Adverse Biophysical Impact of e-Cigarette Flavors on Pulmonary Surfactant

The attractiveness and abundance of flavors are primary factors eliciting youth to use e-cigarettes. Emerging studies in recent years revealed the adverse health impact of e-cigarette flavoring chemicals, including disruption of the biophysical function of pulmonary surfactants in the lung. Nevertheless, a comprehensive understanding of the biophysical impact of various flavoring chemicals is still lacking. We used constrained drop surfactometry as a new alternative method to study the biophysical impact of flavored e-cigarette aerosols on an animal-derived natural pulmonary surfactant. The dose of exposure to e-cigarette aerosols was quantified with a quartz crystal microbalance, and alterations to the ultrastructure of the surfactant film were visualized using atomic force microscopy. We have systematically studied eight representative flavoring chemicals (benzyl alcohol, menthol, maltol, ethyl maltol, vanillin, ethyl vanillin, ethyl acetate, and ethyl butyrate) and six popular recombinant flavors (coffee, vanilla, tobacco, cotton candy, menthol/mint, and chocolate). Our results suggested a flavor-dependent inhibitory effect of e-cigarette aerosols on the biophysical properties of the pulmonary surfactant. A qualitative phase diagram was proposed to predict the hazardous potential of various flavoring chemicals. These results provide novel implications in understanding the environmental, health, and safety impacts of e-cigarette aerosols and may contribute to better regulation of e-cigarette products.

Automated summary

The attractiveness and variety of flavors in e-cigarettes attract young people to use them. However, studies have shown that the flavoring chemicals in e-cigarettes can have adverse effects on the function of pulmonary surfactants. This study used a new method called constrained drop surfactometry to investigate the biophysical impact of flavored e-cigarette aerosols on natural pulmonary surfactants. The results showed that different flavors of e-cigarette aerosols have a flavor-dependent inhibitory effect on the properties of pulmonary surfactants. A qualitative phase diagram was proposed to predict the potential hazards of different flavoring chemicals.