TY - JOUR A1 - Abram, Sarah-Luise A1 - Mrkwitschka, Paul A1 - Thünemann, Andreas A1 - Radnik, Jörg A1 - Häusler, I. A1 - Bresch, Harald A1 - Hodoroaba, Vasile-Dan A1 - Resch-Genger, Ute T1 - Iron Oxide Nanocubes as a New Certified Reference Material for Nanoparticle Size Measurements N2 - The rational design and increasing industrial use of nanomaterials require a reliable characterization of their physicochemical key properties like size, size distribution, shape, and surface chemistry. This calls for nanoscale reference materials (nanoRMs) for the validation and standardization of commonly used characterization methods closely matching real-world nonspherical nano-objects. This encouraged us to develop a nonspherical nanoRM of very small size consisting of 8 nm iron oxide nanocubes (BAM-N012) to complement spherical gold, silica, and polymer nanoRMs. In the following, the development and production of this nanoRM are highlighted including the characterization by transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS) as complementary methods for size and shape parameters, homogeneity and stability studies, and calculation of a complete uncertainty budget of the size features. The determination of the nanocubes’ edge length by TEM and SAXS allows a method comparison. In addition, SAXS measurements can also provide the mean particle number density and the mass concentration. The certified size parameters, area equivalent circular diameter and square edge length, determined by TEM with a relative expanded uncertainty below 9%, are metrologically traceable to a natural constant for length, the very precisely known (111) lattice spacing of silicon. Cubic BAM-N012 qualifies as a certified nanoRM for estimating the precision and trueness, validation, and quality assurance of particle size and shape measurements with electron microscopy and SAXS as well as other sizing methods suitable for nanomaterials. The production of this new iron oxide nanocube RM presents an important achievement for the nanomaterial community, nanomaterial manufacturers, and regulators. KW - Certification KW - SAXS KW - Homogeneity KW - Nano KW - Particle KW - Iron oxide KW - Quality assurance KW - Reference material KW - Size KW - Electron microscopy KW - Stability KW - Shape PY - 2023 DO - https://doi.org/10.1021/acs.analchem.3c00749 SN - 0003-2700 VL - 95 IS - 33 SP - 12223 EP - 12231 PB - American Chemical Society CY - Columbus, Ohio AN - OPUS4-58176 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Abram, Sarah-Luise A1 - Tavernaro, Isabella A1 - Resch-Genger, Ute A1 - Johnston, L. J. A1 - Zou, S. T1 - Nanoscale reference and test materials for the validation of characterization methods for engineered nanomaterials — current state, limitations, and needs N2 - The rational design of engineered nanomaterials (NMs) with improved functionality and their increasing industrial application requires reliable, validated, and ultimately standardized characterization methods for their application-relevant, physicochemical key properties such as size, size distribution, shape, or surface chemistry. This calls for nanoscale (certified) reference materials (CRMs; RMs) and well-characterized reference test materials (RTMs) termed also quality control (QC) samples, assessed, e.g., in interlaboratory comparisons, for the validation and standardization of commonly used characterization methods. Thereby, increasing concerns regarding potential risks of NMs are also addressed and the road for safe and sustainable-by-design concepts for the development of new functional NMs and their use as nanomedicines is paved. With this respect, we will provide an overview of relevant international standardization and regulatory activities, definitions, and recommendations on characterization methods and review currently available organic or inorganic nanoscale CRMs, RMs, and RTMs, including their characterization or certification. In addition, we will highlight typical applications to streamline the regulatory approval process and improve manufacturability including the special challenges imposed by the colloidal nature and sometimes limited stability of NMs. Subsequently, we will critically assess the limitations of currently available nanoscale RMs and RTMs and address the gaps to be filled in the future such as the availability of NMs that come with reference data on properties other than commonly addressed particle size, such as surface chemistry or particle number concentration, or more closely resemble commercially available formulations or address application-relevant matrices. KW - Nano KW - Particle KW - Silica KW - Quality assurance KW - Reference material KW - Review KW - Surface chemistry KW - Size KW - Shape KW - Particle number concentration KW - Lipid nanoparticles KW - Metal nanoparticles KW - Liposomes PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625746 DO - https://doi.org/10.1007/s00216-024-05719-6 SN - 1618-2650 SP - 1 EP - 21 PB - Springer AN - OPUS4-62574 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Acosta-Zepeda, C. A1 - Saavedra, S. A1 - Bonse, Jörn A1 - Haro-Poniatowski, E. T1 - Modelling of single UV nanosecond pulsed laser surface modifications of silicon N2 - Irradiation with a single spatially Gaussian-shaped nanosecond laser pulse in the melting regime can result in a characteristic annular change in the surface morphology of crystalline silicon. This has been verified experimentally in a variety of situations, where dimple-shaped surface topographies are produced. In a recent work we have investigated the induced changes in the surface topography upon exposure to wavelengths in the visible and near infrared spectral region. Irradiation in the UV requires a more detailed analysis due to the enhanced absorption of the material. In the present analysis, we determine under which conditions our previous model can be used and the corresponding results are presented. KW - Laser KW - Silicon KW - Surface modification PY - 2020 DO - https://doi.org/10.1088/1555-6611/ab9b2c SN - 1555-6611 SN - 1054-660X VL - 30 IS - 8 SP - 086003-1 EP - 086003-4 PB - IOP Publishing / Astro Ltd CY - Bristol, United Kingdom AN - OPUS4-51022 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Adamski, Paweł A1 - Zgrzebnicki, Michał A1 - Albrecht, Aleksander A1 - Jurkowski, Artur A1 - Wojciechowska, Agnieszka A1 - Ekiert, Ewa A1 - Sielicki, Krzysztof A1 - Mijowska, Ewa A1 - Smales, Glen J. A1 - Maximenko, Alexey A1 - Moszyński, Dariusz T1 - Ammonia synthesis over γ-Al2O3 supported Co-Mo catalysts N2 - Novel ammonia synthesis catalysts are sought due to energetic transformation and increasing environmental consciousness. Materials containing cobalt and molybdenum are showing state-of-art activities in ammonia synthesis. The application of γ-alumina support was proposed to enhance the properties of Co-Mo nanoparticles. The wet impregnation of the support was conducted under reduced pressure. The active catalysts were obtained by ammonolysis of precursors. The chemical and phase composition, as well as morphology, porosity, and surface composition of precursors and catalysts, were characterized. The Co-Mo nanoparticles phase composition as well as their size and dispersion were determined using X-ray absorption spectroscopy utilizing synchrotron radiation, electron microscopy, and X-ray scattering. The catalytic activity was tested in the ammonia synthesis process under atmospheric pressure. The activity and stability of the supported catalysts were compared with unsupported cobalt molybdenum nitride Co3Mo3N, revealing the superiority of the present approach. KW - Ammonia synthesis KW - Supported catalyst KW - Cobalt molybdenum nitrides KW - Scattering KW - X-ray scattering KW - Gamma-alumina KW - Stability PY - 2025 DO - https://doi.org/10.1016/j.mcat.2025.114907 SN - 2468-8231 VL - 575 SP - 1 EP - 9 PB - Elsevier B.V. AN - OPUS4-64827 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ahiboz, D. A1 - Andresen, Elina A1 - Manley, P. A1 - Resch-Genger, Ute A1 - Würth, Christian A1 - Becker, C. T1 - Enhanced photon upconversion using erbium-doped nanoparticles interacting with silicon metasurfaces N2 - Photon upconversion (UC) using trivalent erbium (Er+3) doped crystals is a promising concept to harness near infrared photons of the solar spectrum which cannot be directly absorbed by silicon solar cells. However, their UC efficiency at low-intensity 1 sun illumination is not relevant on device level so far. Exploiting giant near-field enhancement effects on metasurfaces is an appealing approach to enable efficient UC at low irradiance conditions. Here, we report on more than 1000-fold enhanced photon UC of NaYF4:Er+3 nanoparticles interacting with the near-fields supported by a silicon metasurface under 1550 nm excitation. T2 - 48th Photovoltaic Specialists Conference (PVSC) CY - Online meeting DA - 20.06.2021 KW - Nano KW - Nanomaterial KW - Upconversion nanoparticle KW - Lanthanide KW - Photoluminescence KW - Quantum yield KW - Photophysics KW - Lifetime KW - Sensor KW - Excitation power density KW - Brightness KW - NIR KW - Mechanism KW - Modeling KW - Simulation KW - Energy transfer KW - Photonic crystal KW - Enhancement strategy PY - 2021 DO - https://doi.org/10.1109/pvsc43889.2021.9518495 SP - 1 EP - 3 PB - IEEE CY - Berlin AN - OPUS4-53786 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ahiboz, D. A1 - Andresen, Elina A1 - Manley, P. A1 - Resch-Genger, Ute A1 - Würth, Christian A1 - Becker, C. T1 - Metasurface-Enhanced Photon Upconversion upon 1550 nm Excitation N2 - Photon upconversion upon 1550 nm excitation is of high relevance for applications in the third biological excitation window, for photovoltaics beyond current limitations, and enables appealing options in the field of glass Fiber telecommunications. Trivalent doped erbium ions (Er3+) are the material of choice for 1550 nm excited upconversion, however, they suffer from a low absorption cross-section and a low brightness. Therefore, the ability of Silicon metasurfaces to provide greatly enhanced electrical near-fields is employed to enable efficient photon upconversion even at low external Illumination conditions. Hexagonally shaped β-NaYF4:Er3+ nanoparticles are placed on large-area silicon metasurfaces designed to convert near-infrared (1550 nm) to visible light. More than 2400-fold enhanced photon upconversion luminescence is achieved by using this metasurface instead of a planar substrate. With the aid of optical simulations based on the finite-element method, this result is attributed to the coupling of the excitation source with metasurface resonances at appropriate incident angles. Analysis of the excitation power density dependence of upconversion luminescence and red-to-green-emission ratios enables the estimation of nanoscale near-field enhancement on the metasurface. The findings permit the significant reduction of required external excitation intensities for photon upconversion of 1550 nm light, opening perspectives in biophotonics, telecommunication, and photovoltaics. KW - Nano KW - Nanomaterial KW - Upconversion nanoparticle KW - Lanthanide KW - Photoluminescence KW - Quantum yield KW - Photophysics KW - Lifetime KW - Sensor KW - Excitation power density KW - Single particle KW - Brightness KW - NIR KW - Mechanism KW - Single enhancement KW - SWIR KW - Method PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-537193 DO - https://doi.org/10.1002/adom.202101285. SN - 2195-1071 VL - 9 IS - 24 SP - 2101285 PB - Wiley-VCH-GmbH AN - OPUS4-53719 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ahmed, A. A. A. A1 - Alegret, N. A1 - Almeida, B. A1 - Alvarez-Puebla, R. A1 - Andrews, A. M. A1 - Ballerini, L. A1 - Barrios-Capuchino, J. J. A1 - Becker, C. A1 - Blick, R. H. A1 - Bonakdar, S. A1 - Chakraborty, I. A1 - Chen, X. A1 - Cheon, J. A1 - Chilla, G. A1 - Conceicao, A. L. C. A1 - Delehanty, J. A1 - Dulle, M. A1 - Efros, A. L. A1 - Epple, M. A1 - Fedyk, M. A1 - Feliu, N. A1 - Feng, M. A1 - Fernandez-Chacon, R. A1 - Fernandez-Cuesta, I. A1 - Fertig, N. A1 - Förster, S. A1 - Garrido, J. A. A1 - George, M. A1 - Guse, A. H. A1 - Hampp, N. A1 - Harberts, J. A1 - Han, J. A1 - Heekeren, H. R. A1 - Hofmann, U. G. A1 - Holzapfel, M. A1 - Hosseinkazemi, H. A1 - Huang, Y. A1 - Huber, P. A1 - Hyeon, T. A1 - Ingebrandt, S. A1 - Ienca, M. A1 - Iske, A. A1 - Kang, Y. A1 - Kasieczka, G. A1 - Kim, D.-H. A1 - Kostarelos, K. A1 - Lee, J.-H. A1 - Lin, K.-W. A1 - Liu, S. A1 - Liu, X. A1 - Liu, Y. A1 - Lohr, C. A1 - Mailänder, V. A1 - Maffongelli, L. A1 - Megahed, S. A1 - Mews, A. A1 - Mutas, M. A1 - Nack, L. A1 - Nakatsuka, N. A1 - Oertner, T. G. A1 - Offenhäusser, A. A1 - Oheim, M. A1 - Otange, B. A1 - Otto, F. A1 - Patrono, E. A1 - Peng, B. A1 - Picchiotti, A. A1 - Pierini, F. A1 - Pötter-Nerger, M. A1 - Pozzi, M. A1 - Pralle, A. A1 - Prato, M. A1 - Qi, B. A1 - Ramos-Cabrer, P. A1 - Resch-Genger, Ute A1 - Ritter, N. A1 - Rittner, M. A1 - Roy, S. A1 - Santoro, F. A1 - Schuck, N. W. A1 - Schulz, F. A1 - Seker, E. A1 - Skiba, M. A1 - Sosniok, M. A1 - Stephan, H. A1 - Wang, R. A1 - Wang, T. A1 - Wegner, Karl David A1 - Weiss, P. S. A1 - Xu, M. A1 - Yang, C. A1 - Zargarin, S. S. A1 - Zeng, Y. A1 - Zhou, Y. A1 - Zhu, D. A1 - Zierold, R. A1 - Parak, W. J. T1 - Interfacing with the Brain: How Nanotechnology Can Contribute N2 - Interfacing artificial devices with the human brain is the central goal of neurotechnology. Yet, our imaginations are often limited by currently available paradigms and technologies. Suggestions for brain−machine interfaces have changed over time, along with the available technology. Mechanical levers and cable winches were used to move parts of the brain during the mechanical age. Sophisticated electronic wiring and remote control have arisen during the electronic age, ultimately leading to plug-and-play computer interfaces. Nonetheless, our brains are so complex that these visions, until recently, largely remained unreachable dreams. The general problem, thus far, is that most of our technology is mechanically and/or electrically engineered, whereas the brain is a living, dynamic entity. As a result, these worlds are difficult to interface with one another. Nanotechnology, which encompasses engineered solid-state objects and integrated circuits, excels at small length scales of single to a few hundred nanometers and, thus, matches the sizes of biomolecules, biomolecular assemblies, and parts of cells. Consequently, we envision nanomaterials and nanotools as opportunities to interface with the brain in alternative ways. Here, we review the existing literature on the use of nanotechnology in brain−machine interfaces and look forward in discussing perspectives and limitations based on the authors’ expertise across a range of complementary disciplines from neuroscience, engineering, physics, and chemistry to biology and medicine, computer science and mathematics, and social science and jurisprudence. We focus on nanotechnology but also include information from related fields when useful and complementary. KW - Nanoneuro interface KW - Brain-on-a-chip KW - Nanostructured interface KW - Electrode arrays KW - Neuro-implants KW - Advanced nanomaterials KW - Quality assurance PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634893 DO - https://doi.org/10.1021/acsnano.4c10525 SN - 1936-086X VL - 19 IS - 11 SP - 10630 EP - 10717 PB - ACS Publications AN - OPUS4-63489 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ahmed, R. A1 - Vaishampayan, A. A1 - Cuellar-Camacho, J. L. A1 - Wight, D. J. A1 - Donskyi, Ievgen A1 - Unger, Wolfgang A1 - Grohmann, E. A1 - Haag, R. A1 - Wagner, O. T1 - Multivalent Bacteria Binding by Flexible Polycationic Microsheets Matching Their Surface Charge Density N2 - Aiming at the overall negative surface charge of bacteria, a new strategy of antibacterial agents based on large polymer-modified graphene oxide (GO) sheets is assessed. The presented flexible, polycationic Sheets match the size and charge density of the Escherichia coli surface charge density (2 × 1014 cm−2). These matching parameters create an unspecific but very strong bacteria adsorber by multivalent, electrostatic attraction. Their interaction with bacteria is visualized via atomic force and confocal microscopy and shows that they effectively bind and wrap around E. coli cells, and thereby immobilize them. The incubation of Gram-negative and -positive bacteria (E. coli and methicillin-resistant Staphylococcus aureus, MRSA) with these polycationic sheets leads to the inhibition of proliferation and a reduction of the colony forming bacteria over time. This new type of antibacterial agent acts in a different mode of Action than classical biocides and could potentially be employed in medicinal, technical, or agriculture applications. The presented microsheets and their unspecific binding of cell interfaces could further be employed as adsorber material for bacterial filtration or immobilization for imaging, analysis, or sensor technologies. KW - Surface charge KW - Bacteria KW - Graphene oxide KW - Escherichia coli KW - XPS PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509651 DO - https://doi.org/10.1002/admi.201902066 VL - 7 IS - 15 SP - 1902066 PB - WILEY-VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-50965 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Al-Waqfi, R. A. A1 - Khan, C. J. A1 - Irving, O. J. A1 - Matthews, Lauren A1 - Albrecht, T. T1 - Crowding Effects during DNA Translocation in Nanopipettes N2 - Quartz nanopipettes are an important emerging class of electric single-molecule sensors for DNA, proteins, their complexes, as well as other biomolecular targets. However, in comparison to other resistive pulse sensors, nanopipettes constitute a highly asymmetric environment and the transport of ions and biopolymers can become strongly directiondependent. For double-stranded DNA, this can include the characteristic translocation time and tertiary structure, but as we show here, nanoconfinement can also unlock capabilities for biophysical and bioanalytical studies at the single-molecule level. To this end, we show how the accumulation of DNA inside the nanochannel leads to crowding effects, and in some cases reversible blocking of DNA entry, and provide a detailed analysis based on a range of different DNA samples and experimental conditions. Moreover, using biotin-functionalized DNA and streptavidinmodified gold nanoparticles as target, we demonstrate in a proof-of-concept study how the crowding effect, and the resulting increased residence time in nanochannel, can be exploited by first injecting the DNA into the nanochannel, followed by incubation with the nanoparticle target and analysis of the complex by reverse translocation. We thereby integrate elements of sample processing and detection into the nanopipette, as an important conceptual advance, and make a case for the wider applicability of this device concept. KW - DNA translocation KW - Transport KW - Resistive-pulse sensing KW - Nanopores KW - Nanopipettes KW - Crowding KW - Confinement PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630448 DO - https://doi.org/10.1021/acsnano.5c01529 SN - 1936-086X VL - 19 IS - 17 SP - 1 EP - 9 PB - ACS Publications AN - OPUS4-63044 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Aliyah, K. A1 - Prehal, C. A1 - Diercks, J. S. A1 - Diklić, N. A1 - Xu, L. A1 - Ünsal, S. A1 - Appel, C. A1 - Pauw, Brian Richard A1 - Smales, Glen Jacob A1 - Guizar-Sicairos, M. A1 - Herranz, J. A1 - Gubler, L. A1 - Büchi, F. N. A1 - Eller, J. T1 - Quantification of PEFC Catalyst Layer Saturation via In Silico, Ex Situ, and In Situ Small-Angle X-ray Scattering N2 - The complex nature of liquid water saturation of polymer electrolyte fuel cell (PEFC) catalyst layers (CLs) greatly affects the device performance. To investigate this problem, we present a method to quantify the presence of liquid water in a PEFC CL using small-angle X-ray scattering (SAXS). This method leverages the differences in electron densities between the solid catalyst matrix and the liquid water filled pores of the CL under both dry and wet conditions. This approach is validated using ex situ wetting experiments, which aid the study of the transient saturation of a CL in a flow cell configuration in situ. The azimuthally integrated scattering data are fitted using 3D morphology models of the CL under dry conditions. Different wetting scenarios are realized in silico, and the corresponding SAXS data are numerically simulated by a direct 3D Fourier transformation. The simulated SAXS profiles of the different wetting scenarios are used to interpret the measured SAXS data which allows the derivation of the most probable wetting mechanism within a flow cell electrode. KW - Polymer electrolyte fuel cell KW - Water management KW - Catalyst layer KW - Representative morphology modeling KW - Small-angle X-ray scattering KW - MOUSE KW - SAXS PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575973 DO - https://doi.org/10.1021/acsami.3c00420 SN - 1944-8244 VL - 15 IS - 22 SP - 26538 EP - 26553 PB - ACS Publications AN - OPUS4-57597 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -