Development and characterization of a “Versatile Engineered Nanoparticle Generation System (VENGES)” for toxicological characterization studies

Philip Demokritou (1) Robert Buchel (2) Sotiris Pratsinis (2) Joseph Brain (2)

(1) Harvard School of Public Health, Boston, USA (2) Swiss Institute of Technology, Zurich, Switzerland

     Abstract Number: 181
     Last modified: November 7, 2009

Abstract
The environmental release of engineered nanoparticles appears an inevitable consequence of their increasingly widespread use in numerous applications and commercial products. There is evidence that engineered nanoparticles have a great probability of breaching epithelial barriers and thus escaping traditional clearance mechanisms involving mucociliary and dissolution in alveolar macrophages. However a lack of both detailed physico-chemical characterization of the engineered nanoparticles and consistent aerosol generation systems to deliver exposures to real world engineered nanoparticles over a spectrum of sizes, compositions and morphologies hinder a clear interpretation of the link between the physico-chemical properties and biointeractions. As it was also outlined in the most recent US National Nanotechnology Initiative report and the National Research Council’s recent review of the Federal Government strategy on nanotechnology it is a high priority to develop novel nanoparticle generation systems for the in-situ characterization of engineered nanoparticles within biological matrices. The use of these systems along with the development of new in vitro screening methodologies and in vivo inhalation studies will help to determine which set of physico-chemical properties correlate best with biointeractions.

Such a versatile aerosol generation system suitable for the toxicological characterization studies of engineered nanoparticles will be developed and characterized in our lab. This lab based Versatile Engineered Nanomaterial Generation System (VENGES) will be based on industry relevant, flame spray pyrolysis (FSP) aerosol reactors for their capacity to scaleably produce nanomaterials with closely controlled primary particle size and aggregate sizes, crystallinity and morphology. The developed VENGES system will then be used to produce families of engineered nanomaterials of pure and selected mixtures of zinc-, silicon-, titanium- and in particular iron-oxide nanoparticles with controlled primary particle size, agglomerate size (mobility diameter), composition (amorphous or crystalline) and morphology.

VENGES’s ability to generate families of nanomaterials with “controlled” properties such as particle size, composition, crystallinity and surface properties will be systematically investigated and characterized using a range of state-of-the-art-techniques. Specific surface area will be measured by nitrogen adsorption by the Brunauer-Emmett-Teller (BET) method and crystallinity by X-ray diffraction (XRD). The morphology and particle size will be evaluated by scanning or transmission electron microscopy (SEM/TEM). Particle composition will also be analyzed for its metal content by ICP-MS (inductively coupled plasma-mass spectroscopy). In addition, particle number concentration will also be obtained as a function of the electrical mobility diameter by using a scanning mobility particle sizer (SMPS).