A molecular dynamics simulation of DNA damage induction by ionizing radiation

Area of Science:

• Computational physics and chemistry
• Radiation biology
• Molecular dynamics

Background:

• Ionizing radiation induces DNA damage through indirect action of hydroxyl radicals.
• Understanding early-stage damage is crucial for radiobiology and radiotherapy.

Purpose of the Study:

• To develop and apply a multi-scale computational model for simulating early DNA damage.
• To investigate the differences in DNA damage induced by electrons and protons.

Main Methods:

• Interfacing Geant4-DNA Monte Carlo with ReaxFF molecular dynamics.
• Using a clustering method to map hydroxyl radical distribution.
• First-principles simulation of chemical reactions and DNA lesions.

Main Results:

• Electrons create dispersed hydroxyl radicals, while protons form clustered radicals along their path.
• DNA base and backbone damage leads to single and double-strand breaks.
• Protons induce approximately four times more double-strand breaks than electrons per track.

Conclusions:

• A novel multi-scale computational model accurately simulates ionizing radiation-induced DNA damage.
• The model captures distinct DNA damage mechanisms for electrons and protons.
• This tool can assess the relative biological effectiveness of different ions in radiotherapy.