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Enhanced production of reactive oxygen species by gadolinium oxide nanoparticles under core-inner-shell excitation by proton or monochromatic X-ray irradiation: implication of the contribution from the interatomic de-excitation-mediated nanoradiator effect to dose enhancement.
- Source :
-
Radiation and environmental biophysics [Radiat Environ Biophys] 2015 Nov; Vol. 54 (4), pp. 423-31. Date of Electronic Publication: 2015 Aug 05. - Publication Year :
- 2015
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Abstract
- Core-inner-valence ionization of high-Z nanoparticle atomic clusters can de-excite electrons through various interatomic de-excitation processes, thereby leading to the ionization of both directly exposed atoms and adjacent neutral atoms within the nanoparticles, and to an enhancement in photon-electron emission, which is termed the nanoradiator effect. To investigate the nanoradiator-mediated dose enhancement in the radio-sensitizing of high-Z nanoparticles, the production of reactive oxygen species (ROS) was measured in a gadolinium oxide nanoparticle (Gd-oxide NP) solution under core-inner-valence excitation of Gd with either 50 keV monochromatic synchrotron X-rays or 45 MeV protons. This measurement was compared with either a radiation-only control or a gadolinium-chelate magnetic resonance imaging contrast agent solution containing equal amounts of gadolinium as the separate atomic species in which Gd-Gd interatomic de-excitations are absent. Ionization excitations followed by ROS measurements were performed on nanoparticle-loaded cells or aqueous solutions. Both photoexcitation and proton impact produced a dose-dependent enhancement in the production of ROS by a range of factors from 1.6 to 1.94 compared with the radiation-only control. Enhanced production of ROS, by a factor of 1.83, was observed from Gd-oxide NP atomic clusters compared with the Gd-chelate molecule, with a Gd concentration of 48 μg/mL in the core-level photon excitation, or by a factor of 1.82 under a Gd concentration of 12 μg/mL for the proton impact at 10 Gy (p < 0.02). The enhanced production of ROS in the irradiated nanoparticles suggests the potential for additional therapeutic dose enhancements in radiation treatment via the potent Gd-Gd interatomic de-excitation-driven nanoradiator effect.
- Subjects :
- Contrast Media chemistry
Contrast Media radiation effects
Dose-Response Relationship, Radiation
Linear Energy Transfer radiation effects
Materials Testing
Metal Nanoparticles ultrastructure
Protons
Radiation Dosage
Scattering, Radiation
X-Rays
Gadolinium chemistry
Gadolinium radiation effects
Metal Nanoparticles chemistry
Metal Nanoparticles radiation effects
Reactive Oxygen Species chemical synthesis
Reactive Oxygen Species radiation effects
Subjects
Details
- Language :
- English
- ISSN :
- 1432-2099
- Volume :
- 54
- Issue :
- 4
- Database :
- MEDLINE
- Journal :
- Radiation and environmental biophysics
- Publication Type :
- Academic Journal
- Accession number :
- 26242374
- Full Text :
- https://doi.org/10.1007/s00411-015-0612-7