In Vitro 3D Human Airway and Skin Models for Assessing the Cytotoxicity of Ethanol Mist Used in Cultural Heritage Decontamination

Decontamination of cultural heritage objects requires balancing antimicrobial efficacy, material preservation, and human safety. Although 90% ethanol mist has demonstrated high biocidal efficacy and compatibility with historical objects, its potential effects on personnel remain insufficiently characterized. This study evaluated the cytotoxic effects of aerosolized ethanol on human respiratory and skin epithelia. Fully differentiated primary human tracheobronchial (EpiAirway™) and epidermal (EpiDerm™) tissue models, maintained under air–liquid interface conditions, were exposed in vitro to ethanol mist for 5–30 min using two disinfection chambers. Cellular responses were assessed using membrane integrity and effector caspase activity assays across a range of ethanol doses. In EpiDerm™, the first increase in relative caspase-3/7 activity was observed at 35 mg/cm2 after 30 min, whereas in EpiAirway™, it was observed at 185 mg/cm2 after 5 min. Exposure to ethanol at a dose of 377 mg/cm2 for 15 min induced tissue cytotoxicity levels of 32% in EpiAirway™ and 38% in EpiDerm™ (based on LDH assay), while relative caspase-3/7 activity increased by 21% and 36%, respectively. These findings provide preliminary insights into the cytotoxic effects of aerosolized ethanol in reconstructed tissue models but do not establish its safety under occupational exposure conditions. Further studies incorporating longer exposure durations and more complex experimental conditions are needed to better characterize the potential occupational risks.