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 JF - Analytical chemistry 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 - Hallier, Dorothea C. A1 - Smales, Glen Jacob A1 - Seitz, H. A1 - Hahn, Marc Benjamin T1 - Bio-SAXS of single-stranded DNA-binding proteins: Radiation protection by the compatible solute ectoine JF - Physical chemistry chemical physics (PCCP) N2 - Small-angle X-ray scattering (SAXS) can be used for structural determination of biological macromolecules and polymers in their native states (e.g. liquid phase). This means that the structural changes of (bio-)polymers, such as proteins and DNA, can be monitored in situ to understand their sensitivity to changes in chemical environments. In an attempt to improve the reliability of such experiments, the reduction of radiation damage occurring from exposure to X-rays is required. One such method, is to use scavenger molecules to protect macromolecules against radicals produced during radiation exposure, such as reactive oxygen species (ROS). In this study we investigate the feasibility of applying the compatible solute, osmolyte and radiation protector Ectoine (THP(B)), as a scavenger molecule during SAXS measurements of the single-stranded DNA-binding protein Gene-V Protein (G5P/GVP). In this case, we monitor the radiation induced changes of G5P during bio-SAXS measurments and the resulting microscopic energy-damage relation was determined from microdosimetric calculations by Monte-Carlo based particle scattering simulations with TOPAS/Geant4 and a custom target-model. This resulted in a median-lethal energy deposit of pure G5P at 4 mg mL−1 of E1/2 = 7 ± 5 eV, whereas a threefold increase of energy-deposit was needed under the presence of Ectoine to reach the same level of damage. This indicates that Ectoine increases the possible exposure time before radiation-damage to G5P is observed. Furthermore, the dominant type of damage shifted from aggregation in pure solutions towards a fragmentation for solutions containing Ectoine as a cosolute. These results are interpreted in terms of indirect radiation damage by reactive secondary species, as well as post-irradiation effects, related to preferential-exclusion of the cosolute from the protein surface. Hence, Ectoine is shown to provide a non-disturbing way to improve structure-determination of proteins via bio-SAXS in future studies. KW - BioSAXS KW - Bio-SAXS KW - Cosolute KW - Ectoine KW - G5P KW - GVP KW - Radiation damage KW - Radical Scavenger KW - Single-stranded DNA-binding proteins KW - X-ray scattering KW - DNA KW - ssDNA KW - Protein KW - SAXS KW - Small-angle xray scattering KW - McSAS3 KW - Dosimetry KW - Microdosimetry KW - Geant4 KW - Geant4-DNA KW - Topas KW - Topas-MC KW - Monte-Carlo simulations KW - Particle scattering simulations KW - Topas-nBio KW - OH Radical KW - OH radical scavenger KW - LEE KW - Ionizing radiation damage KW - Protein unfolding KW - Ectoin PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568909 DO - https://doi.org/10.1039/d2cp05053f SN - 1463-9076 SN - 1463-9084 VL - 25 IS - 7 SP - 5372 EP - 5382 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-56890 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -