Generation and Characterization of Reference Ultrafine Soot Particles to Carry Out Toxicological Assessments at the Air-Liquid Interface System
ANUSMITA DAS, Jana Pantzke, Arūnas Meščeriakovas, Nadine Gawlitta, Seongho Jeong, Natalia Ivleva, Mathilde Delaval, Simone Schmitz-Spanke, Sebastiano Di Bucchianico, Jürgen Schnelle-Kreis, Martin Sklorz, Ralf Zimmermann,
Helmholtz Zentrum München and University of Rostock Abstract Number: 420
Working Group: Aerosol Exposure
AbstractUltrafine particles (UFP, Dp ≤100 nm) are discussed to be involved in the global burden of disease associated with air pollution. It is not fully understood to what extent the physical properties of UFP contribute to their toxicity or whether the particles act primarily as carriers of biologically reactive chemicals, that are responsible for the biological responses. Thus, addressing such questions in toxicological testing requires robust methods for the generation and manipulation of UFP, that allow the physical and chemical parameters of UFP to be adjusted in a targeted and reproducible way.
Herein, we focused on the production and characterization of soot UFP with similar elemental carbon cores and similar physical properties but different chemical constituents. The primary soot particles were generated with a Mini CAST burner at fuel-rich conditions (λ=0.80) and immediately diluted by an adjustable porous tube diluter and 10-fold fixed ejector diluters to reduce agglomeration. A catalytic stripper followed by a multichannel activated-charcoal denuder was used to strip off volatile/semi-volatile components. Depending on the temperature of the catalytic stripper, two types of UFP soot were produced: UFP with high semivolatile organic content (T=30°C) and UFP with low semivolatile organic content (T=350°C). Physical characterization showed that both had similar mobility diameter (≈45nm), number (≈5e05/cm
3) and mass concentrations (≈100µg/m
3) along with similar Black Carbon content (eBC≈50µg/m
3) and the same morphology. Filter samples were taken to characterize the chemical composition. Elemental and organic carbon content, polycyclic aromatic hydrocarbons were quantified. The generated aerosols were further assessed for biological responses in human alveolar epithelial cells at the air-liquid interface. The toxicological assessments investigated effects on the cellular metabolic activity, cytotoxicity, genotoxicity and xenobiotic metabolism. Furthermore, repeated cell-exposures were enabled to produce and adjust specific UFP attributes with demonstrated reproducibility for toxicological studies.