TY - JOUR A1 - Zancajo, V. M. R. A1 - Lindtner, T. A1 - Eisele, M. A1 - Huber, A. J. A1 - Elbaum, R. A1 - Kneipp, Janina T1 - FTIR Nanospectroscopy Shows Molecular Structures of Plant Biominerals and Cell Walls N2 - Plant tissues are complex composite structures of organic and inorganic components whose function relies on molecular heterogeneity at the nanometer scale. Scattering-type near-field optical microscopy (s-SNOM) in the mid-infrared (IR) region is used here to collect IR nanospectra from both fixed and native plant samples. We compared structures of chemically extracted silica bodies (phytoliths) to silicified and nonsilicified cell walls prepared as a flat block of epoxy-embedded awns of wheat (Triticum turgidum), thin sections of native epidermis cells from sorghum (Sorghum bicolor) comprising silica phytoliths, and isolated cells from awns of oats (Avena sterilis). The correlation of the scanning-probe IR images and the mechanical phase image enables a combined probing of mechanical material properties together with the chemical composition and structure of both the cell walls and the phytolith structures. The data reveal a structural heterogeneity of the different silica bodies in situ, as well as different compositions and crystallinities of cell wall components. In conclusion, IR nanospectroscopy is suggested as an ideal tool for studies of native plant materials of varied origins and preparations and could be applied to other inorganic–organic hybrid materials. KW - Cells KW - Plants KW - Organic polymers KW - Silica KW - Infrared light PY - 2020 DO - https://doi.org/10.1021/acs.analchem.0c00271 SN - 0003-2700 VL - 92 IS - 20 SP - 13694 EP - 13701 PB - ACS Publications AN - OPUS4-54445 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zhang, Zhiyang A1 - Kneipp, Janina T1 - Surface Molecular Patterning by Plasmon-Catalyzed Reactions N2 - Self-assembled monolayers (SAMs) on plasmonic substrates play a significant role applications of surface-enhanced Raman scattering (SERS). At the same time, localized surface plasmon resonances (LSPRs) can be employed for a broad range of plasmon-supported chemical modifications. Here, micropatterning using the derivatization of SAMs on gold nanosubstrates for rewritable SERS-based security labels or as the basis for sensing arrays functionalized with biomolecules is demonstrated using different plasmon-catalyzed reactions. The formation of 4,4′-dimercaptoazobenzene (DMAB) from p-aminothiophenol (PATP) as well as from p-nitrothiophenol (PNTP) and the reduction of PNTP to PATP are used to change the functionality of the substrate in specified positions. Employing LSPR, the reactions are started by illumination using visible laser light at a high intensity in a focal spot of a microscope objective and yield microscopic patterns of the reaction product. The obtained molecular patterns can be erased by other reactions, enabling different strategies for rewriting, encryption, or stepwise functionalization. KW - 4,4′-dimercaptoazobenzene KW - Surface molecular patterning KW - Plasmon-catalyzed reactions KW - p-aminothiophenol KW - p-nitrothiophenol PY - 2021 DO - https://doi.org/10.1021/acsami.1c12410 SN - 1944-8252 VL - 13 IS - 36 SP - 43708 EP - 43714 PB - ACS Publications AN - OPUS4-53341 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute A1 - Würth, Christian A1 - Kraft, Marco A1 - Kaiser, Martin A1 - Radunz, Sebastian A1 - Muhr, V. A1 - Hirsch, T. T1 - Effect of particle architecture, dopant concentration, size, and excitation power density on the luminescence efficiency of upconversion nanocrystals N2 - Lanthanide-based upconversion nanoparticles (UCNPs) offer new strategies for luminescence-based sensing and imaging. One of the best studied materials are hexagonal ß-NaYF4 UCNPs doped with 20% Yb3+ and 2% Er3+, which efficiently convert 976 nm light to photons emitted at 540 nm, 655 nm, and 845 nm, respectively, reveal Long luminescence lifetimes (> 100 µs), and are very photostable and chemically inters.[1,2] The properties of their upconversion (UC) luminescence (UCL) are, however, strongly influenced by particle size, concentration and spatial arrangement of dopant Ions, surface chemistry, and microenvironment.[3,4] In addition, the multiphotonic absorption processes responsible for UCL render UCL dependent on excitation power density (P). The rational design of brighter UCNPs particle architectures encouraged us to assess systematically the influence of these parameters on UCL for differently doped UCNPs relying on the commonly used ß-NaYf4 matrix using steady state and time resolved fluorometry as well as integrating sphere spectroscopy for P varied over almost three orders of magnitude. This includes comprehensive studies of the influence of size and shell, Yb3+ and Er3+ dopand concentrations, and energy Transfer processes from UCNPs to surface-bound organic dyes or vice versa [5]. Our results underline the need for really quantitative luminescence studies for mechanistic insights, the potential of high p to compensate for UCL surface quenching, and the matrix- and P-dependence of the optimum dopand concentration. T2 - BIOSPIE 2018 CY - San Francisco, USA DA - 27.01.2018 KW - Upconversion KW - Nanoparticle KW - Absolute fluorometry KW - Integrating sphere spectroscopy KW - NIR KW - IR KW - Fluorescence KW - Surface chemistry KW - Deactivation pathways KW - Modeling KW - Size PY - 2018 AN - OPUS4-43939 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Meiling, T. T. A1 - Schürmann, Robin A1 - Vogel, Stefanie A1 - Ebel, Kenny A1 - Nicolas, C. A1 - Milosavljević, A. R. A1 - Bald, Ilko T1 - Photophysics and chemistry of nitrogen-doped carbon nanodots with high photoluminescence quantum yield N2 - Fluorescent carbon nanodots (CNDs) are very promising nanomaterials for a broad range of applications because of their high photostability, presumed selective luminescence, and low cost at which they can be produced. In this respect, CNDs are superior to well-established semiconductor quantum dots and organic dyes. However, reported synthesis protocols for CNDs typically lead to low photoluminescence quantum yield (PLQY) and low reproducibility, resulting in a poor understanding of the CND chemistry and photophysics. Here, we report a one-step synthesis of nitrogen-doped carbon nanodots (N-CNDs) from various carboxylic acids, Tris, and ethylenediaminetetraacetic acid resulting in high PLQY of up to 90%. The reaction conditions in terms of starting materials, temperature, and reaction time are carefully optimized and their influence on the photophysical properties is characterized. We find that citric acid-derived N-CNDs can result in a very high PLQY of 90%, but they do not Show selective luminescence. By contrast, acetic acid-derived N-CNDs show selective luminescence but a PLQY of 50%. The chemical composition of the surface and core of these two selected N-CND types is characterized among others by high-Resolution synchrotron X-ray photoelectron spectroscopy using single isolated N-CND clusters. The results indicate that photoexcitation occurs in the N-CND core, whereas the emission properties are determined by the N-CND surface groups. KW - Carbon nanodots KW - Fluorescence KW - Synchrotron XPS PY - 2018 DO - https://doi.org/10.1021/acs.jpcc.8b00748 SN - 1932-7447 VL - 122 IS - 18 SP - 10217 EP - 10230 PB - American Chemical Society CY - Washington, DC AN - OPUS4-45426 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rühlmann, Madlen A1 - Büchele, Dominique A1 - Ostermann, Markus A1 - Bald, Ilko A1 - Schmid, Thomas T1 - Challenges in the quantification of nutrients in soils using laser-induced breakdown spectroscopy – A case study with calcium N2 - The quantification of the elemental content in soils with laser-induced breakdown spectroscopy (LIBS) is challenging because of matrix effects strongly influencing the plasma formation and LIBS signal. Furthermore, soil heterogeneity at the micrometre scale can affect the accuracy of analytical results. In this paper, the impact of univariate and multivariate data evaluation approaches on the quantification of nutrients in soil is discussed. Exemplarily, results for calcium are shown, which reflect trends also observed for other elements like magnesium, silicon and iron. For the calibration models, 16 certified reference soils were used. With univariate and multivariate approaches, the calcium mass fractions in 60 soils from different testing grounds in Germany were calculated. The latter approach consisted of a principal component analysis (PCA) of adequately pre-treated data for classification and identification of outliers, followed by partial least squares regression (PLSR) for quantification. For validation, the soils were also characterised with inductively coupled plasma optical emission spectroscopy (ICP OES) and X-ray fluorescence (XRF) analysis. Deviations between the LIBS quantification results and the reference analytical results are discussed. KW - Laser-induced breakdown spectroscopy (LIBS) KW - Soil KW - Multivariate data analysis KW - Principal component analysis (PCA) KW - Partial least squares regression (PLSR) PY - 2018 DO - https://doi.org/10.1016/j.sab.2018.05.003 VL - 146 SP - 115 EP - 121 PB - Elsevier B.V. AN - OPUS4-45070 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rackwitz, Jenny A1 - Bald, Ilko T1 - Low‐energy electron‐induced strand breaks in telomere‐derived DNA sequences—influence of DNA sequence and topology N2 - During cancer radiation therapy high‐energy radiation is used to reduce tumour tissue. The irradiation produces a shower of secondary low‐energy (<20 eV) electrons, which are able to damage DNA very efficiently by dissociative electron attachment. Recently, it was suggested that low‐energy electron‐induced DNA strand breaks strongly depend on the specific DNA sequence with a high sensitivity of G‐rich sequences. Here, we use DNA origami platforms to expose G‐rich telomere sequences to low‐energy (8.8 eV) electrons to determine absolute cross sections for strand breakage and to study the influence of sequence modifications and topology of telomeric DNA on the strand breakage. We find that the telomeric DNA 5′‐(TTA GGG)2 is more sensitive to low‐energy electrons than an intermixed sequence 5′‐(TGT GTG A)2 confirming the unique electronic properties resulting from G‐stacking. With increasing length of the oligonucleotide (i.e., going from 5′‐(GGG ATT)2 to 5′‐(GGG ATT)4), both the variety of topology and the electron‐induced strand break cross sections increase. Addition of K+ ions decreases the strand break cross section for all sequences that are able to fold G‐quadruplexes or G‐intermediates, whereas the strand break cross section for the intermixed sequence remains unchanged. These results indicate that telomeric DNA is rather sensitive towards low‐energy electron‐induced strand breakage suggesting significant telomere shortening that can also occur during cancer radiation therapy. KW - DNA radiation damage KW - Telomere KW - DNA origami KW - Electron PY - 2018 DO - https://doi.org/10.1002/chem.201705889 SN - 1521-3765 SN - 0947-6539 VL - 24 IS - 18 SP - 4680 EP - 4688 PB - Wiley AN - OPUS4-44702 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ribar, A. A1 - Huber, S. E. A1 - Smiałek, M. A. A1 - Tanzer, K. A1 - Neustetter, M. A1 - Schürmann, Robin A1 - Bald, Ilko A1 - Denifl, S. T1 - Hydroperoxyl radical and formic acid formation from common DNA stabilizers upon low energy electron attachment N2 - 2-Amino-2-(hydroxymethyl)-1,3-propanediol (TRIS) and ethylene-diaminetetraacetic acid (EDTA) are key components of biological buffers and are frequently used as DNA stabilizers in irradiation studies. Such surface or liquid phase studies are done with the aim to understand the fundamental mechanisms of DNA radiation damage and to improve cancer radiotherapy. When ionizing radiation is used, abundant secondary electrons are formed during the irradiation process, which are able to attach to the molecular compounds present on the surface. In the present study we experimentally investigate low energy electron attachment to TRIS and methyliminodiacetic acid (MIDA), an analogue of EDTA, supported by quantum chemical calculations. The most prominent dissociation channel for TRIS is through hydroperoxyl radical formation, whereas the dissociation of MIDA results in the formation of formic and acetic acid. These compounds are well-known to cause DNA modifications, like strand breaks. The present results indicate that buffer compounds may not have an exclusive protecting effect on DNA as suggested previously. KW - DEA KW - DNA KW - Low energy electrons KW - Mass spectrometry PY - 2018 UR - http://pubs.rsc.org/en/content/articlepdf/2018/cp/c7cp07697e DO - https://doi.org/10.1039/c7cp07697e VL - 20 IS - 8 SP - 5578 EP - 5585 PB - Royal Society of Chemistry AN - OPUS4-44703 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zhang, Zhiyang A1 - Gernert, U. A1 - Gerhardt, R. F. A1 - Höhn, E.-M. A1 - Belder, D. A1 - Kneipp, Janina T1 - Catalysis by Metal Nanoparticles in a Plug-In Optofluidic Platform: Redox Reactions of p-Nitrobenzenethiol and p-Aminothiophenol N2 - The spectroscopic characterization by surface-enhanced Raman scattering (SERS) has shown great potential in studies of heterogeneous catalysis. We describe a plug-in multifunctional optofluidic platform that can be tailored to serve both as a variable catalyst material and for sensitive optical characterization of the respective reactions using SERS in microfluidic systems. The platform enables the characterization of reactions under a controlled gas atmosphere and does not present with limitations due to nanoparticle adsorption or memory effects. Spectra of the gold-catalyzed reduction of p-nitrothiophenol by sodium borohydride using the plug-in probe provide evidence that the borohydride is the direct source of hydrogen on the gold surface, and that a radical anion is formed as an intermediate. The in situ monitoring of the photoinduced dimerization of p-aminothiophenol indicates that the activation of oxygen is essential for the plasmon-catalyzed oxidation on gold nanoparticles and strongly supports the central role of metal oxide species. KW - Gaseous reactants KW - Heterogeneous catalysis KW - Microfluidics KW - Optofluidics KW - Radicals KW - Reusable KW - Surface-enhanced Raman scattering (SERS) PY - 2018 UR - https://pubs.acs.org/doi/10.1021/acscatal.8b00101 DO - https://doi.org/10.1021/acscatal.8b00101 VL - 8 IS - 3 SP - 2443 EP - 2449 PB - American Chemical Society CY - Washington, DC, USA AN - OPUS4-44628 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schürmann, Robin A1 - Vogel, Stefanie A1 - Ebel, Kenny A1 - Bald, Ilko T1 - The physico-chemical basis of DNA radiosensitization: Implications for cancer radiation therapy N2 - High-energy radiation is used in combination with radiosensitizing therapeutics to treat cancer. The most common radiosensitizers are halogenatednucleo-sides and cisplatin derivatives, and recently also metal nanoparticles have been suggested as potentialradiosensitizing agents. The radiosensitizingaction of these compounds can at least partly be ascribed to an enhancedreactivity towards secondary low-energy electrons generated along the radiation track of the high-energyprimary radiation, or to an additional emission of secondary reactive electrons close to the tumor tissue. This is referred to as physico-chem ical radiosensitization. In this Conceptarticle we presentcurrent experimental methodsused to study fundamentalprocesses of physico-chemical radiosensitization and discuss the most relevant classes of radiosensitizers. Open questions in the current discussions are identified and future directions outlined, which can lead to optimized treatment protocols or even novel therapeuticconcepts. KW - DNA KW - Radiosensitization KW - Radiation damage KW - Low energy electrons PY - 2018 DO - https://doi.org/10.1002/chem.201800804 SN - 1521-3765 SN - 0947-6539 VL - 24 IS - 41 SP - 10271 EP - 10279 PB - WILEY AN - OPUS4-45742 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heck, Christian A1 - Kanehira, Y. A1 - Kneipp, Janina A1 - Bald, Ilko T1 - Placement of single proteins within the SERS hot spots of self-assembled silver nanolenses N2 - This study demonstrates the bottom-up synthesis of silver nanolenses.Arobust coating protocol enabled the functionalization of differently sized silver nanoparticles with DNAsingle strands of orthogonal sequence.Coated particles 10 nm, 20 nm, and 60 nm in diameter were self-assembled by DNAorigami scaffolds to form silver nanolenses.Single molecules of the protein streptavidin were selectively placed in the gap of highest electric field enhancement. Streptavidin labelled with alkyne groups served as model analyte in surface- enhanced Raman scattering (SERS) experiments.Bycorre- lated Raman mapping and atomic force microscopy, SERS signals of the alkyne labels of asingle streptavidin molecule, from asingle silver nanolens,were detected. The discrete,self- similar aggregates of solid silver nanoparticles are promising for plasmonic applications. KW - DNA origami KW - Surface enhanced Raman scattering KW - Protein KW - Single molecule KW - Nanotechnology PY - 2018 DO - https://doi.org/10.1002/anie.201801748 SN - 1433-7851 VL - 57 IS - 25 SP - 7444 EP - 7447 PB - WILEY AN - OPUS4-45743 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heck, Christian A1 - Kanehira, Yuya A1 - Kneipp, Janina A1 - Bald, Ilko T1 - Platzierung einzelner Proteine in den SERS-Hot-Spots selbstorganisierte Silbernanolinsen N2 - Diese Studie demonstriert die Bottom-up-Synthese von Silbernanolinsen. Ein robustes Beschichtungsprotokoll ermçglichte die Funktionalisierung unterschiedlich großer Silbernanopartikel mit einzelstr-ngiger DNAunterschiedlicher Sequenz. Derartig beschichtete Partikel mit Durchmessern von 10 nm, 20 nm und 60 nm wurden mithilfe von DNA-Origami- Gergsten zu Silbernanolinsen angeordnet. Ein einzelnes Mo- lekgldes Proteins Streptavidin ist in demjenigen Spalt zwi- schenden Partikeln immobilisiert worden, der die hçchste Feldverst-rkung zur Verfggung stellt. Streptavidin war dabei mit Alkin-Gruppen modifiziert und fungierte als Modellanalyt in Experimenten zur oberfl-chenverst-rkten Raman-Streuung (SERS). Korrelierte Raman- und Rasterkraftmikroskopie- Messungen ermçglichten die Aufnahme von SERS-Signalen der Alkingruppen eines einzelnen Streptavidins,von einer einzelnen Silbernanolinse.Diese diskreten, selbst-hnlichen Silbernanopartikelaggregate versprechen vielf-ltige Anwen- dungen im Feld der Plasmonik KW - DNA Origami KW - Oberflächen verstärkte Raman Streuung KW - Proteine KW - Einzelmolekülspektroskopie KW - Nanotechnologie PY - 2018 DO - https://doi.org/10.1002/ange.201801748 SN - 1521-3757 SN - 0044-8249 VL - 130 IS - 25 SP - 7566 EP - 7569 PB - WILEY AN - OPUS4-45744 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Marques, T. S. A1 - Schürmann, Robin A1 - Ebel, Kenny A1 - Heck, C. A1 - Smialek, M. A1 - Eden, Sam A1 - Mason, N. A1 - Bald, Ilko T1 - Kinetics of molecular decomposition under irradiation of gold nanoparticles with nanosecond laser pulses-A 5-Bromouracil case study N2 - Laser illuminated gold nanoparticles (AuNPs) efficiently absorb light and heat up the surrounding medium, leading to versatile applications ranging from plasmonic catalysis to cancer photothermal therapy. Therefore, an in-depth understanding of the thermal, optical, and electron induced reaction pathways is required. Here, the electrophilic DNA nucleobase analog 5-Bromouracil (BrU) has been used as a model compound to study its decomposition in the vicinity of AuNPs illuminated with intense ns laser pulses under various conditions. The plasmonic response of the AuNPs and the concentration of BrU and resulting photoproducts have been tracked by ultraviolet and visible (UV–Vis) spectroscopy as a function of the irradiation time. A kinetic model has been developed to determine the reaction rates of two parallel fragmentation pathways of BrU, and their dependency on laser fluence and adsorption on the AuNP have been evaluated. In addition, the size and the electric field enhancement of the decomposed AuNPs have been determined by atomic force microscopy and finite domain time difference calculations, respectively. A minor influence of the direct photoreaction and a strong effect of the heating of the AuNPs have been revealed. However, due to the size reduction of the irradiated AuNPs, a trade-off between laser fluence and plasmonic response of the AuNPs has been observed. Hence, the decomposition of the AuNPs might be limiting the achievable temperatures under irradiation with several laser pulses. These findings need to be considered for an efficient design of catalytic plasmonic systems. KW - Kinetics KW - Gold nanoparticles KW - 5-Bromouracil PY - 2020 DO - https://doi.org/10.1063/1.5137898 VL - 152 IS - 12 SP - 24712 EP - 24712 PB - AIP Publishing AN - OPUS4-50787 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zhang, Zhiyang A1 - Li, Y. A1 - Frisch, J. A1 - Bär, M. A1 - Rappich, J. A1 - Kneipp, Janina T1 - In situ surface-enhanced Raman scattering shows ligand-enhanced hot electron harvesting on silver, gold, and copper nanoparticles N2 - Hot carriers (electrons and holes) generated from the decay of localized surface plasmon resonances can take a major role in catalytic reactions on metal nanoparticles. By obtaining surface enhanced Raman scattering (SERS) spectra of p-aminothiophenol as product of the reduction of p-nitrothiophenol by hot electrons, different catalytic activity is revealed here for nanoparticles of silver, gold, and copper. As a main finding, a series of different ligands, comprising halide and non-halide species, are found to enhance product formation in the reduction reaction on nanoparticles of all three metals. A comparison with the standard electrode potentials of the metals with and without the ligands and SERS data obtained at different electrode potential indicate that the higher catalytic activity can be associated with a higher Fermi level, thereby resulting in an improved efficiency of hot carrier generation. The concept of such a ligand-enhanced hot electron reduction provides a way to make light-to-chemical energy conversion more efficient due to improved electron harvesting. KW - Ligands KW - Hot electrons KW - SERS KW - p-Nitrothiophenol KW - p-Aminothiophenol PY - 2020 DO - https://doi.org/10.1016/j.jcat.2020.01.006 VL - 383 SP - 153 EP - 159 PB - Elsevier Inc. CY - Amsterdam, NL AN - OPUS4-50626 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ebel, Kenny A1 - Bald, Ilko T1 - Length and Energy Dependence of Low-Energy Electron-Induced Strand Breaks in Poly(A) DNA N2 - The DNA in living cells can be effectively damaged by high-energy radiation, which can lead to cell death. Through the ionization of water molecules, highly reactive secondary species such as low-energy electrons (LEEs) with the most probable energy around 10 eV are generated, which are able to induce DNA strand breaks via dissociative electron attachment. Absolute DNA strand break cross sections of specific DNA sequences can be efficiently determined using DNA origami nanostructures as platforms exposing the target sequences towards LEEs. In this paper, we systematically study the effect of the oligonucleotide length on the strand break cross section at various irradiation energies. The present work focuses on poly-adenine sequences (d(A4), d(A8), d(A12), d(A16), and d(A20)) irradiated with 5.0, 7.0, 8.4, and 10 eV electrons. Independent of the DNA length, the strand break cross section shows a maximum around 7.0 eV electron energy for all investigated oligonucleotides confirming that strand breakage occurs through the initial formation of negative ion resonances. When going from d(A4) to d(A16), the strand break cross section increases with oligonucleotide length, but only at 7.0 and 8.4 eV, i.e., close to the maximum of the negative ion resonance, the increase in the strand break cross section with the length is similar to the increase of an estimated geometrical cross section. For d(A20), a markedly lower DNA strand break cross section is observed for all electron energies, which is tentatively ascribed to a conformational change of the dA20 sequence. The results indicate that, although there is a general length dependence of strand break cross sections, individual nucleotides do not contribute independently of the absolute strand break cross section of the whole DNA strand. The absolute quantification of sequence specific strand breaks will help develop a more accurate molecular level understanding of radiation induced DNA damage, which can then be used for optimized risk estimates in cancer radiation therapy. KW - DNA origami KW - DNA radiation damage KW - DNA strand breaks KW - Low-energy electrons KW - Sequence dependence PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503563 DO - https://doi.org/10.3390/ijms21010111 VL - 21 IS - 1 SP - 1 EP - 11 PB - MDPI CY - Basel, Switzerland AN - OPUS4-50356 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, C. A1 - Schierack, P. A1 - Gerber, U. A1 - Schröder, C. A1 - Choi, Youngeun A1 - Bald, Ilko A1 - Lehmann, W. A1 - Rödiger, S. T1 - Streptavidin Homologues for Applications on Solid Surfaces at High Temperatures N2 - One of the most commonly used bonds between two biomolecules is the bond between biotin and streptavidin (SA) or streptavidin homologues (SAHs). A high dissociation constant and the consequent high-temperature stability even allows for its use in nucleic acid detection under polymerase chain reaction (PCR) conditions. There are a number of SAHs available, and for assay design, it is of great interest to determine as to which SAH will perform the best under assay conditions. Although there are numerous single studies on the characterization of SAHs in solution or selected solid phases, there is no systematic study comparing different SAHs for biomolecule-binding, hybridization, and PCR assays on solid phases. We compared streptavidin, core streptavidin, traptavidin, core traptavidin, neutravidin, and monomeric streptavidin on the surface of microbeads (10–15 μm in diameter) and designed multiplex microbead-based experiments and analyzed simultaneously the binding of biotinylated oligonucleotides and the hybridization of oligonucleotides to complementary capture probes. We also bound comparably large DNA origamis to capture probes on the microbead surface. We used a real-time fluorescence microscopy imaging platform, with which it is possible to subject samples to a programmable time and temperature profile and to record binding processes on the microbead surface depending on the time and temperature. With the exception of core traptavidin and monomeric streptavidin, all other SA/SAHs were suitable for our investigations. We found hybridization efficiencies close to 100% for streptavidin, core streptavidin, traptavidin, and neutravidin. These could all be considered equally suitable for hybridization, PCR applications, and melting point analysis. The SA/SAH–biotin bond was temperature-sensitive when the oligonucleotide was mono-biotinylated, with traptavidin being the most stable followed by streptavidin and neutravidin. Mono-biotinylated oligonucleotides can be used in experiments with temperatures up to 70 °C. When oligonucleotides were bis-biotinylated, all SA/SAH–biotin bonds had similar temperature stability under PCR conditions, even if they comprised a streptavidin variant with slower biotin dissociation and increased mechanostability. KW - Biopolymers Probes KW - Hybridization KW - Fluorescence KW - Genetics PY - 2020 DO - https://doi.org/10.1021/acs.langmuir.9b02339 VL - 36 IS - 2 SP - 628 EP - 636 PB - American Chemical Society Publication CY - Washington AN - OPUS4-50357 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kneipp, Janina A1 - Zancajo, Victor M.R. A1 - Diehn, S. A1 - Filiba, N. A1 - Elbaum, R. T1 - Spectroscopic Discrimination of Sorghum Silica Phytoliths N2 - Grasses accumulate silicon in the form of silicic acid, which is precipitated as amorphous silica in microscopic particles termed phytoliths. These particles comprise a variety of morphologies according to the cell type in which the silica was deposited. Despite the evident morphological differences, phytolith chemistry has mostly been analysed in bulk samples, neglecting differences between the varied types formed in the same species. In this work, we extracted leaf phytoliths from mature plants of Sorghum bicolor (L.) Moench. Using solid state NMR and thermogravimetric analysis, we show that the extraction methods alter greatly the silica molecular structure, its condensation degree and the trapped organic matter. Measurements of individual phytoliths by Raman and synchrotron FTIR microspectroscopies in combination with multivariate analysis separated bilobate silica cells from prickles and long cells, based on the silica molecular structures and the fraction and composition of occluded organic matter. The variations in structure and composition of sorghum phytoliths suggest that the biological pathways leading to silica deposition vary between these cell types. KW - Phytoliths KW - Biosilicification KW - Raman KW - Sorghum KW - Solid state NMR KW - Synchrotron FTIR PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-502672 DO - https://doi.org/10.3389/fpls.2019.01571 VL - 10 SP - 1571 PB - Frontiers Media CY - Lausanne AN - OPUS4-50267 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schürmann, Robin A1 - Ebel, Kenny A1 - Nicolas, C. A1 - Milosavljevic, A. R. A1 - Bald, Ilko T1 - Role of valence band states and plasmonic enhancement in electron-transfer-induced transformation of nitrothiophenol N2 - Hot-electron-induced reactions are more and more recognized as a critical and ubiquitous reaction in heterogeneous catalysis. However, the kinetics of these reactions is still poorly understood, which is also due to the complexity of plasmonic nanostructures. We determined the reaction rates of the hot-electron-mediated reaction of 4-nitrothiophenol (NTP) on gold nanoparticles (AuNPs) using fractal kinetics as a function of the laser wavelength and compared them with the plasmonic enhancement of the system. The reaction rates can be only partially explained by the plasmonic response of the NPs. Hence, synchrotron X-ray photoelectron spectroscopy (XPS) measurements of isolated NTP-capped AuNP clusters have been performed for the first time. In this way, it was possible to determine the work function and the accessible valence band states of the NP systems. The results show that besides the plasmonic enhancement, the reaction rates are strongly influenced by the local density of the available electronic states of the system. KW - Photocatalytic reduction KW - Raman-spectroscopy KW - Hot-electrons KW - Work function KW - Surface KW - Nanaoparticles KW - Scattering KW - Molecule KW - Carriers KW - Layers PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-486464 DO - https://doi.org/10.1021/acs.jpclett.9b00848 SN - 1948-7185 VL - 10 IS - 11 SP - 3153 EP - 3158 PB - American Chemical Society CY - Washington, DC AN - OPUS4-48646 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heck, Christian A1 - Kanehira, Y. A1 - Kneipp, Janina A1 - Bald, Ilko T1 - Amorphous Carbon Generation as a Photocatalytic Reaction on DNA-Assembled Gold and Silver Nanostructures N2 - Background signals from in situ-formed amorphous carbon, despite not being fully understood, are known to be a common issue in few-molecule surface-enhanced Raman scattering (SERS). Here, discrete gold and silver nanoparticle aggregates assembled by DNA origami were used to study the conditions for the formation of amorphous carbon during SERS measurements. Gold and silver dimers were exposed to laser light of varied power densities and wavelengths. Amorphous carbon prevalently formed on silver aggregates and at high power densities. Time-resolved measurements enabled us to follow the formation of amorphous carbon. Silver nanolenses consisting of three differently-sized silver nanoparticles were used to follow the generation of amorphous carbon at the single-nanostructure level. This allowed observation of the many sharp peaks that constitute the broad amorphous carbon signal found in ensemble measurements. In conclusion, we highlight strategies to prevent amorphous carbon formation, especially for DNA-assembled SERS substrates. KW - Amorphous carbon KW - DNA origami KW - SERS KW - Nanoparticle dimers KW - Nanolenses PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-486484 DO - https://doi.org/10.3390/molecules24122324 SN - 1420-3049 VL - 24 IS - 12 SP - Article Number: 2324-1 EP - 10 PB - MDPI AN - OPUS4-48648 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zhang, Z. A1 - Kneipp, Janina T1 - Ligand-Supported Hot Electron Harvesting: Revisiting the pHResponsive Surface-Enhanced Raman Scattering Spectrum of p‑Aminothiophenol N2 - The discussion of the surface-enhanced Raman scattering (SERS) spectra of p-aminothiophenol (PATP) and of ist photocatalytic reaction product 4,4′-dimercaptoazobenzene (DMAB) is important for understanding plasmon-supported spectroscopy and catalysis. Here, SERS spectra indicate that DMAB forms also in a nonphotocatalytic reaction on silver nanoparticles. Spectra measured at low pH, in the presence of the acids HCl, H2SO4, HNO3, and H3PO4, show that DMAB is reduced to PATP when both protons and chloride ions are present. Moreover, the successful reduction of DMAB in the presence of other, halide and nonhalide, ligands suggests a central role of these species in the reduction. As discussed, the ligands increase the efficiency of hot-electron harvesting. The pH-associated reversibility of the SERS spectrum of PATP is established as an Observation of the DMAB dimer at high pH and of PATP as a product of its hot-electron reduction at low pH, in the presence of the appropriate ligand. KW - Redox reactions KW - Metal nanoparticles KW - Ligands KW - Raman spectroscopy KW - Nanoparticle formation PY - 2021 DO - https://doi.org/10.1021/acs.jpclett.0c03732 SN - 1948-7185 VL - 12 IS - 5 SP - 1542 EP - 1547 PB - ACS Publications AN - OPUS4-52140 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Konar, S. A1 - Michalchuk, Adam A1 - Sen, N. A1 - Bull, C. L. A1 - Morrison, C. A. A1 - Pulham, C. R. T1 - High-Pressure Study of Two Polymorphs of 2,4,6-Trinitrotoluene Using Neutron Powder Diffraction and Density Functional Theory Methods N2 - A high-pressure neutron diffraction study was conducted on polycrystalline samples of the two known polymorphs of 2,4,6-trinitrotoluene [monoclinic (m) and orthorhombic (o) TNT] under hydrostatic conditions. Isothermal equations of state were obtained for both polymorphic forms. Neither polymorph was observed to undergo a phase transition in the pressure region 0–5 GPa, with both polymorphs displaying smooth compression behavior across the pressure range. This differs somewhat from previous X-ray diffraction and Raman spectroscopy investigations in which discontinuities were observed in the P–V curves and spectral changes were reported at ∼2 GPa. The high-pressure response of these materials is supported by dispersion-corrected density functional theory calculations which, while overestimating the experimental bulk moduli, give excellent agreement with the observed smooth compression response of both phases. KW - Energetic Materials PY - 2019 DO - https://doi.org/10.1021/acs.jpcc.9b07658 VL - 123 SP - 26095 EP - 26105 PB - ACS AN - OPUS4-49811 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yadav, Anur A1 - Iost, R. M. A1 - Neubert, T. J. A1 - Baylan, S. A1 - Schmid, Thomas A1 - Balasubramanian, Kannan T1 - Selective electrochemical functionalization of the graphene edge N2 - We present a versatile and simple method using electrochemistry for the exclusive functionalization of the edge of a graphene monolayer with metal nanoparticles or polymeric amino groups. The attachment of metal nanoparticles allows us to exploit surface-enhanced Raman scattering to characterize the chemistry of both the pristine and the functionalized graphene edge. For the pristine patterned graphene edge, we observe the typical edge-related modes, while for the functionalized graphene edge we identify the chemical structure of the functional layer by vibrational fingerprinting. The ability to obtain single selectively functionalized graphene edges routinely on an insulating substrate opens an avenue for exploring the effect of edge chemistry on graphene properties systematically. KW - Graphene KW - Nanoparticles KW - Nanosciences KW - Surface-enhanced Raman scattering KW - Atomic force microscopy PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-474357 DO - https://doi.org/10.1039/C8SC04083D SN - 2041-6520 VL - 10 IS - 3 SP - 936 EP - 942 PB - Royal Society of Chemistry AN - OPUS4-47435 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zeise, I. A1 - Heiner, Z. A1 - Holz, S. A1 - Joester, Maike A1 - Buttner, C. A1 - Kneipp, Janina T1 - Raman imaging of plant cell walls in sections of cucumis sativus N2 - Raman microspectra combine information on chemical composition of plant tissues with spatial information. The contributions from the building blocks of the cell walls in the Raman spectra of plant tissues can vary in the microscopic sub-structures of the tissue. Here, we discuss the analysis of 55 Raman maps of root, stem, and leaf tissues of Cucumis sativus, using different spectral contributions from cellulose and lignin in both univariate and multivariate imaging methods. Imaging based on hierarchical cluster analysis (HCA) and principal component analysis (PCA) indicates different substructures in the xylem cell walls of the different tissues. Using specific signals from the cell wall spectra, analysis of the whole set of different tissue sections based on the Raman images reveals differences in xylem tissue morphology. Due to the specifics of excitation of the Raman spectra in the visible wavelength range (532 nm), which is, e.g., in resonance with carotenoid species, effects of photobleaching and the possibility of exploiting depletion difference spectra for molecular characterization in Raman imaging of plants are discussed. The reported results provide both, specific information on the molecular composition of cucumber tissue Raman spectra, and general directions for future imaging studies in plant tissues. KW - Raman KW - Imaging KW - Pants PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-474610 DO - https://doi.org/10.3390/plants7010007 SN - 2223-7747 VL - 7 IS - 1 SP - 7, 1 EP - 16 PB - MDPI, ST ALBAN-ANLAGE 66, CH-4052 BASEL, SWITZERLAND AN - OPUS4-47461 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Vogel, Stefanie A1 - Ebel, Kenny A1 - Schürmann, Robin M. A1 - Miloavljevic, A. R. A1 - Guliani, A. A1 - Bald, Ilko T1 - Vacuum-UV induced DNA strand breaks – influence of the radiosensitizers 5-bromouracil and 8-bromoadenine N2 - Radiation therapy is a basic part of cancer treatment. To increase the DNA damage in carcinogenic cells and preserve healthy tissue at the same time, radiosensitizing molecules such as halogenated nucleobase analogs can be incorporated into the DNA during the cell reproduction cycle. In the present study 8.44 eV photon irradiation induced single strand breaks (SSB) in DNA sequences modified with the radiosensitizer 5-bromouracil (5BrU) and 8-bromoadenine (8BrA) are investigated. 5BrU was incorporated in the 13mer oligonucleotide flanked by different nucleobases. It was demonstrated that the highest SSB cross sections were reached, when cytosine and thymine were adjacent to 5BrU, whereas guanine as a neighboring nucleobase decreases the activity of 5BrU indicating that competing reaction mechanisms are active. This was further investigated with respect to the distance of guanine to 5BrU separated by an increasing number of adenine nucleotides. It was observed that the SSB cross sections were decreasing with an increasing number of adenine spacers between guanine and 5BrU until the SSB cross sections almost reached the level of a non-modified DNA sequence, which demonstrates the high sequence dependence of the sensitizing effect of 5BrU. 8BrA was incorporated in a 13mer oligonucleotide as well and the strand breaks were quantified upon 8.44 eV photon irradiation in direct comparison to a non-modified DNA sequence of the same composition. No clear enhancement of the SSB yield of the modified in comparison to the non-modified DNA sequence could be observed. Additionally, secondary electrons with a maximum energy of 3.6 eV were generated when using Si as a substrate giving rise to further DNA damage. A clear enhancement in the SSB yield can be ascertained, but to the same degree for both the non-modified DNA sequence and the DNA sequence modified with 8BrA. KW - Vacuum-UV KW - 5-bromouracil KW - 8-bromoadenine PY - 2019 DO - https://doi.org/10.1039/c8cp06813e SN - 1463-9084 VL - 21 IS - 4 SP - 1972 EP - 1979 PB - RSC AN - OPUS4-47462 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Vogel, Stefanie A1 - Ebel, Kenny A1 - Schürmann, Robin M. A1 - Heck, Christian A1 - Meiling, T. A1 - Milosavljevic, A. A1 - Giuliani, A. A1 - Bald, Ilko T1 - Vacuum-UV and low-energy electron induced DNA strand breaks - Influence of the DNA sequence and substrate N2 - DNA is effectively damaged by radiation, which can on the one hand lead to cancer and is on the other hand directly exploited in the treatment of tumor tissue. DNA strand breaks are already induced by photons having an energy below the ionization energy of DNA. At high photon energies, most of the DNA strand breaks are induced by low-energy secondary electrons. In the present study we quantified photon and electron induced DNA strand breaks in four different 12mer oligonucleotides. They are irradiated directly with 8.44 eV vacuum ultraviolet (VUV) photons and 8.8 eV low energy electrons (LEE). By using Si instead of VUV transparent CaF2 as a substrate the VUV exposure leads to an additional release of LEEs, which have a maximum energy of 3.6 eV and can significantly enhance strand break cross sections. Atomic force microscopy is used to visualize strand breaks on DNA origami platforms and to determine absolute values for the strand break cross sections. Upon irradiation with 8.44 eV photons all the investigated sequences show very similar strand break cross sections in the range of 1.7 - 2.3 x 10-16 cm2. The strand break cross sections for LEE irradiation at 8.8 eV are one to two orders of magnitude larger than the ones for VUV photons, and a slight sequence dependence is observed. The sequence dependence is even more pronounced for LEEs with energies < 3.6 eV. The present results help to assess DNA damage by photons and electrons close to the ionization threshold. KW - Vacuum-UV KW - Low-Energy KW - DNA KW - DNA-Sequence PY - 2019 DO - https://doi.org/10.1002/cphc.201801152 SN - 1439-7641 VL - 20 IS - 6 SP - 823 EP - 830 PB - WILEY-VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-47464 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Diehn, Sabrina A1 - Zimmermann, B. A1 - Bagcioglu, M. A1 - Seifert, Stephan A1 - Kohler, A. A1 - Ohlson, M. A1 - Fjellheim, S. A1 - Weidner, Steffen A1 - Kneipp, Janina T1 - Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) shows adaption of grass pollen composition N2 - MALDI time-of-flight mass spectrometry (MALDI-TOF MS) has become a widely used tool for the classification of biological samples. The complex chemical composition of pollen grains leads to highly specific, fingerprint-like mass spectra, with respect to the pollen species. Beyond the species-specific composition, the variances in pollen chemistry can be hierarchically structured, including the level of different populations, of environmental conditions or different genotypes. We demonstrate here the sensitivity of MALDI-TOF MS regarding the adaption of the chemical composition of three Poaceae (grass) pollen for different populations of parent plants by analyzing the mass spectra with partial least squares discriminant analysis (PLS-DA) and principal component analysis (PCA). Thereby, variances in species, population and specific growth conditions of the plants were observed simultaneously. In particular, the chemical pattern revealed by the MALDI spectra enabled discrimination of the different populations of one species. Specifically, the role of environmental changes and their effect on the pollen chemistry of three different grass species is discussed. Analysis of the Group formation within the respective populations showed a varying influence of plant genotype on the classification, depending on the species, and permits conclusions regarding the respective rigidity or plasticity towards environmental changes. KW - Pollen KW - MALDI-TOF MS KW - Classification KW - Partial least square discriminant analysis (PLS-DA) KW - Principal component analysis (PCA) PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-465294 DO - https://doi.org/10.1038/s41598-018-34800-1 SN - 2045-2322 VL - 8 IS - 1 SP - 16591, 1 EP - 11 PB - Nature AN - OPUS4-46529 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Choi, Youungeun A1 - Kotthoff, Lisa A1 - Olejko, L. A1 - Resch-Genger, Ute A1 - Bald, Ilko T1 - DNA origami-based Förster resonance energy-transfer nanoarrays and their application as ratiometric sensors N2 - DNA origami nanostructures provide a platform where dye molecules can be arranged with nanoscale accuracy allowing to assemble multiple fluorophores without dye–dye aggregation. Aiming to develop a bright and sensitive ratiometric sensor system, we systematically studied the optical properties of nanoarrays of dyes built on DNA origami platforms using a DNA template that provides a high versatility of label choice at minimum cost. The dyes are arranged at distances, at which they efficiently interact by Förster resonance energy transfer (FRET). To optimize array brightness, the FRET efficiencies between the donor fluorescein (FAM) and the acceptor cyanine 3 were determined for different sizes of the array and for different arrangements of the dye molecules within the array. By utilizing nanoarrays providing optimum FRET efficiency and brightness, we subsequently designed a ratiometric pH nanosensor using coumarin 343 as a pH-inert FRET donor and FAM as a pH-responsive acceptor. Our results indicate that the sensitivity of a ratiometric sensor can be improved simply by arranging the dyes into a well-defined array. The dyes used here can be easily replaced by other analyte-responsive dyes, demonstrating the huge potential of DNA nanotechnology for light harvesting, signal enhancement, and sensing schemes in life sciences. KW - DNA origami KW - FRET KW - Sensing KW - Ratiometric sensing KW - Fluorescence PY - 2018 DO - https://doi.org/10.1021/acsami.8b03585 SN - 1944-8244 SN - 1944-8252 VL - 10 IS - 27 SP - 23295 EP - 23302 PB - ACS AN - OPUS4-46002 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Raysyan, Anna T1 - Breaking the wall of complicated laboratory methods N2 - How intricate lab methods make it to the lay(wo)men’s hand. T2 - Falling Walls Lab Adlershof CY - Berlin, Germany DA - 28.09.2018 KW - Easy-use device PY - 2018 AN - OPUS4-46755 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bremser, Wolfram T1 - The new ISO Guide 35:2017: New airflow, new approaches, and more freedom for RMP N2 - An overlook over the new ISO Guide 35:2017 is given, with focus on the new, sometimes challenging opprotunities and approaches of this Guide. T2 - DAkkS Informationsveranstaltung zur Akkreditierung von RMP CY - Berlin, Germany DA - 15.02.2018 KW - reference materials, requirements, guidance PY - 2018 AN - OPUS4-46772 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heck, C. A1 - Michaeli, Y. A1 - Bald, Ilko A1 - Ebenstein, Y. T1 - Analytical epigenetics: single-molecule optical detection of DNA and histone modifications N2 - The field of epigenetics describes the relationship between genotype and phenotype, by regulating gene expression without changing the canonical base sequence of DNA. It deals with molecular genomic information that is encoded by a rich repertoire of chemical modifications and molecular interactions. This regulation involves DNA, RNA and proteins that are enzymatically tagged with small molecular groups that alter their physical and chemical properties. It is now clear that epigenetic alterations are involved in development and disease, and thus, are the focus of intensive research. The ability to record epigenetic changes and quantify them in rare medical samples is critical for next generation diagnostics. Optical detection offers the ultimate single-molecule sensitivity and the potential for spectral multiplexing. Here we review recent progress in ultrasensitive optical detection of DNA and histone modifications. KW - Epigenetics KW - Fluorescence KW - SERS PY - 2019 UR - https://www.sciencedirect.com/science/article/pii/S095816691830082X DO - https://doi.org/10.1016/j.copbio.2018.09.006 SN - 0958-1669 VL - 55 SP - 151 EP - 158 PB - Elsevier AN - OPUS4-46680 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Abdoul-Carime, H. A1 - Bald, Ilko A1 - Illenberger, E. A1 - Kopyra, J. T1 - Selective synthesis of ethylene and acetylene from dimethyl sulfide cold films controlled by slow electrons N2 - One of the major challenges in chemical synthesis is to trigger and control a specific reaction route leading to a specific final product, while side products are avoided. Methodologies based on resonant processes at the molecular level, for example, photochemistry, offer the possibility of inducing selective reactions. Electrons at energies below the molecular ionization potential (<10 eV) are known to dissociate molecules via resonant processes with higher cross sections and specificity than photons. Here we show that even subexcitation electrons with energies as low as 1 eV produce ethylene and acetylene from dimethyl sulfide in competing reactions. However, the production of ethylene can specifically be targeted by controlling the energy of electrons (∼3 to 4 eV). Finally, pure ethylene is selectively desorbed by heating the substrate from 90 to 105 K. Beyond the synthesis of these versatile hydrocarbons for various industrial applications from a biogenic sulfur compound, our findings demonstrate the feasibility of electron-induced selective chemistry applicable on the nanoscale. KW - Low-energy electrons KW - Dissociative electron attachment KW - Green chemistry PY - 2018 DO - https://doi.org/10.1021/acs.jpcc.8b07377 SN - 1932-7447 VL - 122 IS - 42 SP - 24137 EP - 24142 PB - ACS AN - OPUS4-46679 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Choi, Youngeun A1 - Schmidt, Carsten A1 - Tinnefeld, Philip A1 - Bald, Ilko A1 - Roedinger, Stefan T1 - A new reporter design based on DNA origami nanostructures for quantification of short oligonucleotides using microbeads N2 - The DNA origami technique has great potential for the development of brighter and more sensitive reporters for fluorescence based detection schemes such as a microbead-based assay in diagnostic applications. The nanostructures can be programmed to include multiple dye molecules to enhance the measured signal as well as multiple probe strands to increase the binding strength of the target oligonucleotide to these nanostructures. Here we present a proof-of-concept study to quantify short oligonucleotides by developing a novel DNA origami based reporter system, combined with planar microbead assays. Analysis of the assays using the VideoScan digital imaging platform showed DNA origami to be a more suitable reporter candidate for quantification of the target oligonucleotides at lower concentrations than a conventional reporter that consists of one dye molecule attached to a single stranded DNA. Efforts have been made to conduct multiplexed analysis of different targets as well as to enhance fluorescence signals obtained from the reporters. We therefore believe that the quantification of short oligonucleotides that exist in low copy numbers is achieved in a better way with the DNA origami nanostructures as reporters. KW - Origami KW - Nanostructures KW - Microbeads KW - DNA origami KW - Oligonucleotides PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-476443 DO - https://doi.org/10.1038/s41598-019-41136-x SN - 2045-2322 VL - 9 SP - 4769, 1 EP - 8 PB - Nature AN - OPUS4-47644 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ferreira da Silva, F. A1 - do N. Varella, M. T. A1 - Jones, N. C. A1 - Vrönning Hoffmann, S. A1 - Denifl, S. A1 - Bald, Ilko A1 - Kopyra, J. T1 - Electron-Induced Reactions in 3-Bromopyruvic Acid N2 - 3-Bromopyruvic acid (3BP) is a potential anticancer drug, the action of which on cellular metabolism is not yet entirely clear. The presence of a bromine atom suggests that it is also reactive towards low-energy electrons, which are produced in large quantities during tumour Radiation therapy. Detailed knowledge of the interaction of 3BP with secondary electrons is a prerequisite to gain a complete picture of the effects of 3BP in different forms of Cancer therapy. Herein, dissociative electron attachment (DEA) to 3BP in the gas phase has been studied both experimentally by using a crossed-beam setup and theoretically through scattering and quantum chemical calculations. These results are complemented by a vacuum ultraviolet absorption spectrum. The main fragmentation channel is the formation of Br@ close to 0 eV and within several resonant features at 1.9 and 3–8 eV. At low electron energies, Br@ formation proceeds through s* and p* shape resonances, and at higher energies through core-excited resonances. It is found that the electron-capture cross-section is clearly increased compared with that of non-brominated pyruvic acid, but, at the same time, fragmentation reactions through DEA are significantly altered as well. The 3BP transient negative ion is subject to a lower number of fragmentation reactions than those of pyruvic acid, which indicates that 3BP could indeed act by modifying the electron-transport chains within oxidative phosphorylation. It could also act as a radio-sensitiser. KW - Density functional calculations KW - Dissociative electron attachment KW - Drug discovery KW - Gas-phase reactions KW - Sensitizers PY - 2019 DO - https://doi.org/10.1002/chem.201806132 SN - 0947-6539 VL - 25 IS - 21 SP - 5498 EP - 5506 PB - WILEY-VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-48003 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - El-Athman, Rukeia A1 - Bresch, Harald A1 - Muth, Thilo A1 - Rädler, Jörg A1 - Rühle, Bastian T1 - Datenmanagement im Nanomaterial-Labor: Einsatz von ELN-Software zur digitalen Transformation des Laboralltags N2 - Angesichts der zunehmenden Digitalisierung und dem Einsatz datenintensiver Methodiken in der Wissenschaft stehen Forschende vor der Herausforderung, stetig wachsende Datenmengen nachvollziehbar zu dokumentieren, langfristig zu speichern und für Dritte nachnutzbar zu machen. Um diesen Anforderungen gerecht zu werden, bietet sich die Nutzung von Software-Lösungen an, welche Forschungsdatenmanagement mit der digitalen Dokumentation von Laborinventar und Experimenten in elektronischen Laborbüchern (engl. electronic lab notebooks (ELN)) verknüpfen. KW - NanoPlattform KW - BAM Data Store KW - OpenBIS KW - Forschungsdatenmanagement KW - Research data management KW - Elektronisches Laborbuch KW - Electronic lab notebook (ELN) PY - 2023 UR - https://analyticalscience.wiley.com/content/article-do/datenmanagement-im-nanomaterial-labor SN - 0016-3538 IS - 9 SP - 24 EP - 26 PB - Wiley Analytical Science CY - Weinheim AN - OPUS4-59600 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Temgoua, Ranil C.T. A1 - Dontsi, Fabiola T. A1 - Lebègue, Estelle A1 - Thobie-Gautier, Christine A1 - Tonlé, Ignas K. A1 - Boujtita, Mohammed T1 - Understanding the behavior of phenylurazole-tyrosine-click electrochemical reaction using hybrid electroanalytical techniques N2 - In this work, the electrochemical behavior of 4-phenylurazole (Ph-Ur) was studied and the latter was used as a molecular anchor for the electrochemical bioconjugation of tyrosine (Y). Cyclic voltammetry (CV) and controlled potential coulometry (CPC) allowed the in-situ generation of the PTAD (4-phenyl-3 H-1,2,4-triazole-3,5(4 H)-dione) species from phenylurazole on demand for tyrosine electrolabeling. The chemoselectivity of the reaction was studied with another amino acid (lysine, Lys) and no changes in Lys were observed. To evaluate the performance of tyrosine electrolabeling, coulometric analyses at controlled potentials were performed on solutions of phenylurazole and the phenylurazole-tyrosine mixture in different proportions (2:1, 1:1, and 1:2). The electrolysis of the phenylurazole-tyrosine mixture in the ratio (1:2) produced a charge of 2.07 C, very close to the theoretical value (1.93 C), with high reaction kinetics, a result obtained here for the first time. The products obtained were identified and characterized by liquid chromatography coupled to high-resolution electrospray ionization mass spectrometry (LC-HRMS and LC- HRMS2). Two products were formed from the click reactions, one of which was the majority. Another part of this work was to study the electrochemical degradation of the molecular anchor 4-phenylazole (Ph-Ur). Four stable degradation products of phenylurazole were identified (C7H9N2O, C6H8N, C6H8NO, C14H13N4O2) based on chromatographic profiles and mass spectrometry results. The charge generated during the electrolysis of phenylurazole (two-electron process) (2.85 C) is inconsistent with the theoretical or calculated charge (1.93 C), indicating that secondary/parasitic reactions occurred during the electrolysis of the latter. In conclusion, the electrochemically promoted click phenylurazole-tyrosine reactions give rise to click products with high reaction kinetics and yields in the (1:2) phenylurazole-tyrosine ratios, and the presence of side reactions is likely to affect the yield of the click phenylurazole-tyrosine reaction. KW - Clinical Biochemistry KW - Spectroscopy KW - Drug Discovery KW - Pharmaceutical Science KW - Analytical Chemistry PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599267 DO - https://doi.org/10.1016/j.jpba.2024.116147 VL - 245 SP - 1 EP - 8 PB - Elsevier BV AN - OPUS4-59926 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan A1 - Rühle, Bastian A1 - Bresch, Harald T1 - Competence Center nano@BAM Welcomes ISO/TC 229 Meeting in Berlin N2 - The Competence Center nano@BAM is presented. Examples directly related to the activities of the ISO Technical Committee TC 229 Nanotechnologies as well as BAM projects on nano reference measurement procedures, nano reference materials and nano reference data sets are showed. T2 - The 32nd ISO/TC 229 IEC/TC 113 JWG2 General Meeting CY - Berlin, Germany DA - 06.11.2023 KW - ISO/TC 229 Nanotechnologies KW - Nanoparticles KW - Nano@BAM KW - Reference materials KW - Reference data KW - Reference procedures PY - 2023 AN - OPUS4-58814 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mrkwitschka, Paul A1 - Rühle, Bastian A1 - Kuchenbecker, Petra A1 - Löhmann, Oliver A1 - Lindemann, Franziska A1 - Hodoroaba, Vasile-Dan T1 - Embedding and cross-sectioning as a sample preparation procedure for accurate and representative size and shape measurement of nanopowders N2 - Reliable measurement of the size of polydisperse, complex-shaped commercial nanopowders is a difficult but necessary task, e.g., for regulatory requirements and toxicity risk assessment. Suitable methods exist for the accurate characterization of the size of non-aggregated, stabilized, spherical and monodisperse nanoparticles. In contrast, industrial nanoscale powders usually require dedicated sample preparation procedures developed for the analysis method of choice. These nano-powders tend to agglomerate and/or aggregate, a behavior which in combination with an innate broad particle size distribution and irregular shape often significantly alters the achievable accuracy of the measured size parameters. The present study systematically tests two commercially available nanoscale powders using different sample preparation methods for correlative analysis by scanning electron microscopy, dynamic light scattering, Brunauer–Emmet–Teller method and differential mobility analysis. One focus was set on the sample preparation by embedding nanoparticles in carbon-based hot-mounting resin. Literature on this topic is scarce and the accuracy of the data extracted from cross sections of these particles is unclearly stated. In this paper systematic simulations on the deviation of the size parameters of well-defined series of nanoparticles with different shapes from the nominal value were carried out and the contributing factors are discussed. KW - Nanopowder KW - Electron microscopy KW - Sample preparation KW - Cross-sectioning KW - Cerium oxide KW - Zinc oxide PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593289 DO - https://doi.org/10.1038/s41598-023-51094-0 SN - 2045-2322 VL - 14 SP - 1 EP - 10 PB - Springer Nature CY - London AN - OPUS4-59328 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Fischer, Janina T1 - Suspensionsarray-Fluoreszenzimmunoassay zur Multiplexbestimmung von SARS-CoV-2-Antikörpern N2 - Übergeordnetes Ziel der Arbeit war die Entwicklung und Optimierung eines Suspensionsarray-Fluoreszenzimmunoassays (SAFIA) für die simultane Bestimmung verschiedener gegen SARS-CoV-2-Proteine gerichtete Antikörper mittels Multiplexdetektion in komplexen Matrices wie humanen Blutserumproben. KW - SARS-CoV-2 KW - Corona KW - COVID-19 KW - Coronavirus KW - Virus KW - Spike-Protein KW - Nucleocapsid-Protein KW - RBD KW - SAFIA KW - LFIA KW - ELISA KW - Partikel KW - Mutationen KW - Neutralisierende Antikörper KW - Durchflusszytometrie KW - ACE2 PY - 2022 SP - 1 EP - 99 PB - Humboldt-Universität zu Berlin CY - Berlin AN - OPUS4-54722 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kipphardt, Heinrich A1 - Tuma, Dirk A1 - Khanipour, Peyman A1 - Maiwald, Michael T1 - Voll normal - Normen in der Gasanalytik N2 - In dieser Arbeit werden die Grundlagen der Normung, die Entstehung einer Norm und die für die Gasanalytik relevanten Normungsgremien kurz dargestellt. Dazu werden die wichtigsten Normen zur Gasanalytik entlang des analytischen Prozesses gruppiert und aufgeführt. Schließlich wird als Anwendungsbeispiel aus der eigenen Praxis der Prozess von der Herstellung bis zur Zertifizierung eines Kalibriergases beschrieben. KW - Zertifikat KW - Regel- und Messtechnik KW - Normung KW - Gasanalytik KW - Gasgualität KW - Gasreinheit PY - 2022 SN - 2366-9594 VL - 10 SP - 73 EP - 80 PB - Vulkan Verlag CY - Essen AN - OPUS4-56083 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Beyer, Sebastian A1 - Schürmann, Robin A1 - Feldmann, Ines A1 - Blocki, A. A1 - Bald, Ilko A1 - Schneider, Rudolf A1 - Emmerling, Franziska T1 - Maintaining Stable Zeolitic Imidazolate Framework (ZIF) Templates during Polyelectrolyte Multilayer Coating N2 - Equipping ZIF particles with a polyelectrolyte membrane provides functional groups at their interface, enabling further conjugations necessary for applications such as targeted drug delivery. Previous approaches to coat ZIF particles with polyelectrolytes led to surface corrosion of the template material. This work overcomes previous limitations by performing a Layer-by-Layer (LbL) polyelectrolyte coating onto ZIF-8 and ZIF-67 particles in nonaqueous environment. Using the 2-methylimidazolium salt of polystyrensulfonic acid instead of the acid itself and polyethyleneimine in methanol led to intact ZIF particles after polyelectrolyte coating. This was verified by electron microscopy. Further, zetapotential and atomic force microscopy measurements confirmed a continuous polyelectrolyte multilayer built up. The here reported adaption to the well-studied (LbL) polyelectrolyte selfassembly process provides a facile method to equip ZIF particles with a nanometer thin polyelectrolyte multilayer membrane. KW - Zeolithe KW - Molecular Organic Frameworks KW - MOF KW - ZIF KW - Layer-by-Layer KW - Beschichtung KW - Polyelektrolyt PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-447729 DO - https://doi.org/10.1016/j.colcom.2017.11.004 SN - 2215-0382 VL - 22 SP - 14 EP - 17 PB - Elsevier B.V. CY - Amsterdam, NL AN - OPUS4-44772 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Riedel, Soraya A1 - Hülagü, Deniz A1 - Bennet, Francesca A1 - Carl, Peter A1 - Flemig, Sabine A1 - Schmid, Thomas A1 - Schenk, J. A. A1 - Hodoroaba, Vasile-Dan A1 - Schneider, Rudolf T1 - Electrochemical Immunomagnetic Ochratoxin A Sensing: Steps Forward in the Application of 3,3’,5,5’- Tetramethylbenzidine in Amperometric Assays N2 - Electrochemical methods offer great promise in meeting the demand for user-friendly on-site devices for Monitoring important parameters. The food industry often runs own lab procedures, for example, for mycotoxin analysis, but it is a major goal to simplify analysis, linking analytical methods with smart technologies. Enzyme-linked immunosorbent assays, with photometric detection of 3,3’,5,5’-tetramethylbenzidine (TMB),form a good basis for sensitive detection. To provide a straightforward approach for the miniaturization of the detectionstep, we have studied the pitfalls of the electrochemical TMB detection. By cyclic voltammetry it was found that the TMB electrochemistry is strongly dependent on the pH and the electrode material. A stable electrode response to TMB could be achieved at pH 1 on gold electrodes. We created a smartphonebased, electrochemical, immunomagnetic assay for the detection of ochratoxin A in real samples, providing a solid basis forsensing of further analytes. KW - Ochratoxin A KW - Amperometry KW - Cyclic voltammetry KW - Electrochemistry KW - Immunoassay PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530421 DO - https://doi.org/10.1002/celc.202100446 N1 - Geburtsname von Riedel, Soraya: Höfs, S. - Birth name of Riedel, Soraya: Höfs, S. VL - 8 IS - 13 SP - 2597 EP - 2606 AN - OPUS4-53042 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mrkwitschka, Paul A1 - Abram, Sarah-Luise A1 - Thünemann, Andreas A1 - Rühle, Bastian A1 - Radnik, Jörg A1 - Bresch, Harald A1 - Resch-Genger, Ute A1 - Hodoroaba, Vasile-Dan T1 - The Role of Electron Microscopy in the Development of Monodisperse Cubic Iron Oxide Nanoparticles as Certified Reference Material for Size and Shape N2 - BAM is currently building up a platform of novel nanoRMs relying on iron oxide nanoparticles of different shape, size and surface chemistry. Iron oxide was chosen as a core material because of its relevance to the material and life sciences. As a first candidate of this series, we present cubic iron oxide nanoparticles with a nominal edge length of 8 nm. These particles were synthesized by thermal decomposition of iron oleate in high boiling organic solvents adapting well-known literature procedures. After dilution to a concentration suitable for electron microscopy (TEM and SEM) as well as for small-angle X-ray scattering (SAXS) measurements, the candidate nanoRM was bottled and assessed for homogeneity and stability by both methods following the guidelines of ISO 17034 and ISO Guide 35. The particle sizes obtained by both STEM-in-SEM and TEM are in excellent agreement with a minimum Feret of 8.3 nm ± 0.7 nm. The aspect ratio (AR) of the iron oxide cubes were extracted from the images as the ratio of minimum Feret to Feret resulting in an AR of 1.18 for TEM to 1.25 for SEM. Alternatively, a rectangular bounding box was fitted originating from the minimum Feret and the longest distance through the particle in perpendicular direction. This led to AR values of 1.05 for TEM and 1.12 for SEM, respectively. The results confirm the almost ideal cubic shape. KW - Reference nanoparticles KW - Iron oxide KW - Cubical shape KW - Electron microscopy KW - SAXS KW - Nano CRM KW - Size PY - 2022 DO - https://doi.org/10.1017/S1431927622003610 SN - 1435-8115 VL - 28 IS - Suppl. 1 SP - 802 EP - 805 PB - Cambridge University Press AN - OPUS4-55599 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Abad Andrade, Carlos Enrique A1 - Florek, S. A1 - Becker-Ross, H. A1 - Huang, M.-D. A1 - Heinrich, Hans-Joachim A1 - Recknagel, Sebastian A1 - Vogl, Jochen A1 - Jakubowski, Norbert A1 - Panne, Ulrich T1 - Stable Isotope Analysis Using Molecular Absorption Spectrometry N2 - We propose an alternative faster and low-cost optical method for isotope analysis: high-resolution continuum source molecular absorption spectrometry (HR-CS-MAS). Stable isotope amount composition of X = Li, B, Mg, Ca and Sr were determined by monitoring the absorption spectra of their in situ generated mono-hydrides (XH) in graphite furnace HR-CS-MAS. Isotopes of boron (10B and 11B) were studied via their hydrides for the electronic transition X1Σ+ → A1Π (Fig. 1a). The spectrum of a given sample is a linear combination of the 10BH molecule and its isotopologue 11BH. Therefore, the isotopic composition of samples can be calculated by a partial least square regression (PLS). For this, a spectral library is built by using samples with known isotope composition. Results with an accuracy of 0.15 ‰ are metrologically compatible with those reported by mass spectrometric methods. Similar results are obtained for n isotope systems like Mg (24Mg, 25Mg, and 26Mg), where isotope shifts of their isotopologues can be resolved as shown in Fig.1b. The extension of this methodology to other elements like Li, Ca and Sr is discussed. T2 - Goldschmidt Conference 2018 CY - Boston, MA, USA DA - 12.08.2018 KW - Isotope KW - HR-CS-MAS KW - Mono-hydride KW - Spectrometry PY - 2018 AN - OPUS4-45825 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kaufmann, Jan Ole A1 - Brangsch, J. A1 - Kader, A. A1 - Saatz, Jessica A1 - Mangarova, D. B. A1 - Zacharias, M. A1 - Kempf, W. E. A1 - Schwaar, T. A1 - Wilke, Marco A1 - Adams, L. C. A1 - Möckel, J. A1 - Botnar, R. M. A1 - Taupitz, M. A1 - Mägdefessel, L. A1 - Traub, Heike A1 - Hamm, B. A1 - Weller, Michael G. A1 - Makowski, M. R. T1 - ADAMTS4-specific MR-probe to assess aortic aneurysms in vivo using synthetic peptide libraries N2 - The incidence of abdominal aortic aneurysms (AAAs) has substantially increased during the last 20 years and their rupture remains the third most common cause of sudden death in the cardiovascular field after myocardial infarction and stroke. The only established clinical parameter to assess AAAs is based on the aneurysm size. Novel biomarkers are needed to improve the assessment of the risk of rupture. ADAMTS4 (A Disintegrin And Metalloproteinase with ThromboSpondin motifs 4) is a strongly upregulated proteoglycan cleaving enzyme in the unstable course of AAAs. In the screening of a one-bead-one-compound library against ADAMTS4, a low-molecular-weight cyclic peptide is discovered with favorable properties for in vivo molecular magnetic resonance imaging applications. After identification and characterization, it’s potential is evaluated in an AAA mouse model. The ADAMTS4-specific probe enables the in vivo imaging-based prediction of aneurysm expansion and rupture. KW - Peptide KW - Peptide library KW - OBOC library KW - Combinatorial chemistry KW - Peptide aptamers KW - Binding molecule KW - Affinity KW - Synthetic peptides KW - Contrast agent KW - Magnetic resonance imaging KW - One-bead-one-compound library KW - On-chip screening KW - Lab-on-a-chip KW - MALDI-TOF MS KW - SPR KW - Surface plasmon resonance KW - Alanine scan KW - Fluorescence label KW - MST KW - Docking KW - Chelate PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560930 DO - https://doi.org/10.1038/s41467-022-30464-8 VL - 13 IS - 1 SP - 1 EP - 18 PB - Springer Nature Limited CY - Heidelberg AN - OPUS4-56093 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Abad Andrade, Carlos Enrique A1 - Florek, S. A1 - Becker-Ross, H. A1 - Huang, M.-D. A1 - Heinrich, Hans-Joachim A1 - Recknagel, Sebastian A1 - Vogl, Jochen A1 - Jakubowski, Norbert A1 - Panne, Ulrich T1 - Stable isotope analysis via hydrides using molecular absorption spectrometry N2 - Small variations in the isotopic composition of some elements have been used as proof of provenance of mineral and biological samples, to describe geological processes, and to estimate a contamination source. Routinely, isotope compositions are measured by mass spectrometry; the working horse of the isotope analysis. However, mass spectrometric methods are expensive, time-consuming and they require a high qualified analyst. Here, an alternative faster and low-cost optical method for isotope ratio determination is investigated: high-resolution continuum source molecular absorption spectrometry (HR-CS-MAS). Stable isotope amount composition of X = Li, B, Mg, Ca and Sr have been determined by monitoring the absorption spectra of their in situ generated hydrides (XH) in graphite furnace HR-CS-MAS. For example, the system of two stable isotopes of boron (10B and 11B) was studied via its hydride for the electronic transition X1Σ+ → A1Π (Fig. 1a). The spectrum of a given sample is a linear combination of the 10BH molecule and its isotopologue 11BH. Therefore, isotopic composition of samples and reference materials are calculated by a partial least square regression (PLS). For this, a spectral library is built by using samples with known isotope composition. Results are metrologically compatible with those reported by mass spectrometric methods. [1] Similar results are obtained for n isotope systems like Mg (24Mg, 25Mg, and 26Mg), where isotope shift of their isotopologues can be resolved as shown in Fig.1 b. The extension of this methodology to other elements like Li, Ca and Sr is discussed [2]. References: [1] C. Abad, S. Florek, H. Becker-Ross, M.-D. Huang, H.-J. Heinrich, S. Recknagel, J. Vogl, N. Jakubowski, U. Panne, Determination of boron isotope ratios by high-resolution continuum source molecular absorption spectrometry using graphite furnace vaporizers, Spectrochim. Acta, Part B, 136 (2017) 116-122. [2] C. Abad et al., unpublished results, 2018. T2 - ESAS & CANAS 2018 CY - Berlin, Germany DA - 20.03.2018 KW - Isotope KW - HR-CS-MAS KW - Mono-hydride KW - Spectrometry PY - 2018 AN - OPUS4-45826 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Abad Andrade, Carlos Enrique A1 - Florek, S. A1 - Becker-Ross, H. A1 - Huang, M.-D. A1 - Muench, S. A1 - Okruss, M. A1 - Heinrich, Hans-Joachim A1 - Recknagel, Sebastian A1 - Tatzel, Michael A1 - Vogl, Jochen A1 - Jakubowski, Norbert A1 - Panne, Ulrich T1 - Optical spectrometry versus mass spectrometry for stable isotope analysis of B and Mg N2 - Mass spectrometric methods (MC-ICP-MS and TIMS) are without doubt the working horse of stable isotope analysis. However, drawbacks of these methods include the high costs for instruments and their operation, experienced operators and elaborate chromatographic sample preparation which are time consuming. We propose a lower-cost and faster optical alternative for the analysis of isotope ratios of selected elements: high-resolution continuum source molecular absorption spectrometry (HR-CS-MAS). Stable isotope amount compositions of boron (B) and magnesium (Mg) were determined based on the absorption spectra of in-situ generated mono-hydrides and halide (MH and MX) using graphite furnace HR-CS-MAS. The use of a modular simultaneous echelle spectrograph (MOSES) helps to find the maximal isotope shift in the diatomic molecular spectra produced in a graphite furnace by using isotopic spike solutions. Isotopes of boron (10B and 11B) were studied via their hydrides for the electronic transition X 1Σ+ → A 1Π. The spectrum of a given sample is a linear combination of the 10BH molecule and its isotopologue 11BH. Therefore, the isotopic composition of samples can be calculated by a partial least square regression (PLS). For this, a spectral library was built by using samples and spikes with known isotope composition. Boron isotope ratios measured by HR-CS-MAS are identical with those measured by mass spectrometric methods at the 0.15 ‰ level. Similar results were obtained for a multiple isotope system like Mg (24Mg, 25Mg, and 26Mg), where isotope shifts of their isotopologues can be resolved in the MgF molecule for the electronic transition X 2Σ → A 2 Πi. The extension of this methodology to other elements like Li, Ca, Cu, and Sr is discussed. T2 - 13. Symposium „Massenspektrometrische Verfahren der Elementspurenanalyse“ zusammen mit dem 26. ICPMS-Anwendertreffen CY - Berlin, Germany DA - 03.09.2018 KW - Isotope KW - HR-CS-MAS KW - Isotopic shift KW - Spectrometry KW - Boron monohydride KW - Magnesium monofluoride KW - Molecular absorption spectrometry PY - 2018 AN - OPUS4-45868 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kozdras, Mark A1 - Ruehle, Bastian T1 - Towards a Self-driving Lab for Nanoparticle Research N2 - Society is currently confronted with two global challenges, climate change and sustainable development. This reality reverberates amongst the leading nations of the world and is articulated as a priority by the United Nations through the Framework Convention on Climate Change and its seventeen Sustainable Development Goals. In 2016, under the Paris Accord, Mission Innovation, MI, emerged as a global response to climate change and developed eight innovation challenges to mitigate its effect, including Clean Energy Materials, IC6. This innovation challenge focused its efforts on accelerating the development and deployment of clean energy materials by more than a factor of ten through Materials Acceleration Platforms, MAPs – autonomous, self-driving materials laboratories and renewed itself under the current mandate as Materials for Energy, M4E. Self-driving labs deploy artificial intelligence, robotic automation and high-performance simulation and modeling in a closed loop system of material synthesis and characterization. An international ecosystem for accelerated materials discovery has been established and finds applications in many enabling materials technologies, including nanomaterials. The importance of nanomaterials to catalysis for hydrogen production and carbon dioxide conversion as well as energy storage in batteries is well known. In this work, the international efforts under Materials for Energy will be elaborated including the development of MINERVA - MAP for Intelligent Nanomaterial synthesis Enabled by Robotics for Versatile Applications. MINERVA was specifically built to include the specialized equipment required for the synthesis, characterization and closed-loop optimization of various nano- and advanced materials, ranging from simple inorganic (silica, metal, metal oxide) or polymeric nanoparticles to more complex core-shell architectures and materials with well-defined porosity or surface chemistry. Currently, we are investigating materials for applications in antimicrobial and antibiofouling surface coatings, sensor materials, as well as the reproducible synthesis of reference materials with this platform. T2 - Nanotek 2024 CY - Barcelona, Spain DA - 25.03.2024 KW - Self-driving Labs KW - SDLs KW - Advanced Materials KW - Autonomous Materials Discovery KW - Nanoparticles Synthesis and Characterization PY - 2024 AN - OPUS4-60382 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ruehle, Bastian A1 - Özcan, Özlem T1 - The potential of Material Acceleration Platforms (MAPs) for creating resilient and sustainable technology value chains N2 - Material Acceleration Platforms (MAPs) represent a transformative approach to the development of resilient and sustainable technology value chains. These platforms can identify candidate chemistries and structures via simulations, and database searches and leverage machine learning-based rapid screening to accelerate the discovery and deployment of novel materials, thereby addressing critical challenges in modern technology sectors. Incorporating high-fidelity advanced characterization in the early phases of material development is crucial for early de-risking. Advanced characterization techniques, such as X-ray diffraction, advanced electrochemical and spectroscopic techniques provide comprehensive insights into the structural, chemical, and physical properties of materials. Long-term testing further contributes to the de-risking process by evaluating the durability and stability of materials under various environmental and operational conditions. Early identification of potential degradation mechanisms enables the refinement of material compositions and processing methods, ultimately leading to the development of more resilient materials. Early upscaling attempts are integral to assessing the feasibility of material leads generated through machine learning-based rapid screening to evaluate the scalability of synthesis and processing techniques. This step is critical for identifying potential challenges in manufacturing, such as issues related to reproducibility, yield, and cost-effectiveness. Process design has to be a major part of the MAP-based material design to cope with the increasing share of secondary raw materials in supply chains. This presentation will briefly summarize possible strategies to address these issues and provide deep-dives on best practices. As the demand for advanced materials continues to grow, MAPs will play an increasingly vital role in driving technological advancements and addressing global challenges. T2 - Materials Week Cyprus 2024 CY - Limassol, Cyprus DA - 17.06.2024 KW - MAPs KW - SDLs KW - Sustainability PY - 2024 AN - OPUS4-60379 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mrkwitschka, Paul A1 - Abram, Sarah-Luise A1 - Rühle, Bastian A1 - Hodoroaba, Vasile-Dan T1 - Correlative analysis with electron microscopy applied in different operating modes (SEM, STEM-in-SEM and TEM) for the accurate morphological characterisation of non-spherical fine nanoparticles N2 - Electron microscopy applied in different operating modes, e.g., SEM, TEM or STEM-in-SEM, is the gold standard method to investigate the exact size and shape of individual nanoparticles. However, when fine nanoparticles with a non-monodisperse size distribution and non-spherical shapes are analysed, achieving an accurate result is challenging. Deviations in size measurements of more than 10% may occur. Understanding of the contrasts and sensitivities characteristic to the individual operating modes of an electron microscope is key in interpreting and evaluating quantitatively the measurement uncertainties needed for an eventual certification of specific nanoparticles via traceable results. Further, beyond the pure measurement, the other components in the analysis workflow with significant impact on the overall measurement uncertainties are the sample preparation and the image segmentation. In the present study the same areas of selected iron oxide fine nanoparticles (<25 nm) as reference nanomaterial (candidate) prepared on substrate for electron microscopy imaging are analysed correlatively with SEM, STEM-in-SEM and TEM with respect to their size and shape distribution. Individual significant measurement uncertainties are discussed, e.g., the sensitivity of secondary electron detectors of InLens-type to the surface morphology, particularly to the presence of an ultrathin organic coating or signal saturation effects on the particle edges, to electron beam exposure, to surface contamination, or the selection of the threshold for image segmentation. Another goal of this study is to establish a basis of analysis conditions which shall guarantee accurate results when both manual and particularly (semi-)automated segmentation approaches are applied. Advantages as well as limitations of the use of different electron microscopy operating modes, applied individually and correlatively, are highlighted. T2 - E-MRS 2024 Spring Meeting CY - Strasbourg, France DA - 27.05.2024 KW - Nanoparticles KW - Electron Microscopy KW - Metrology KW - Imaging KW - Reference materials PY - 2024 AN - OPUS4-60436 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -