Speaker
Description
A way to induce local damage to cancerous tissue is by using radiotherapy-amplifying bioagents doped with high-Z elements. This enables deep core-level ionisation during radiotherapy with X-rays above the K-edge threshold, significantly increasing radiation absorption. Core electron ejection from high-Z elements also triggers a cascade of secondary particles, amplifying damage.
We studied the iodine- and bromine-doped nitroimidazole molecule, an oxygen mimetic that accumulates in oxygen-deficient tumours. We analysed fragmentation mechanisms and radiotherapy-relevant fragments in the gas phase using synchrotron light tuned to K- and L-edges. Additionally, DFT-based molecular dynamics simulations explored bond strengths and fragmentation pathways. To approximate biological conditions, we also examined monosolvated nitroimidazole.
High-Z ionisation produces large quantities of single-atom ions, while C, N, or O 1s-ionization yields heavier fragments like NO2, which can inhibit DNA repair. The addition of a single water molecule affects the local chemical environment and is thus reshaping the dissociation landscape, possibly through hydrogen bonding and charge redistribution—suggested to protect biomolecules from radiation damage.
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