapidly in many biomedical applications since these analytes are important indicators of cell function or certain diseases. Therefore, sensor particles are needed that are small enough to penetrate cells, non-toxic, and allow for close-up optical monitoring. When developing such sensor systems, one must consider the pH and oxygen range detectable by the sensor dye and the matrix material of the used carrier particles. Here, we present the development of pH- and oxygen-responsive polymeric beads functionalized with fluorescent dyad molecules that consist of an analyte-responsive fluorophore and an analyte-inert dye. T2 - MiGraGen Project Meeting 09.08.2023 CY - Online Meeting DA - 09.08.2023 KW - Nano- and microsensors KW - Functionalized silica and polymeric particles KW - pH sensing KW - Oxygen sensing KW - Fluorescence PY - 2023 AN - OPUS4-58071 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - López-Puertollano, Daniel T1 - Superparamagnetic core-shell particles application: from cytometry assay to simplified fluidic system N2 - Superparamagnetic hybrid polystyrene-core silica-shell beads have emerged as promising alternatives to traditional in flow cytometry-based competitive antibody assays [1]. These materials consist of a polystyrene core and a silica shell, in which magnetic nanoparticles are embedded, facilitating the handling and retention in tests. The outer silica surface allows for easy modification through silane chemistry, allowing the attachment of antibodies, or other molecules of interest. Ochratoxin A (OTA), a mycotoxin that can be found in grain products, coffee, cacao, or grapes, was chosen as the main target analyte to detect [2]. In this study, previously in house produced anti-OTA antibodies [3] were attached to the surface of the particles and the whole system was used as detection entity. In a first approach, the system was used for the development of a competitive cytometry assay using an OTA-fluorescein (OTA-F) adduct as competitor and marker. In this assay the fluorescence emitted by the OTA-F competitor on the surface of the particle was detected at a wavelength of 518 nm using a 533/30.H filter and was correlated to the forward scatter (FSC) to distinguish it from the excess of competitor still in solution. Under optimised conditions, the final assay showed a limit of detection of 0.03 nM. In a second approach, a simplified ready-to-inject fluidic system was built based on a laser (488 nm) and a photomultiplier detector to measure the signal of competitor still in solution. The competition step was carried out in a vial and the whole mixture was injected into the fluidic system. To avoid signal scattering, the particles were separated in-line using a magnet and only the OTA-F competitor still in solution was detected, reaching a limit of detection of 1.2 nM. With the aim to reduce user manipulation, the final assay is still under development for in-line incubation during the competitive step. T2 - 15th Rapid Methods Europe Conference CY - Amsterdam, Netherlands DA - 06.11.2023 KW - Microfluidics KW - Flow cytometry KW - Bead-based assays KW - Magnetic beads KW - Core-shell particles KW - Immunoassays PY - 2023 AN - OPUS4-58817 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute T1 - Design and Quantitative Characterization of Functional Molecular Chromophores and Nanomaterials with UV/vis/NIR/IR Emission – An Overview of Research Activities in Division Biophotonics N2 - In the focus of division Biophotonics are the design, preparation, analytical and spectroscopic characterization, and application of molecular and nanoscale functional materials, particularly materials with a photoluminescence in the visible, near infrared (NIR) and short-wave infrared (SWIR). This includes optical reporters for bioimaging and sensing, security and authentication barcodes, and materials for solid state lighting, energy conversion, and photovoltaics. For the identification of optimum particle structures quantitative spectroscopic studies are performed under application-relevant conditions, focusing on the key performance parameter photoluminescence quantum yield. In addition, simple, cost-efficient, and standardizable strategies for quantifying functional groups on the surface of nano- and microparticles are developed, here with a focus on optical assays and electrochemical titration methods, cross-validated by more advanced methods such as quantitative NMR. In addition, reference materials and reference products are developed for optical methods, particularly luminescence techniques, and for analytical methods utilized for the characterization of nanomaterials. T2 - Projekttreffen Nile-Chrome 2.0 CY - Mainz, Germany DA - 11.12.2023 KW - Fluorescence KW - Quantum yield KW - Optical spectroscopy KW - Reference material KW - Reference data KW - Quality assurance KW - Dye KW - Reference product KW - NIR KW - SWIR KW - Nano KW - Particle KW - Silica KW - Polymer KW - Surface group analysis KW - Sensor molecules PY - 2023 AN - OPUS4-59123 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tavernaro, Isabella T1 - Design of Fluorescent, Amorphous Silica-NPs and their Versatile Use in Sensing Applications N2 - Surface functionalized silica nanoparticles (SiO2-NP) gained great interest in the life and material sciences, as they can be used e.g. as drug carriers, fluorescent sensors, and multimodal labels in bioanalytical assays and imaging applications. They are highly stable, are easily produced and modified on a large scale at low cost and can be labeled or stained with a multitude of sensor dyes. These dye modified particle conjugates have several advantages as compared to conventional molecular probes like enhanced brightness, ease of designing ratiometric systems by combining analyte-sensitive and inert reference dyes, and increased photostability. Moreover, stained nanoparticles can enable the use of hydrophobic dyes in aqueous environments. Here we present our work on multicolored sensors for the measurement of pH, oxygen and saccharides utilizing amorphous SiO2 NPs. T2 - Focus Area Day Analytical Sciences 2023 CY - Berlin, Germany DA - 20.04.2023 KW - Amorphous silica particles KW - Particle Synthesis KW - Nano KW - Ratiometric Sensors KW - Fluorescence KW - pH probe KW - Dye PY - 2023 AN - OPUS4-59151 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krenzer, Julius A1 - Mueller, Thomas T1 - Aroyl-S,N-ketene acetal based bichromophores exhibiting energy transfer and aggregation induced (dual) emission N2 - A series of aroyl-S,N-ketene acetal based bichromophores is readily synthesized by Buchwald-Hartwig amination and Ullmann reaction in moderate to good yields. The aminated aroyl-S,N-ketene acetals are emissive in the solid state and in the aggregate, but not in solution, thus, they are AIEgens (aggregation induced emission chromogens). Aggregation is induced by fractional alternation of the solvent mixture, here by increasing the water fraction of ethanol/water mixtures. For most derivatives, the emission upon induced aggregation stems solely from the aroyl-S,N-ketene acetal chromophore, regardless whether excitation occurs at the absorption maximum of the triarylamine or the aroyl-S,N-ketene acetal. Therefore, a pronounced energy transfer from the triarylamine donor to the aroyl-S,N-ketene acetal acceptor can be inferred. The color of the emission can be controlled by choosing the para-aroyl substituent. A partial energy transfer could also be observed for some bichromophores, leading to aggregation-induced dual emission (AIDE). In addition, four examples of aminated diaroyl-S,N-ketene acetals were added to the compound library. The electron-withdrawing properties of the additional aroyl group provide a bathochromic shift of the emission band of the aroyl-S,N-ketene acetal. These bichromophores also show AIDE and in one case even aggregation-induced white light emission as a result of additive color mixing. T2 - Beilstein Symposium on pi-Conjugated Molecules and Materials CY - Limburg, Germany DA - 07.11.2023 KW - aggregation-induced dual emission (AIDE) PY - 2023 AN - OPUS4-59006 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tavernaro, Isabella T1 - A Multimodal Approach to Quantify Surface Functional Groups on Nanomaterials for Safe and Sustainable by Design N2 - Engineered nanomaterials (NM) with their large surface-to-volume ratios and their for some materials observed size-dependent functional properties are of increasing relevance for current and future developments in various fields such as medical and pharmaceutical industry, computing and electronics or food and consumer products. The performance and safety of NM are determined by the sum of their intrinsic physicochemical properties. Especially, the particle surface chemistry, which is largely controlled by the chemical nature and density of functional groups (FG) and ligands, is an important key driver for NM performance, stability, and processibility as well as the interaction of NM with the environment. Thus, methods for FG quantification can foster the sustainable development of functional and safe(r) NM. Aiming at the development of simple, versatile, and multimodal tools for the quantification of many bioanalytically relevant FG and ligands, we investigated and compared various analytical methods commonly used for FG quantification. This includes electrochemical titration methods, dye-based optical assays, and other instrumental analytical techniques such as nuclear magnetic resonance and thermal analysis methods. The potential of our multimodal approach for FG quantification was demonstrated for commercial and custom-made polymeric and silica particles of varying FG, used as optical pH sensors. In the future, our strategy can contribute to establish multi-method characterization strategies to provide a more detailed picture of the structure-properties relationship. T2 - NanoSAFE & NanoSafety Cluster 2023 CY - Grenoble, France DA - 05.06.2023 KW - Engineered Nanomaterials KW - Safe-by-Design KW - Sustainable-by-Design KW - Surface Group Analysis KW - Silica and Polystyrene Particles KW - Surface Modification KW - Dye KW - Optical Spectroscopy KW - Quantitative NMR KW - Electrochemical Titration KW - Functionalized Nanomaterials KW - Nanosafety PY - 2023 AN - OPUS4-59126 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Osipova, Viktoriia T1 - Incorporation of near-infrared light emitting chromium (III) complexes into silica nanoparticles and spectroscopic characterization N2 - In recent years, chromium (III) complexes have received a lot of attention as novel near-infrared (NIR) emitters triggered by the report on the first molecular ruby Cr(ddpd)2(BF4)3 with a high photoluminescence quantum yield of 13.7% of its near infrared (NIR) emission band and a long luminescence lifetime of 1.122 ms at room temperature.[1] However, in an oxygen-containing environment, the photoluminescence quantum yields and luminescence lifetimes of these chromium(III) complexes show only very small values. This hampers their application as NIR luminescence labels. This application, that cannot be tackled by conventional deoxygenating approaches, requires suitable strategies to protect the luminescence of the chromium(III) complexes from oxygen quenching. An elegant approach to reduce the undesired luminescence quenching by triplet oxygen explored by us presents the incorporation of these chromium(III) complexes into different types of amorphous, non-porous silica nanoparticles, that can be simply surface functionalized, e.g., with targeting ligands and/or other sensor molecules. In this work, as first proof-of-concept experiments, a set of chromium (III) complexes constituting of different ligands and counter anions, were embedded into the core of silica nanoparticles. Subsequently, the optical properties of the resulting luminescent silica nanoparticles were spectroscopically assessed by steady state and time-resolved luminescence spectroscopy. First results of time-resolved luminescence measurements confirm our design concept of nanoscale NIR emissive Cr(III) complex-based reporters T2 - Projekttreffen Nile-Chrome 2.0 CY - Mainz, Germany DA - 11.12.2023 KW - Cr(III) complex KW - NIR KW - Luminescence KW - Nano KW - Silica KW - Lifetime KW - Quantum Yields KW - Particle Synthesis KW - Sensors KW - Probe KW - Surface Group Analysis PY - 2023 AN - OPUS4-59149 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute T1 - Functional Luminophores – From Photophysics to Standardized Luminescence Measurements N2 - Inorganic nanocrystals with linear and nonlinear luminescence in the ultraviolet, visible, near infrared and short-wave infrared like semiconductor quantum dots and spectrally shifting lanthanide-based nanophosphors have meanwhile found applications in the life and material sciences ranging from optical reporters for bioimaging and sensing over security barcodes to solid state lighting and photovoltaics. These nanomaterials commonly have increasingly sophisticated core/shell particle architectures with shells of different chemical composition and thickness to minimize radiationless deactivation at the particle surface that is usually the main energy loss mechanism [1]. For lanthanide-based spectral shifters, particularly for very small nanoparticles, also surface coatings are needed which protect near-surface lanthanide ions from luminescence quenching by high energy vibrators like O-H groups and prevent the disintegration of these nanoparticles under high dilution conditions. [2,3,4]. The identification of optimum particle structures requires quantitative spectroscopic studies focusing on the key performance parameter photoluminescence quantum yield [5,6], ideally flanked by single particle studies to assess spectroscopic inhomogeneities on a particle-to-particle level for typical preparation methods [7,8], Moreover, in the case of upconversion nanoparticles with a multi-photonic and hence, excitation power density (P)-dependent luminescence, quantitative luminescence studies over a broad P range are required to identify particle architectures that are best suited for applications in fluorescence assays up to fluorescence microscopy. Here, we present methods to quantify the photoluminescence of these different types of emitters in the vis/NIR/SWIR and as function of P and demonstrate the importance of such measurements for a profound mechanistic understanding of the nonradiative deactivation pathways in semiconductor and upconversion nanocrystals of different size and particle architecture in different environments. T2 - Eingeladener Vortrag Uni Erlangen CY - Erlangen, Germany DA - 18.01.2023 KW - Semiconductor quantum dot KW - Upconversion nanocrystal KW - Luminescence KW - Quantitative spectroscopy KW - Photophysics KW - Quality assurance KW - Nano KW - Particle KW - Quantum yield KW - Lifetime KW - Standard KW - Reference material KW - Surface analysis KW - Quantification PY - 2023 AN - OPUS4-57011 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tavernaro, Isabella T1 - pH-Responsive Dyad Molecules: MiGraGen Project N2 - Optical pH sensors utilizing colorimetric or fluorescent indicator dyes are highly promising in many biomedical and life science applications where electrochemical sensors fail. For instance, optical sensors are not prone to electrical interferences, they are noninvasive and enable remote measurements. Moreover, fluorescence detection is very fast, highly sensitive, and provides several readout parameters ideal for multiplexing with nanometer resolution using simple, inexpensive, and miniaturizable instrumentation. Here, we present the design of a dyad sensor molecule, consisting of an analyte-responsive and an analyte inert reference fluorophore. T2 - MiGraGen Project Meeting 16.06.2023 CY - Online Meeting DA - 16.06.2023 KW - Dyad molecules KW - pH sensing KW - Fluorescent indicator KW - Ratiometric sensors PY - 2023 AN - OPUS4-58070 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wegner, Karl David T1 - Exploring the photoluminescence of gold NCs and Ag2S NPs to boost their SWIR emission N2 - Current challenges and objectives for non-invasive optical bioimaging are deep tissue penetration, high detection sensitivity, high spatial and temporal resolution, and fast data acquisition. A promising spectral window to tackle these challenges is the short-wave infrared (SWIR) ranging from 900 nm to 1700 nm where scattering, absorption, and autofluorescence of biological components are strongly reduced compared to the visible/NIR. At present, the best performing SWIR contrast agents are based on nanomaterials containing toxic heavy-metal ions like cadmium or lead, which raises great concerns for biological applications. Promising heavy-metal free nanoscale candidates are gold nanoclusters (AuNCs) and Ag2S nanoparticles (NPs). The photoluminescence (PL) of both types of nanomaterials is very sensitive to their size, composition of their surface ligand shell, and element composition, which provides an elegant handle to fine-tune their absorption and emission features and boost thereby the size of the signals recorded in bioimaging studies. Aiming for the development of SWIR contrast agents with optimum performance, we dived deeper into the photophysical processes occurring in these nanomaterials, thereby exploring in depth how the environment, surface ligand composition, and the incorporation of transition metals influence the optical properties of AuNCs and Ag2S NPs. We observed a strong enhancement of the SWIR emission of AuNCs upon exposure to different local environments (in solution, polymer, and in the solid state). Addition of metal ions such as Zn2+ to Ag2S based NPs led to a strong PL enhancement, yielding PL quantum yields of about 10% and thus making them highly suitable for non-invasive deep imaging of vascular networks and 3D fluid flow mapping. T2 - NaNaX 10 - Nanoscience with Nanocrystals CY - Klosterneuburg, Austria DA - 03.07.2023 KW - Quantum dots KW - Ag2S KW - Fluorescence KW - SWIR KW - Gold nanocluster KW - Nanomaterial KW - bioimaging PY - 2023 AN - OPUS4-58104 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pauli, J. A1 - Güttler, Arne A1 - Schneider, T. A1 - Würth, Christian A1 - Resch-Genger, Ute T1 - Fluorescence Quantum Yield Standards for the UV/Visible/NIR: Development, Traceable Characterization, and Certification N2 - The rational design of next generation molecular and nanoscale reporters and the comparison of different emitter classes require the determination of the fluorometric key performance parameter fluorescence quantum yield (Φf), i.e., the number of emitted photons per number of absorbed photons. Main prerequisites for reliable Φf measurements, which are for transparent luminophore solutions commonly done relative to a reference, i.e., a fluorescence quantum yield standard of known Φf, are reliable and validated instrument calibration procedures to consider wavelength-, polarization-, and time-dependent instrument specific signal contributions, and sufficiently well characterized fluorescence quantum yield standards. As the standard’s Φf value directly contributes to the calculation of the sample’s Φf, its accuracy presents one of the main sources of uncertainty of relative Φf measurements. To close this gap, we developed a first set of 12 fluorescence quantum yield standards, which absorb and emit in the wavelength region of 330−1000 nm and absolutely determined their Φf values with two independently calibrated integrating sphere setups. Criteria for standard selection and the configuration of these novel fluorescence reference materials are given, and the certification procedure is presented including homogeneity and stability studies and the calculation of complete uncertainty budgets for the certified Φf values. The ultimate goal is to provide the community of fluorescence users with available reference materials as a basis for an improved comparability and reliability of quantum yield data since the measurement of this spectroscopic key property is an essential part of the characterization of any new emitter. KW - Optical spectroscopy KW - Traceability KW - Reference product KW - Dye KW - Fluorescence KW - Quantum yield KW - Reference material KW - Reference data KW - Certification KW - Quality assurance PY - 2023 DO - https://doi.org/10.1021/acs.analchem.2c05530 VL - 95 SP - 5671 EP - 5677 PB - American Chemical Society AN - OPUS4-58151 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tavernaro, Isabella T1 - Multicolored sensors based on silica and polymeric particles for ratiometric monitoring of pH, oxygen and saccharides N2 - In recent years, the use of functionalized micro- and nanomaterials has increased rapidly for a wide range of applications in the life and material sciences, due to their unique properties in combination with their high surface-to-volume ratio and stability. For instance, functionalized micro- and nanomaterials, that are labeled or stained with a multitude of sensor dyes can be used for monitoring, and quantification of neutral and ionic analytes. These materials have several advantages as compared to conventional molecular probes like enhanced brightness, ease of designing ratiometric systems by combining analyte-sensitive and inert reference dyes, and increased photostability. Moreover, stained nanoparticles can enable the use of hydrophobic dyes in aqueous environments. Versatile templates and carriers for the fabrication of nanosensors by staining and/or labeling with different fluorophores and sensor molecules are biocompatible silica and polymeric particles, because they can be synthesized in large scales at low costs with different surface chemistries. Here we present our work on multicolored sensors for the measurement of pH, oxygen and saccharides utilizing commercially available or in-house synthesized silica and polymeric particles. T2 - 4th European Biosensor Symposium 2023 CY - Aachen, Deutschland DA - 27.08.2023 KW - Nano- and microsensors KW - Silica and polystyrene nanoparticles KW - PH probe KW - Ratiometric sensors KW - Optical spectroscopy KW - Dye KW - Saccharide sensing KW - Multicolored PY - 2023 AN - OPUS4-59125 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute T1 - New project on the quantification of functional groups (FGS) on nanomaterials N2 - The surface chemistry of nanomaterials controls their interaction with the environment and biological species and their fate and is hence also relevant for their potential toxicity. This has meanwhile led to an increasing interest in validated and preferably standardized methods for the determination and quantification of surface functionalities on nanomaterials and initiated different standardization projects within ISO/TC 229 and IEC/TC 113 as well as interlaboratory comparisons (ILCs) of different analytical methods for the quantification of surface coatings by OECD. Here we present the results of a first ILC on the quantification of the amount of amino functionalities on differently sized inorganic nanoparticles done by division Biophotonics and the National Research Council of Canada (NRC) and the PWI 19257 on the Characterization and Quantification of Surface Functional Groups and Coatings on Nanoobjects approved by ISO/TC 229 (WG2) in fall 2022 that will result in a VAMAS study on this topic organized by division Biophotonics. Key words: nanoparticles, surface analysis, surface functional groups, quantification, optical assay, qNMR, VAMAS, standardization, ICL, quality assurance, reference material. T2 - Eingeladener Vortrag Universität Erlangen CY - Erlangen, Germany DA - 18.01.2023 KW - Quality assurance KW - Nano KW - Particle KW - Standard KW - Reference material KW - Surface analysis KW - Quantification KW - Interlaboratory comparison KW - Standardization KW - VAMAS PY - 2023 AN - OPUS4-57044 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Scholtz, Lena A1 - Resch-Genger, Ute T1 - Behind the Paper - Dual color pH probes made from silica and polystyrene nanoparticles and their performance in cell studies N2 - In this contribution we highlight the importance of comparison for scientific research while developing a new, functional pH sensor system, and the valuable insights this can provide. KW - Dye KW - Optical Spectroscopy KW - pH probe KW - Silica and Polystyrene Particles KW - Nano KW - Surface groups KW - Safe-by-Design KW - Cell studies KW - Sensors KW - Particle Synthesis KW - Fluorescence PY - 2023 UR - https://communities.springernature.com/posts/dual-color-ph-probes-made-from-silica-and-polystyrene-nanoparticles-and-their-performance-in-cell-studies SP - 1 EP - 2 PB - Springer Nature CY - London AN - OPUS4-59150 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute A1 - Pauli, J. A1 - Güttler, Arne A1 - Richter, Maria A1 - Fiedler, Saskia A1 - Frenzel, Florian A1 - Wegner, Karl David A1 - Würth, Christian T1 - Photoluminescence Quantum Yields of Luminescent Nanocrystals and Particles in the UV/vis/NIR/SWIR N2 - The rational design of functional luminescent materials such as semiconductor quantum dots and lanthanide-based upconversion nanoparticles, all photophysical and mechanistic studies, and the comparison of different emitters require accurate and quantitative photoluminescence measurements. Particularly the reliable determination of the key performance parameter photoluminescence quantum yield (f), the number of emitted per absorbed photons, and the brightness are of special importance for luminescence applications in the life and material sciences and nano(bio)photonics.[1] In this context, examples for absolute measurements of the photoluminescence quantum yields of UV/vis/NIR/SWIR emissive semiconductor quantum dots and rods, made from different materials, and spectrally shifting lanthanide upconversion nanocrystals with different surface chemistries in transparent matrices are presented including excitation wavelength and power density dependent studies utilizing integration sphere spectroscopy.[2,3] In addition, procedures for the absolute determination of the photoluminescence quantum yields of scattering dispersions of larger size quantum rods and differently sized inorganic particles have been developed as well as procedures for the characterization of solid luminescent nanomaterials such as different perovskites and YAG:Cer converter materials.[4] Thereby, challenges and pitfalls of f measurements in different wavelength regions including the SWIR and material-specific effects related to certain emitter classes are addressed, achievable uncertainties are quantified, and relative and absolute measurements of photoluminescence quantum yield measurements are compared to underline limitations of the former approach. Finally, a set of novel UV/vis/NIR quantum yield standards is presented including their certification with a complete uncertainty budget.[5] T2 - NANAX 10 CY - Klosterneuburg, Austria DA - 03.07.2023 KW - Fluorescence KW - Optical spectroscopy KW - Reference data KW - Traceability KW - NIR KW - Scattering KW - Reference material KW - Certification KW - Quality assurance KW - Dye KW - Reference product KW - SWIR KW - Nano KW - Particle KW - Perovskite KW - Integrating sphere spectroscopy KW - Quantum yield PY - 2023 AN - OPUS4-58238 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tavernaro, Isabella T1 - A Multimodal Approach to Quantify Surface Functional Groups and Ligands on Amorphous Silica Nanoparticles N2 - Nowadays amorphous silica nanoparticles (SiO2-NP) are one of the most abundant engineered nanomaterials, that are highly stable and can be easily produced on a large scale at low cost. Surface functionalized SiO2-NP are of great interest in the life and material sciences, as they can be used e.g. as drug carriers, fluorescent sensors, and multimodal labels in bioanalytical assays and imaging applications. Their performance in such applications depends not only on particle size, size distribution, and morphology, but also on surface chemistry, i.e. the total number of surface functional groups (FG) and the number of FG accessible for subsequent functionalization with ligands or biomolecules, which in turn determines surface charge, colloidal stability, biocompatibility, and toxicity. Aiming at the development of simple, versatile, and multimodal tools for the quantification of many bioanalytically relevant FG and ligands, we investigated and compared various analytical methods commonly used for FG quantification. This includes electrochemical titration methods, dye-based optical assays, and other instrumental analytical techniques such as nuclear magnetic resonance and thermal analysis methods. The potential of our multimodal approach for FG quantification was demonstrated for commercial and custom-made silica particles of varying FG, showing not only an influence of the synthesis methods on the number of FG but also on the performance. In the future, our strategy can contribute to establish multi-method characterization strategies to provide a more detailed picture of the structure-properties relationship. T2 - Advanced Materials Safety 2023 CY - Saarbrücken, Germany DA - 08.11.2023 KW - Amorphous silica particles KW - Surface group analysis KW - Ligands KW - Reference material KW - Optical spectroscopy KW - Quantitative NMR KW - Optical assays KW - Titration KW - Engineered nanomaterials KW - Advanced Materials PY - 2023 AN - OPUS4-59124 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - VIDEO A1 - Pauw, Brian Richard T1 - The human factor: A round robin study on the variation in data analyses N2 - This is a remote presentation I gave at the 2022 Small-angle Scattering conference in Campinas, Brazil. The video has been obtained from the conference organisers with their explicit permission for use on YouTube. I've tried to spruce up the audio from the remote recording the best I could. The conference abstract for this talk was: "How much do we, the small-angle scatterers, influence the results of an investigation? What uncertainty do we add by our human diversity in thoughts and approaches, and is this significant compared to the uncertainty from the instrumental measurement factors? After our previous Round Robin on data collection, we know that many laboratories can collect reasonably consistent small-angle scattering data on easy samples. To investigate the next, human component, we compiled four existing datasets from globular (roughly spherical) scatterers, each exhibiting a common complication, and asked the participants to apply their usual methods and toolset to the quantification of the results (https://lookingatnothing.com/index.php/archives/3274). Accompanying the datasets was a modicum of accompanying information to help with the interpretation of the data, similar to what we normally receive from our collaborators. More than 30 participants reported back with volume fractions, mean sizes and size distribution widths of the particle populations in the samples, as well as information on their self-assessed level of experience and years in the field. While the Round Robin is still underway (until the 25th of April, 2022), the initial results already show significant spread in the results. Some of these are due to the variety in interpretation of the meaning of the requested parameters, as well as simple human errors, both of which are easy to correct for. Nevertheless, even after correcting for these differences in understanding, a significant spread remains. This highlights an urgent challenge to our community: how can we better help ourselves and our colleagues obtain more reliable results, how could we take the human factor out of the equation, so to speak? In this talk, we will introduce the four datasets, their origins and challenges. Hot off the press, we will summarize the anonymized, quantified results of the Data Analysis Round Robin. (Incidentally, we will also see if a correlation exists between experience and proximity of the result to the median). Lastly, potential avenues for improving our field will be offered based on the findings, ranging from low-effort yet somehow controversial improvements, to high-effort foundational considerations." T2 - International Small-Angle Scattering Conference (SAS2022) CY - Campinas, Brazil DA - 11.09.2022 KW - Round robin KW - Data analysis KW - X-ray scattering KW - Neutron scattering KW - Nanomaterials KW - Metrology KW - Interlaboratory comparison PY - 2023 UR - https://www.youtube.com/watch?v=t1Rowo--Osg DO - https://doi.org/10.26272/opus4-56897 PB - YouTube, LLC CY - San Bruno, CA, USA AN - OPUS4-56897 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - VIDEO A1 - Pauw, Brian Richard T1 - "Ultima Ratio": Multi-scale, high-resolution 3D-FFT scattering pattern simulations N2 - This talk highlights a proof-of-concept that demonstrates the ability to calculate high-resolution Fourier transforms. These can be combined with multi-scale modeling to simulate scattering over a wide range, from small-angle scattering to XRD and PDF. The preprint documenting this is available on the ArXiv here: https://doi.org/10.48550/arXiv.2303.13435 The Jupyter notebook, VASP calculation details and MOUSE measured scattering patterns are available from this Zenodo repository: https://dx.doi.org/10.5281/zenodo.7764045 T2 - Shapespyer/MuSSIC Launch Workshop CY - Didcot, UK DA - 20.02.2023 KW - Video KW - Simulation KW - High-resolution KW - Fourier Transform KW - 3D FFT KW - Nanomaterial KW - Metal organic framework KW - MOF KW - SAXS KW - XRD KW - PDF KW - X-ray diffraction KW - Pair distribution function KW - Small-angle X-ray scattering PY - 2023 UR - https://www.youtube.com/watch?v=lEApkOqR5e8 DO - https://doi.org/10.26272/opus4-57212 PB - YouTube, LLC CY - San Bruno, CA, USA AN - OPUS4-57212 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Durlo Tambara, Luís Urbano A1 - Matos, P. R. de A1 - Lima, G. T. S. A1 - Silvestro, L. A1 - Rocha, J.C. A1 - Campos, C. E. M. de A1 - Gleize, P. J. P. T1 - Influence of Nanosilica and Superplasticizer Incorporation on the Hydration, Strength, and Microstructure of Calcium Sulfoaluminate Cement Pastes N2 - This study investigated the effect of incorporating three types of nanosilica (NS), two powders, and one colloidal suspension on the hydration, strength, and microstructure of calcium sulfoaluminate (CSA) cement pastes prepared with and without a superplasticizer (SP). X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), and compressive strength tests were performed after 2, 5, and 28 days of hydration. The results showed that both NS powders delayed cement hydration at an early age, which was attributed to particle agglomeration (confirmed by dynamic light scattering). Whereas well-dispersed colloidal NS did not significantly affect the hydration of CSA at the investigated ages. SP incorporation improved the dispersion of CSA cement particles, resulting in a 10% increase in the degree of hydration of ye’elimite at 28 days for the system without NS. Conversely, when the SP was incorporated in NS-containing mixtures, it hindered cement hydration of the systems with powdered NS, but did not significantly affect the cement hydration of the system containing colloidal NS. The SEM images suggested that the SP changed the ettringite morphology, thereby negatively affecting the mechanical strength of the CSA pastes. KW - Calcium sulfoaluminate (CSA) cement KW - Nanosilica (NS) KW - Hydration KW - Microstructure PY - 2023 DO - https://doi.org/10.1061/JMCEE7.MTENG-15570 SN - 0899-1561 VL - 35 IS - 7 SP - 04023216 PB - ASCE AN - OPUS4-57404 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Baglo, K. A1 - Sauermoser, M. A1 - Lid, M. A1 - Paschke, T. A1 - Bin Afif, A. A1 - Lunzer, M. A1 - Bock, Robert A1 - Steinert, M. A1 - Flaten, A. A1 - Torgersen, J. T1 - Overcoming the transport limitations of photopolymer-derived architected carbon N2 - Photopolymer derived carbon grows in popularity, yet the range in available feature sizes is limited. Here we focus on expanding the field to low surface to volume ratio (SVR) structures. We describe a high temperature acrylic photopolymerizable precursor with FTIR and DSC and develop a thermal inert-gas treatment for producing architected carbon in the mm scale with SVR of 1.38 x10-3 μm-1. Based on TGA and MS, we distinguish two thermal regimes with activation energies of ~79 and 169 kJ mol-1, which we reason with mechanisms during the polymer’s morphologic conversion between 300 - 500 °C. The temperature range of the major dimensional shrinkage (300-440 °C, 50%) does not match the range of the largest alteration in elemental composition (440-600 °C, O/C 0.25-0.087%). The insights lead to an optimized thermal treatment with an initial ramp (2 °C min-1 to 350 °C), isothermal hold (14h), post hold ramp (0.5 °C min-1 to 440 °C) and final ramp (10 °C min-1 to 1000 °C). The resulting carbon structures are dimensionally stable, non-porous at the μm scale, and comprise an unprecedented variation in feature sizes (from mm to μm scale). The findings shall advance architected carbon to industrially relevant scales. KW - Carbon KW - Photopolymer KW - Transport limitations KW - Porous materials KW - Additive manufacturing PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575038 DO - https://doi.org/10.1002/admt.202300092 SN - 2365-709X SP - 2300092 PB - Wiley-VCH GmbH AN - OPUS4-57503 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gawek, Marcel A1 - Omar, Hassan A1 - Szymoniak, Paulina A1 - Schönhals, Andreas T1 - Growth kinetics of the adsorbed layer of poly(2-vinylpyridine) - An indirect observation of desorption of polymers from substrates N2 - The growth kinetics of the adsorbed layer of poly(2-vinylpiridine) on silicon oxide is studied using a leaching technique which is based on the Guiselin brushes approach. The adsorbed layer is grown from a 200 nm thick P2VP film for several annealing time periods at different annealing temperatures. Then the film is solvent-leached, and the height of the remaining adsorbed layer is measured by atomic force microscopy. At the lowest annealing temperature only a linear growth regime is observed, followed by a plateau. Here, the molecular mobility of segments is too low to allow for a logarithmic growth. At higher annealing temperatures, both linear and logarithmic growth regimes are observed, followed by a plateau. At even higher annealing temperatures, the growth kinetics of the adsorbed layer changes. A linear growth followed by logarithmic growth kinetics is observed for short annealing time periods. For longer annealing time periods, an upturn of the growth kinetics is observed. At the highest annealing temperature, only a logarithmic growth regime is found. The change in the growth kinetics is discussed by an alteration in the structure of the adsorbed layer. Moreover, the interaction between the polymer segments and the substrate becomes weaker due to both enthalpic and entropic effects. Therefore, at high annealing temperatures the polymer segments might more easily desorb from the substrate. KW - Ultra thin polymer films PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575423 DO - https://doi.org/10.1039/d3sm00129f SN - 1744-683X SN - 1744-6848 VL - 19 IS - 21 SP - 3975 EP - 3982 PB - Royal Society of Chemistry (RSC) CY - London AN - OPUS4-57542 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Srivastava, Priyanka A1 - Tavernaro, Isabella A1 - Scholtz, Lena A1 - Genger, C. A1 - Welker, P. A1 - Schreiber, Frank A1 - Meyer, Klas A1 - Resch-Genger, Ute T1 - Dual color pH probes made from silica and polystyrene nanoparticles and their performance in cell studies N2 - Ratiometric green–red fluorescent nanosensors for fluorometrically monitoring pH in the acidic range were designed from 80 nm-sized polystyrene (PS) and silica (SiO2) nanoparticles (NPs), red emissive reference dyes, and a green emissive naphthalimide pH probe, analytically and spectroscopically characterized, and compared regarding their sensing performance in aqueous dispersion and in cellular uptake studies. Preparation of these optical probes, which are excitable by 405 nm laser or LED light sources, involved the encapsulation of the pH-inert red-fuorescent dye Nile Red (NR) in the core of self-made carboxylated PSNPs by a simple swelling procedure and the fabrication of rhodamine B (RhB)-stained SiO2-NPs from a silane derivative of pH-insensitive RhB. Subsequently, the custom-made naphthalimide pH probe, that utilizes a protonation-controlled photoinduced electron transfer process, was covalently attached to the carboxylic acid groups at the surface of both types of NPs. Fluorescence microscopy studies with the molecular and nanoscale optical probes and A549 lung cancer cells confirmed the cellular uptake of all probes and their penetration into acidic cell compartments, i.e., the lysosomes, indicated by the switching ON of the green naphthalimide fluorescence. This underlines their suitability for intracellular pH sensing, with the SiO2-based nanosensor revealing the best performance