A new in vitro testing module for the cytotoxic evaluation of e-cigarette vapour
The e-cigarette market has recently been booming, and e-cigarettes are often described as “reduced-risk” nicotine products or alternatives to combustible cigarettes. However, no regulations for e-cigarettes are currently in force, so that the quality and safety of e-liquids is not necessarily guaranteed. There are two major ways to analyse e-cigarette vapour: chemically and biologically. Whereas chemical evaluations are mostly restricted to known toxic components, biological analysis gives information about effects triggered in the human body after inhalation. For the generation of relevant data, a system is needed which is able to produce stable data. Therefore, the smoking machine has to produce e-liquid vapour of reproducible quality, which can then be used to expose human bronchial epithelial cells directly at the air-liquid interface. A new flexible compact version of smoking machine and exposition module set-up is introduced. The suitability of the system is demonstrated by presenting dose-response curves for normal human bronchial epithelial cells after direct cigarette smoke and e-cigarette vapour exposure at the air-liquid interface. The low standard deviation of the results confirms the robustness of the system and proves the ability to generate reproducible data. In summary, the in vitro testing module represents a platform for the generation of stable data to evaluate the toxicological potential of e-cigarette vapour.