title: DNA-backbone radio resistivity induced by spin blockade effect.
abstract: Coherent control of OH-free radicals interacting with the spin-triplet state of a DNA molecule is investigated. A model Hamiltonian for molecular spin singlet-triplet resonance is developed. We illustrate that the spin-triplet state in DNA molecules can be efficiently populated, as the spin-injection rate can be tuned to be orders of magnitudes greater than the decay rate due to small spin-orbit coupling in organic molecules. Owing to the nano-second life-time of OH free radicals, a non-equilibrium free energy barrier induced by the injected spin triplet state that lasts approximately longer than one-micro second in room temperature can efficiently block the initial Hydrogen abstraction and DNA damage. For a direct demonstration of the spin-blockade effect, a molecular simulation based on an ab-initio Car-Parrinello molecular dynamics is deployed.
authors.affiliation: Department of Radiation Oncology, University of Texas, Southwestern Medical Center, Dallas, Texas 75390, USA. Ramin.Abolfath@utdallas.edu
authors.forename: Ramin M
authors.initials: RM
authors.lastname: Abolfath
authors.forename: Thomas
authors.initials: T
authors.lastname: Brabec
mesh_terms: D004247:DNA / Q000737:chemistry*; D017665:Hydroxyl Radical / Q000737:chemistry; D056004:Molecular Dynamics Simulation; D011789:Quantum Theory
chemical_list: D017665:Hydroxyl Radical; D004247:DNA