Methodology for generating nanoparticle aerosols-From benchtop to inhalation laboratory
Ostraat, M. L., Swain, K. A., McDermott, E., Reed, K. L., Sayes, C. M., & Warheit, D. B. (2008). Methodology for generating nanoparticle aerosols-From benchtop to inhalation laboratory. In 47th Annual Meeting and ToxExpo, Seattle, WA, March 16-20, 2008, , pp. 310–310. .
Issues surrounding occupational safety of workers exposed to nano-sized particles and materials are becoming increasingly pertinent in nanotechnology today. We have developed a novel approach to generating and characterizing a nanoparticle aerosol stream appropriate for testing, both in the workplace environment as well as for animal toxicity exposures. Although other methods are known to produce nano particulate matter, a limited number of techniques are available to synthesize fully characterized particle aerosols in the nano-size regime with precise control over size, size distribution, and concentration. The work described herein presents a proven method of producing amorphous nano-sized SiO2 particles via an aerosol nanoparticle reactor. Other particles consisting of different chemical composition can be synthesized as well (e.g., citric acid, TiO2, NaCl). The reactor is capable of synthesizing particles ranging d50 = 10 – 70 nm at concentrations ranging 10E4 – 10E7 particles/cm3. Characterization instrumentation in-line with the generation system allows for crystallinity (XRD), size and size distribution (DMA), and concentration (AE) measurements to be made in situ and upstream of the animal exposure chamber. This un-aggregated particle generation methodology enables subsequent testing with a continuous, stable supply of aerosol nanoparticles to facilitate inhalation toxicological profiles of animals exposed to aerosolized nanoparticle systems. This system was utilized in a short-term inhalation study with rats exposed to uncoated as-synthesized, amorphous SiO2 in two different nanoparticle size range populations (i.e. number distributions centered at d50 = 30 nm and d50 = 70 nm). The pulmonary toxicity results are described in a companion presentation.