Nano Aerosol Chamber forIn-VitroToxicity (NACIVT) studies

Abstract

Inhalation of ambient air particles or engineered nanoparticles (NP) handled as powders, dispersions or sprays in industrial processes and contained in consumer products pose a potential and largely unknown risk for incidental exposure. For efficient, economical and ethically sound evaluation of health hazards by inhaled nanomaterials, animal-free and realistic in vitro test systems are desirable. The new Nano Aerosol Chamber for in-vitro Toxicity studies (NACIVT) has been developed and fully characterized regarding its performance. NACIVT features a computer-controlled temperature and humidity conditioning, preventing cellular stress during exposure and allowing long-term exposures. Airborne NP are deposited out of a continuous air stream simultaneously on up to 24 cell cultures on Transwell® inserts, allowing high-throughput screening. In NACIVT, polystyrene as well as silver particles were deposited uniformly and efficiently on all 24 Transwell® inserts. Particle-cell interaction studies confirmed that deposited particles reach the cell surface and can be taken up by cells. As demonstrated in control experiments, there was no evidence for any adverse effects on human bronchial epithelial cells (BEAS-2B) due to the exposure treatment in NACIVT. The new, fully integrated and transportable deposition chamber NACIVT provides a promising tool for reliable, acute and sub-acute dose-response studies of (nano)particles in air-exposed tissues cultured at the air-liquid interface.

Acute toxicity of silver and carbon nanoaerosols to normal and cystic fibrosis human bronchial epithelial cells

“…Design, function and characterization of NACIVT (http:// www.nacivt.ch) have been previously described in detail (Jeannet et al, 2015). Briefly, NACIVT has a fully integrated design with stability of temperature and relative humidity and allows parallel exposure of up to 24 individual ALI cell cultures on Transwell Õ inserts (Corning, VWR, Dietikon, Switzerland) to (nano)aerosols under dose-controlled and realistic conditions.…”

“…In order to deposit different NP doses, the exposure time was varied (AgNP: 36, 360 and 3600 s; CNP: 90, 1200 and 3600 s), while the aerosol flow rate (25 mL/min/insert) and NP concentration (AgNP: 2 Â 10 6 particles/cm 3 ; CNP: 7 Â 10 6 or 1 Â 10 7 particles/cm 3 ) in the deposition chamber remained constant. The total number of deposited NP per Transwell Õ insert of each exposure experiment can be calculated based on the previously determined deposition efficiency of about 40% for 20 nm-sized particles (Jeannet et al, 2015) (Table 1). Two independent experiments were performed for each NP type and concentration.…”

“…Cells were exposed to the aerosols using the Nano Aerosol Chamber for In-Vitro Toxicity (NACIVT). This chamber allows realistic and efficient delivery of NP out of a conditioned air-flow to the apical surface of up to 24 individual ALI cell cultures (Jeannet et al, 2015). As shown in the experimental setup given in Figure 1, we evaluated effects on cell death, secretion of pro-inflammatory mediators and epithelial integrity within 24 h after exposure to the aerosols.…”

Investigations of the Biological Effects of Airborne and Inhalable Substances by Cell-Based In Vitro Methods: Fundamental Improvements to the ALI Concept

“…When setups in the "incubator-type" alignment [26,27] are used, but also in stagnation flow setups [25,31], the test atmosphere can readily diffuse into the culture medium and will therefore readily react with culture medium components, which include many reactive substances such as glutathione and others. Hence, the cell exposure is not only by way of air-liquid cell exposure but also by a route via the culture medium, which is normally not intended in these studies.…”

“…The current setups based on ALI technologies can be classified into two fundamental strategies. One type of exposure setup is based on a so-called stagnation flow arrangement where single cultures are exposed individually to an airflow that is directed towards the culture surface [23][24][25]. This type of setup satisfies the principal requirements for a reproducible and highly efficient exposure of cultures to inhalable substances.…”