Photon-induced Auger effect in biological systems: a review

Abstract

Purpose: In this paper, we review interesting findings reported in the studies of the biological effects induced by inner-shell ionization with the aim of interpreting them from a mechanistic viewpoint, in particular, of the Auger effect of atoms on different biological systems.

Materials and methods: More than 70 published papers are cited on the Auger effects ranging from DNA-related elements (carbon, nitrogen, oxygen and phosphorus) to mammalian cells. Externally administrated bromine, iodine, and platinum have also been cited for the present endeavor. Those significant works all needed a highly monochromatized X-rays from brilliant synchrotron light sources.

Results: We have assembled a coherent view on the inner-shell effects of the Auger process that contrasts to the overall effects with the outer-shell ionization processes.

Conclusion: Some of these studies have reported that the Auger effect significantly enhances biological effects as compared with irradiation at below K-ionization energy. The Auger-specific molecular degradation mode of DNA, involving extensive fragmentation of the deoxypentose moiety, has also been revealed. We conclude that the selectively localized effect on the specified atoms through inner-shell ionization followed by the Auger process should have a definite impact on the current radiation effect studies, which are largely based on non-selective outer-shell ionizations.

Keywords:

• Synchrotron radiation
• Auger effect
• inner-shell ionization
• DNA damage
• radiobiological effect

Acknowledgements

This work was supported by the Japan Society for the Promotion of Science KAKENHI (Grant no. 15H02823).

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Additional information

Funding

This work was supported by the Japan Society for the Promotion of Science KAKENHI (Grant no. 15H02823).