Biological test procedure for fresh generated cigarette smoke and e-cigarette aerosols under air-liquid interface (ALI) exposure in 24 and 96 multi-well plates
Cigarette smoke and e cigarette aerosol contain particulate matter/liquid droplets in the solid phase as well as volatile substances in the gas phase. Both fractions are of potential toxicological relevance and should be considered when assessing biological activity of cigarette smoke and e cigarette aerosol. Experimentally, rapid ageing of the mixtures leads to problems regarding trapping and effective delivery of both fractions to the cells. Therefore, dedicated exposure systems have been developed allowing the exposure of biological in vitro systems to freshly generated smoke/aerosols.
Imperial Brands’ Smoke Aerosol Exposure In Vitro System (SAEIVS) was designed to expose cells in multi-well plates (MWP) at the air-liquid interface (ALI). SAEIVS enables in vitro testing of aerosols generated from different product categories encompassing tobacco products and e cigarette devices. Using this system, up to five tobacco products or e cigarette devices can be puffed simultaneously and deliver the smoke/aerosol in undiluted or diluted form to defined rows of wells. Two exposure chambers allow parallel exposure of the same smoke and aerosol in different dilution levels per plate. Furthermore, the separate chambers enable exposure to the same product in different MWPs.
The cytotoxicity of the products is tested by exposure of BEAS2B cells on Type I collagen matrix in 96 MWPs. The collagen layer guarantees stable exposure conditions over an extended time period sufficient for the testing of several hundreds of puffs. Genotoxicity testing is performed with hamster lung cells V79 grown on inserts and placed in 24 MWPs. Mutagenicity testing is conducted by bubbling a bacterial suspension directly with freshly generated smoke/aerosol. Salmonella typhimurium strain TA100 was used as it is highly sensitive to mutagenic substances in both fractions of smoke/aerosol.
The presented methods by Imperial Brands allow testing in vitro of aerosols generated from different product categories encompassing tobacco products and e cigarette devices.