TY - JOUR A1 - Hahn, Marc Benjamin A1 - Uhlig, F. A1 - Solomun, Tihomir A1 - Smiatek, J. A1 - Sturm, Heinz T1 - Combined influence of ectoine and salt: spectroscopic and numerical evidence for compensating effects of aqueous solutions JF - Physical Chemistry Chemical Physics N2 - Ectoine is an important osmolyte, which allows microorganisms to survive in extreme environmental salinity. The hygroscopic effects of ectoine in pure water can be explained by a strong water binding behavior whereas a study on the effects of ectoine in salty solution is yet missing. We provide Raman spectroscopic evidence that the influence of ectoine and NaCl are opposing and completely independent of each other. The effect can be explained by the formation of strongly hydrogen-bonded water molecules around ectoine which compensate the influence of the salt on the water dynamics. The mechanism is corroborated by first principles calculations and broadens our understanding of zwitterionic osmolytes in aqueous solution. Our findings allow us to provide a possible explanation for the relatively high osmolyte concentrations in halotolerant bacteria. KW - Ectoine KW - Aqueous solution KW - Biological structure KW - Organic osmolytes KW - Raman spectroscopy KW - Water structure PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-376761 UR - http://pubs.rsc.org/en/content/articlelanding/2016/cp/c6cp05417j#!divAbstract DO - https://doi.org/10.1039/c6cp05417j VL - 18 IS - 41 SP - 28398 EP - 28402 PB - Royal Society of Chemistry CY - UK AN - OPUS4-37676 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fritzsche, Sven A1 - Pauw, Brian Richard A1 - Weimann, Christiane A1 - Sturm, Heinz T1 - First of its kind: a test artifact for direct laser writing JF - Measurement Science and Technology N2 - With femtosecond-laser direct writing (fs-LDW) maturing in all aspects as a manufacturing technology, a toolset for quality assurance must be developed. In this work we introduce a first of its kind test artifact. Test artifacts are standardized 3D models with specific geometric features to evaluate the performance of writing parameters. Test artifacts are already common in other 3D additive manufacturing technologies e.g. selective laser melting. The test artifact introduced in this work was developed in particular to accommodate the high geometrical resolution of fs-LDW structures and the limited possibilities to examine the resulting structure. Geometric accuracy, surface adhesion as well as confocal Raman spectroscopy results were considered when evaluating the design of the test artifact. We will explain the individual features and design considerations of our fs-LDW test artifact. The difference between two slicers, Cura and 3DPoli, and the implications on measured feature sizes and the general shape is quantified. The measured geometries are used to derive a general design guide for a specific combination of photoresists, laser power and scanning speed and to analyze the geometric accuracy of a structure produced using these guidelines. The shown test artifact is publicly available as STL file on GitHub (https://github.com/BAMresearch/2PP-TestArtifact) and in the supplement. KW - Laser direct writing KW - Multi photon lithography KW - Reference material KW - Raman spectroscopy KW - Confocal raman imaging KW - Slicers KW - Open data on zenodo PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-580951 DO - https://doi.org/10.1088/1361-6501/acc47a VL - 34 IS - 7 SP - 1 EP - 14 PB - IOP Science AN - OPUS4-58095 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fankhänel, J. A1 - Silbernagl, Dorothee A1 - Ghasem Zadeh Khorasani, Media A1 - Daum, B. A1 - Kempe, A. A1 - Sturm, Heinz A1 - Rolfes, R. T1 - Mechanical properties of Boehmite evaluated by Atomic Force Microscopy experiments and Molecular Dynamic Finite Element simulations JF - Journal of Nanomaterials N2 - Boehmite nanoparticles show great potential in improving mechanical properties of fiber reinforced polymers. In order to predict the properties of nanocomposites, knowledge about the material parameters of the constituent phases, including the boehmite particles, is crucial. In this study, the mechanical behavior of boehmite is investigated using Atomic Force Microscopy (AFM) experiments and Molecular Dynamic Finite Element Method (MDFEM) simulations. Young’s modulus of the perfect crystalline boehmite nanoparticles is derived from numerical AFM simulations. Results of AFM experiments on boehmite nanoparticles deviate significantly. Possible causes are identified by experiments on complementary types of boehmite, that is, geological and hydrothermally synthesized samples, and further simulations of imperfect crystals and combined boehmite/epoxy models. Under certain circumstances, the mechanical behavior of boehmite was found to be dominated by inelastic effects that are discussed in detail in the present work.The studies are substantiated with accompanying X-ray diffraction and Raman experiments. KW - AFM KW - MDFEM KW - Nanocomposite KW - Epoxy KW - X-ray diffraction KW - Raman spectroscopy KW - Young’s modulus KW - Slippage of weakly linked layers PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-384230 UR - https://www.hindawi.com/journals/jnm/2016/5017213/#B26 DO - https://doi.org/10.1155/2016/5017213 VL - 2016 IS - Article ID 5017213 SP - 1 EP - 13 PB - Hindawi Publishing Corporation AN - OPUS4-38423 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hahn, Marc Benjamin A1 - Susann, Meyer A1 - Schröter, Maria-Astrid A1 - Kunte, Hans-Jörg A1 - Solomun, Tihomir A1 - Sturm, Heinz T1 - DNA protection by ectoine from ionizing radiation: molecular mechanisms JF - Physical Chemistry Chemical Physics N2 - Ectoine, a compatible solute and osmolyte, is known to be an effective protectant of biomolecules and whole cells against heating, freezing and extreme salinity. Protection of cells (human keratinocytes) by ectoine against ultraviolet radiation has also been reported by various authors, although the underlying mechanism is not yet understood. We present the first electron irradiation of DNA in a fully aqueous environment in the presence of ectoine and at high salt concentrations. The results demonstrate effective protection of DNA by ectoine against the induction of single-strand breaks by ionizing radiation. The effect is explained by an increase in low-energy electron scattering at the enhanced free-vibrational density of states of water due to ectoine, as well as the use of ectoine as an ˙OH-radical scavenger. This was demonstrated by Raman spectroscopy and electron paramagnetic resonance (EPR). KW - Ectoine KW - DNA KW - Radiation protection KW - Ionizing radiation KW - Compatible solute KW - Biomolecules KW - Sodium chloride KW - Aqueous solution KW - Hydroxyectoine KW - Raman spectroscopy KW - Electron irradiation KW - Cancer KW - Radical scavenger KW - Low energy electrons KW - Hydroxyl radical KW - OH-radical KW - Ectoin KW - UV radiation KW - Sun KW - Salt KW - Radiation therapy PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-419332 UR - http://pubs.rsc.org/en/content/articlehtml/2017/cp/c7cp02860a DO - https://doi.org/10.1039/C7CP02860A SN - 1463-9076 VL - 19 IS - 37 SP - 25717 EP - 25722 PB - Royal Society of Chemistry CY - United Kingdom AN - OPUS4-41933 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hahn, Marc Benjamin A1 - Smales, Glen Jacob A1 - Seitz, H. A1 - Solomun, Tihomir A1 - Sturm, Heinz T1 - Ectoine interaction with DNA: Influence on ultraviolet radiation damage JF - Physical Chemistry Chemical Physics N2 - Ectoine is a small zwitterionic osmolyte and compatible solute, which does not interfere with cell metabolism even at molar concentrations. Plasmid DNA (pUC19) was irradiated with ultraviolet radiation (UV-C at 266 nm) under quasi physiological conditions (PBS) and in pure water in the presence and absence of ectoine (THP(B)) and hydroxyectoine (THP(A)). Different types of UV induced DNA damage were analysed: DNA single-strand breaks (SSBs), abasic sites and cyclobutane pyrimidine dimers (CPDs). A complex interplay between these factors was observed with respect to the nature and occurrence of DNA damage with 266 nm photons. In PBS, the cosolutes showed efficient protection against base damage, whilst in pure water, a dramatic shift from SSB damage to base damage was observed when cosolutes were added. To test whether these effects are caused by ectoine binding to DNA, further experiments were conducted: small-angle X-ray scattering (SAXS), surface-plasmon resonance (SPR) measurements and Raman spectroscopy. The results show, for the first time, a close interaction between ectoine and DNA. This is in stark contrast to the assumption made by preferential exclusion models, which are often used to interpret the behaviour of compatible solutes within cells and with biomolecules. It is tentatively proposed that the alterations of UV damage to DNA are attributed to ectoine influence on nucleobases through the direct interaction between ectoine and DNA. KW - Ectoine KW - DNA KW - Radiation damage KW - Radiation protection KW - SSB KW - DNA damage KW - DNA protection KW - Compatible solute KW - Zwitterion KW - Hydroxyectoine KW - Salt KW - PBS KW - UV absorption KW - DNA strand-break KW - DNA base damage KW - Ectoine UV absorption KW - Ectoine DNA protection KW - Excited states KW - UV irradiation KW - UV-A KW - UV-B KW - UV-C KW - 266nm KW - UV photons KW - Ectoine-DNA binding KW - Raman spectroscopy KW - UV-Vis KW - Radical scavenger KW - OH scavenger KW - Hydroxyl radicals KW - CPD KW - Abasic site KW - Agarose gel electrophorese KW - SYBR gold KW - DNA melting temperature KW - Counterions KW - Preferential exclusion KW - Cancer KW - Therapy KW - UV protection KW - Sunscreen PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-505772 DO - https://doi.org/10.1039/d0cp00092b SN - 1463-9076 SN - 1463-9084 VL - 22 IS - 13 SP - 6984 EP - 6992 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-50577 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -