Langmuir trough studies of the interactions between per- and polyfluoroalkyl substances (PFAS) and a model cell membrane

Bioaccumulative per- and polyfluoroalkyl substances (PFAS), a large class of highly fluorinated organic chemicals, are used as surfactants and nonstick coatings in industrial and commercial applications. Their resistance to degradation and their ubiquitous presence in water, soil, animals and humans are cause for concern. PFAS chemicals such as perfluorobutane sulfonate (PFBS),Gen-X, and other chemicals that have recently replaced potentially harmful legacy PFAS, have the potential to adversely affect cellular functions. In this study, interactions of PFAS with a model cell membrane, specifically monolayers of 1,2-dipalmitoyl-sn-glycero-3- phosphocholine (DPPC), are investigated to better understand the alterations these chemicals may cause to the cell. This project reports surface pressure measurements obtained using a Langmuir trough to monitor changes in the fluidity and packing of a DPPC monolayer at the air-water interface upon addition of PFBS, Gen-X, and other replacement chemicals to the aqueous phase. The maximum decrease in the area per lipid with added PFBS was 39%. These preliminary results suggest that the lipid monolayer becomes more compressible in the presence of PFBS, which indicates the intercalation of PFBS into the lipid monolayer. Ongoing studies are focused on using imaging techniques to better understand the interactions of PFAS with the lipid monolayer.