Unravelling radiation damage of microsolvated biomolecules

Living organisms are constantly exposed to radiation, which is both beneficial and detrimental.

Irradiation of living tissue with energetic, ionizing radiation (?, ?, ? rays) can induce various types of cell damage, most importantly ruptures within the genome (DNA) causing cancer or cell death. The goal of this project is to unravel how radiation damage occurs on the molecular scale – and how we may control it for targeted cell protection or destruction, e.g. for cancer treatment. Using synchrotron radiation, we will probe isolated biomolecules and specifically designed complexes thereof with regard to their response to ionizing radiation (ultraviolet up to x-ray).

In particular, irreparable radiation damage of DNA is mainly caused by secondary species instead of the primary radiation. The most abundant secondary species are slow electrons (0-20 eV) created by non-local auto-ionization processes involving two or more neighbouring molecules, e.g. water surrounding the biomolecule. These processes, called intermolecular Coulombic decay (ICD) and electron transfer-mediated decay (ETMD), rely on the ultrafast transfer of energy or charge from one weakly bound molecule to another one nearby. These processes will be studied in a bottom-up approach by synthesizing isolated biomolecules and tailored complexes thereof inside superfluid helium nanodroplets and water clusters. Detailed insight into the ionization dynamics is obtained from detecting emitted electrons, ions, and photons when the complexes are irradiated by extreme ultraviolet radiation generated by synchrotrons and free-electron lasers.

Contact:
Associate Professor Marcel Mudrich,
Department of Physics and astronomy,
E-mail: mudrich@phys.au.dk