TY - JOUR A1 - Tchipilov, Teodor A1 - Meyer, Klas A1 - Weller, Michael G. T1 - Quantitative 1H nuclear magnetic resonance (qNMR) of aromatic amino acids for protein quantification N2 - Hydrolysis of protein samples into amino acids facilitates the use of NMR spectroscopy for protein and peptide quantification. Different conditions have been tested for quantifying aromatic amino acids and proteins. The pH-dependent signal shifts in the aromatic region of amino acid samples were examined. A pH of 12 was found to minimize signal overlap of the four aromatic amino acids. Several aromatic compounds, such as terephthalic acid, sulfoisophthalic acid, and benzene tricarboxylic acid, were applied as internal standards. The quantification of amino acids from an amino acid standard was performed. Using the first two suggested internal standards, recovery was ~97% for histidine, phenylalanine, and tyrosine at a concentration of approximately 1 mM in solution. Acidic hydrolysis of a certified reference material (CRM) of bovine serum albumin (BSA) and subsequent quantification of Phe and Tyr yielded recoveries of 98% ± 2% and 88% ± 4%, respectively, at a protein concentration of 16 g/L or 250 µM. KW - Amino acid analysis KW - Aromatic amino acid analysis KW - AAA KW - AAAA KW - Protein hydrolysis KW - Hydrochloric acid KW - Metrology KW - Traceability KW - NIST KW - Reference materials KW - Internal standard KW - Calibration KW - Compound-independent calibration KW - Histidine KW - Tyrosine KW - Tryptophan KW - Phenylalanine KW - Terephthalic acid KW - Benzene-1,3,5-tricarboxylic acid KW - Bovine serum albumin (BSA) KW - Quantitative protein analysis KW - Phenylketonuria PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-570943 DO - https://doi.org/10.3390/mps6010011 VL - 6 IS - 1 SP - 1 EP - 13 PB - MDPI CY - Basel, Schweiz AN - OPUS4-57094 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Paul, Martin A1 - Tscheuschner, Georg A1 - Herrmann, Stefan A1 - Weller, Michael G. T1 - Fast Detection of 2,4,6-Trinitrotoluene (TNT) at ppt Level by a Laser-Induced Immunofluorometric Biosensor N2 - The illegal use of explosives by terrorists and other criminals is an increasing issue in public spaces, such as airports, railway stations, highways, sports venues, theaters, and other large buildings. Security in these environments can be achieved by different means, including the installation of scanners and other analytical devices to detect ultra-small traces of explosives in a very short time-frame to be able to take action as early as possible to prevent the detonation of such devices. Unfortunately, an ideal explosive detection system still does not exist, which means that a compromise is needed in practice. Most detection devices lack the extreme analytical sensitivity, which is nevertheless necessary due to the low vapor pressure of nearly all explosives. In addition, the rate of false positives needs to be virtually zero, which is also very difficult to achieve. Here we present an immunosensor system based on kinetic competition, which is known to be very fast and may even overcome affinity limitation, which impairs the performance of many traditional competitive assays. This immunosensor consists of a monolithic glass column with a vast excess of immobilized hapten, which traps the fluorescently labeled antibody as long as no explosive is present. In the case of the explosive 2,4,6-trinitrotoluene (TNT), some binding sites of the antibody will be blocked, which leads to an immediate breakthrough of the labeled protein, detectable by highly sensitive laser-induced fluorescence with the help of a Peltier-cooled complementary metal-oxide-semiconductor (CMOS) camera. Liquid handling is performed with high-precision syringe pumps and chip-based mixing-devices and flow-cells. The system achieved limits of detection of 1 pM (1 ppt) of the fluorescent label and around 100 pM (20 ppt) of TNT. The total assay time is less than 8 min. A cross-reactivity test with 5000 pM solutions showed no signal by pentaerythritol tetranitrate (PETN), 1,3,5-trinitroperhydro-1,3,5-triazine (RDX), and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX). This immunosensor belongs to the most sensitive and fastest detectors for TNT with no significant cross-reactivity by non-related compounds. The consumption of the labeled antibody is surprisingly low: 1 mg of the reagent would be sufficient for more than one year of continuous biosensor operation. KW - Airport KW - Aviation KW - Bombs KW - Terrorism KW - Biosensing KW - Continuous Sensor KW - High-Speed KW - Ultrasensitive PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-511245 DO - https://doi.org/10.3390/bios10080089 VL - 10 IS - 8 SP - 89 PB - MDPI CY - Basel AN - OPUS4-51124 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Costa, Elena A1 - Climent Terol, Estela A1 - Gawlitza, Kornelia A1 - Wan, Wei A1 - Weller, Michael G. A1 - Rurack, Knut T1 - Optimization of analytical assay performance of antibody-gated indicator-releasing mesoporous silica particles N2 - Antibody-gated indicator delivery (gAID) systems based on mesoporous silica nano- and microparticle scaffolds are a promising class of materials for the sensitive chemical detection of small-molecule analytes in simple test formats such as lateral flow assays (LFAs) or microfluidic chips. Their architecture is reminiscent of drug delivery systems, only that reporter molecules instead of drugs are stored in the voids of a porous host particle. In addition, the pores are closed with macromolecular “caps” through a tailored “gatekeeping” recognition chemistry so that the caps are opened when an analyte has reacted with a “gatekeeper”. The subsequent uncapping leads to a release of a large number of indicator molecules, endowing the system with signal amplification features. Particular benefits of such systems are their modularity and adaptability. With the example of the immunochemical detection of type-I pyrethroids by fluorescent dye-releasing gAID systems, the influence of several tuning modes on the optimisation of such hybrid sensory materials is introduced here. In particular, different mesoporous silica supports (from nano- and microparticles to platelets and short fibres), different functionalisation routes and different loading sequences were assessed. The materials’ performances were evaluated by studying their temporal response behaviour and detection sensitivity, including the tightness of pore closure (through the amount of blank release in the absence of analyte) and the release kinetics. Our results indicate that the better the paratope-accommodating Fab region of the antibody “cap” fits into the host material's pore opening, the better the closing/opening mechanism can be controlled. Because such materials are well-suited for LFAs, performance assessment included a test-strip format besides conventional assays in suspension. In combination with dyes as indicators and smartphones for read-out, simple analytical tests for use by untrained personnel directly at a point-of-need such as an aeroplane cabin can be devised, allowing for sensitivities down to the μg kg−1 range in <5 min with case-required selectivities. KW - Antibody-gated indicator delivery KW - Lateral flow assay KW - SBA-15 KW - SBA-16 KW - Type-I pyrethroids KW - Phenothrin KW - Permethrin KW - Etofenprox KW - Amplification KW - Biosensors KW - Immunoassays KW - Mesoporous particles KW - Optical detection PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517053 DO - https://doi.org/10.1039/d0tb00371a VL - 8 IS - 22 SP - 4950 EP - 4961 PB - Royal Society of Chemistry AN - OPUS4-51705 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tscheuschner, Georg A1 - Schwaar, Timm A1 - Weller, Michael G. T1 - Fast Confirmation of Antibody Identity by MALDI-TOF MS Fingerprints N2 - Thousands of antibodies for diagnostic and other analytical purposes are on the market. However, it is often difficult to identify duplicates, reagent changes, and to assign the correct original publications to an antibody. This slows down scientific progress and might even be a cause of irreproducible research and a waste of resources. Recently, activities were started to suggest the sole use of recombinant antibodies in combination with the open communication of their sequence. In this case, such uncertainties should be eliminated. Unfortunately, this approach seems to be rather a long-term vision since the development and manufacturing of recombinant antibodies remain quite expensive in the foreseeable future. Nearly all commercial antibody suppliers also may be reluctant to publish the sequence of their antibodies, since they fear counterfeiting. De novo sequencing of antibodies is also not feasible today for a reagent user without access to the hybridoma clone. Nevertheless, it seems to be crucial for any scientist to have the opportunity to identify an antibody undoubtedly to guarantee the traceability of any research activity using antibodies from a third party as a tool. For this purpose, we developed a method for the identification of antibodies based on a MALDI-TOF MS fingerprint. To circumvent lengthy denaturation, reduction, alkylation, and enzymatic