TY - CONF A1 - Hahn, Marc Benjamin T1 - Water structuring induced by Ectoine as a possible explanation for its protection against radiation T2 - Annual Conference 2015 of the Association for General and Applied Microbiology CY - Marburg, Germany DA - 2015-03-01 PY - 2015 AN - OPUS4-32905 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Marc Benjamin T1 - Ectoine induced water structuring as a possible explanation for its radiation protection properties T2 - Deutsche Physikalische Gesellschaft (DPG) 2015 CY - Berlin, Germany DA - 2015-03-15 PY - 2015 AN - OPUS4-32906 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Marc Benjamin T1 - DNA strand break induction by secondary radiation products: damage yields of OH-radicals, low energy electrons and prehydrated electrons N2 - The damage caused by ionizing radiation to biomolecules, especially DNA, is the reason to treat cancer via radiation therapy. A better understanding of the molecular processes and the quantification of the various damaging mechanisms is the prerequisit to develope efficient therapies. Hereby the understanding of the processes involved in the damage to DNA are of key interest due to its central role in reproduction and mutation. Due to the high amount of water in biological tissue, most of the damage is caused by the secondary particles produced by the interaction of the IR with water. Thereby a multitude of species are produced, e.g. kinetic low energy electrons, prehydrated electrons, OH-radicals and ions. The quantification of the contribution to DNA damage of the various species is of interest. Here we present an experimental approach to disentangle their relative DNA strand break yield. Plasmid DNA is irradiated in water with electrons under the presence of different scavengers. With the presented method it will be possible to reveal the relative contributions of OH-radicals, low energy electrons and prehydrated electrons to the DNA single and double strand break yield. T2 - Radiation Research Conference 2017 CY - Cancun, Mexico DA - 15.10.2017 KW - DNA KW - Dosimetry KW - Radiation damage KW - low energy electrons KW - OH radicals KW - Prehydrated electrons KW - LEE KW - Geant4 KW - Hydroxyl radicals KW - Radiation protection KW - Biomolecules KW - Microdosimetry PY - 2017 AN - OPUS4-42617 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Marc Benjamin T1 - From sensing to dosimetry: Immobilized single-stranded DNA on surfaces as versatile sensor for protein activity and irradiation damage N2 - We report on the design, preparation and application of immobilized Oligonucleotides as biological sensors for dosimetry and protein activity. Oligonucleotides can be custom tailored in terms of sequence and length to the needs of the specific application. The preparation can be scaled from small lab-scales to higher output via spotting technology on various surfaces such as glass, silicon-dioxide or gold. They can be applied for the sensing of DNA-protein interaction and surface-plasmon resonance to detect the influence of cosolutes on the protein activity. This can be applied in the testing of pharmaceutical or cosmsetic applications and incorporated in microfluidic devices. Other important use cases are the usage in dosimetric application where the oligonucleotides are subjected to ionizing radiation. They can directly act as a sensor for biological damage which is detected and quantified by the subsequent hybridization of complementary strands who carry a fluorescence dye. The quantification can be performed by an array scanner or fluorescence microscope. Investigation on a molecular level can be performed with the AFM-IR technique. Applications are calibration of radiation sources and the investigation of interaction of ionizing radiation with biomolecules. T2 - Euromat 2017 CY - Thessaloniki, Greece DA - 17.09.2017 KW - DNA KW - Protein KW - Dosimetry KW - Radiation damage KW - SPR KW - Surface modification PY - 2017 AN - OPUS4-42619 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Marc Benjamin T1 - Ectoine protects biomolecules from ionizing radiation: Molecular mechanisms N2 - The compatible solute and osmolyte ectoine is an effective protectant of biomolecules and whole cells against heating, freezing and high salinity. The protection of cells (human Keratinocytes) by ectoine against ultraviolet radiation was also reported by various authors, although the underlying mechanism is not yet understood. We present results on the irradiation of biomolecules (DNA) with ionizing radiation (high energy electrons) in fully aqueous environment in the presence of ectoine and high salt concentrations. The results demonstrate an effective radiation protection of DNA by ectoine against the induction of single strand breaks by ionizing radiation. The effect is explained by an increased in low-energy electron scattering at the enhanced free-vibrational density of states of water due to ectoine, as well as the action of ectoine as an OH-radical scavenger. This was demonstrated by Raman spectroscopy, electron paramagnetic resonance (EPR) and Monte-Carlo simulations (Geant4). T2 - DPG-Frühjahrstagung der Sektion Kondensierte Materie gemeinsam mit der EPS CY - Berlin, Germany DA - 11.03.2018 KW - Ionizing radiation KW - Ectoine KW - Radiation damage KW - Radiation protection KW - Dosimetry KW - Ectoin KW - Ectoine radiation protection KW - Compatible solute KW - Osmolyte KW - Aqueous solution KW - OH-radical KW - Radical scavenger KW - Hydroxyl radical KW - Hydroxyectoine KW - Ectoine radical scavenger KW - Low energy electrons KW - Geant4 PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-446202 N1 - Poster basiert auf: https://nbn-resolving.org/urn:nbn:de:kobv:b43-419332 AN - OPUS4-44620 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Marc Benjamin T1 - A standard procedure for the irradiation of biomolecules with radiation of varying linear energy transfer N2 - The damage caused by ionizing radiation to DNA and proteins is the reason to treat cancer by radiation therapy. A better understanding of the molecular processes and quantification of the different damaging mechanisms is the prerequisite to develop more efficient therapies. Hereby the understanding of the processes involved in the damage to DNA are of key interest due to its central role in reproduction and mutation. For radiation with low linear energy transfer (LET), most of the damage is caused by the secondary particles produced by scattering of the ionizing radiation with water. Thereby a multitude of species are produced, whereby especially kinetic low energy electrons, prehydrated electrons, OH-radicals and ions are of importance. With higher LET the relative amount of the direct damaging effects increases. This is especially important considering the increased usage of high LET nucleons in radiation therapy. Therefore, the quantification of the contribution to DNA damage of direct and indirect effects and the different secondary species is of high interest due to the increase of radio biological efficiency when applying high LET radiation. Here we present an approach to investigate the relative contributions to DNA strand break yield for radiation of different LET within a single electron microscope in combination with electron scattering simulations. T2 - IRPA 2018 CY - Havanna, Cuba DA - 16.04.2018 KW - Dosimetry KW - Microdosimetry KW - LET KW - SEM KW - DNA KW - Radiation damage KW - OH radicals KW - LEE KW - Ionizing radiation KW - Geant4 PY - 2018 AN - OPUS4-44820 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Marc Benjamin T1 - Combination of Monte-Carlo simulations and experimental results to determine the microscopic energy depoit at DNA N2 - The quantification of radiation induced damage to DNA in aqueous en- vironment is of fundamental interest for dosimetry and its application in radiation-therapy and protection. We present a combined experi- mental and simulational approach to quantify and compare radiation induced damage to biomolecules in liquid environment for a wide range of primary radiation sources e. g. photons, electrons or ions and tar- gets, such as DNA, proteins or cells.[1] To show its viability, we will apply this method to an experimentally challenging systems, the di- rect irradiation of plasmid DNA (pUC19) in water with electrons as primary particles. Here we combine Geant4 electron-scattering simula- tions with calculations concerning the diffusion and convection induced movement of the biomolecules, within a coarse-grained model of the irradiated liquid. Additionally a microscopic target model for the plas- mid DNA based on the relation of lineal energy and radiation quality is used to calculate the effective target volume. T2 - DPG-Frühjahrstagung der Sektion Kondensierte Materie gemeinsam mit der EPS CY - Berlin, Germany DA - 11.03.2018 KW - DNA KW - Radiation damage KW - Dosimetry KW - Microdosimetry KW - Low energy electrons KW - Hydroxyl radicals KW - Monte-Carlo simulation KW - Geant4 KW - Electron scattering KW - Target volume KW - DNA damage KW - DNA radiation damage PY - 2018 AN - OPUS4-44565 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Marc Benjamin T1 - Irradiation of biomolecules in liquid with electrons of different linear energy transfer N2 - The damage caused by ionizing radiation to DNA and proteins is the reason to treat cancer by radiation therapy. A better understanding of the molecular processes and quantification of the different damaging mechanisms is the prerequisite to develop more efficient therapies. Hereby the understanding of the processes involved in the damage to DNA are of key interest due to its central role in reproduction and mutation. For radiation with low linear energy transfer (LET), most of the damage is caused by the secondary particles produced by scattering of the ionizing radiation with water. Thereby a multitude of species are produced, whereby especially kinetic low energy electrons, prehydrated electrons, OH-radicals and ions are of importance. With higher LET the relative amount of the direct damaging effects increases. This is especially important considering the increased usage of high LET particles in radiation therapy. Therefore, the quantification of the contribution to DNA damage of direct and indirect effects and the different secondary species is of high interest due to the increase of radio biological efficiency when applying high LET radiation. Here we present an approach to investigate the relative contributions to DNA strand break yield for radiation of different LET within a single electron microscope in combination with electron scattering simulations. T2 - International workshop on radiation damage to DNA CY - Aussois, France DA - 27.05.2018 KW - Radiation damage KW - LET KW - Geant4 KW - DNA KW - Radiation therapy KW - Hydroxyl radical KW - Low energy electrons KW - Dosimetry KW - Microdosimetry KW - Electron irradiation KW - Sem KW - Linear energy transfer KW - MCS KW - Monte-Carlo simulations PY - 2018 AN - OPUS4-45103 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Marc Benjamin T1 - Measurement and Simulation of the Microscopic Energy Deposit: A general approach applicable to Ionizing Radiation Sources of varying Linear Energy Transfer N2 - The determination of microscopic dose-damage relations in aqueous environment is of fundamental interest for dosimetry and its application in radiation-therapy and protection. We present a combined experimental and simulational approach to quantify the microscopic energy deposit at biomolecules in liquid environment which is applicable to a wide range of primary radiation sources, e.g. photons, electrons or ions, and targets, such as DNA, proteins or cells.Therefore, we combine Geant4 particle-scattering simulations in water with calculations concerning the movement of biomolecules to obtain the energy deposit in the biologically relevant nanoscopic volume. We present, how to combine these simulational results and experimental data via a generalised damage model to determine the microscopic dose-damage relation at a molecular level. To show the viability of this approach, we apply this method to an experimentally challenging system, the direct irradiation of plasmid DNA (pUC19) in water with electrons as primary particles. Here we combine electron-scattering simulations with calculations concerning the diffusion and convection induced movement of the DNA, within a coarse-grained model of the irradiated liquid. Additionally a microscopic target model for DNA molecules based on the relation of lineal energy and radiation quality is used to calculate their effective target volume. It was found that on average fewer than two ionisations within a 7.5\,nm radius around the sugar-phosphate backbone are sufficient to cause a single strand break, with a corresponding median lethal energy deposit being E\textsubscript{1/2}=6+-4\,eV. The presented method is applicable for all types of ionising radiation and a broad variety of biological targets. T2 - CCQM Workshop CY - Paris, France DA - 09.04.2019 KW - Dosimetry KW - Microdosimetry KW - Geant4 KW - Geant4-DNA KW - DNA KW - Electron irradiation KW - Monte-Carlo Simulation PY - 2019 UR - https://www.bipm.org/utils/en/pdf/Workshop-CCQM2019-EP1.pdf AN - OPUS4-47810 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Marc Benjamin T1 - Electron beam therapy: Microdosimetric calculations for the quantification of fundamental damaging processes N2 - Electron beam therpy is used to treat tumor cells by irradiation with high energy electrons (HEE). The irradiation is performed by medical linear accelerators. By interaction of the HEE with the irradiated tissue a broad spectra of secondary electrons and water dissoziation products is generated. These products interact with biomolecules, especially DNA, by various processes. The disentanglement of the resulting direct- and indirect damage to DNA and other cellular components is still under debate. To increase the efficiency of future therapies a better understanding of the microscopic damaging processes is highly important. Especially the various contributions of the secondary species produced, such as low energy electrons (LEE) and radicals is far from understood and quantified. To increase the understanding we present a combination of a microdosimetric simulations and experiments to quantify the damage by means of electron scattering and diffusion simulations within the Geant4-DNA framework. In combination with in-liquid irradiation of plasmid DNA it possible to determine microdosimetric quantities for biomolecules in liquid environment. The presented method was applied to the irradiation of plasmid DNA (pUC19) in water. This opens up new possibilities in radiation research to quantify the dosage-damage relationship for microscopic plasmid volumes under well defined physiological condition. T2 - IWBBIO17 CY - Granada. Spain DA - 25.04.2017 KW - DNA KW - Dosimetry KW - Monte-Carlo simulation KW - Electron irradiation KW - Microdosimetry PY - 2017 AN - OPUS4-40043 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -