Design and characterization of a nanoparticle aerosol generator.
Yi-J; Knuckles-T; Chen-B; Sabolsky-E; Castranova-V; Nurkiewicz-Y
Toxicologist 2012 Mar; 126(Suppl 1):276
The generation of nanoparticle aerosols for inhalation toxicology studies is challenging because nanoparticles tend to agglomerate due to very strong inter-particle forces and form large fractal structures in tens or hundreds of microns in size, which are difficult to be broken up. To perform inhalation toxicology studies with nanoparticles, the aerosols in an environmental chamber housing the animal subjects must have: 1) a consistent concentration maintained at a desired level for the entire exposure period; 2) a homogenous composition free of contaminants; and 3) a stable size distribution with a geometric mean diameter < 200 nm and a geometric standard deviation óg < 2.5. We designed and tested a nanoparticle aerosol generator that consists of a vibrating fluidized bed with a baffle, a vibrating Venturi disperser, and a cyclone separator. Nano-sized titanium dioxide (TiO2) dry power (P25, Evonik, Germany) with primary diameter of 21 nm and density of 3.8 g/cm3, and Cerium oxide (CeO2) dry powder with primary diameter of 3 nm and density of 7.1 g/cm3 were used to test the aerosol generator. The aerosols were delivered into a 0.5 m3 inhalation exposure chamber at a flowrate of 90 LPM and measured with a scanning mobility particle sizer and an electric low pressure impactor. The mass concentration of the aerosols was verified gravimetrically. The nanoparticle aerosol generator created TiO2 and CeO2 aerosols with: 1) stable mass concentrations during a 4-hour-study (6.2 mg/m3 and 3.9 mg/m3 for TiO2 and CeO2 aerosols, respectively); and 2) stable particle size distributions during a 4-hour-study (count-median aerodynamic diameters of 157 nm and 145 nm for TiO2 and CeO2 aerosols, respectively). These results indicate that our system has the capability to generate nanoparticle aerosols for inhalation toxicology studies.
Nanotechnology; Particulates; Toxic-materials; Health-hazards; Biohazards; Biomedical-engineering; Immune-reaction; Immune-system; Autoimmunity; Cell-function; Microorganisms; Pulmonary-clearance; Bacteria; Phagocytic-activity; Cellular-uptake; Oxidative-processes; Toxic-effects; Inhalation-studies; Aerosol-particles; Aerosols
The Toxicologist. Society of Toxicology 51st Annual Meeting and ToxExpo, March 11-15, 2012, San Francisco, California