digestion steps, the fragmentation was performed with a simple formic acid hydrolysis step. Eighty-nine unknown monoclonal antibodies were used for this study to examine the feasibility of this approach. Although the molecular assignment of peaks was rarely possible, antibodies could be easily recognized in a blinded test, simply from their mass-spectral fingerprint. A general protocol is given, which could be used without any optimization to generate fingerprints for a database. We want to propose that, in most scientific projects relying critically on antibody reagents, such a fingerprint should be established to prove and document the identity of the used antibodies, as well as to assign a specific reagent to a datasheet of a commercial supplier, public database record, or antibody ID. KW - Reproducibility KW - Quality Control KW - Traceability KW - Diagnostics KW - Hybridoma KW - Monoclonal Antibody KW - Recombinant Antibody PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506611 DO - https://doi.org/10.3390/antib9020008 SN - 2073-4468 VL - 9 IS - 2 SP - 1 EP - 17 PB - MDPI CY - Basel AN - OPUS4-50661 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ziegler, K. A1 - Kunert, A. T. A1 - Reinmuth-Selzle, K. A1 - Leifke, A. L. A1 - Widera, D. A1 - Weller, Michael G. A1 - Schuppan, D. A1 - Fröhlich-Nowoisky, J. A1 - Lucas, K. A1 - Pöschl, U. T1 - Chemical modification of pro-inflammatory proteins by peroxynitrite increases activation of TLR4 and NF-κB: Implications for the health effects of air pollution and oxidative stress N2 - Environmental pollutants like fine particulate matter can cause adverse health effects through oxidative stress and inflammation. Reactive oxygen and nitrogen species (ROS/RNS) such as peroxynitrite can chemically modify proteins, but the effects of such modifications on the immune system and human health are not well understood. In the course of inflammatory processes, the Toll-like receptor 4 (TLR4) can sense damage-associated molecular patterns (DAMPs). Here, we investigate how the TLR4 response and pro-inflammatory potential of the proteinous DAMPs α-Synuclein (α-Syn), heat shock protein 60 (HSP60), and high-mobility-group box 1 protein (HMGB1), which are relevant in neurodegenerative and cardiovascular diseases, changes upon chemical modification with peroxynitrite. For the peroxynitrite-modified proteins, we found a strongly enhanced activation of TLR4 and the pro-inflammatory transcription factor NF-κB in stable reporter cell lines as well as increased mRNA expression and secretion of the pro-inflammatory cytokines TNF-α, IL-1β, and IL-8 in human monocytes (THP-1). This enhanced activation of innate immunity via TLR4 is mediated by covalent chemical modifications of the studied DAMPs. Our results show that proteinous DAMPs modified by peroxynitrite more potently amplify inflammation via TLR4 activation than the native DAMPs, and provide first evidence that such modifications can directly enhance innate immune responses via a defined receptor. These findings suggest that environmental pollutants and related ROS/RNS may play a role in promoting acute and chronic inflammatory disorders by structurally modifying the body's own DAMPs. This may have important consequences for chronic neurodegenerative, cardiovascular or gastrointestinal diseases that are prevalent in modern societies, and calls for action, to improve air quality and climate in the Anthropocene. KW - Protein nitration KW - Protein oligomerization KW - Damage-associated molecular patterns (DAMPs) KW - Pattern recognition receptor KW - Anthropocene KW - Environmental pollutants PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517128 DO - https://doi.org/10.1016/j.redox.2020.101581 VL - 37 SP - 101581 PB - Elsevier B.V. AN - OPUS4-51712 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Brangsch, J. A1 - Reimann, C. A1 - Kaufmann, Jan Ole A1 - Adams, L. C. A1 - Onthank, D. A1 - Thöne-Reineke, C. A1 - Robinson, S. A1 - Ponader, Marco A1 - Weller, Michael G. A1 - Buchholz, R. A1 - Karst, U. A1 - Botnar, R. A1 - Hamm, B. A1 - Makowski, M. R. T1 - Molecular MR-Imaging for Noninvasive Quantification of the Anti-Inflammatory Effect of Targeting Interleukin-1β in a Mouse Model of Aortic Aneurysm N2 - Background: Molecular-MRI is a promising imaging modality for the assessment of abdominal aortic aneurysms (AAAs). Interleukin-1β (IL-1β) represents a new therapeutic tool for AAA-treatment, since pro-inflammatory cytokines are key-mediators of inflammation. This study investigates the potential of molecular-MRI to evaluate therapeutic effects of an anti-IL-1β-therapy on AAA-formation in a mouse-model. Methods: Osmotic-minipumps were implanted in apolipoprotein-deficient-mice (N = 27). One group (Ang-II+01BSUR group, n = 9) was infused with angiotensin-II (Ang-II) for 4 weeks and received an anti-murine IL-1β-antibody (01BSUR) 3 times. One group (Ang-II-group, n = 9) was infused with Ang-II for 4 weeks but received no treatment. Control-group (n = 9) was infused with saline and received no treatment. MR-imaging was performed using an elastin-specific gadolinium-based-probe (0.2 mmol/kg). Results: Mice of the Ang-II+01BSUR-group showed a lower aortic-diameter compared to mice of the Ang-II-group and control mice (p < 0.05). Using the elastin-specific-probe, a significant decrease in elastin-destruction was observed in mice of the Ang-II+01BSUR-group. In vivo MR-measurements correlated well with histopathology (y = 0.34x-13.81, R2 = 0.84, p < 0.05), ICP-MS (y = 0.02x+2.39; R2 = 0.81, p < 0.05) and LA-ICP-MS. Immunofluorescence and western-blotting confirmed a reduced IL-1β-expression. Conclusions: Molecular-MRI enables the early visualization and quantification of the anti-inflammatory-effects of an IL-1β-inhibitor in a mouse-model of AAAs. Responders and non-responders could be identified early after the initiation of the therapy using molecular-MRI. KW - Cardiovascular KW - Molecular-MRI KW - Magnetic resonance imaging KW - Gadolinium-based contrast agent KW - Elastin-specific contrast agent ESMA KW - Gadovist KW - Gadofosveset KW - MR Angiography KW - Inductively Coupled Mass Spectroscopy KW - Element Specific Bioimaging Using Laser Ablation KW - Visualization PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517150 DO - https://doi.org/10.1177/1536012120961875 N1 - Geburtsname von Ponader, Marco: Wilke, M. - Birth name of Ponader, Marco: Wilke, M. VL - 19 SP - 61875 PB - SAGE AN - OPUS4-51715 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weller, Michael G. T1 - The Protocol Gap N2 - Although peer review is considered one of the main pillars of modern science, experimental methods and protocols seem to be not a rigorous subject of this process in many papers. Commercial equipment, test kits, labeling kits, previously published concepts, and standard protocols are often considered to be not worth a detailed description or validation. Even more disturbing is the extremely biased citation behavior in this context, which sometimes leads to surrogate citations to avoid low-impact journals, preprints, or to indicate traditional practices. This article describes some of these surprising habits and suggests some measures to avoid the most unpleasant effects, which in the long term may undermine the credibility of science as a whole. KW - Validation KW - Peer review KW - Experiment KW - Documentation KW - Scientific publication KW - Reproducibility crisis KW - Replication crisis KW - Trust KW - Citation KW - References KW - Surrogate citations KW - Impact PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521440 DO - https://doi.org/10.3390/mps4010012 SN - 2409-9279 VL - 4 IS - 1 SP - 1 EP - 5 PB - MDPI CY - Basel AN - OPUS4-52144 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chapartegui-Arias, Ander A1 - Raysyan, A. A1 - Belenguer, A. M. A1 - Jaeger, Carsten A1 - Tchipilov, Teodor A1 - Prinz, Carsten A1 - Abad Andrade, Carlos Enrique A1 - Beyer, S. A1 - Schneider, Rudolf A1 - Emmerling, Franziska T1 - Tailored mobility in a zeolite imidazolate framework (ZIF) antibody conjugate N2 - Zeolitic imidazolate framework (ZIF) hybrid fluorescent nanoparticles and ZIF antibody conjugates have been synthesized, characterized, and employed in lateral-flow immunoassay (LFIA). The bright fluorescence of the conjugates and the possibility to tailor their mobility gives a huge potential for diagnostic assays. An enzyme-linked immunosorbent assay (ELISA) with horseradish peroxidase (HRP) as label, proved the integrity, stability, and dispersibility of the antibody conjugates, LC-MS/MS provided evidence that a covalent link was established between these metal-organic frameworks and lysine residues in IgG antibodies. KW - ZIF KW - ELISA PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-532096 DO - https://doi.org/10.1002/chem.202100803 SN - 0947-6539 SN - 1521-3765 VL - 27 IS - 36 SP - 9414 EP - 9421 PB - Wiley-VCH CY - Weinheim AN - OPUS4-53209 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fischer, Janina A1 - Kaufmann, Jan Ole A1 - Weller, Michael G. T1 - Simple Determination of Affinity Constants of Antibodies by Competitive Immunoassays N2 - The affinity constant, also known as the equilibrium constant, binding constant, equilibrium association constant, or the reciprocal value, the equilibrium dissociation constant (Kd), can be considered as one of the most important characteristics for any antibody–antigen pair. Many methods based on different technologies have been proposed and used to determine this value. However, since a very large number of publications and commercial datasheets do not include this information, significant obstacles in performing such measurements seem to exist. In other cases where such data are reported, the results have often proved to be unreliable. This situation may indicate that most of the technologies available today require a high level of expertise and effort that does not seem to be available in many laboratories. In this paper, we present a simple approach based on standard immunoassay technology that is easy and quick to perform. It relies on the effect that the molar IC50 approaches the Kd value in the case of infinitely small concentrations of the reagents. A two-dimensional dilution of the reagents leads to an asymptotic convergence to Kd. The approach has some similarity to the well-known checkerboard titration used for the optimization of immunoassays. A well-known antibody against the FLAG peptide, clone M2, was used as a model system and the results were compared with other methods. This approach could be used in any case where a competitive assay is available or can be developed. The determination of an affinity constant should belong to the crucial parameters in any quality control of antibody-related products and assays and should be mandatory in papers using immunochemical protocols. N2 - Die Affinitätskonstante, auch bekannt als Gleichgewichtskonstante, Bindungskonstante, Gleichgewichtsassoziationskonstante oder der reziproke Wert, die Gleichgewichtsdissoziationskonstante (Kd), kann als eine der wichtigsten Eigenschaften für jedes Antikörper-Antigen-Paar angesehen werden. Zur Bestimmung dieses Wertes wurden zahlreiche Methoden auf der Grundlage verschiedener Technologien vorgeschlagen und verwendet. Da jedoch eine sehr große Anzahl von Veröffentlichungen und kommerziellen Datenblätter diese Information nicht enthalten, scheint es erhebliche Hindernisse bei der Durchführung solcher Messungen zu geben. In anderen Fällen, in denen solche Daten angegeben werden, haben sich die Ergebnisse häufig als unzuverlässig erwiesen. Diese Situation könnte darauf hindeuten, dass die meisten der heute verfügbaren Technologien ein hohes Maß an Fachwissen und Aufwand erfordern, das in vielen Labors nicht vorhanden zu sein scheint. In diesem Beitrag stellen wir einen einfachen Ansatz vor, der auf der Standard-Immunoassay-Technologie basiert und einfach und schnell durchführbar ist. Er beruht auf dem Effekt, dass sich der molare IC50 bei unendlich kleinen Reagenz-Konzentrationen dem Kd-Wert annähert. Eine zweidimensionale Verdünnung der Reagenzien führt zu einer asymptotischen Konvergenz zu Kd. Der Ansatz hat eine gewisse Ähnlichkeit mit der bekannten Checkerboard-Titration, die zur Optimierung von Immunoassays verwendet wird. Ein bekannter Antikörper gegen das FLAG-Peptid, Klon M2, wurde als Modellsystem verwendet, und die Ergebnisse wurden mit anderen Methoden verglichen. Dieser Ansatz kann überall dort angewendet werden, wo ein kompetitiver Assay verfügbar ist oder entwickelt werden kann. Die Bestimmung einer Affinitätskonstante sollte zu den entscheidenden Parametern bei der Qualitätskontrolle von Antikörperprodukten und -assays gehören und in Arbeiten, die immunchemische Protokolle verwenden, obligatorisch sein. KW - ELISA KW - Competitive immunoassay KW - IC50 KW - Test midpoint KW - Point of inflection KW - Equilibrium constant KW - Dissociation constant KW - Binding strength KW - Antibody antigen complex KW - Bio-interaction KW - SPR KW - Surface-plasmon resonance KW - FLAG peptide KW - Clone M2 KW - Antibody quality PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-605607 DO - https://doi.org/10.3390/mps7030049 SN - 2409-9279 VL - 7 IS - 3 SP - 1 EP - 11 PB - MDPI CY - Basel AN - OPUS4-60560 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Becker, Roland A1 - Altmann, Korinna A1 - Sommerfeld, Thomas A1 - Braun, Ulrike T1 - Quantification of microplastics in a freshwater suspended organic matter using different thermoanalytical methods – outcome of an interlaboratory comparison N2 - A sedimented freshwater suspended organic matter fortified with particles of polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyethylene terephthalate (PET) was employed in an interlaboratory comparison of thermoanalytical methods for microplastics identification and quantification. Three laboratories performed pyrolysis gas chromatography-mass spectrometry (Py-GC-MS), three others provided results using thermal extraction desorption followed by gas chromatography coupled to mass spectrometry (TED-GC-MS). One participant performed thermogravimetry-infrared spectroscopy (TGA-FTIR) and two participants used thermogravimetry coupled to mass spectrometry (TGA-MS). Further participants used differential scanning microscopy (DSC), a procedure based on micro combustion calorimetry (MCC) and a procedure based on elemental analysis. Each participant employed a different combination of sample treatment, calibration and instrumental Settings for polymer identification and quantification. Though there is obviously room for improvements regarding the between-laboratory reproducibility and the harmonization of procedures it was seen that the participants Performing Py-GC-MS, TED-GC-MS, and TGA-FTIR were able to correctly identify all polymers and to report reasonable quantification results in the investigated concentration range (PE: 20.0 μg/mg, PP: 5.70 μg/mg; PS: 2.20 μg/mg, PET: 18.0 μg/mg). Although for the other methods limitations exists regarding the detection of specific polymers, they showed potential as alternative approaches for polymer quantification in solid environmental matrices. KW - Interlaboratory comparison KW - Microplastics KW - Suspended organic matter KW - Pyrolysis PY - 2020 DO - https://doi.org/10.1016/j.jaap.2020.104829 VL - 148 SP - 1 EP - 6 PB - Elsevier B.V. AN - OPUS4-50977 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fünning, Tabea A1 - Peczek, Anna A1 - Kroh, Aleksandra A1 - Mai, Christian A1 - Paul, Martin A1 - Thomsen, Florian A1 - Tannenberg, Robert A1 - Schumann, Christoph A1 - Weller, Michael G. A1 - Mai, Andreas A1 - Steglich, Patrick C. ED - Lieberman, Robert A. ED - Baldini, Francesco ED - Homola, Jiri T1 - Optimization of local backside released micro-ring resonators for sensing applications using silicon photonic integrated circuits in a SOI technology N2 - Photonic micro-ring resonators (MRR) are widely studied for their high sensitivity across applications like environmental monitoring, healthcare, and chemical analysis. Their evanescent field sensing requires partially unembedded waveguides compatible with CMOS processing. Our approach uses local backside etching with an additional buried oxide (BOX) etch to release waveguides while preserving the back-end of line (BEOL) structure, enabling spatial separation of the sensing area and electronics. The BOX etch critically affects sensor performance, as waveguide surface roughness can alter MRR properties and coupling. We analyzed MRR design variations, comparing wet and dry etching techniques for their effects on optical performance across rib and strip waveguides in quasi-TE and quasi-TM modes. Wafer-level measurements show that backside-released MRR achieve high extinction ratios with slightly reduced quality factors, advancing high-sensitivity photonic sensors. T2 - SPIE Optics + Optoelectronics 2025 CY - Prague, Czech Republic DA - 23.05.2025 KW - Photonic sensors KW - Micro-ring resonator (MRR) KW - Silicon on insulator (SOI) KW - CMOS KW - Local backside etching PY - 2025 SN - 978-1-5106-8851-3 DO - https://doi.org/10.1117/12.3056481 VL - 13527 SP - 1 EP - 8 PB - SPIE CY - Bellingham, WA , USA AN - OPUS4-63585 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Steglich, Patrick A1 - Paul, Martin A1 - Fünning, Tabea A1 - Schumann, Christoph A1 - Mai, Christian A1 - Tannenberg, Robert A1 - Mai, Andreas ED - Cheben, Pavel ED - Čtyroký, Jiří ED - Molina-Fernández, Iñigo T1 - Towards monolithic integration of polymer-based electro-optical devices in silicon photonic integrated circuits using a 250nm SOI technology N2 - Photonic micro-ring resonators (MRR) are widely studied for their high sensitivity across applications like environmental monitoring, healthcare, and chemical analysis. Their evanescent field sensing requires partially unembedded waveguides compatible with CMOS processing. Our approach uses local backside etching with an additional buried oxide (BOX) etch to release waveguides while preserving the back-end of line (BEOL) structure, enabling spatial separation of the sensing area and electronics. The BOX etch critically affects sensor performance, as waveguide surface roughness can alter MRR properties and coupling. We analyzed MRR design variations, comparing wet and dry etching techniques for their effects on optical performance across rib and strip waveguides in quasi-TE and quasi-TM modes. Wafer-level measurements show that backside-released MRR achieve high extinction ratios with slightly reduced quality factors, advancing high-sensitivity photonic sensors. T2 - SPIE Optics + Optoelectronics 2025 CY - Prague, Czech Republic DA - 05.06.2025 KW - Photonic sensors KW - Micro-ring resonator (MRR) KW - Silicon on insulator (SOI) KW - CMOS KW - Local backside etching (LBE) PY - 2025 DO - https://doi.org/10.1117/12.3056280 VL - 13530 SP - 1 EP - 8 PB - SPIE CY - Bellingham, WA , USA AN - OPUS4-63587 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schumann, Christoph T1 - Design and optimization of integrated multimode interferometers (MMIs) for dual-polarization photonic biosensors for biomedical applications in a silicon-on-insulator platform N2 - Faster, more sensitive, and cost-efficient diagnostic tests are crucial, as conventional lab tests are slow and expensive, while rapid tests often lack specificity. Advancements in medical diagnostics are crucial for early disease detection, reducing costs and testing time. Optical biosensors, particularly multimode interferometers (MMIs), offer high sensitivity and integration potential for Point-of-Care applications [1-2]. This work introduces a novel MMI biosensor utilizing orthogonal TE and TM modes, significantly minimizing the footprint. T2 - SPIE Optics + Optoelectronics 2025 CY - Prague, Czech Republic DA - 23.05.2025 KW - Interferometry KW - Semiconductor KW - Chip KW - Point-of-Care applications KW - Biomarker PY - 2025 UR - https://www.spiedigitallibrary.org/conference-proceedings-of-spie/PC13527/PC135270R/Design-and-optimization-of-integrated-multimode-interferometers-MMIs-for-dual/10.1117/12.3056490.short DO - https://doi.org/10.1117/12.3056490 AN - OPUS4-63568 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Döring, Sarah T1 - Surface Immobilization of Recombinant Trypsin onto Corundum Particles for Optimized Antibody Digestion N2 - Therapeutic monoclonal antibodies are the fastest-growing class of biological agents and the development of reliable analytical methods for their quantification is becoming increasingly important. Liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS) represents one of the leading technologies for antibody quantification. The serin protease trypsin has emerged as the gold standard enzyme for digesting intact protein into peptides for this approach. However, many protocols exist that often lead to different results depending on the digestion procedure. In particular, the type and amounts of detergents added during sample preparation for protein unfolding before digestion is known to create undesirable structure modifications of proteins (e.g. carbamylation) and significant bias in measurement results by inhibiting enzyme activity. The source and nature of the enzyme itself can also have an influence, whereby immobilized variants are increasingly being used to improve their stability, minimize self-digestion and enable a higher substrate-enzyme ratio. Here, we explored the potential of a novel thermostable trypsin and surface-functionalised corundum particles for enhanced antibody digestion. For this purpose, the inactive zymogen was recombinantly produced in E. coli, activated with enterokinase digestion and finally affinity purified by benzamidine purification. The enzyme activity was analogous to commercially available MS-grade trypsin product. In addition, produced trypsin showed increased thermal stability under typical digestion conditions compared to reference product. Furthermore, APTES-silanization followed by glutaraldehyde modification of corundum surface with an additional blocking step prevents nonspecific protein adsorption during the protein digestion procedure and the immobilized enzyme still showed substrate activity after covalent binding. Compared to wild-type and a non-immobilized enzyme, the surface-functionalized thermostable variant showed increased activity at elevated temperatures. Thus, this novel type of trypsin particles promises to not only improve antibody digestion at high temperatures, but also to prevent self-digestion and enable the separation of trypsin from target peptides in LC–MS analysis. T2 - ANAKON 2025 CY - Leipzig, Germany DA - 10.03.2025 KW - Antibody Quantification KW - Corundum KW - Enzyme Immobilization KW - LC-MS/MS PY - 2025 AN - OPUS4-63480 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tannenberg, Robert T1 - Troponin I Assay in Wafer-Level Backside Optofluidics N2 - Cardiovascular diseases are the number one cause of death worldwide and responsible for 17.9 million casualities worldwide in 2019. Cardiac Troponin I (cTnI) is the most important biomarker for acute events such as heart attacks. The development of novel photonic integrated microchips (PIC) is a promising approach to allow the convenient detection of key biomarkers in complex matrices through multichannel real-time analysis in a highly compact package. This study presents the development and proof-of-concept of a backside released CMOS chip designed for the multichannel real-time detection of biomarkers. In this work, we introduce a Troponin I assay as well that utilizes a potential and practical approach to backside optofluidics on a wafer-level platform. T2 - Biosensors 2025 - 35th Anniversary World Congress on Biosensors CY - Lisbon, Portugal DA - 19.05.2025 KW - Ring resonator KW - Semiconductor KW - CMOS KW - cTnI KW - Heart attack KW - Biomarker KW - Sandwich immunoassay PY - 2025 AN - OPUS4-63481 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tannenberg, Robert T1 - Multichannel real-time detection of biomarkers with highly miniaturized photonic microchips N2 - The development of novel photonic microchips is a promising approach to advance the detection of biomarkers through multichannel real-time analysis. This study reports the successful development of a backside released CMOS chip designed for the multichannel real-time detection of biomarkers. Operating at a wavelength of 1550 nm, the microchip features three detection channels in addition to a reference channel, enabling simultaneous analysis of multiple biomarkers. The microchip incorporates micro-ring resonators that are directly functionalized with specific bioreceptors, which significantly improves the affinity towards target biomarkers. The employed surface functionalization strategy enables versatile immobilization of receptor molecules and serves as a starting point for various analytical applications. A tunable laser is utilized as the excitation source, providing precise wavelength tuning and stable optical output, essential for achieving optimal resonance conditions within the micro-ring resonators. Our chips use integrated multi-mode interferometers as beam-splitter, grating coupler and Ge-photodiodes, resulting in an ultra-small footprint. The complete chip including metal pads has an area of 1 mm2. The results indicate that the developed multichannel photonic microchip system enables online detection of multiple biomarkers. The compact and highly miniaturized design of this microchip positions them as promising candidates for point-of-care diagnostics and personalized medicine applications. With further advancements, this technology opens a path to transform biomarker detection across various medical fields, offering rapid, reliable, and cost-effective diagnostic solutions. In conclusion, the presented multichannel photonic microchips signify a substantial leap forward in real-time biomarker detection, providing a robust platform for future research and clinical applications. T2 - SPIE Optics + Optoelectronics 2025 CY - Prague, Czech Republic DA - 07.04.2025 KW - Biosensor KW - Optics KW - Silicon semiconductor KW - Proteins KW - Clinical chemistry PY - 2025 AN - OPUS4-62954 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Döring, Sarah T1 - Optimization of Polymer Interface: Novel Surface-functionalized Corundum Particles for Improved Antibody Digestion N2 - Therapeutic monoclonal antibodies are the fastest-growing class of biological agents and the development of reliable analytical methods for their quantification is becoming increasingly important. Liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS) represents one of the leading technologies for antibody quantification. The serin protease trypsin has emerged as the gold standard enzyme for digesting intact protein into peptides for this approach. However, many protocols exist that often lead to different results. The talk will provide a brief introduction to the application of novel thermostable and surface-functionalized trypsin particles for improved antibody digestion as well as initial successes in polymer functionalization of the corundum surface to prevent nonspecific protein adsorption during the digestion procedure. T2 - SALSA Make and Measure 2024: Interfaces CY - Berlin, Germany DA - 11.09.2024 KW - Antibody Quantification KW - Recombinant Enzymes KW - LC-MS/MS KW - Enzyme Immobilisation KW - Surface Functionalisation KW - Corundum PY - 2024 AN - OPUS4-61041 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Döring, Sarah T1 - Sequence of Mus Musculus monoclonal IgG2c anti-CCMV Immunoglobulin N2 - We report the full-length nucleotide and amino acid sequences of the light (κ) and heavy chain of the IgG2c anti-CCMV monoclonal antibody (hybridoma clone BAM-CCMV-29-81), generated against Cowpea Chlorotic Mottle Virus (CCMV). Sequencing of hybridoma clone was performed using a cost-effective Sanger-based workflow that includes DNA-level subclass determination and peptide mass fingerprint confirmation. The κ-chain sequence was assigned to IGKV4-6101 / IGKJ101, while the heavy chain was assigned to IGHV2-601 / IGHD1-101 / IGHJ3*01 with IgG2c constant regions from the NOD strain. Both chains were validated against RNA Illumina sequencing, confirming 100% identity. The sequences are available in GenBank under accession numbers PX123807 (κ-chain) and PX123808 (heavy chain). KW - Antibody Sequencing KW - BAM-CCMV-29-81 KW - anti-CCMV-antibody PY - 2025 UR - https://www.ncbi.nlm.nih.gov/nuccore/PX123807 UR - https://www.ncbi.nlm.nih.gov/nuccore/PX123808 PB - National Library of Medicine CY - Bethesda AN - OPUS4-63968 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - INPR A1 - Fischer, Janina A1 - Kaufmann, Jan Ole A1 - Weller, Michael G. T1 - Simple Determination of Affinity Constants of Antibodies by Competitive Immunoassays N2 - The affinity constant, also known as the equilibrium constant, binding constant, equilibrium association constant, or the reciprocal value, the equilibrium dissociation constant (Kd), can be considered as one of the most important characteristics for any antibody-antigen pair. Many methods based on different technologies have been proposed and used to determine this value. However, since a very large number of publications and commercial datasheets do not include this nformation, significant obstacles in performing such measurements seem to exist. In other cases where such data are reported, the results have often proved to be unreliable. This situation may indicate that most of the technologies available today require a high level of expertise that does not seem to be available in many laboratories. In this paper, we present a simple approach based on standard immunoassay technology that is easy and quick to perform. It relies on the effect that the molar IC50 approaches the Kd value in the case of infinitely small concentrations of the reagent concentrations. A two-dimensional dilution of the reagents leads to an asymptotic convergence to Kd. The approach has some similarity to the well-known checkerboard titration used for the optimization of immunoassays. A well-known antibody against the FLAG peptide, clone M2, was used as a model system and the results were compared with other methods. This approach could be used in any case where a competitive assay is available or can be developed. The determination of an affinity constant should belong to the crucial parameters in any quality control of antibody-related products and assays and should be mandatory in papers using immunochemical protocols. N2 - Die Affinitätskonstante, auch bekannt als Gleichgewichtskonstante, Bindungskonstante, Gleichgewichtsassoziationskonstante oder der Kehrwert, die Gleichgewichtsdissoziationskonstante (Kd), kann als eine der wichtigsten Eigenschaften für jedes Antikörper-Antigen-Paar angesehen werden. Es wurden viele Methoden auf der Grundlage verschiedener Technologien vorgeschlagen und verwendet, um diesen Wert zu bestimmen. Da jedoch eine sehr große Anzahl von Veröffentlichungen und kommerziellen Datenblättern diese Informationen nicht enthalten, scheint es erhebliche Hindernisse bei der Durchführung solcher Messungen zu geben. In anderen Fällen, in denen solche Daten angegeben werden, haben sich die Ergebnisse oft als unzuverlässig erwiesen. Diese Situation könnte darauf hindeuten, dass die meisten der heute verfügbaren Technologien ein hohes Maß an Fachwissen erfordern, das in vielen Laboren nicht vorhanden zu sein scheint. In diesem Artikel stellen wir einen einfachen Ansatz vor, der auf der Standard-Immunoassay-Technologie basiert und einfach und schnell durchzuführen ist. Er beruht auf dem Effekt, dass sich der molare IC50-Wert dem Kd-Wert im Fall unendlich kleiner Konzentrationen der Reagenzienkonzentrationen nähert. Eine zweidimensionale Verdünnung der Reagenzien führt zu einer asymptotischen Konvergenz zu Kd. Der Ansatz weist eine gewisse Ähnlichkeit mit der bekannten Schachbrett-Titration auf, die zur Optimierung von Immunoassays verwendet wird. Ein bekannter Antikörper gegen das FLAG-Peptid, Klon M2, wurde als Modellsystem verwendet und die Ergebnisse wurden mit anderen Methoden verglichen. Dieser Ansatz kann in allen Fällen verwendet werden, in denen ein kompetitiver Test verfügbar ist oder entwickelt werden kann. Die Bestimmung einer Affinitätskonstante sollte zu den entscheidenden Parametern in jeder Qualitätskontrolle von Antikörper-bezogenen Produkten und Tests gehören und in Veröffentlichungen, die immunchemische Protokolle verwenden, obligatorisch sein. KW - ELISA KW - Microplate KW - Microtiter plate KW - IC50 KW - Test midpoint KW - Competitive immunoassay KW - Law of mass action KW - Thermodynamics KW - Equilibrium constant KW - SPR KW - Surface plasmon resonance KW - Clones KW - Interaction KW - kd value KW - ITC KW - MST PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621298 DO - https://doi.org/10.20944/preprints202404.0996.v1 SN - 2310-287X SP - 1 EP - 11 PB - MDPI CY - Basel AN - OPUS4-62129 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Möckel, J. A1 - Brangsch, J. A1 - Reimann, C. A1 - Kaufmann, Jan Ole A1 - Sack, I. A1 - Mangarova, D. B. A1 - Kader, A. A1 - Taupitz, M. A1 - Adams, L. C. A1 - Keller, S. A1 - Ludwig, A. A1 - Hamm, B. A1 - Botnar, R. M. A1 - Makowski, M. R. T1 - Assessment of Albumin ECM Accumulation and Inflammation as Novel In Vivo Diagnostic Targets for Multi-Target MR Imaging N2 - Atherosclerosis is a progressive inflammatory vascular disease characterized by endothelial dysfunction and plaque burden. Extracellular matrix (ECM)-associated plasma proteins play an important role in disease development. Our magnetic resonance imaging (MRI) study investigates the feasibility of using two different molecular MRI probes for the simultaneous assessment of ECM-associated intraplaque albumin deposits caused by endothelial damage and progressive inflammation in atherosclerosis. Male apolipoprotein E-deficient (ApoE-/-)-mice were fed a high-fat diet (HFD) for 2 or 4 months. Another ApoE-/--group was treated with pravastatin and received a HFD for 4 months. T1- and T2*-weighted MRI was performed before and after albumin-specific MRI probe (gadofosveset) administration and a macrophage-specific contrast agent (ferumoxytol). Thereafter, laser ablation inductively coupled plasma mass spectrometry and histology were performed. With advancing atherosclerosis, albumin-based MRI signal enhancement and ferumoxytol-induced signal loss areas in T2*-weighted MRI increased. Significant correlations between contrast-to-noise-ratio (CNR) post-gadofosveset and albumin stain (R2 = 0.78, p < 0.05), and signal loss areas in T2*-weighted MRI with Perls’ Prussian blue stain (R2 = 0.83, p < 0.05) were observed. No interference of ferumoxytol with gadofosveset enhancement was detectable. Pravastatin led to decreased inflammation and intraplaque albumin. Multi-target MRI combining ferumoxytol and gadofosveset is a promising method to improve diagnosis and treatment monitoring in atherosclerosis. KW - Magnetic resonance imaging KW - MRI KW - Imaging KW - Human serum albumin KW - Extracellular matrix KW - Macrophages KW - Contrast agent KW - Atherosclerotic plaques KW - Gadofosveset KW - Aneurysm PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-536725 DO - https://doi.org/10.3390/biology10100964 VL - 10 IS - 10 SP - 1 EP - 16 PB - MDPI CY - Basel AN - OPUS4-53672 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Backes, A. T. A1 - Reinmuth-Selzle, K. A1 - Leifke, A. L. A1 - Ziegler, K. A1 - Krevert, C. S. A1 - Tscheuschner, Georg A1 - Lucas, K. A1 - Weller, Michael G. A1 - Berkemeier, T. A1 - Pöschl, U. A1 - Fröhlich-Nowoisky, J. T1 - Oligomerization and Nitration of the Grass Pollen Allergen Phl p 5 by Ozone, Nitrogen Dioxide, and Peroxynitrite: Reaction Products, Kinetics, and Health Effects N2 - The allergenic and inflammatory potential of proteins can be enhanced by chemical modification upon exposure to atmospheric or physiological oxidants. The molecular mechanisms and kinetics of such modifications, however, have not yet been fully resolved. We investigated the oligomerization and nitration of the grass pollen allergen Phl p 5 by ozone (O3), nitrogen dioxide (NO2), and peroxynitrite (ONOO–). Within several hours of exposure to atmospherically relevant concentration levels of O3 and NO2, up to 50% of Phl p 5 were converted into protein oligomers, likely by formation of dityrosine cross-links. Assuming that tyrosine residues are the preferential site of nitration, up to 10% of the 12 tyrosine residues per protein monomer were nitrated. For the reaction with peroxynitrite, the largest oligomer mass fractions (up to 50%) were found for equimolar concentrations of peroxynitrite over tyrosine residues. With excess peroxynitrite, the nitration degrees increased up to 40% whereas the oligomer mass fractions decreased to 20%. Our results suggest that protein oligomerization and nitration are competing processes, which is consistent with a two-step mechanism involving a reactive oxygen intermediate (ROI), as observed for other proteins. The modified proteins can promote pro-inflammatory cellular signaling that may contribute to chronic inflammation and allergies in response to air pollution. KW - Protein KW - Nitrotyrosine KW - Dityrosine KW - Allergy KW - Hay fever KW - Diesel exhaust KW - Combustion KW - Exhaust PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-529729 DO - https://doi.org/10.3390/ijms22147616 VL - 22 IS - 14 PB - MDPI CY - Basel AN - OPUS4-52972 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Adams, L. C. A1 - Brangsch, J. A1 - Reimann, C. A1 - Kaufmann, Jan Ole A1 - Buchholz, R. A1 - Karst, U. A1 - Botnar, R. M. A1 - Hamm, B. A1 - Makowski, M. R. T1 - Simultaneous molecular MRI of extracellular matrix collagen and inflammatory activity to predict abdominal aortic aneurysm rupture N2 - Abdominal aortic aneurysm (AAA) is a life-threatening vascular disease with an up to 80% mortality in case of rupture. Current biomarkers fail to account for size-independent risk of rupture. By combining the information of different molecular probes, multi-target molecular MRI holds the potential to enable individual characterization of AAA. In this experimental study, we aimed to examine the feasibility of simultaneous imaging of extracellular collagen and inflammation for size-independent prediction of risk of rupture in murine AAA. The study design consisted of: (1) A outcome-based longitudinal study with imaging performed once after one week with follow-up and death as the end-point for assessment of rupture risk. (2) A week-by-week study for the characterization of AAA development with imaging after 1, 2, 3 and 4 weeks. For both studies, the animals were administered a type 1 collagen-targeted gadolinium-based probe (surrogate marker for extracellular matrix (ECM) remodeling) and an iron oxide-based probe (surrogate marker for inflammatory activity), in one imaging session. In vivo measurements of collagen and iron oxide probes showed a significant correlation with ex vivo histology (p < 0.001) and also corresponded well to inductively-coupled plasma-mass spectrometry and laser-ablation inductively-coupled plasma mass spectrometry. Combined evaluation of collagen-related ECM remodeling and inflammatory activity was the most accurate predictor for AAA rupture (sensitivity 80%, specificity 100%, area under the curve 0.85), being superior to information from the individual probes alone. Our study supports the feasibility of a simultaneous assessment of collagen-related extracellular matrix remodeling and inflammatory activity in a murine model of AAA. KW - Atherosclerosis KW - Specific probe KW - Magnetic resonance imaging KW - Gadolinium KW - Iron oxide KW - Ferumoxytol KW - Inductively‑coupled mass spectrometry KW - ICP-MS KW - LA-ICP-MS KW - Laser ablation PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-525864 UR - https://www.nature.com/articles/s41598-020-71817-x DO - https://doi.org/10.1038/s41598-020-71817-x VL - 10 IS - 1 SP - 15206 PB - Springer Nature Limited CY - London, New York, Berlin, Shanghai and Tokyo AN - OPUS4-52586 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - INPR A1 - Paul, Martin A1 - Tannenberg, Robert A1 - Tscheuschner, Georg A1 - Ponader, Marco A1 - Weller, Michael G. T1 - Cocaine detection by a laser-induced immunofluorometric biosensor N2 - The trafficking of illegal drugs by criminal networks at borders, harbors, or airports is an increasing issue in public health as these routes ensure the main supply of illegal drugs. The prevention of drug smuggling, including the installation of scanners and other analytical devices to detect ultra-small traces of drugs within a reasonable time frame, remains a challenge. The presented immunosensor is based on a monolithic affinity column with a large excess of immobilized hapten, which traps fluorescently labeled antibodies as long as the analyte cocaine is absent. In the presence of the drug, some binding sites of the antibody will be blocked, which leads to an immediate breakthrough of the labeled protein, detectable by highly sensitive laser-induced fluorescence with the help of a Peltier-cooled complementary metal-oxide-semiconductor (CMOS) camera. Liquid handling is performed with high-precision syringe pumps and microfluidic chip-based mixing devices and flow cells. The biosensor achieved limits of detection of 23 pM (7 ppt) of cocaine with a response time of 90 seconds and a total assay time below 3 minutes. With surface wipe sampling, the biosensor was able to detect 300 pg of cocaine. This immunosensor belongs to the most sensitive and fastest detectors for cocaine and offers near-continuous analyte measurement. KW - Drug search KW - Customs KW - Confiscation KW - Border surveillance KW - Narcotics KW - International drug trade KW - Drug trafficking KW - Illicit drug KW - Immunosensor KW - Antibodies KW - Detection PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-529951 DO - https://doi.org/10.20944/preprints202107.0521.v1 SN - 2310-287X N1 - Geburtsname von Ponader, Marco: Wilke, M. - Birth name of Ponader, Marco: Wilke, M. SP - 1 PB - MDPI CY - Basel AN - OPUS4-52995 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ponader, Marco A1 - Röder, Bettina A1 - Paul, Martin A1 - Weller, Michael G. T1 - Sintered glass monoliths as supports for affinity columns N2 - A novel stationary phase for affinity separations is presented. This material is based on sintered borosilicate glass readily available as semi-finished filter plates with defined porosity and surface area. The material shows fast binding kinetics and excellent long-term stability under real application conditions due to lacking macropores and high mechanical rigidity. The glass surface can be easily modified with standard organosilane chemistry to immobilize selective binders or other molecules used for biointeraction. In this paper, the manufacturing of the columns and their respective column holders by 3D printing is shown in detail. The model system protein A/IgG was chosen as an example to examine the properties of such monolithic columns under realistic application conditions. Several specifications, such as (dynamic) IgG capacity, pressure stability, long-term performance, productivity, non-specific binding, and peak shape, are presented. It could be shown that due to the very high separation speed, 250 mg antibody per hour and column can be collected, which surpasses the productivity of most standard columns of the same size. The total IgG capacity of the shown columns is around 4 mg (5.5 mg/mL), which is sufficient for most tasks in research laboratories. The cycle time of an IgG separation can be less than 1 min. Due to the glass material’s excellent pressure resistance, these columns are compatible with standard HPLC systems. This is usually not the case with standard affinity columns, limited to manual use or application in low-pressure systems. The use of a standard HPLC system also improves the ability for automation, which enables the purification of hundreds of cell supernatants in one day. The sharp peak shape of the elution leads to an enrichment effect, which might increase the concentration of IgG by a factor of 3. The final concentration of IgG can be around 7.5 mg/mL without the need for an additional nano-filtration step. The purity of the IgG was > 95% in one step and nearly 99% with a second polishing run. KW - Affinity Chromatography KW - Affinity Extraction KW - Affinity Separation KW - Protein Purification KW - Down Stream Processing KW - Antibody Purification KW - Diagnostic Antibodies KW - Therapeutic Antibodies KW - Automated Purification KW - HPLC KW - FPLC KW - IgG determination KW - Concentration step KW - Monoclonal Antibodies KW - Polyclonal Antibodies KW - Human Plasma KW - Glass Support KW - Borosilicate Glass KW - Monolith KW - Sintered Material KW - Additive Manufacturing KW - Column holder KW - Construction KW - Open Science KW - Citizen Science KW - Protein A KW - Regeneration KW - High-Speed Separations KW - Robustness PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527581 DO - https://doi.org/10.3390/separations8050056 SN - 2297-8739 N1 - Geburtsname von Ponader, Marco: Wilke, M. - Birth name of Ponader, Marco: Wilke, M. VL - 8 IS - 5 SP - 1 EP - 16 PB - MDPI CY - Basel AN - OPUS4-52758 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Adams, L. C. A1 - Brangsch, J. A1 - Reimann, C. A1 - Kaufmann, Jan Ole A1 - Nowak, K. A1 - Buchholz, R. A1 - Karst, U. A1 - Botnar, R. M. A1 - Hamm, B. A1 - Makowski, M. R. T1 - Noninvasive imaging of vascular permeability to predict the risk of rupture in abdominal aortic aneurysms using an albumin binding probe N2 - Abdominal aortic aneurysm (AAA) remains a fatal disease. Its development encompasses a complex interplay between hemodynamic stimuli on and changes in the arterial wall. Currently available biomarkers fail to predict the risk of AAA rupture independent of aneurysm size. Therefore, novel biomarkers for AAA characterization are needed. In this study, we used a mouse model of AAA to investigate the potential of magnetic resonance imaging (MRI) with an albumin-binding probe to assess changes in vascular permeability at different stages of aneurysm growth. Two imaging studies were performed: a longitudinal study with follow-up and death as endpoint to predict rupture risk and a week-by-week study to characterize AAA development. AAAs, which eventually ruptured, demonstrated a significantly higher in vivo MR signal enhancement from the albumin-binding probe (p = 0.047) and a smaller non-enhancing thrombus area compared to intact AAAs (p = 0.001). The ratio of albumin-binding-probe enhancement of the aneurysm wall to size of non-enhancing-thrombus-area predicted AAA rupture with high sensitivity/specificity (100%/86%). More advanced aneurysms with higher vascular permeability demonstrated an increased uptake of the albumin-binding-probe. These results indicate that MRI with an albumin-binding probe may enable noninvasive assessment of vascular permeability in murine AAAs and prediction of rupture risk. KW - Magnetic resonance imaging KW - Imaging KW - Tomography KW - Gadolinium KW - Contrast agent KW - Atherosclerosis KW - ICP-MS KW - Gadofosveset KW - Angiography KW - LA-ICP-MS PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-525541 DO - https://doi.org/10.1038/s41598-020-59842-2 VL - 10 SP - Article number: 3231 PB - Springer Nature Limited CY - London, New York, Berlin, Shanghai and Tokyo AN - OPUS4-52554 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - INPR A1 - Ponader, Marco A1 - Röder, Bettina A1 - Paul, Martin A1 - Weller, Michael G. T1 - Sintered glass monoliths as new supports for affinity columns N2 - A novel stationary phase for affinity separations is presented. This material is based on sintered borosilicate glass readily available as semi-finished filter plates with defined porosity and surface area. The material shows fast binding kinetics and excellent long-term stability under real application conditions due to lacking macropores and high mechanical rigidity. The glass surface can be easily modified with standard organosilane chemistry to immobilize selective binders or other molecules used for biointeraction. In this paper, the manufacturing of the columns and their respective column holders by 3D printing is shown in detail. The model system protein A/IgG was chosen as an example to examine the properties of such monolithic columns under realistic application conditions. Several specifications, such as (dynamic) IgG capacity, pressure stability, long-term performance, productivity, non-specific binding, and peak shape, are presented. It could be shown that due to the very high separation speed, 250 mg antibody per hour and column can be collected, which surpasses the productivity of most standard columns of the same size. The total IgG capacity of the shown columns is around 4 mg (5.5 mg/mL), which is sufficient for most tasks in research laboratories. The cycle time of an IgG separation can be less than 1 minute. Due to the glass material's excellent pressure resistance, these columns are compatible with standard HPLC systems. This is usually not the case with standard affinity columns, limited to manual use or application in low-pressure systems. The use of a standard HPLC system also improves the ability for automation, which enables the purification of hundreds of cell supernatants in one day. The sharp peak shape of the elution leads to an enrichment effect, which might increase the concentration of IgG by a factor of 3. The final concentration of IgG can be around 7.5 mg/mL without the need for an additional nanofiltration step. The purity of the IgG was > 95% in one step and nearly 99% with a second polishing run. KW - Affinity Chromatography KW - Glass KW - Purification KW - Antibodies KW - Solid support KW - HPLC KW - FPLC KW - Separation PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-529117 DO - https://doi.org/10.20944/preprints202103.0298.v1 SN - 2310-287X N1 - Geburtsname von Ponader, Marco: Wilke, M. - Birth name of Ponader, Marco: Wilke, M. SP - 1 EP - 17 PB - MDPI CY - Basel AN - OPUS4-52911 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - INPR A1 - Morcillo, Dalia A1 - Oelze, Marcus A1 - Seena Prem, Pranav A1 - de Oliveira Guilherme Buzanich, Ana A1 - Emmerling, Franziska A1 - Recknagel, Sebastian A1 - Panne, Ulrich A1 - Abad Andrade, Carlos Enrique T1 - Lithium isotope fractionation as an early indicator of degradation mechanisms in lithium-ion batteries N2 - Aging in lithium-ion batteries (LIBs) degrades performance and hinders sustainability, demanding advanced diagnostics for early failure prediction. We investigate lithium isotope fractionation (LIF) as an innovative probe of degradation in lithium cobalt oxide (LCO) coin cells aged over 0−700 cycles. High-precision multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) quantified δ7Li variations across cell stages: non-cycled (0 cycles), newly formed (5 cycles), semi-aged (250 cycles), and fully aged (700 cycles). During early cycling (≤ 45 cycles), chemical processes drive 7Li enrichment at the anode (δ7Li vs LSVEC = +12 ‰) through solid electrolyte interphase (SEI) formation, while the cathode depletes in 7Li (δ7Li vs LSVEC = −0.7 ‰). Beyond 45 cycles, electric field-induced migration predominates, promoting 6Li intercalation into the anode and increasing the δ7Li of the cathode by 8.1 ‰. Mass balance verifies isotope conservation, attributing shifts to redistribution and trapping. Complementary electrochemical impedance spectroscopy (EIS) and X-ray absorption spectroscopy and diffraction confirm SEI expansion, cobalt oxidation, lattice shrinkage, and changes in electrode structure, corroborating LIF trends. Notably, a δ7Li inflection at approximately 270 cycles anticipates end-of-life by 70 cycles, surpassing traditional methods in sensitivity. LIF emerges as a predictive indicator of aging mechanisms, informing optimized designs for durable LIBs. KW - Lithium isotope fractionation KW - Lithium-ion batteries KW - Degradation mechanisms KW - LiCoO2 cathodes KW - LCO KW - Isotopic tracing KW - Lithium isotopes PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-650945 DO - https://doi.org/10.26434/chemrxiv-2025-16lvq SP - 1 EP - 19 AN - OPUS4-65094 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hoque, Maroof Arshadul A1 - Sommerfeld, Thomas A1 - Lisec, Jan A1 - Das, Prasenjit A1 - Prinz, Carsten A1 - Heinekamp, Christian A1 - Stolar, Tomislav A1 - Etter, Martin A1 - Rosenberger, David A1 - George, Janine A1 - Bhattacharya, Biswajit A1 - Emmerling, Franziska T1 - Mechanochemically Synthesized Covalent Organic Framework Effectively Captures PFAS Contaminants N2 - Per‐ and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants that pose significant health risks, prompting urgent efforts to develop effective removal methods and adsorbers. Covalent organic frameworks (COFs) are metal‐free adsorbers with high stability and tunable porosity. A highly crystalline COF is synthesised mechanochemically using 1,3,5‐tris(4‐aminophenyl)benzene (TAPB) and 1,3,5‐triformylbenzene (TFB). The formation dynamics are monitored in real time with time‐resolved in situ synchrotron X‐ray diffraction. The TAPB‐TFB COF demonstrates good efficiency in eliminating PFAS from water. Perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) are effectively extracted, and most of the adsorption occurred within the first 10 min. Additionally, X‐ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and DFT calculations are employed to elucidate the molecular interactions between PFAS and the COF framework. The rapid and efficient removal of PFAS makes TAPB‐TFB COF a promising material for water treatment applications. KW - COFs KW - Ball-milling KW - PFAS PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-648712 DO - https://doi.org/10.1002/smll.202509275 SN - 1613-6810 VL - 21 IS - 44 SP - 1 EP - 8 PB - Wiley CY - Weinheim AN - OPUS4-64871 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Karafiludis, Stephanos A1 - Kochovski, Z. A1 - Scoppola, E. A1 - Retzmann, Anika A1 - Hodoroaba, Vasile-Dan A1 - ten Elshof, J. E. A1 - Emmerling, Franziska A1 - Stawski, Tomasz Maciej T1 - Nonclassical Crystallization Pathway of Transition Metal Phosphate Compounds N2 - Here, we elucidate nonclassical multistep crystallization pathways of transition metal phosphates from aqueous solutions. We followed precipitation processes of M-struvites, NH4MPO4·6H2O, and M-phosphate octahydrates, M3(PO4)2·8H2O, where M = Ni, Co, or NixCo1–x, by using in situ scattering and spectroscopy-based techniques, supported by elemental mass spectrometry analyses and advanced electron microscopy. Ni and Co phosphates crystallize via intermediate colloidal amorphous nanophases, which change their complex structures while agglomerating, condensing, and densifying throughout the extended reaction times. We reconstructed the three-dimensional morphology of these precursors by employing cryo-electron tomography (cryo-ET). We found that the complex interplay between metastable amorphous colloids and protocrystalline units determines the reaction pathways. Ultimately, the same crystalline structure, such as struvite, is formed. However, the multistep process stages vary in complexity and can last from a few minutes to several hours depending on the selected transition metal(s), their concentration, and the Ni/Co ratio. KW - Non-classical crystallization theory KW - Transition metals KW - Phosphates KW - Amorphous phases KW - Intermediate phases PY - 2023 DO - https://doi.org/10.1021/acs.chemmater.3c02346 SN - 1520-5002 VL - 35 IS - 24 SP - 10645 EP - 10657 PB - American Chemical Society (ACS) CY - Washington D.C. AN - OPUS4-59135 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gugin, Nikita A1 - Villajos Collado, José Antonio A1 - Dautain, O. A1 - Maiwald, Michael A1 - Emmerling, Franziska T1 - Optimizing the Green Synthesis of ZIF-8 by Reactive Extrusion Using In Situ Raman Spectroscopy 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. KW - Mechanochemistry KW - In situ Raman KW - Large-scale processing KW - Metal−organic frameworks KW - Twin-screw extrusion (TSE) PY - 2023 DO - https://doi.org/10.1021/acssuschemeng.2c07509 SN - 2168-0485 VL - 11 IS - 13 SP - 5175 EP - 5183 PB - ACS Publications AN - OPUS4-57366 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hoell, A. 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 - THES A1 - Kazlagić, Anera T1 - Provenancing of cement by the means of isotope techniques N2 - Concrete is the most important human-made material because it serves as the basis of our built environment. Since the properties of concretes are dominated by their key compound, cement, devising a way to determine the cement’s origin, known as provenancing, is of great importance for answering different provenance-related questions. These questions range from liability issues when damage occurs to concrete-made structures, to forensic investigations where cement particles are found at crime scenes. This thesis showcases the use of isotope techniques to answer these provenance-related questions. Conventional 87Sr/86Sr and 143Nd/144Nd isotope and elemental ratios consisting of Ca, Sr, K, Mn, Mg, and Ti are used as fingerprints for ordinary Portland cement (OPC) provenancing. The first part of this thesis describes research previously conducted in fingerprinting cementitious materials, providing an overview of provenance studies of cement and the main approaches commonly used. In several studies, the origin of clinker for certain locations was determined via different approaches. However, clinker is an intermediate product, which is available only at the production site and therefore, the practical relevance is rather limited. Furthermore, the use of Sr and Nd isotope systems, together with elemental fingerprints are presented as state of the art in the field. Therein, the principal approach for the overall study is sketched. For the second part of the study, a sample preparation technique for Sr isotopes in Portland cement was developed. The aim was to find the most appropriate sample preparation procedure for cement provenancing and selection was realised by comparing the 87Sr/86Sr isotope ratios of differently treated OPCs with those of the corresponding clinkers. Based on these findings, the third part of the study focused on the measurements of Sr and Nd isotope ratios, together with elemental ratios, to establish a reliable technique for OPC provenancing. The outcomes of this final stage are then used to establish a procedure for fingerprinting cements. This becomes possible with the use of Sr and Nd isotope ratios and geochemical profiles. To perform isotope ratio measurements and obtain reliable data, it was necessary to establish a quality control procedure. Thus, an interlaboratory comparison (ILC) was organised to characterise 87Sr/86Sr isotope ratios in geological and industrial reference materials by applying the conventional method for 87Sr/86Sr isotope ratios. As reference material, four cements (VDZ 100a, VDZ 200a, VDZ 300a, IAG OPC-1), one limestone (IAG/CGL ML-3) and one slate (IAG OU-6) were selected, thus covering a wide range of Sr isotope signatures. KW - Isotope ratio KW - Strontium KW - Neodymium KW - Ordinary Portland cement PY - 2023 SP - 1 EP - 148 CY - Berlin AN - OPUS4-59172 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Martins, Ines A1 - Al-Sabbagh, Dominik A1 - Bentrup, U. A1 - Marquardt, Julien A1 - Schmid, Thomas A1 - Scoppola, E. A1 - Kraus, Werner A1 - Stawski, Tomasz A1 - de Oliveira Guilherme Buzanich, Ana A1 - Yusenko, Kirill A1 - Weidner, Steffen A1 - Emmerling, Franziska T1 - Formation Mechanism of a Nano-Ring of Bismuth Cations and Mono-Lacunary Keggin-Type Phosphomolybdate N2 - A new hetero-bimetallic polyoxometalate (POM) nano-ring was synthesized in a one-pot procedure. The structure consists of tetrameric units containing four bismuth-substituted monolacunary Keggin anions including distorted [BiO8] cubes. The nano-ring is formed via self-assembly from metal precursors in aqueous acidic medium. The compound (NH4)16[(BiPMo11O39)4] ⋅ 22 H2O; (P4Bi4Mo44) was characterized by single-crystal X-ray diffraction, extended X-ray absorption fine structure spectroscopy (EXAFS), Raman spectroscopy, matrix-assisted laser desorption/ionisation-time of flight mass spectrometry (MALDI-TOF), and thermogravimetry/differential scanning calorimetry mass spectrometry (TG-DSC-MS). The formation of the nano-ring in solution was studied by time-resolved in situ small- and wide-angle X-ray scattering (SAXS/WAXS) and in situ EXAFS measurements at the Mo−K and the Bi−L3 edge indicating a two-step process consisting of condensation of Mo-anions and formation of Bi−Mo-units followed by a rapid self-assembly to yield the final tetrameric ring structure. KW - Bismuth KW - In situ EXAFS KW - In situ SAXS/WAXS KW - Lacunary Keggin ion KW - Polyoxometalates KW - Self-assembly PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546823 DO - https://doi.org/10.1002/chem.202200079 SN - 0947-6539 VL - 28 IS - 27 SP - 1 EP - 7 PB - Wiley-VCH CY - Weinheim AN - OPUS4-54682 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - You, Zengchao A1 - Nirmalananthan-Budau, Nithiya A1 - Resch-Genger, Ute A1 - Panne, Ulrich A1 - Weidner, Steffen T1 - Separation of polystyrene nanoparticles bearing different carboxyl group densities and functional groups quantification with capillary electrophoresis and asymmetrical flow field flow fractionation N2 - Two sets of polystyrene nanoparticles (PSNPs) with comparable core sizes but different carboxyl group densities were made and separated using asymmetric flow field flow fractionation (AF4), capillary electrophoresis (CE), and the off-line hyphenation of both methods. Our results revealed the significant potential of two-dimensional off-line AF4-CE hyphenation to improve the separation and demonstrated for the first time, the applicability of CE to determine the functional group density of nanoparticles (NPs). Compared to the result acquired with conductometric titration, the result obtained with synthesized 100 nm sized PSNPs revealed only a slight deviation of 1.7%. Commercial 100 nm sized PSNPs yielded a deviation of 4.6 %. For 60 nm sized PSNPs, a larger deviation of 10.6 % between both methods was observed, which is attributed to the lower separation resolution. KW - Nanoparticle KW - A4F KW - Capillary electrophoresis KW - Carboxyl group PY - 2020 DO - https://doi.org/10.1016/j.chroma.2020.461392 VL - 1626 SP - 461392 PB - Elsevier B.V. AN - OPUS4-51080 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Becker, Roland A1 - Scholz, Philipp A1 - Jung, Christian A1 - Weidner, Steffen T1 - Thermo-Desorption Gas Chromatography-Mass Spectrometry for investigating the thermal degradation of polyurethanes N2 - Thermo-Desorption Gas Chromatography-Mass Spectrometry (TD-GC-MS) was used to investigate the thermal degradation of two different polyurethanes (PU). PU samples were heated at different heating rates and the desorbed products were collected in a cold injection system and thereafter submitted to GC-MS. Prospects and limitations of the detection and quantification of semi-volatile degradation products were investigated. A temperature dependent PU depolymerization was found at temperatures above 200 °C proved by an increasing release of 1,4-butanediol and methylene diphenyl diisocyanate (MDI) representing the main building blocks of both polymers. Their release was monitored quantitatively based on external calibration with authentic compounds. Size Exclusion Chromatography (SEC) of the residues obtained after thermodesorption confirmed the initial competitive degradation mechanism indicating an equilibrium of crosslinking and depolymerization as previously suggested. Matrix-Assisted Laser Desorption Ionization (MALDI) mass spectrometry of SEC fractions of thermally degraded PUs provided additional hints on degradation mechanism. KW - Thermo-desorption KW - Mass spectrometry KW - Polyurethanes KW - Thermal degradation PY - 2023 DO - https://doi.org/10.1039/D3AY00173C SN - 1759-9660 SP - 1 EP - 6 PB - Royal Society for Chemistry AN - OPUS4-57307 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -