title: Nanoscale energy deposition by X-ray absorbing nanostructures.
abstract: Here we wish to demonstrate a unique property of nanomaterials: energy deposition with nanometer precision from low-energy electrons released from these nanostructures interacting with hard X-ray radiation in aqueous solution. Three effects combine to cause this phenomenon: (1) localized absorption of X-rays by nanostructures, (2) effective release of low-energy electrons from small nanostructures, and (3) efficient deposition of energy in water in the form of radicals and electrons. This combination creates localized X-ray absorption and localized energy deposition of nanometer precision. We confirmed the theoretically predicted nanoscale energy deposition distribution by measuring hydroxyl radical-induced DNA strand breaks, and observed enhanced damage to a 5600-bp DNA molecule from approximately 10 chemically conjugated small gold nanoparticles under X-ray radiation. These results provide a general guidance to applications of this new concept in many fields including radiation chemistry, radiology, radiation oncology, biochemistry, biology, and nanotechnology.
authors.affiliation: Department of Chemistry, University of California, Davis, CA 95616, USA.
authors.forename: Joshua D
authors.initials: JD
authors.lastname: Carter
authors.forename: Neal N
authors.initials: NN
authors.lastname: Cheng
authors.forename: Yongquan
authors.initials: Y
authors.lastname: Qu
authors.forename: George D
authors.initials: GD
authors.lastname: Suarez
authors.forename: Ting
authors.initials: T
authors.lastname: Guo