This paper has been prepared to commemorate the 70th anniversary of the Institute of Biophysics of the Czech Academy of Sciences (IBP CAS), which has a long-standing tradition in researching the biological effects of ionizing radiation (IR). Radiobiology has recently gained renewed importance due to several compelling factors. The demand for a better understanding of the biological effects of both low and high doses of various types of ionizing radiation, along with improved radiation protection, is increasing-particularly in the context of critical ongoing human activities such as medical diagnostics, radiotherapy, and the operation of nuclear power plants. This demand also extends to newly emerging scenarios, including the development of hadron and FLASH radiotherapy, as well as mixed radiation field exposures related to planned manned missions to Mars. Unfortunately, there is also an urgent need to address the heightened risk of nuclear materials and weapons misuse by terrorists or even rogue states. Additionally, nuclear energy is currently the only viable alternative that can provide efficient, sustainable, and ecological coverage for the dramatically increasing current and future energy demands. Understanding the risks of IR exposure necessitates exploring how different types of IR interact with living organisms at the most fundamental level of complexity, specifically at the level of molecules and their complexes. The rising interest in radiobiology is, therefore, also driven by new experimental opportunities that enable research at previously unimaginable levels of detail and complexity. In this manuscript, we will address the important questions in radiobiology, focusing specifically on the mechanisms of radiation-induced DNA damage and repair within the context of chromatin architecture. We will emphasize the differing effects of photon and high-LET particle radiation on chromatin and DNA. Both forms of IR are encountered on Earth but are particularly significant in space.

• Keywords
• Biological effects of ionizing radiation, Chromatin architecture at micro- and nano-scale, DNA damage and repair, Densely ionizing (high-LET) particle radiation, Institute of biophysics of the Czech academy of sciences, Microscopy, Photon radiation, Radiobiological research, Single molecule localization microscopy (SMLM),
• Publication type
• Journal Article MeSH
• Review MeSH

Reactivity toward low-energy electrons (LEE) has been hypothesized as a cause of radio-modifying properties for various molecules. LEE's transient nature, however, prevents the establishment of clear links between initial processes at the sub-ps time scale and the final products of radiolysis. Here, such links are explored for the radio-modifying compound RRx-001 (1-bromoacetyl-3,3-dinitroazetidine). Picosecond pulse radiolysis demonstrates the high scavenging capacity of the molecule for secondary quasi-free and solvated electrons forming stable parent anions confirmed by studies of microsolvated RRx-001 in clusters. The anions decay either via auto-detachment of an electron or dissociate involving hydrogen transfer from solvent, resulting in NO2 and 1-(bromoacetyl)-3-nitroazetidine. Surprisingly, no Br dissociation is observed despite its high electron affinity. We assign this behavior to the "inaccessibility" of sigma virtual states for electrons in the solvent, which can be of a general nature.

• Keywords
• catalytic electron, electron attachment, low‐energy electrons, radiosensitizer, state selective,
• Publication type
• Journal Article MeSH

The interest in the electron impact-induced ligand release from MeCpPtMe3 [trimethyl(methylcyclopentadienyl)platinum(IV)] is motivated by its widespread use as a precursor in focused electron and ion beam nanofabrication. By experimentally studying the electron impact dissociative ionization of MeCpPtMe3 under single-collision conditions, we have found that the removal of two methyl radicals is energetically more favorable than the removal of one radical and even energetically comparable to the nondissociative ionization of MeCpPtMe3. This observation is explained by the structural rearrangement of the MeCpPtMe3+ ion prior to dissociation, resulting in the removal of ethane instead of two methyl groups. This fragmentation pathway is computationally confirmed and studied by irradiation-driven molecular dynamics (IDMD) simulations. The formation of complex molecules in irradiation-induced molecular dissociation is a general phenomenon that can occur in various molecular systems. This study explains the puzzling results of previous experiments with MeCpPtMe3 molecules and highlights the use of the IDMD approach to describe radiation-induced chemical transformations in molecular systems.

• Publication type
• Journal Article MeSH

DNA nanotechnology has emerged as a groundbreaking field, using DNA as a scaffold to create nanostructures with customizable properties. These DNA nanostructures hold potential across various domains, from biomedicine to studying ionizing radiation-matter interactions at the nanoscale. This review explores how the various types of radiation, covering a spectrum from electrons and photons at sub-excitation energies to ion beams with high-linear energy transfer influence the structural integrity of DNA origami nanostructures. We discuss both direct effects and those mediated by secondary species like low-energy electrons (LEEs) and reactive oxygen species (ROS). Further we discuss the possibilities for applying radiation in modulating and controlling structural changes. Based on experimental insights, we identify current challenges in characterizing the responses of DNA nanostructures to radiation and outline further areas for investigation. This review not only clarifies the complex dynamics between ionizing radiation and DNA origami but also suggests new strategies for designing DNA nanostructures optimized for applications exposed to various qualities of ionizing radiation and their resulting byproducts.

• Keywords
• DNA damage, DNA structures, Nanostructures, Nanotechnology,
• MeSH
• DNA * chemistry   MeSH
• Electrons MeSH
• Radiation, Ionizing MeSH
• Nucleic Acid Conformation radiation effects   MeSH
• Nanostructures * chemistry   MeSH
• Nanotechnology * MeSH
• Reactive Oxygen Species chemistry   MeSH
• Publication type
• Journal Article MeSH
• Review MeSH
• Names of Substances
• DNA * MeSH
• Reactive Oxygen Species MeSH

This roadmap reviews the new, highly interdisciplinary research field studying the behavior of condensed matter systems exposed to radiation. The Review highlights several recent advances in the field and provides a roadmap for the development of the field over the next decade. Condensed matter systems exposed to radiation can be inorganic, organic, or biological, finite or infinite, composed of different molecular species or materials, exist in different phases, and operate under different thermodynamic conditions. Many of the key phenomena related to the behavior of irradiated systems are very similar and can be understood based on the same fundamental theoretical principles and computational approaches. The multiscale nature of such phenomena requires the quantitative description of the radiation-induced effects occurring at different spatial and temporal scales, ranging from the atomic to the macroscopic, and the interlinks between such descriptions. The multiscale nature of the effects and the similarity of their manifestation in systems of different origins necessarily bring together different disciplines, such as physics, chemistry, biology, materials science, nanoscience, and biomedical research, demonstrating the numerous interlinks and commonalities between them. This research field is highly relevant to many novel and emerging technologies and medical applications.

• Publication type
• Journal Article MeSH
• Review MeSH