Development and evaluation of an in vitro test system for toxicity screening of aerosols released from consumer products and first application to aerosols from a hair straightening process

A cell-based in vitro test system was set up and evaluated for investigations of effects from inhalable aerosols that might be released during use of consumer products. It included a box for generation of aerosols, which was optimized by computational fluid dynamics simulations, aerosol analysis, and a cell exposure device (P.R.I.T. ExpoCube ) for air/liquid interface exposure of A549 human lung epithelial cells. The in vitro inhalation model was characterized using lactose or sodium dodecyl sulfate (SDS) or copper-II-sulfate (CuSO4) aerosols as negative or positive controls. In a first application, aerosols were generated during use of a commercial hair straightener product, considering a relevant protocol with respect to its use by professional hairdressers. Cellular toxicity and interleukin-8 (IL-8) secretion were analyzed as biological effects of exposure in a worst-case exposure scenario for acute local lung toxicity. Generation of aerosols from controls and the product in comparable particle sizes and efficient aerosol deposition on the cellular surface during exposure enabled dose/response relationships in large dosage ranges. Dose-dependent toxicity was found for the positive controls but not for lactose and different IL-8 responses from SDS, CuSO4, and lactose. Aerosols from the hair straightening product induced nonsignificant effects on IL-8 secretion in one exposure situation only, which were comparable with lactose effects in the same range of dosage. In summary, the cell-based in vitro testing system was successfully established. It might define a relevant basis to get insight into the toxicology of inhalable aerosols with workplace and daily-life relevance using an alternative testing method under highly controlled experimental conditions