EPJ D Highlight - Identifying biomolecule fragments in ionising radiation

Glycine fragments during heavy ion bombardment. Source

Research published in EPJ D has revealed how the nature of biomolecule fragmentation varies with the energies of electrons produced when living cells are irradiated with heavy ions.

When living cells are bombarded with fast, heavy ions, their interactions with water molecules can produce randomly scattered ‘secondary’ electrons with a wide range of energies. These electrons can then go on to trigger potentially damaging reactions in nearby biological molecules, producing electrically charged fragments. So far, however, researchers have yet to determine the precise energies at which secondary electrons produce certain fragments. In a new study published in EPJ D, researchers in Japan led by Hidetsugu Tsuchida at Kyoto University define for the first time the precise exact ranges in which positively and negatively charged fragments can be produced.

Through a better understanding of how biomolecules such as DNA are damaged by ionising radiation, researchers could make important new advances towards more effective cancer therapies. Like molecular bullets, heavy ions will leave behind nanometre-scale tracks as they pass through water; scattering secondary electrons as they deposit their energy. These electrons may then either attach themselves to nearby molecules if they have lower energies, potentially causing them to fragment afterwards; or they may trigger more direct fragmentation if they have higher energies. Since water comprises 70% of all molecules in living cells, this effect is particularly pronounced in biological tissues.

In their previous research, Tsuchida’s team bombarded liquid droplets containing the amino acid glycine with fast, heavy carbon ions, then identified the resulting fragments using mass spectrometry. Drawing on these results, the researchers have now used computer models incorporating random sampling methods to simulate secondary electron scattering along a carbon ion’s water track. This allowed them to calculate the precise energy spectra of secondary electrons produced during ion bombardment; revealing how they related to the different types of glycine fragment produced. Through this approach, Tsuchida and colleagues showed that while electrons with energies lower 13 electronvolts (eV) went on to produce negatively charged fragments including ionised cyanide and formate, those in the range between 13eV and 100eV created positive fragments such as methylene amine.

This was our first experience of publishing with EPJ Web of Conferences. We contacted the publisher in the middle of September, just one month prior to the Conference, but everything went through smoothly. We have had published MNPS Proceedings with different publishers in the past, and would like to tell that the EPJ Web of Conferences team was probably the best, very quick, helpful and interactive. Typically, we were getting responses from EPJ Web of Conferences team within less than an hour and have had help at every production stage.
We are very thankful to Solange Guenot, Web of Conferences Publishing Editor, and Isabelle Houlbert, Web of Conferences Production Editor, for their support. These ladies are top-level professionals, who made a great contribution to the success of this issue. We are fully satisfied with the publication of the Conference Proceedings and are looking forward to further cooperation. The publication was very fast, easy and of high quality. My colleagues and I strongly recommend EPJ Web of Conferences to anyone, who is interested in quick high-quality publication of conference proceedings.

On behalf of the Organizing and Program Committees and Editorial Team of MNPS-2019, Dr. Alexey B. Nadykto, Moscow State Technological University “STANKIN”, Moscow, Russia. EPJ Web of Conferences vol. 224 (2019)

ISSN: 2100-014X (Electronic Edition)

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