TY - CONF A1 - Tavernaro, Isabella A1 - Chaudhary, A. A1 - Resch-Genger, Ute T1 - Development of amorphous silica particle based reference materials for surface functional group quantification N2 - Functionalized nanomaterials (NM) with their unique size-dependent properties are of increasing relevance for current and future developments in various fields such as medical and pharmaceutical industry, computing, electronics or food and consumer products. The performance and safety of NM are determined by the sum of their intrinsic physicochemical properties.1 Besides other key parameters, the particle surface chemistry, which is largely controlled by the chemical nature and density of functional groups and ligands, must be considered for a better performance, stability, and processibility of NM, as well as their interaction with the environment. Thus, particle standards with well-designed surfaces and methods for functional group quantification can foster the sustainable development of functional and safe(r) NM.2 Here we provide a brief overview of the ongoing research in division Biophotonics to design tailored amorphous silica reference particles with bioanalytically relevant functional groups and ligands, for the development of standardized and validated surface functional group quantification methods. T2 - Workshop NanoRiskSD project CY - Berlin, Germany DA - 09.06.2022 KW - Nanoparticle KW - Surface analysis KW - Silica KW - Fluorescence KW - Assay PY - 2022 AN - OPUS4-55004 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Karafiludis, Stephanos A1 - Kochovski, Z. A1 - Retzmann, Anika A1 - Scoppola, E. A1 - Emmerling, Franziska A1 - Stawski, Tomasz T1 - How do transition metal phosphates crystallise? N2 - Industrial and agricultural waste streams (waste waters, sludges, tailings etc.), which contain high concentrations of NH4+, PO43- and transition metals, are environmentally harmful due to their toxic pollutants. At the same time, phosphorus and selective transition metals such as Cobalt could be potentially depleted as a critical raw material due to the high demand and rapidly declining natural ore deposits. Therefore, due to simultaneous scarcity and abundance, the phosphorus and 3d metal recovery from agricultural, industrial, mining, or urban wastewaters have been an important factor in sustaining our global consumption and preservation of the natural environment. Typically, separate pathways have been considered to extract hazardous substances such as transition metals or phosphate, independently from each other. Here, we investigate the crystallization of transition metal phosphate (TMP) compounds (NH4MPO4∙6H2O, M3(PO4)2∙8H2O with M = Ni2+, Co2+, NixCo1-x2+ M-struvite and M-phosphate octahydrate) out of aqueous solutions, which allow for P, ammonia and metal co-precipitation. The precipitation of these compounds from industrial and agricultural waste waters has high potential as a P- and 3d metal recovery route. For this purpose, a detailed understanding of the crystallization process beginning from combination of solved ions and ending in a final crystalline product is required. Through adjusting the reaction conditions, the stability, crystallite size and morphology of the as-obtained TMPs could be controlled. Detailed investigations of the precipitation process in time using ex- and in-situ techniques provided new insights into their non-classical crystallization mechanism/crystal engineering of these materials. These TMPs involve transitional colloidal nanophases during the crystallization process. Over time, their complex amorphous framework changes significantly resulting simultaneously in an agglomeration and densification of the compound. After extended reaction times these colloidal nanophases condensed to a final crystal. However, the reaction kinetics of the formation of a final crystalline product and the lifetime of these intermediate phases vary significantly depending on the metal cation involved in the precipitation process. Ni-struvite is stable in a wide reactant concentration range and at different metal/phosphorus (M/P)-ratios, whereas Co tends to form Co-struvite and/or Co-phosphate octahydrate depending on the (M/P)-ratio. The mixed NixCo1-x system shows a significantly different crystallization behavior and reaction kinetics of the precipitation compared to the pure endmembers. The observed various degree of stability could be linked to the octahedral metal coordination environment in these compounds. The achieved level of control over the precipitates, is highly desirable for 3d- and P-recovery methods. Under this paradigm, the crystals can be potentially upcycled as precursor materials for (electro)catalytical applications. T2 - Granada Münster Discussion Meeting (GMDM) CY - Granada, Spain DA - 30.11.2022 KW - Struvite KW - Transition metal KW - Phosphates KW - Amorphous phases KW - Non-classical crystallization PY - 2022 AN - OPUS4-56478 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Abram, Sarah-Luise A1 - Mrkwitschka, Paul A1 - Prinz, Carsten A1 - Rühle, Bastian A1 - Haase, Oskar A1 - Kuchenbecker, Petra A1 - Löhmann, Oliver A1 - Hodoroaba, Vasile-Dan A1 - Bresch, Harald A1 - Resch-Genger, Ute T1 - Iron oxide nanoparticles as a reference material candidate for particle size measurements N2 - This poster presentation covers the development of iron oxide nanoparticles as reference material candidate in the context of the project "Nanoplattform". T2 - EMRS Spring Meeting CY - Online meeting DA - 31.05.2021 KW - Iron oxide nanoparticles KW - Reference material KW - Particle size KW - Transmission electron microscopy KW - Small angle x-ray scattering PY - 2021 AN - OPUS4-52773 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Dinter, Adelina-Elisa A1 - An-Stepec, Biwen A1 - Wurzler, Nina A1 - Özcan Sandikcioglu, Özlem A1 - Koerdt, Andrea A1 - Meermann, Björn T1 - Deciphering corrosion processes of MIC organisms - single cell-ICP-ToF-MS analysis of archaea on solid steels N2 - ICP-ToF (time of flight) MS enables the analysis of the multi-element fingerprint of single cells. The single cell ICP-ToF-MS is used in the presented poster for the analysis of archaea involved in microbiologically influenced corrosion (MIC) of steel. By means of sc-ICP-ToF-MS, the possible uptake of individual elements from the respective steel is investigated - the information obtained will be used in the future to elucidate underlying mechanisms and develop possible material protection concepts. The work combines modern methods of analytical sciences with materials. T2 - SALSA - Make & Measure 2021 CY - Online meeting DA - 16.09.2021 KW - Sc-ICP-ToF-MS KW - Single cell analysis KW - Microbiologically influenced corrosion KW - Archaea KW - Poster presentation PY - 2021 AN - OPUS4-53337 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Güttler, Arne A1 - Richter, Maria A1 - Würth, Christian A1 - Resch-Genger, Ute T1 - New Reference Materials for the Quantification and Standardization of Fluorescence-based Measurements N2 - Luminescence techniques are amongst the most commonly used analytical methods in the life and material sciences due to their high sensitivity and non-destructive and multiparametric character. Photoluminescence signals are, however, affected by wavelength-, polarization-, and time-dependent instrument specific effect and the compound-specific photoluminescence quantum yield. The former hamper the comparability of fluorescence measurements, while the relative determination of the latter requires suitable quantum yield standards with well-known photoluminescence quantum yields (QY). For the simple correction of instrument specific effects in the wavelength region of 300 nm to 950 nm, the set of the five certified spectral fluorescence standards BAM-F001 – BAM-F005, has been extended to the NIR range by including two new fluorescence standards currently under certification. For the reliable and accurate determination of QY which is the key performance parameter for the comparison of different luminophores, we certified a set of 12 quantum yield standards, which absorb and emit in the wavelength range from 300 nm to 1000 nm. T2 - Methods and Applications in Fluorescence CY - Gothenburg, Sweden DA - 11.09.2022 KW - Luminescence KW - Photoluminescence KW - Fluorescence KW - Quantum yield KW - Certified reference material KW - Standard PY - 2022 AN - OPUS4-55914 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Srivastava, Priyanka A1 - Tavernaro, Isabella A1 - Scholtz, Lena A1 - Resch-Genger, Ute T1 - Multi-color nanosensors for ratiometric measurements of acidic, neutral, and basic pH based on silica and polystyrene particles N2 - pH presents one of the most important analytes in the life and material sciences, indicating, e.g., diseases and corrosion processes. This includes the optical monitoring of pH in living cells for studying cellular internalization pathways, such as phagocytosis, endocytosis, and receptor mediated internalization with the aid of molecular and nanoscale fluorescent sensors. Nanoparticle (NP)-based sensors, that are labelled or stained with a multitude of sensor dyes, have several advantages as compared to conventional molecular probes like enhanced brightness, i.e., amplified signals, ease of designing ratiometric systems by combining analyte-sensitive and inert reference dyes, and increased photostability. Moreover, this can enable the use of hydrophobic dyes in aqueous environments. Versatile templates and carriers for the fabrication of nanosensors by staining and/or labelling with different fluorophores and sensor molecules are surface-functionalized particles like silica (SiO2) and polystyrene (PS) particles. Here we present a platform of blue-red-green fluorescent pH nanosensors for the measurement of acidic, neutral, and basic pH utilizing both types of matrices and two spectrally distinguishable sensor dyes with an integrated reference dye and demonstrate its applicability for cellular studies. T2 - E-MRS Spring Meeting 2022 CY - Online meeting DA - 30.05.2022 KW - Nanosensors KW - pH sensing KW - Silica- and polystyrene particles KW - Ratiometric sensors KW - Fluorescence PY - 2022 AN - OPUS4-55597 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hinsch, Alexandra A1 - Strelow, Christian A1 - Kipp, Tobias A1 - Würth, Christian A1 - Geißler, Daniel A1 - Resch-Genger, Ute A1 - Mews, Alf T1 - The influence of the individual Particles on the ensemble Quantum Yield of elongated CdSe/cds core/Shell nanoparticles N2 - Colloidal semiconductor nanoparticles with a spherical core and an elongated shell form bright emitters with a high absorption cross section. They show great potential for a multitude of optoelectronic applications such as LEDs or photovoltaic cells and can be used as gain material or as markers for bio imaging. For most of these applications high fluorescence quantum yields are a figure of merit for the emitter quality. In this work we investigate how the ensemble quantum yield is affected by the properties of the individual particles. In particular, we prove the role of non-emitting particles as well as the role of blinking. Using a combination of AFM and spatially resolved photoluminescence spectroscopy we measured hundreds of individual CdSe/CdS dot/rod particles of different shell lengths exciting with two different excitation wavelengths for shell or core excitation, respectively. T2 - SPIE Photonics West CY - San Francisco, CA, USA DA - 27.01.2018 KW - Exciton diffusion KW - Quantum Dot-Rod KW - Quantum Yield PY - 2018 AN - OPUS4-44759 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kimani, Martha Wamaitha A1 - Zhang, Y. A1 - Gawlitza, Kornelia A1 - Rurack, Knut T1 - Fluorescent core/shell molecularly-imprinted nanoparticles for staining sialic acid (SA) residues on tumor cells N2 - Cancer is a leading cause of death worldwide, and its early detection and resultant treatment contributes significantly to patient recovery and survival. Detection is currently based on magnetic resonance imaging and computed tomography, methods that are expensive, while processing of the results is time consuming. There is a need for low-cost cancer-detection techniques that give conclusive results in the shortest time possible. Molecularly imprinted polymers (MIPs) targeting tumor markers on cancerous cells may provide a cheaper solution for cancer detection. Thin MIP layers immobilized on particle platforms are known to give faster response times and increased selectivity in comparison to bulk MIPs. It has been reported that a fluorescent monomer can be incorporated into the MIP layer, allowing for faster detection of the target group, thus significantly shortening the turn-around time for biopsies. Changes in sialylation patterns of cell surface glycoproteins indicate malignancy. Here, we present the development of MIPs that target sialic acid-terminated glycoproteins (SA MIPs), prepared as a thin layer on a silica nanoparticle platform. A fluorescent monomer is incorporated into the MIP layer, and upon binding of the target group to the specific binding pockets in the MIP, the fluorescence signal is enhanced. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) are used for structural characterization. To validate the specificity, fluorescence changes of MIPs in the presence and absence of template are compared to their corresponding non-imprinted polymer particles (NIP). Initial binding experiments with tumor cells using fluorescence microscopy demonstrate that the presented technique shows promise as a cheaper alternative to current detection methods, while allowing for relatively shorter analysis of biopsy results. T2 - MIP 2018 CY - Hebrew University Jerusalem, Belgium House, Israel DA - 24.07.2018 KW - Sialic acid KW - MIPs KW - Fluorescence PY - 2018 AN - OPUS4-45419 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sternbaek, L. A1 - Kimani, Martha Wamaitha A1 - Shinde, S. A1 - Alm, K. A1 - Sellegren, B. A1 - Gjörloff-Wingren, A. T1 - Macrophage-uptake of sialic acid-targeted molecularly imprinted polymers (SA-MIPs) N2 - Sialic acid (SA) is a cell surface glycan, which has a decisive role in many cell activities including differentiation, proliferation, and the immune response. The amount of SA has been found to correlate with cancer, with an upregulation on more aggressive cancers. Therefore, there is a great interest in developing methods for detection of SA on cancer cells. We are screening SA on cancer cell lines by using fluorescent molecularly imprinted polymers, SA-MIPs. Macrophages, which evolve from mono-cytes, are well known for their extraordinary ability to phagocytose foreign objects. This could lead to the hypothesis that the SA-MIPs can be recognized by macrophages as foreign object; thus leading to internalization and potentially degradation. We have demonstrated that SA-MIPs can be detected after incubation with the RAW macrophage cells, with increasing fluorescence over time. The microscopy analysis shows that the RAW cells ingest the SA-MIP particles. This information is important when planning to use SA-MIPs in future in vivo applications. T2 - 1st National Meeting of the Swedish Chemical Society CY - Lund University, Sweden DA - 17.06.2018 KW - Sialic acid KW - MIPs KW - Macrophages PY - 2018 AN - OPUS4-45421 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sternbaek, L. A1 - Kimani, Martha Wamaitha A1 - Shinde, S. A1 - Alm, K. A1 - Sellegren, B. A1 - Gjörloff-Wingren, A. T1 - Macrophage-uptake of sialic acid-targeted molecularly imprinted polymers (SA-MIPs) N2 - Sialic acid (SA) is a cell surface glycan, which has a strong role in many cell activities including differentiation, proliferation, and the immune response. The amount of SA has been found to be correlated with cancer, with an upregulation on more aggressive cancers. Therefore, there is great interest in developing methods for detection of SA on cancer cells. We are screening SA on cancer cell lines by using fluorescent molecularly imprinted polymers, SA-MIPs.Macrophages, which evolve from mono-cytes, are well known for their extraordinary ability to phagocytose foreign objects. This could lead to the hypothesis that the SA-MIPs can be recognized by macrophages as foreign object; thus leading to internalization and potential degradation. We have discovered that SA-MIPs can be detected after incubation with the RAW macrophage cells, with increasing fluorescence over time. The microscopy analysis shows that the RAW cells ingest the SA-MIP particles. This information is important when planning to use SA-MIPs in future in vivo applications. T2 - The 69th Annual Conference of the Nordic Microscopy Society, 2018 CY - Lyngby, Denmark DA - 25.06.2018 KW - Sialic acid KW - MIPs KW - Macrophages PY - 2018 AN - OPUS4-45422 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan A1 - Rühle, Bastian T1 - Towards automated electron microscopy image segmentation for nanoparticles of complex shape by convolutional neural networks N2 - In this contribution different ways are explored with the aim to generate suitable training data for ‘non-ideal’ samples using various approaches, e.g., computer-generated images or unsupervised learning algorithms such as generative adversarial networks (GANs). We used these data to train simple CNNs to produce segmentation masks of SEM images and tested the trained networks on real SEM images of complex nanoparticle samples. The novel use of CNN for the automated analysis of the size of nanoparticles of complex shape and with a high degree of agglomeration has proved to be a promising tool for the evaluation of particle size distribution on a large number of constituent particles. Further development and validation of the preliminary model, respectively larger training and validation data sets are necessary. T2 - Microscopy and Microanalysis 2020 CY - Online meeting DA - 03.08.2020 KW - Nanoparticles KW - Automatisation KW - Image segmentation KW - Convolutional neural networks KW - Electron microscopy PY - 2020 AN - OPUS4-51114 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Geißler, Daniel A1 - Nirmalananthan-Budau, Nithiya A1 - Resch-Genger, Ute T1 - Preparation and characterization of reference particles for the calibration of flow cytometry for the detection of extracellular vesicles within the EMPIR project MetVes II N2 - Extracellular vesicles (EV) are cell-derived particles in body fluids, which have excellent potential as next-generation biomarkers. The exploitation of EV requires reliable measurements, which is currently very difficult, as most EV are smaller than 200 nm. At present, flow cytometry (FCM) is the most appropriate technique for EV analysis in biological samples, as FCM is readily available in many clinical laboratories and allows to identify cell-specific EV at high throughput. However, due to technical variations between different FCM instruments, EV concentration measurements are currently not well comparable between most laboratories. Therefore, EV reference materials and standardized reference methods are urgently needed to calibrate flow rate, light scattering intensity, and fluorescence intensity of FCM in the sub-micrometer size range. This requires a better matching of the optical properties of calibration beads and EV as can be realized with current polystyrene calibration beads. The EMPIR project 18HLT01 “MetVes II” aims to develop synthetic reference materials and traceable measurement methods to standardize EV measurements. The reference materials should resemble EV properties, so that calibrations are reliable and do not require a change of acquisition settings. Hence, the reference materials should contain particles with a traceable number concentration in the range of 109–1012 particles/mL to calibrate flow rate, a traceable size with discrete diameters between 50–1000 nm and a refractive index (RI) in the range of 1.37–1.42 to calibrate scattering intensity, and a traceable fluorescence intensity between 100–100,000 molecules of equivalent soluble fluorochromes (MESF). At BAM, various approaches to prepare such low-RI nanometer-sized reference materials will be studied, preliminary results of the primary characterization of these candidate reference particles will be presented, and possible applications besides FCM-based EV detection will be outlined. T2 - 29th Meeting of the German Society for Cytometry (DGfZ) CY - Berlin, Germany DA - 25.09.2019 KW - Extracellular vesicles (EV) KW - Flow cytometry KW - Reference particles KW - EMPIR project KW - 18HLT01 MetVes II PY - 2019 AN - OPUS4-50394 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mrkwitschka, Paul A1 - Abram, Sarah-Luise A1 - Kuchenbecker, Petra A1 - Würth, Christian A1 - Rühle, Bastian A1 - Resch-Genger, Ute A1 - Hodoroaba, Vasile-Dan T1 - Fine iron oxide nanoparticles as a candidate reference material for reliable measurement of particle size N2 - Background, Motivation and Objective Nanomaterials are at the core of some of the 21st century’s most promising technologies. In order to utilize and rationally design materials at the nanoscale the reliable characterization of their physico-chemical properties is highly important. Furthermore, the European Commission has taken measures via the REACH Regulations to control the classification of nanomaterials. REACH Annexes which entered into force in January 2020 require manufacturers to register nanomaterials that are traded in larger quantities (at least 1 ton). Every powder or dispersion where 50% (number distribution) of the constituent particles have sizes ≤ 100 nm in at least one dimension are defined as a nanomaterial. This creates a need for both industrial manufacturers and research and analytical service facilities to reliably characterize potential nanomaterials. Currently, BAM is working on developing reference nanoparticles, which shall expand the scarce list of worldwide available nano reference materials certified for particle size distribution, but also targeting other key parameters such as shape, structure (including porosity) and functional properties. Thus, candidate materials are considered to complement the already available spherical and monodisperse silica, Au and polystyrene reference nanoparticles, e.g. iron oxide and titanium oxide, with an average atomic number between those of silica and gold. Particularly for the imaging by electron microscopies, new nanoparticles of well-defined size in the range of 10 nm are decisive for the accurate particle segmentation by setting precise thresholds. Statement of Contribution/Methods Synthesis: Highly monodisperse iron oxide nanoparticles can be synthesized in large quantities by thermal decomposition of iron oleate or iron acetylacetonate precursors in high boiling solvents such as octadecene or dioctyl ether in the presence of oleic acid and oleylamine as capping agents. Scanning Electron Microscope: An SEM of type Supra 40 from Zeiss has been used including the dedicated measurement mode transmission in SEM (STEM-in-SEM) with a superior material contrast for the nanoparticle analysis. The software package ImageJ has been used for the analysis of the STEM-in-SEM images and to determine the particle size distribution. Dynamic Light scattering (DLS): Particles in suspension were measured in comparison by means of Zetasizer Nano (Malvern Panalytical; cumulants analysis) and NanoFlex (Microtrac; frequency power spectrum). Results/Discussion In this study iron oxide nanoparticles synthesized at BAM and pre-characterized by DLS, SEM (including the transmission mode STEM-in-SEM) are presented. The particles are spherical and highly monodisperse with sizes slightly larger than 10 nm. T2 - Nanosafe 2020 CY - Online meeting DA - 16.11.2020 KW - Reference nanomaterials KW - Imaging techniques KW - Size and size distribution KW - Reliable characterization KW - Iron oxide nanoparticles PY - 2020 AN - OPUS4-51767 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meierhofer, F. A1 - Dissinger, F. A1 - Weigert, Florian A1 - Resch-Genger, Ute A1 - Waldvogel, S. R. A1 - Voss, T. T1 - Citric-Acid-Based Carbon Dots with Luminescence Quantum Yields > 50%: spectral tuning of the luminescence by ligand exchange and pH adjustment N2 - We report the synthesis and characterization of carbon nanodots (CDs) with high quantum yield (>50%) and tailored optical absorption as well as emission properties. A well-described protocol with polyethyleneimine (PEI) as amine precursor is used as a reference to a new CD system which is stabilized by aromatic 2,3-diaminopyridine (DAP) molecules instead. The DAP stabilizer is installed in order to red-shift the absorption peak of the n-π* electron transition allowing efficient radiative recombination and light emission. Size, shape, and chemical composition of the samples are determined by (HR)TEM, EDX and FTIR-spectroscopy. Optical parameters are investigated using UV-VIS, PL and QY measurements. Several parameters such as concentration, excitation wavelength and pH are studied. Zeta-potential analysis indicate that pH-induced (de-)protonation processes of functional moieties directly affect the n-π* energy bands. This results in unique pH-dependent absorption and emission characteristics which are discussed on the specific chemical composition of each CD system. T2 - MRS 2019 CY - Boston, MA, USA DA - 03.12.2019 KW - Nanoparticle KW - Carbon dot KW - Surface chemistry KW - Fluorescence KW - PH KW - Ligand KW - FTIR KW - Synthesis KW - Characterization PY - 2019 AN - OPUS4-49968 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rühle, Bastian A1 - Nirmalananthan-Budau, Nithiya A1 - Roloff, Alexander A1 - Resch-Genger, Ute T1 - Surface Functional Group Quantification on Micro- and Nanoparticles N2 - Organic and inorganic micro- and nanoparticles are increasingly used as drug carriers, fluorescent sensors, and multimodal labels in the life and material sciences. Typically, these applications require further functionalization of the particles with, e.g., antifouling ligands, targeting bioligands, stimuli-responjsive caps, or sensor molecules. Besides serving as an anchor point for subsequent functionalization, the surface chemistry of these particles also fundamentally influences their interaction with the surrounding medium and can have a significant effect on colloidal stability, particle uptake, biodistribution, and particle toxicity in biological systems. Moreover, functional groups enable size control and tuning of the surface during the synthesis of particle systems. For these reasons, a precise knowledge of the chemical nature, the total number of surface groups, and the number of groups on the particle surface that are accessible for further functionalization is highly important. In this contribution, we will will discuss the advantages and limitiations of different approaches to quantify the amount of commonly used surface functional groups such as amino,[1,2] carboxy,[1,2] and aldehyde groups.[3] Preferably, the quantification is carried out using sensitive and fast photometric or fluorometric assays, which can be read out with simple, inexpensive instrumentation and can be validated by complimentary analytic techniques such as ICP-OES and quantitative NMR. T2 - NANAX Hamburg CY - Hamburg, Germany DA - 16.09.2019 KW - Microparticles KW - Nanoparticles KW - Quantitative Analysis KW - Surface KW - Funtional Groups PY - 2019 AN - OPUS4-49616 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Würth, Christian A1 - Radunz, Sebastian A1 - Frenzel, Florian A1 - Resch-Genger, Ute T1 - Understanding Nucleation and Optical Properties of Upconverting Nanoparticles N2 - Non-linear optical emitters are promising materials for energy applications and biotechnologies. Solid-state multi-band emitters like lanthanide doped up-conversion nanoparticles (UCNPs) show excellent photostability, are excitable in the near infrared (NIR), and show emission bands from the UV to SWIR spectral regions. The optical properties of these materials strongly depend on the excitation power density, i.e., the number of photons absorbed per time interval. The upconversion (ΦUC) and downshifting quantum efficiencies (ΦDS) of these materials, the excitation power dependent population, and the deactivation dynamics are influenced by nanoparticle architecture, doping concentration, and the microenvironment. We studied the fundamental changes of the luminescence properties of ß-NaYF4 UCNPs doped with Yb3+ and Er3+ depending on size, different surroundings such as aqueous and organic media, and different surface chemistries. We obtained further insights into shelling procedures, FRET optimization, influence of doping concentration, and advantages of different sensitizer ions. T2 - NaNaX CY - Hamburg, Germany DA - 16.09.2019 KW - UpConversion KW - Optical properties KW - Nanoparticle KW - Nanomaterial PY - 2019 AN - OPUS4-49700 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hübner, Oskar A1 - Resch-Genger, Ute T1 - Spectral and Lifetime Encoding of Polymer Particles with Cd-free Ternary Semiconductor Nanocrystals for Flow Cytometry with Time Resolved Fluorescence Detection N2 - Multiplexed encoding schemes of nano- and micrometer sized particles with fluorescent dyes or quantum dots (QDs) and their optical detection, are of increasing interest for applications in the life sciences, for example in flow cytometry. Almost all strategies utilizing fluorescence focus on spectrally distinguishable emission bands or colors and different intensity levels as fluorescence codes. The fluorescence parameter lifetime has been, however, barely exploited. In this work the goal is to perform multiplexing with encoding fluorophores with different fluorescence lifetimes (LTs). In comparison to the spectral multiplexing strategies this has the advantage, that the different fluorescence LT codes can be measured with the excitation and emission wavelength, thus reducing instrument costs. Moreover, LTs should not depend on emitter concentration. Unlike organic dyes, the LTs of which are typically < 10 ns, the fluorescence LTs of ternary semiconductor QDs that represent a “green” alternative to conventional Cd-containing QDs are in the range of several hundred ns, independent of oxygen concentration, and can be tuned to a certain extent by chemical composition and surface chemistry. This present a time region that can be barely covered by other emitters that have either much shorter or longer lifetimes. In this project, different encoding strategies will be assessed and the encoded particles will be then used for fluorescence assays for the analysis of several targets in parallel. Therefor the encoded particles will be functionalized with different target-specific bioligands and read out with a specifically designed flow cytometer enabling time-resolved fluorescence detection. With this instrument, the particles will be discriminated by their fluorescence LTs In one detection channel while the analytes will be quantified by fluorescence labels in a second channel in the intensity domain. T2 - Bad Honnef Physics School Exciting nanostructures: Characterizing advanced confined systems CY - Bad Honnef, Germany DA - 21.07.2019 KW - Multiplexing KW - Lifetime KW - Bead KW - Flow cytometry KW - Fluorescence KW - Quantum dot KW - InP KW - AIS KW - Dye KW - Encoding KW - Barcoding KW - Assay KW - Method PY - 2019 AN - OPUS4-49723 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Radunz, Sebastian A1 - Schavkan, A. A1 - Wahl, S. A1 - Tschiche, Harald Rune A1 - Würth, Christian A1 - Krumrey, M. A1 - Resch-Genger, Ute T1 - Investigation of upconverting nanoparticle growth utilizing in-situ luminescence monitoring in combination with offline small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) N2 - - UCNPs were succesfully synthesized and characterized - Various stages of UCNP growth were tracked using different analytical methods including real time in-situ & time-resolved luminescence spectroscopy, SAXS and TEM measurements - Additional size determination will be performed using inductively coupled plasma - mass spectrometry (ICP-MS) T2 - BAM-PTB-Nanoworkshop CY - PTB, Berlin, Germany DA - 14.05.2018 KW - Rare earth nanoparticles KW - Upconversion KW - TEM KW - SAXS PY - 2018 AN - OPUS4-45884 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weltschev, Margit A1 - Hoffmann, Gabi A1 - Rehfeldt, Rainer A1 - Kohl, Anka T1 - Investigations on the degree of damage of polyethylene grades as materials of heating oil storage tanks after a service life of more than 30 years N2 - Tanks for heating oil made of polyethylene grades have been on the market since the early 1970s in Germany. Tank manufacturers recommend the replacement of the tanks after a period of 30 years due to guarantee safety. Polyethylene grades are subject to ageing by alteration of the properties during their life cycle. The degree of ageing and the nature of the degradation process mainly depend on the chemical degradation of the polyethylene, the wall thickness of the tank and the environmental conditions. There are no results available on the long-term behavior of the polyethylene grades, especially after a service life of more than 30 years. The aim of this investigation was the determination of the factual degree of damage in comparison to the uncontaminated polyethylene grades. Material data of the used polyethylene grades are available because the BAM was the competent authority for the tests and expert reports for the approval of these tanks until the middle of the 1990s. The determination of the Melt Flow Rate (MFR) and the Fourier Transmission IR Spectroscopy (FTIR) of tank sections from the bottom, the shell and the roof of 10 segregated heating oil storage tanks produced of polyethylene grades A and B were used as tests methods. The MFR measurements of the tank sections showed differences in the values depending on the weight which was used (5 kg or 21.6 kg). A reduction of the MFR values was measured for most of the sections of tanks made of polyethylene grade B after a service life of the tanks of more than 30 years. This grade is mainly subject to the internal ageing by cross-linkages, increased degree of branched molecules and loss of the plasticizer, and to a lesser extent by oxidative degradation. The FTIR analysis, especially of tank sections of the bottom and the shell showed that the intensity of the CH2 asymmetric and symmetric stretching vibrations in the range: 2800 - 2900 cm-1 and the CH2 bending deformation vibration at 1400 cm-1 increased due chain scissions. The intensity of the carbonyl stretching vibration C=O at 1740 cm-1 is low. The carbonyl index characterizes the degree of oxidation. T2 - EUROCORR 2018 CY - Krakow, Poland DA - 09.09.2018 KW - Heating oil storage tanks KW - Polyethylene KW - Degree of damage KW - Melt Flow Rate (MFR) KW - FTIR PY - 2018 AN - OPUS4-45939 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kern, Simon A1 - Wander, Lukas A1 - Bornemann-Pfeiffer, Martin A1 - Guhl, Svetlana A1 - Meyer, Klas A1 - Maiwald, Michael T1 - Novel Flow Cell Designs for Process Monitoring with Compact NMR Spectroscopy N2 - Compact nuclear magnetic resonance (NMR) instruments make NMR spectroscopy and relaxometry accessible in industrial and harsh environments for reaction characterization and process control. Robust field integration of NMR systems have to face explosion protection or integration into process control systems with short set-up times. This paves the way for industrial automation in real process environments. The design of failsafe, temperature and pressure resistant flow through cells along with their NMR-specific requirements is an essential cornerstone to enter industrial production plants and fulfill explosion safety requirements. Additionally, if fast reactions are monitored, suitable mixing devices need to be placed in close vicinity to the measuring volume to mix the reactants properly. NMR-specific requirements aim at full quantitative pre-magnetization and acquisition with maximum sensitivity while reducing sample transfer times and dwell-times. All parameters are individually dependent on the applied NMR instrument. Luckily, an increasing number of applications are reported together with an increasing variety of commercial equipment. However, these contributions have to be reviewed thoroughly. The performance of sample flow cells commonly used in online analytics and especially for low-field NMR spectroscopy was experimentally and theoretically investigated by 1H-NMR experiments and numerical simulations. Especially, the applicability of 3D printed zirconium dioxide for innovative flow cell designs was of interest. Here, we demonstrate and discuss an automated test method to determine the critical parameters of flow through cells for quantitative online NMR spectroscopy. The setup is based on randomized setpoints of flow rates in order to reduce temperature related effects. Five flow cells and tubing were assessed and compared for high-field as well as low-field NMR spectrometers. T2 - Practical Applications of NMR in Industry Conference ​(PANIC) 2018 CY - La Jolla, California, USA DA - 04.03.2018 KW - Process Monitoring KW - Process Control KW - Flow Cell KW - Online NMR Spectroscopy KW - Additive Manufacturing KW - CONSENS PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-444364 N1 - Geburtsname von Bornemann-Pfeiffer, Martin: Bornemann, M. - Birth name of Bornemann-Pfeiffer, Martin: Bornemann, M. AN - OPUS4-44436 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gugin, Nikita A1 - Villajos Collado, José Antonio A1 - Dautain, Olivier A1 - Maiwald, Michael A1 - Emmerling, Franziska T1 - Optimizing the Green Synthesis of ZIF-8 by Reactive Extrusion Using In Situ Raman Spectroscopy N2 - ZIF-8 is a prominent member of the zeolitic imidazolate frameworks (ZIFs) subfamily of MOFs which possesses high thermal, chemical, and mechanical stabilities. Different routes have been explored to achieve the large-scale production of ZIF-8. However, these synthetic procedures are often inconsistent with the principles of sustainable chemical manufacturing. Aimed at developing scalable and greener production of ZIF-8, we adapted our previously reported in-batch „mix and wait“ synthesis[2] to continuous extrusion. To optimize the process, in-situ Raman spectroscopy was applied. Finally, we developed a simple and comprehensive approach to evaluating the environmental friendliness and scalability of MOF syntheses in view of their large-scale production. The synthesis of ZIF-8 was performed using a twin-screw extruder ZE 12 HMI equipped with an automatic volumetric feeder ZD 12B (Three-Tec GmbH, Switzerland) and peristaltic pump BT-L (Lead Fluid, China). The process was monitored in six different zones using a Raman RXN1TM analyzer (Kaiser Optical Systems, France) with a non-contact probe head. PMMA screw-in parts, which are transparent to Raman laser radiation, were specially manufactured to provide the laser focus within the barrel. PXRD, TGA, N2 adsorption measurements, and SEM were used as complementary techniques to characterize the extrudates. The batch ‘mix and wait’ synthesis of ZIF-8, consisting of bringing solid basic zinc carbonate and 2-methylimidazole in contact in a closed vial, was successfully adapted to reactive extrusion. The crystalline ZIF-8 continuously forms in the extruder under the mixing of solid reagents in the presence of a catalytic amounts of H2O or EtOH. The temperature, type of liquid, feeding rate, and excess of linker were optimized using in situ Raman spectroscopy. Pure and highly crystalline ZIF-8 was isolated at 40 °C by adding a catalytic amount of EtOH and a linker excess of 25%. The resulting material has excellent porosity with the BET surface area slightly exceeding that of the reference Basolite® Z1200 (1816 vs. 1734 m2 g–1). The reaction could yield ~ 3 kg d–1 assuming a continuous operation, with a space-time yield of ca. 67,000 kg m–3 d–1. The present method was compared to the published pathways based on Green Chemistry principles and proved to have the highest potential for large-scale production of ZIF-8. T2 - 5th European Conference on Metal Organic Frameworks and Porous Polymers (EuroMOF2023) CY - Granada, Spain DA - 24.09.2023 KW - In situ Raman KW - Reactive extrusion KW - Green chemistry KW - Mechanochemistry KW - MOFs KW - Large-scale synthesis PY - 2023 AN - OPUS4-58950 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gugin, Nikita A1 - Villajos Collado, José Antonio A1 - Maiwald, Michael A1 - Emmerling, Franziska T1 - Mixing Reactions Enable Green Synthesis of ZIF-8 at Large Scale: Batch and Continuous Modes N2 - We report the scale-up of a batch solid synthesis of zeolitic imidazolate framework-8 (ZIF-8) for reactive extrusion. The crystalline product forms in the extruder directly under the mixture of solid 2-methylimidazole and basic zinc carbonate in the presence of a catalytic amount of liquid. The process parameters such as temperature, liquid type, feeding rate, and linker excess were optimized using the setup specifically designed for in situ Raman spectroscopy. Highly crystalline ZIF-8 with a Brunauer–Emmett–Teller (BET) surface area of 1816 m2 g–1 was quantitatively prepared at mild temperature using a catalytic amount of ethanol and a small excess of the linker. Finally, we developed a simple and comprehensive approach to evaluating the environmental friendliness and scalability of metal–organic framework (MOF) syntheses in view of their large-scale production. T2 - 2023 #RSCPoster Twitter Conference CY - Online meeting DA - 28.02.2023 KW - MOFs KW - Green chemistry KW - Reactive extrusion KW - Large-scale production KW - Mechanochemistry KW - Zeolitic imidazolate framework PY - 2023 UR - https://twitter.com/NikitaGugin/status/1630538555675099139 AN - OPUS4-58951 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Winckelmann, Alexander A1 - Hoffmann, V. A1 - Morcillo, Dalia A1 - Agudo Jácome, Leonardo A1 - Leonhardt, Robert A1 - Richter, Silke A1 - Recknagel, Sebastian A1 - Abad Andrade, Carlos Enrique A1 - You, Zengchao T1 - Investigation of degradation of the aluminum current collector in lithium-ion batteries by glow-discharge optical emission spectroscopy N2 - Lithium-ion batteries (LIBs) are one technology to overcome the challenges of climate and energy crisis. They are widely used in electric vehicles, consumer electronics, or as storage for renewable energy sources. However, despite innovations in batteries' components like cathode and anode materials, separators, and electrolytes, the aging mechanism related to metallic aluminum current collector degradation causes a significant drop in their performance and prevents the durable use of LIBs. Glow-discharge optical emission spectroscopy (GD-OES) is a powerful method for depth-profiling of batteries' electrode materials. This work investigates aging-induced aluminum deposition on commercial lithium cobalt oxide (LCO) batteries' cathodes. The results illustrate the depth-resolved elemental distribution from the cathode surface to the current collector. An accumulation of aluminum is found on the cathode surface by GD-OES, consistent with results from energy-dispersive X-ray spectroscopy (EDX) combined with focused ion beam (FIB) cutting. In comparison to FIB-EDX, GD-OES allows a fast and manageable depth-profiling. Results from different positions on an aged cathode indicate an inhomogeneous aluminum film growth on the surface. The conclusions from these experiments can lead to a better understanding of the degradation of the aluminum current collector, thus leading to higher lifetimes of LIBs. T2 - Adlershofer Forschungsforum 2022 CY - Berlin, Germany DA - 11.11.2022 KW - Lithium Ion Batteries KW - GD-OES KW - FIB KW - SEM KW - EDX PY - 2022 AN - OPUS4-56246 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hübner, Oskar A1 - Resch-Genger, Ute A1 - Wegner, Karl David A1 - Hoffmann, Kristin T1 - Lifetime Barcoding of Polystyrene Beads with Fluorescent Nanocrystals for Fluorescent Lifetime Detection in Flow Cytometry N2 - Multiplexed encoding schemes of nano- and micrometer sized polymer particles with fluorescent dyes or quantum dots (QDs) and their optical detection, are of increasing interest for applications in the life sciences, for example in flow cytometry. Almost all strategies utilizing fluorescence focus on spectrally distinguishable emission bands or colors and different intensity levels as fluorescence codes. In this work the goal is to perform multiplexing with encoding fluorophores with different fluorescence lifetimes (LTs). In comparison to the spectral multiplexing strategies this has the advantage, that the different fluorescence LT codes can be measured with the same excitation and emission wavelength, thus reducing instrumental costs. Moreover, LTs should not depend on emitter concentration. Unlike organic dyes, the LTs of which are typically <10ns, the fluorescence LTs of ternary semiconductor QDs which represent a “green” alternative to conventional Cd-containing QDs are in the range of several hundred ns, independent of oxygen concentration, and can be tuned to a certain extent by chemical composition and surface chemistry. This presents a time region that can barely be covered by other emitters that have either much shorter or longer lifetimes. In this project, different encoding strategies will be assessed, and the encoded particles will then be used for fluorescence assays for the analysis of several targets in parallel. Therefore, the encoded particles will be functionalized with different target-specific bioligands and read out with a specifically designed flow cytometer enabling time-resolved fluorescence detection. With this instrument, the particles will be discriminated by their fluorescence LTs in one detection channel while the analytes will be quantified by fluorescence labels in a second channel in the intensity domain. T2 - Tag der Chemie 2019 CY - Berlin, Germany DA - 11.07.2019 KW - Multiplexing KW - Lifetime KW - Bead KW - Flow cytometry KW - Fluorescence KW - Quantum dot KW - InP KW - AIS KW - Dye KW - Encoding KW - Barcoding KW - Assay KW - Method PY - 2019 AN - OPUS4-49722 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hoell, A. A1 - Heimann, M. A1 - Wegner, Karl David A1 - Haas, S. A1 - Emmerling, Franziska A1 - Schorr, S. T1 - On the usage of anomalous SAXS to analyzethe structure and composition of bimetallic nanoparticles and quantum dots N2 - Tailor-made nanoparticles are of increasing interest in e.g. catalysis, as sensor materials, analytical assays, or can have superior photophysical properties. A major issue concerning the preparation of high-quality and functional nanoparticles is a good control of particle size, shape, polydispersity, and composition. Small Angle X-ray Scattering (SAXS) is a non-destructive method for the analysis of nanostructures in a wide variety of materials. This method allows determining averaged structural parameters on a length scale from just above atomic sizes up to several 100 nanometers such as sizes, size distributions, volume fractions, and inner surface sizes. Moreover, anomalous Small Angle X-ray Scattering (ASAXS) exploits the anomalous dispersion of the scattering amplitudes near the X-ray absorption edges of the elements contained in the sample. These element sensitive contrast variations can be used to analyse average composition fluctuations on the nm scale. Two kinds of nanoparticles are chosen here to elaborate the advantages of ASAXS in the analysis of complex materials. A facile and efficient methodology is developed for the thermal synthesis of size-tunable, stable, and uniform bimetallic NiCu core–shell nanoparticles (NPs) for various application in catalysis. Their diameter can be tuned in a range from 6 nm to 30 nm and the Ni:Cu ratio is adjustable in a wide range from 1:1 to 30:1. The NPs are structurally characterized by a method combination of transmission electron microscopy, anomalous small-angle X-ray scattering (ASAXS), X-ray absorption fine structure, and X-ray photoelectron spectroscopy. Here, we focus on the ASAXS method and its ability to analyses nanostructure parts and their compositions at once. As a result, a NiCu alloyed core surrounded by a Ni enriched shell and an outer NiO shell was found. Semiconductor nanocrystals (quantum dots, QDs) are well known for their superior photophysical properties and enabled advancements in several key technologies of the 21st century and numerous technological applications like in photovoltaics, LED displays, photocatalysis, and biosensing. To achieve high photoluminescence quantum yields (PLQY) and enhanced photostability the QD core needs to be passivated by a second semiconductor, which possess a larger band gap to confine the charges within the QD core. An important parameter is thereby the lattice mismatch between the core and shell. To avoid strong lattice strain, which would alter the photophysical properties, an intermediary shell can be used as a lattice adapter between the core and the outer shell leading to core/shell/shell systems. These systems have shown to possess high PLQYs combined with a strong long-term stability and can be found in modern QLED displays. ASAXS was used here to better understand the core/shell/shell structure of InP/ZnSe/ZnS QDs to enable a correlation between their structural and photophysical properties. T2 - IUCr - International Union of Crystallography CY - Melbourne, Australia DA - 22.08.2023 KW - ASAXS KW - Quantum dot KW - Core/shell materials KW - Safer by design PY - 2023 AN - OPUS4-58812 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wegner, Karl David A1 - Coro, A. A1 - Marquez, R. M. A1 - Le Guevel, X. A1 - Juarez, B. H. A1 - Resch-Genger, Ute 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 - CONF A1 - Wegner, Karl David A1 - Coro, A. A1 - Le Guevel, X. A1 - Juarez, B. H. A1 - Resch-Genger, Ute T1 - SWIR luminescent nanomaterials – key chemical parameters for bright probes for in vivo bioimaging N2 - A current challenge for studying physio-pathological phenomena and diseaserelated processes in living organisms with non-invasive optical bioimaging is the development of bright optical reporters that enable deep tissue penetration, a high detection sensitivity, and a high spatial and temporal resolution. The focus of this project are nanomaterials, which absorb and emit in the shortwave infrared (SWIR) between ~900–2500 nm where scattering, absorption, and autofluorescence of the tissue are strongly reduced compared to the visible and NIR. T2 - QD2024 - 12th International Conference on Quantum Dots CY - Munich, Germany DA - 18.03.2024 KW - Quantum dots KW - Advanced nanomaterials KW - Fluorescence KW - Quality assurance KW - Gold nanocluster KW - Shortwave infrared KW - Spectroscopy KW - Bioimaging PY - 2024 AN - OPUS4-59783 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 - Matiushkina, Anna A1 - Litvinov, I. A1 - Bazhenova, A. A1 - Belyaeva, T. A1 - Dubavik, A. A1 - Veniaminov, A. A1 - Maslov, V. A1 - Kornilova, E. A1 - Orlova, A. A1 - Tavernaro, Isabella A1 - Andresen, Elina A1 - Prinz, Carsten A1 - Resch-Genger, Ute T1 - Synthesis and physical properties studies of bifunctional nanocomposites N2 - At present, the field of research on nanostructures is actively developing, which is due to their unique physico-chemical properties compared to bulk materials. Many research activities are focused on obtaining nanocomposites, which combine various types of nanostructures with different properties and function. For example, the development of magneto-luminescent nanocomposites makes it possible to use their luminescence for optical imaging, and their magnetic properties for magnetic targeted delivery and as agents of hyperthermia and magnetic resonance imaging. My master studies as part of the project Goszadanie 2019-1080 at ITMO were focused on the investigation of nanocomposites, consisting of semiconductor quantum dots (QDs) as luminescent component and superparamagnetic iron oxide nanoparticles (SPIONs) as magnetic one, in solution and during their incubation with HeLa cells. The spectrally resolved analysis of the QD photoluminescence (PL) kinetics of the free QDs and the QDs incorporated in these nanocomposites undergoing energy transfer processes allowed for (1) understanding the reasons for the quenching of QD luminescence in cells, (2) evaluating the average distance between the QDs and, based on this, concluding the degree of QD aggregation in cells, and (3) drawing conclusions about the QD-quencher composites integrity in cells. Overall, the analysis of the PL kinetics confirmed that QDs and SPIONs remain bound in the obtained nanocomposites during incubation with cells. To ensure the successful advancement of nanomaterials in biomedicine and the transition from their laboratory preparation and studies to their use in different applications and in industry, it is crucial to develop reliable measurement methods and reference materials candidates for the characterization of functional nanomaterials and assessing the quality of the obtained nanostructures. My recently started project at BAM, which is part of the EU metrology project MeTrINo, will be devoted to this topic. There we will focus on the development of methodologies for the synthesis and characterization of iron oxide nanoparticles, already used in biomedicine, and multi-element lanthanide-based nanoparticles with attractive upconversion luminescence, as reference materials with high monodispersity and reproducibility. Also, these nanoparticles will be functionalized with organic dyes for optical imaging and, probably, the study of the energy transfer phenomena. T2 - Bad Honnef Summer School CY - Bad Honnef, Germany DA - 30.07.2023 KW - Quantum dots KW - Iron oxide nanoparticles KW - Upconversion nanoparticles PY - 2023 AN - OPUS4-58075 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Osipova, Viktoriia A1 - Tavernaro, Isabella A1 - Prinz, Carsten A1 - Langhammer, N. A1 - Heinze, K. A1 - Resch-Genger, Ute T1 - Incorporation of near-infrared light emitting chromium (III) complexes into the core and shell of silica nanoparticles and optimisation of their optical properties N2 - In recent years, chromium (III) complexes have received a lot of attention as novel near-infrared (NIR) emitters. This interest was 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. Meanwhile, the influence of triplet oxygen, temperature, and pressure on the optical properties of different molecular rubies have been assessed. These features make these molecular rubies promising candidates for multi-analyte optical sensing applications and the generation of singlet oxygen for photocatalysis and photodynamic therapy. 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. Typical approaches to reduce the oxygen sensitivity of long-lived luminophores include the encapsulation into an oxygen-shielding matrix or less commonly employed, by tuning the bulkiness of the ligands for oxygen-sensitive coordination compounds. An elegant approach to reduce the undesired luminescence quenching by triplet oxygen explored by us presents the incorporation of these chromium(III) complexes into amorphous, non-porous silica nanoparticles, that can be simply surface functionalized, e.g., with targeting ligands and/or other sensor molecules. This can enable the use of such chromium(III) complexes as reporters for bioanalytical assays and bioimaging without the need to introduce reactive groups into the ligands and can pave the road to lifetime tuning. 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. As an alternative synthesis strategy, selected complexes were incorporated into a silica shell formed around the core of self-made 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 of the Cr(ddpd)2(PF6)3 complex incorporated into 25nm large silica nanoparticles dispersed in aerated water in comparison to the decay kinetics obtained for this complex in acetonitrile in air showed an increase in lifetime from 46 µs to 1147 µs. This confirming our design concept of nanoscale NIR emissive Cr(III) reporters. T2 - Bad Honnef summer school CY - Bad Honnef, Germany DA - 30.07.2023 KW - Chromium (III) complexes KW - Silica Nanoparticles KW - Luminescence lifetime measurments PY - 2023 AN - OPUS4-58076 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krenzer, Julius A1 - Mueller, Thomas A1 - El Abbassi, Abdelouahad A1 - Resch-Genger, Ute A1 - Petrov, Eugene 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 - Gugin, Nikita A1 - Schwab, Alexander A1 - Villajos Collado, José Antonio A1 - Emmerling, Franziska T1 - Reactive extrusion of a model BSA@ZIF-8 biocomposite: a scalable, continuous and sustainable approach N2 - Metal-organic framework-based biocomposites (MOF-biocomposites) are promising materials for biosensing, biocatalysis, and delivery of biopharmaceuticals. One of the most studied MOFs for bioapplications is ZIF-8 (zeolitic imidazolate framework 8) due to its high surface area, high thermal and chemical stability, and low cytotoxicity. The conventional synthesis of ZIF-8-biocomposites called biomimetic mineralization includes mixing selected biomolecules 2-methylimidazole, and soluble Zn2+ source in water. Despite the high efficiency of the method, it does not allow for large-scale production and is restricted to hydrophilic biomolecules. Aimed at developing a scalable and versatile approach, we adapted our recently-reported ZIF-8 reactive extrusion for biocomposite production. We selected bovine serum albumin (BSA) as an inexpensive model biomacromolecule for the preparation of biocomposites. The synthesis of BSA@ZIF-8 was performed using a twin-screw extruder ZE 12 HMI (Three-Tec Gmbh) at a mild temperature of 40 °C. Automatic volumetric feeder ZD 12B (Three-Tec GmbH) was used to supply the reagent mixture consisting of 2-methylimidazole, zinc source, and BSA. To initiate the reaction, a catalytic amount of EtOH was added using a peristaltic pump BT-L (Lead Fluid, China). Powder X-Ray diffraction (PXRD), thermogravimetric analysis (TGA), FTIR, and N2 adsorption were used to characterize the extrudates. Highly crystalline and pure BSA@ZIF-8 with different BSA loadings was isolated after washing the extrudate with EtOH and sodium dodecyl sulfate. The EtOH feeding rate was optimized by following the protein encapsulation efficiency at a BSA mass fraction of 10%. A continuous extruder operation under optimized conditions showed good reproducibility and capability of producing biocomposites on the kilograms scale. These results provide highly valuable information for cheap and large-scale production of ZIF-8-based biocomposites. Due to the lack of restrictions on molecule size and solubility, our proof-of-concept study may significantly expand the selection of biomolecules for immobilization in ZIF-8, making the method applicable to various functional applications T2 - Tag der Chemie 2023 CY - Berlin, Germany DA - 05.07.2023 KW - Biocomposite KW - MOFs KW - Reactive extrusion KW - Zeolitic imidazolate framework PY - 2023 AN - OPUS4-58949 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tavernaro, Isabella A1 - Nirmalananthan-Budau, Nithiya A1 - Scholtz, Lena A1 - Resch-Genger, Ute 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 - Tavernaro, Isabella A1 - Osipova, Viktoriia A1 - Srivastava, Priyanka A1 - Huang, Zixuan A1 - Merei, Rabih A1 - Resch-Genger, Ute 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 - Winckelmann, Alexander A1 - Hoffmann, V. A1 - Morcillo, Dalia A1 - Agudo Jacome, Leonardo A1 - Leonhardt, Robert A1 - Richter, Silke A1 - Recknagel, Sebastian A1 - Abad Andrade, Carlos Enrique T1 - Investigation of degradation of the aluminum current collector in lithium-ion batteries by glow-discharge optical emission spectroscopy N2 - Lithium-ion batteries (LIBs) are one technology to overcome the challenges of climate and energy crisis. They are widely used in electric vehicles, consumer electronics, or as storage for renewable energy sources. However, despite innovations in batteries' components like cathode and anode materials, separators, and electrolytes, the aging mechanism related to metallic aluminum current collector degradation causes a significant drop in their performance and prevents the durable use of LIBs.[1] Glow-discharge optical emission spectroscopy (GD-OES) is a powerful method for depth-profiling of batteries' electrode materials. This work investigates aging-induced aluminum deposition on commercial lithium cobalt oxide (LCO) batteries' cathodes. The results illustrate the depth-resolved elemental distribution from the cathode surface to the current collector. An accumulation of aluminum is found on the cathode surface by GD-OES, consistent with results from energy-dispersive X-ray spectroscopy (EDX) combined with focused ion beam (FIB) cutting. In comparison to FIB-EDX, GD-OES allows a fast and manageable depth-profiling. Results from different positions on an aged cathode indicate an inhomogeneous aluminum film growth on the surface. The conclusions from these experiments can lead to a better understanding of the degradation of the aluminum current collector, thus leading to higher lifetimes of LIBs. T2 - European Winter Conference on Plasma Spectrochemistry (EWCPS 2023) CY - Ljubljana, Slovenia DA - 29.01.2023 KW - Lithium-ion batteries KW - Aging mechanisms KW - Depth-profiling PY - 2023 AN - OPUS4-56992 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Straße, Anne A1 - Gumenyuk, Andrey A1 - Altenburg, Simon A1 - Pignatelli, Giuseppe A1 - Baensch, Franziska A1 - Rethmeier, Michael T1 - Laser Metal Deposition (LMD) in ProMoAM N2 - During the last years Additive Manufacturing (AM) became increasingly important. That becomes clear, while looking at the advantages like a high degree of freedom concerning the geometry of the parts, low waste rates and a reduction of postprocessing, to name just three. Laser Metal Deposition (LMD) is one of those AM- methods. It can be used for different kinds of applications, e.g. repair weldings of used parts, coatings to increase the corrosion resistance or to build up new components. But for all applications, the production of defect free parts is crucial. Therefore, different kinds of non-destructive monitoring techniques were tested for the LMD-process to identify their potential to detect imperfections in-situ. T2 - Workshop on Additive Manufacturing: Process, materials, testing, simulation & implants CY - Berlin, Germany DA - 13.05.2019 KW - Acoustic Emission KW - LMD KW - Thermography KW - Optical Emission Spectroscopy PY - 2019 AN - OPUS4-49657 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Winckelmann, Alexander A1 - Hoffmann, V. A1 - Richter, Silke A1 - Abad, Carlos T1 - Fluorine Depth Profiling in Lithium-Ion Battery Materials by GD-OES N2 - Lithium-ion batteries are a key technology for tackling challenges in energy and climate crisis, but up to 30 % are discarded right after production. Quality is closely related to the homogeneity of the used materials and coatings. Fluorine compounds, both in the polymer and from degradation of the electrolyte, are of special interest for the formation and aging of LIBs. Glow-discharge optical emission spectroscopy (GD-OES) emerged as a fast and convenient method for depth-profiling of battery materials. However, fluorine remains a spectroscopic challenge due to a high excitation energy and only few strong emission lines in the UV/Vis spectral range. We investigated the partial substitution of argon with neon in the plasma gas. The main emission line at 685.603 nm was monitored by both photo multiplier tube (PMT) with Czerny-Turner monochromator at 20 µm slit-size, and charge-coupled device (CCD) with 1200 lines/mm grating. For calibration, we used a set of hot-pressed copper cylinders with varying calcium fluoride amount fraction, ranging from 1.6 % to 4.4 %. Plasma gas mixtures with a mole fraction of 5 %, 10 % and 20 % neon in argon were used. Sensitivity in comparison to pure argon was increased by factor 4, 7 and 14, respectively. In general, PMT detection was more sensitive than CCD. As expected, sputter rates decreased with higher neon content in the plasma gas. Depth-profiling of the cathodes was performed in pulsed mode at constant voltage and pressure, which resulted in stable plasma conditions. We achieve matrix-independent quantitative information on fluorine distribution by correction based on sputter rates. This advancement in GD-OES provides a more accurate analytical approach for evaluating the homogeneity of lithium-ion battery materials, potentially leading to more sustainable and cost-effective manufacturing processes. T2 - 6th International Glow Discharge Spectroscopy Symposium CY - Liverpool, United Kingdom DA - 21.04.2024 KW - Lithium Ion Batteries KW - GD-OES KW - depth-profiling KW - fluorine PY - 2024 AN - OPUS4-60200 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Chapartegui, Ander A1 - Emmerling, Franziska A1 - Schneider, Rudolf T1 - MOFs as optical sensor elements against endocrine disrupting phthalates N2 - The development of optical sensing technologies for Endocrine Disrupting Chemicals (EDCs) was urgently needed to facilitate currently unmet demands on comprehensive monitoring of These substances, thus ensuring consumer safety. T2 - SALSA CY - Berlin, Germany DA - 01.05.2018 KW - MOF KW - Short chained phthalates PY - 2018 AN - OPUS4-46889 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Juds, Carmen A1 - Conrad, T. A1 - Weller, Michael G. A1 - Börner, H. G. T1 - Finding peptide binders for polypropylene using phage display and next generation sequencing N2 - Phage display is used to find specific target binding peptides for polypropylene (PP) surfaces. PP is one of the most commonly used plastics in the world. Millions of tons are produced every year. PP binders are of particular interest because so far gluing or printing on PP is challenging due to its low surface energy. A phage display protocol for PP was developed followed by Next Generation DNA Sequencing of the whole phage library. Data analysis of millions of sequences yields promising peptide candidates which were synthesized as PEG conjugates. Fluorescence-based adsorption-elution-experiments show high adsorption on PP for several sequences. T2 - BAM PhD Day CY - Berlin-Adlershof, Germany DA - 31.05.2018 KW - Polymer KW - Glue KW - Amplification KW - Illumina KW - PEG KW - Sanger sequencing KW - SALSA KW - Data analysis KW - Fluorescence PY - 2018 AN - OPUS4-45055 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Altenburg, Simon A1 - Maierhofer, Christiane A1 - Hilgenberg, Kai A1 - Mohr, Gunther A1 - Gumenyuk, Andrey A1 - Straße, Anne A1 - Pittner, Andreas A1 - Günster, Jens A1 - Gornushkin, Igor B. A1 - Pelkner, Matthias A1 - Ehlers, Henrik A1 - Heckel, Thomas A1 - Zscherpel, Uwe A1 - Seeger, Stefan A1 - Bruno, Giovanni T1 - ProMoAM - Verfahrensentwicklung für das Prozessmonitoring in der additiven Fertigung N2 - Verfahren zum in-situ Monitoring der Prozess- und Bauteilparameter sollen Fehlstellen und Inhomogenitäten bereits während der Fertigung nachweisen und zukünftig auch die Regelung der Prozessparameter ermöglichen. T2 - Challenges in Additive Manufacturing: Innovative Materials and Quality Control, Berlin Partner Workshop CY - Berlin, Germany DA - 12.09.2018 KW - Additive Fertigung KW - Prozessmonitoring KW - ProMoAM PY - 2018 AN - OPUS4-46300 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Völzke, Jule L. A1 - Hodjat Shamami, Parya A1 - Gawlitza, Kornelia A1 - Feldmann, Ines A1 - Zimathies, Annett A1 - Meyer, Klas A1 - Weller, Michael G. T1 - Corundum as a novel affinity platform for the isolation of human IgG from plasma N2 - Nonporous corundum powder was functionalized covalently with protein binders to isolate and enrich specific proteins from complex matrices.The common crosslinker glutaraldehyde was compared with a hyperbranched polyglycerol (PG) of around 10 kDa. The latter was oxidized with periodate to generate aldehyde groups that can covalently react with the amines of the surface and the amino groups from the protein via a reductive amination process. The amount of bound protein was quantified via aromatic amino acid analysis (AAAA). As a proof of concept, IgG was extracted with protein A from crude human plasma. The advantages of corundum include the very low price, extremely high physical and chemical stability, pressure resistance, favorable binding kinetics, convenient handling, and flexible application. T2 - Adlershofer Forschungsforum 2022 CY - Berlin, Germany DA - 11.11.2022 KW - Affinity support KW - Affinity chromatography KW - Affinity extraction KW - Phosphonic acids KW - Polyglycerol KW - Reductive amination KW - Amino acid analysis KW - Tyrosine KW - Protein quantification KW - SDS-PAGE KW - Antibodies KW - Antibody purification KW - Downstream processing KW - Bovine serum albumin KW - BSA KW - Protein a KW - TEM KW - ESEM KW - Aluminum oxide KW - Sapphire KW - Human plasma KW - Protein immobilization KW - Protein hydrolysis KW - Glutaraldehyde KW - Aromatic amino acid analysis AAAA PY - 2022 AN - OPUS4-56154 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wegner, Karl David A1 - Häusler, I. A1 - Knigge, Xenia A1 - Hodoroaba, Vasile-Dan A1 - Emmerling, Franziska A1 - Reiss, P. A1 - Resch-Genger, Ute T1 - One-Pot Heat-Up Synthesis of ZnSe Magic-Sized Clusters Using Thiol Ligands N2 - The unique optoelectronic properties of semiconductor nanocrystals, also termed quantum dots (QDs), have led to many advances in optoelectronic devices, bioimaging, and biosensing. This strong potential in a wide range of applications sparked the interest for a better understanding of the QD formation mechanisms. Recent studies have shown that atomically defined, zero-dimensional magic-size clusters (MSCs) play a crucial role during the nucleation and growth of QDs. Thereby MSCs consist of discrete numbers of ions leading to narrow size distributions and thus narrow absorption peaks, which evolve in discrete steps from one stable size to the next. The formation of MSCs was found in the synthesis of II-VI and III-V QDs but only limited synthesis approaches are available for the synthesis of MSCs in single-ensemble form without coexistence of other-size QDs. These MSCs can further self-assemble into two- and three-dimensional hybrid structures using organic ligands like diamines, leading to enhanced photoluminescence properties and catalytic activities. In this contribution, we present a synthesis strategy for the preparation of single-sized ZnSe MSCs. With a band gap of 2.7 eV and being an earth-abundant material, ZnSe QDs are interesting for light-emitting devices, blue-green lasers, photocatalysis, and fluorescence probes. In contrast to other studies, our approach is based on a one-pot heat-up synthesis and uses less toxic and dangerous zinc precursors (e.g. zinc stearate). Knowing that thiol-based ligands can alter the formation process of ZnSe QDs, we investigated the influence of 1-dodecanethiol on the ZnSe MSC formation using absorption spectroscopy, TEM, XPS, and XRD. By variation of the thiol ligand concentration and reaction temperature, we were able to synthesize two new ZnSe MSC sizes, the largest so far, by using easy-to-handle precursors. T2 - NANOHYBRID - Hamburg Conference on Complex Nanostructures CY - Hamburg, Germany DA - 04.10.2022 KW - ZnSe KW - Magic-sized cluster KW - Nanoparticle KW - Synthesis KW - Nanomaterial PY - 2022 AN - OPUS4-56193 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute A1 - Giovannozzi, A. A1 - Rossi, A. A1 - Kovac, J. A1 - Ekar, J. A1 - Goenaga-Infante, H. A1 - Clarkson, C. A1 - Clifford, C. A1 - Cant, D. A1 - Minelli, C. A1 - Reithofer, M. A1 - Lindner, G. A1 - Venzago, C. A1 - Bohmer, N. A1 - Drexler, C.-P. A1 - Schedler, U. A1 - Thiele, T. A1 - Lechart, F. A1 - Kästner, B. A1 - Sjövall, P. A1 - Johnston, L. A1 - Tan, Gunnar A1 - Radnik, Jörg 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 - CONF A1 - Winckelmann, Alexander A1 - Abad Andrade, Carlos Enrique A1 - Richter, Silke A1 - Recknagel, Sebastian A1 - Riedel, Jens A1 - Vogel, Jochen A1 - Panne, Ulrich T1 - Next level lithium isotope analysis by atomic absorption spectrometry in combination with machine learning N2 - An alternative method for lithium isotope amount ratio analysis is proposed by combining atomic absorption spectrometry with spectra data analysis by machine leaning. It is based on the well-known isotope shift of around 15 pm for the electronic transition at wavelength 670.7845 nm which can be measured by a high-resolution continuum source atomic absorption spectrometer (HR-CS-AAS). For isotope amount ratio analysis, a scalable three boosting machine learning algorithm (XGBoost) was employed and calibrated with a set of samples with a 6Li isotope amount fraction ranging from 99% to 6%. The absolute Li isotope amount fractions of these calibration samples were previously measured by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) and used as ab-initio data for the machine learning algorithm. Validation of the machine leaning model was performed with two standard reference materials (LSVEC and IRMM-016). The procedure was employed for the isotope amount ratio determination of a set of stock chemicals (Li2CO3, LiNO3, LiCl, LiOH, and LiF) as well as a BAM candidate LiMNC cathode reference material. Achieved uncertainties are one order of magnitude higher than those obtained by MC-ICP-MS. This precision and accuracy is nonetheless sufficient to resolve natural occurring variations in Lithium isotope ratios. Also, the LiMNC material was analyzed by HR-CS-AAS with and without matrix purification. The results are comparable within statistical error. T2 - Make and Measure 2020 CY - Online Meeting DA - 15.10.2020 KW - Lithium batteries KW - HR-CS-AAS KW - Machine learning KW - Isotope analysis KW - Spectrometry PY - 2020 AN - OPUS4-51541 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -