Electron and biomolecular interactions

Working Group One
Chair: D Field

First meeting of the working group: 14th/15th February 2004, Aarhus, Denmark - Website

Second meeting of the working group: 23-25th February 2006, Lisbon, Portugal - Website
      Report from the meeting

List of group participants: (Last Updated 11/04-06)

Name	Email
1.  Jacqueline Bergès
2.  Stephan Denifl
3.  A Fernandes
4.  David Field
5.  Melvyn Folkard
6.  Gustavo Garcia
7.  Alexandre Giuliani
8.  Jimena Gorfinkiel
9.  Chantal Houee-Levin
10. Eugen Illenberger
11. Nykola Jones
12. Joao Lourenco
13. Viktor Kohkan
14. Paulo Limao-Vieira
15. Manuel JP Maneira
16. Bratislav Marinkovic
17. Nigel Mason
18. Stefan Matejcik
19. Marta Nobre
20. Maria Raposo
21. Paulo A Ribeiro
22. Filipe Silva
23. Gosia Śmiałek
24. Jan Skalny
25. Marian Wolszczak

Description of Working Group Aims: The theme of WG1 is the experimental investigation of the interactions of electrons with biomolecules and water. Experimental investigations embrace a broad range of processes and studies of dissociative events, electron transfer, electronic and vibrational excitation, photon induced events and techniques of quantitative assessment of damage.

The impetus for these studies is as follows. When high energy ionizing radiation, including photons and all types of particles, penetrates biological material, ionization tracks form, creating excited atoms, molecules, ions and secondary electrons within the bulk of the material.

Secondary electrons are generated in large quantities and are a major cause of radiation damage in biological systems. Electrons initiate a complex series of events in both water and in biomolecules. These include ionization, electronic and vibrational excitation, which may be followed by chemical decomposition, ion pair formation and negative ion formation, leading to dissociation into negative ions and neutral radicals. In order to pinpoint the most potent effects of electrons, it is necessary to study the mechanism of these individual processes with water, ribose, aminoacids, peptides, nucleotides, nucleosides, oligonucleotides, DNA and proteins as prime targets. The destructive effects of electrons are strongly electron impact energy dependent. Experiments will therefore be carried out as a function of electron energy in the range from meV to 100 keV, covering the full range of energy of electrons prevalent in radiation damage.

Experiments will be performed in the gas, liquid and condensed phases Gas phase data are important in identifying how destructive pathways in biological systems, involving direct electron-biomolecule collisions, may be initiated on the femtosecond timescale of isolated, or nearly isolated, dissociative events. Gas phase data also serve as reference data for comparison with theory and therefore as a test of the predictive power of theory.

The brief of WG1 is to pursue the studies outlined above to build up a body of knowledge on which to base realistic models of electron-induced damage in biological cells. The aims of WG1 are complementary to those of the other working groups, which are concerned with the effects of ions on biomolecules and the extension into true physiological environments, including track structure in cells.