SU‐FF‐T‐483: Optical Enhancement of DNA‐Base Radio‐Resistivity

Purpose: Manipulation of the radio‐sensitivity of the DNA molecules driven by the spin blockade mechanism of diffusive free radicals against ionizing radiation. Materials and methods: We propose a mechanism which uses the simultaneous application of circularly polarized light and an external magnetic field to control the polarization of the free radicals and create S=1 electron‐hole spin excitations (excitons) on DNA molecules. We deploy an ab‐initio molecular dynamics model to calculate the characteristic parameters of the light needed for optical transitions. Results: As a specific example, we present the numerical results calculated for a nucleotide‐base, e.g., Guanine, in the presence of an OH free radical. To increase the radio‐resistivity of this system, an infra‐red and a blue light source for the optical pumping of free radicals and induction of excitons on guanine can be used. Conclusions: The effect of spin‐injection on the formation of a free energy barrier in diffusion controlled chemical reaction pathways leads to the control of radiation‐induced DNA damage. The proposed method allows us to manipulate and partially suppress the damage induced by ionizing radiation.