Determination of stoichiometric ROS degeneration and relationship between redox potential and bioavailability to design safe CNTs.
Tsuruoka-S; Matsumoto-H; Takeuchi-K; Koyama-K; Saito-N; Usui-Y; Kobayashi-S; Akiba-E; Porter-DW; Castranova-V; Cassee-FR; Endo-M
Toxicologist 2014 Mar; 138(1):156
An important goal is to design safe carbon nanotubes (CNTs) by controlling their properties. Biological evaluations have been conducted with individual CNTs, and such results have been used for risk assessment (NIOSH CIB 65, 2013). However, information is lacking to define the relationships between the chemical properties of CNTs and their bioavailability. The present work aimed to obtain a stoichiometric expression of ROS degeneration by CNTs, which predicted ROS scavenging results with CNTs. ROS degeneration rate was measured with an ESR-DMPO method. The Fenton reaction was used to generate OH radicals. To evaluate CNT surface reactions, surfactant concentration was minimized to eliminate its influence, and reactivity of CNTs was determined. Results indicate that this allows kinetic quantification of the relationship between degeneration reactions and CNT morphology. Since the degeneration of ROS is attributed to a redox reaction according to the hypothesis in reaction kinetics on CNT surface, CNT bioactivity is defined as a redox potential that can be used to elucidate the relationship between bioactivity and CNT physicochemical properties. In conclusion, redox potential will be used to predict CNT bioactivity using its surface morphology and to design safer CNTs. [This work was supported by the Exotic Nanocarbon Project, Japan Regional Innovation Strategy Program by the Excellence, JST(Japan Science and Technology Agency)(ST, KK, YU, ME)].
Toxicology; Cell-function; Cellular-function; Cell-damage; Nanotechnology; Exposure-levels; Pulmonary-disorders; Pulmonary-function; Pulmonary-system; Pulmonary-system-disorders; Molecular-structure; Molecular-biology;
The Toxicologist. Society of Toxicology 53rd Annual Meeting and ToxExpo, March 23-27, 2014, Phonex, Arizona