Interaction of per- and polyfluoroalkyl substance with phase-separated phospholipid vesicles

Per- and polyfluoroalkyl substances (PFAS), a newly emerging pollutant, are surface-active, amphiphilic molecules that are known to strongly interact with biological membranes. Recent studies have indicated that important cellular activities governed by membrane phase separation, such as cell signaling, may be disrupted by PFAS through lipid-PFAS interactions. Here, we experimentally investigate how the phase separation of ternary phospholipid vesicles (DOPC/DPPC/cholesterol) is affected by perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), which are common PFAS compounds widely found in the environment. To uncover how PFAS interacts with each phase domain, we deconstruct the ternary system into solitary (DOPC, DPPC) and binary (DOPC/DPPC, DOPC/chol, DPPC/chol) vesicles, with which PFAS impact is evaluated. Using a microfluidic platform and fluorescence microscopy, we show that phase-separated lipid vesicles undergo various morphological changes upon exposure to PFAS. We rationalize our findings by quantifying the interaction strengths of multicomponent lipid/chol/PFAS mixtures. Our results may provide helpful insights into the potential health impacts of PFAS.