regarding uptake speed and stability. KW - Sensors KW - Silica and polystyrene nanoparticles KW - pH probe KW - Fluorescence spectroscopy KW - Cell studies KW - Dye KW - Particle synthesis PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569198 DO - https://doi.org/10.1038/s41598-023-28203-0 SN - 2045-2322 VL - 13 IS - 1 SP - 1321 EP - 1336 PB - Nature CY - London AN - OPUS4-56919 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute T1 - Standardised Measurements of Surface Functionalities on Nanoparticles N2 - Engineered nanoparticles (NPs) with various chemical compositions and surface functionalities are routinely fabricated for industrial applications such as medical diagnostics, drug delivery, sensing, catalysis, energy conversion and storage, opto-electronics, and information storage which improve the quality of life and European prosperity. NP function, performance, interaction with biological species, and environmental fate are largely determined by their surface functionalities. Standardized repeatable surface characterization methods are therefore vital for quality control of NPs, and to meet increasing concerns regarding their safety. Therefore, industry, regulatory agencies, and policymakers need validated traceable measurement methods and reference materials. This calls for fit-for-purpose, validated, and standardized methods, and reference data and materials on the surface chemistry of engineered NPs. Here, we present a concept for the development of such standardized measurement protocols utilizing method cross-validation and interlaboratory comparisons (ILCs) with emphasis on both advanced measurement methods such as quantitative Nuclear Magnetic Resonance (qNMR), X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS) and cost-efficient, non-surface specific methods like optical assays and electrochemical titration methods. T2 - European Partnership on Metrology 2023 Review Conference CY - Amsterdam, Netherlands DA - 07.11.2023 KW - Surface chemistry KW - Quality assurance KW - Traceability PY - 2023 AN - OPUS4-59142 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Knigge, Xenia A1 - Radnik, Jörg T1 - Physico-chemical characterization of sterilized TiO2 D540 nanoparticles by XPS / HAXPES / SEM N2 - Here a dataset of XPS, HAXPES and SEM measurements for the physico-chemical characterization of sterilized TiO2 D540 nanoparticles is presented. The measurements are part of the H2020 project “NanoSolveIT”. KW - XPS KW - HAXPES KW - SEM KW - NanoSolveIT KW - TiO2 D540 nanoparticles PY - 2023 DO - https://doi.org/10.5281/zenodo.7961317 PB - Zenodo CY - Geneva AN - OPUS4-57669 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Knigge, Xenia A1 - Radnik, Jörg T1 - Physico-chemical characterization of sterilized ZnO nanoparticles by XPS / HAXPES / SEM N2 - Here a dataset of XPS, HAXPES and SEM measurements for the physico-chemical characterization of sterilized ZnO nanoparticles is presented. The measurements are part of the H2020 project “NanoSolveIT”. KW - XPS KW - HAXPES KW - SEM KW - ZnO nanoparticles KW - NanoSolveIT PY - 2023 DO - https://doi.org/10.5281/zenodo.7990301 PB - Zenodo CY - Geneva AN - OPUS4-57661 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Knigge, Xenia A1 - Radnik, Jörg T1 - Physico-chemical characterization of sterilized CeO2 nanoparticles by XPS / HAXPES / SEM N2 - Here a dataset of XPS, HAXPES and SEM measurements for the physico-chemical characterization of sterilized CeO2 nanoparticles is presented. The measurements are part of the H2020 project “NanoSolveIT”. KW - XPS KW - HAXPES KW - SEM KW - NanoSolveIT KW - CeO2 nanoparticles PY - 2023 DO - https://doi.org/10.5281/zenodo.7941461 PB - Zenodo CY - Geneva AN - OPUS4-57667 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Reed, B.P. A1 - Marchesini, S. A1 - Chemello, Giovanni A1 - Morgan, D.J. A1 - Vyas, N. A1 - Howe, T. A1 - Radnik, Jörg A1 - Clifford, C,A. A1 - Pollard, A.J. T1 - The influence of sample preparation on XPS quantification of oxygen-functionalised graphene nanoplatelets N2 - X-ray photoelectron spectroscopy (XPS) is widely used for characterising the chemistry of graphene-related two-dimensional materials (GR2M), however the careful preparation of the sample for analysis is important in obtaining representative quantifications. We report an investigation by three laboratories showing that the preparation method for oxygen-functionalised graphene nanoplatelet (GNP) powders has a significant effect on the homogeneous-equivalent elemental composition measured in XPS. We show that pressing GNP powders onto adhesive tapes, into recesses, or into solid pellets results in inconsistencies in the XPS quantification. The measured oxygen-to-carbon atomic ratio from GNP pellets depends upon the die pressure used to form them and the morphology of the GNPs themselves. We recommend that powder samples of GR2Ms are pelletised prior to XPS analysis to improve repeatability and reproducibility of measurements. KW - X-ray photoelectron spectroscopy KW - Graphene related two-dimensional materials (GR2M) KW - Pelletization KW - Powder PY - 2023 DO - https://doi.org/10.1016/j.carbon.2023.118054 SN - 0008-6223 VL - 211 SP - 1 EP - 6 PB - Elsevier Ltd. AN - OPUS4-57694 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Knigge, Xenia A1 - Radnik, Jörg T1 - Physico-chemical characterization of sterilized Co2.25Fe0.75O4 nanoparticles by XPS / HAXPES / SEM N2 - Here a dataset of XPS, HAXPES and SEM measurements for the physico-chemical characterization of sterilized Co2.25Fe0.75O4 nanoparticles is presented. The measurements are part of the H2020 project “NanoSolveIT”. KW - XPS KW - HAXPES KW - SEM KW - NanoSolveIT KW - Co2.25Fe0.75O4 nanoparticles PY - 2023 DO - https://doi.org/10.5281/zenodo.7940538 PB - Zenodo CY - Geneva AN - OPUS4-57663 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -