A safer-by-design formulation concept for flame-generated engineered nanomaterials

S. Gass, G. Pyrgiotakis, J.M. Cohen, G.A. Sotiriou, S.E. Pratsinis, P. Demokritou
Harvard School of Public Health, US

Keywords: nanoparticle, silica-coated, flame generated


As more consumers and factory workers become exposed to engineered nanomaterials (ENMs), the question of exposure risks is rapidly gaining importance. Engineering less toxic ENMs that maintain valuable functional properties is therefore crucial to the sustainability of the nanotech industry. Core-shell nanoparticles are particularly interesting in this regard. Here, a systematic study was conducted to test this novel concept for four industry-relevant ENMs (CeO2, Fe2O3, Ag, ZnO) with varying degrees of toxicity. The ENMs were synthesized and coated using a modified FSP-based Versatile Engineered Nanomaterial Generation System (VENGES). The surface coating of the ENMs takes place in-situ, in a one step, dry process. Both the SiO2-coated and uncoated ENMs were characterized with respect to primary particle size, crystallinity, morphology, and electrophoretic mobility by XRD, BET powder-specific surface area (SSA) measurements, TEM, and DLS. The SiO2 coating efficiency of this process was evaluated by XPS and Isopropanol Chemisorption. The toxicity of coated vs. uncoated ENMs was evaluated by in-vitro cellular assays (MTT, LDH) on various cells over a period of 24 hrs. In addition inhalation studies of coated and uncoated ceria nanoparticles were done to investigate the effect on animals. Although none of the particles caused injury the uncoated caused significant higher inflammation.